G'MIC(1)

NAME
gmic - manage generic image processing operations, through the G'MIC language interpreter.

HELP
 gmic : GREYC's Magic Image Converter (Sep 9 2010, 23:18:24).
        Version 1.4.1.0, Copyright (C) 2008-2010, David Tschumperle
        (http://gmic.sourceforge.net)
 Usage
 -----
 gmic [item1 [arg1_1,arg1_2,..]] .. [itemN [argN_1,argN_2,..]]
 'gmic' is an open-source interpreter of the G'MIC language, a script-based programming
  language dedicated to the design of image processing pipelines. It can be used to
  convert, manipulate, and visualize datasets composed of one or several 1d/2d/3d
  multi-spectral images.
 The G'MIC language is quite minimalist. It is entirely defined by the following rules :
 ** Overall context :
  - At any time, G'MIC manages three lists of numbered (and optionally labelled) items, stored
     in computer memory :
    _ One list of pixel-based images, each representing 1d/2d/3d scalar or multi-spectral data.
       This is actually the most important and significant dataset in G'MIC and we will focus
       mainly on it in the followings. An image may have a label associated to it.
    _ One list of text strings (named 'local stack'), used to manage local variables in G'MIC
       pipelines and custom commands. A local stack element may have a label associated to it.
       Each G'MIC custom command gets its own local stack.
    _ One list of display windows, which are useful objects to manage real-time animations or
       to handle user interactions. Up to 10 windows can be managed at the same time.
       A display windows cannot be labelled, but is referenced by its number, from 0 to 9.
  - The first item of a list has indice number '0' and is denoted by '[0]'.
  - Negative indices are treated in a cyclic way (i.e. '[-1]' stands for the last item of
     a list, '[-2]' the penultimate one, and so on..). Thus, in a list of 4 items, notations
     '[1]' and '[-3]' both refer to the second item.
  - A labelled item is referenced by '[label]'. A label is specified when inserting a new
     image or a new local stack element.
  - The G'MIC language defines a set of commands and substitution mechanisms to create
     pipelines for managing these lists of image or text data in a flexible way.
  - Created pipelines can then become a part of the G'MIC language, and re-used afterwards,
     through the definition of user-defined custom commands.
 ** Image definition and terminology :
  - In G'MIC, an image is always stored as a 4d array of scalar-valued pixels, whose dimensions
     are respectively denoted by :
    _ 'width', for the number of image columns (size along the 'x'-axis).
    _ 'height', for the number of image lines (size along the 'y'-axis).
    _ 'depth', for the number of image slices (size along the 'z'-axis).
        The depth is equal to 1 for usual 2d color images.
    _ 'spectrum', for the number of image channels (size along the 'c'-axis).
        The spectrum is equal respectively to 3 and 4 for usual RGB and RGBA color images.
  - There are no limitations on the number of image slices or channels G'MIC can handle
     except the amount of available memory.
  - The width, height and depth of an image are considered as 'spatial' dimensions, while
     the spectrum has a 'spectral' meaning. Thus, a 4d image in G'MIC should preferably be
     regarded as a 3d dataset of multi-spectral voxels.
  - All pixel values of all images of the list have the same datatype. It can be one of :
    _ 'bool' : Value range is { 0=false | 1=true }.
    _ 'uchar' : Stands for 'unsigned char'. Value range is [0,255].
        This type of pixel coding is commonly used to store 8bits/channels RGB[A] color images
        in corresponding file formats.
    _ 'char' : Value range is [-128,127].
    _ 'ushort' : Stands for 'unsigned short'. Value range is [0,65535].
        This type of pixel coding is commonly used to store 16bits/channels RGB[A] color images
        in corresponding file formats.
    _ 'short' : Value range is [-32768,32767].
    _ 'uint' : Stands for 'unsigned int'. Value range is [0,2^32-1] (32 bits integers).
    _ 'int' : Value range is [-2^31,2^31-1] (32 bits signed integers).
    _ 'float' : This type of coding is able to store pixels as 32 bits float-valued numbers.
        This is the default datatype considered in G'MIC to perform image processing operations.
    _ 'double' : This type of coding is able to store pixels as 64 bits float-valued numbers.
  - Considering pixel datatypes different than 'float' is generally useless, except to force
     the input/output of image data to be done in a prescribed binary format. Hence, most G'MIC
     image processing commands are available only for the default 'float' pixel datatype.
 ** Items and processing pipeline :
  - In G'MIC, an image processing pipeline is described as a sequence of items separated by
     spaces ' '. Such items are interpreted and executed from the left to the right.
     For instance, the expression 'input.jpg -blur 3,0 -sharpen 10 -r 200%,200% -o output.jpg'
     defines a valid sequence of 9 G'MIC items.
  - A G'MIC item is a text string which stands either for a command, command arguments,
     a filename, a special input string or a local stack variable assignment.
  - When invoking 'gmic' from the command-line, any word following the executable name is
     considered as one specified G'MIC item.
  - Escape characters '\' and double quotes '
     containing spaces, or any other character sequences.
 ** Input data items :
  - If a specified G'MIC item appears to be a filename, the corresponding image data are loaded
     and inserted at the end of the image list.
  - Special filenames '-' and '-.ext' stand for the standard input/output streams, optionally
     forced to be in a specific 'ext' file format (e.g. '-.jpg' or '-.png').
  - The following special input strings can be used as G'MIC items in order to create and
     insert new images with prescribed values, at the end of the image list :
    _ '[image]' or '[image]xN' : Insert 1 or N copies of the existing image [image].
    _ 'width[%],_height[%],_depth[%],_spectrum[%],_values' :
       Insert a new image with specified size and values (adding '%' to a dimension means
       'percentage of the size along the same axis, taken from the last available image').
       Any specified dimension can be also replaced by '[image]', and is then replaced by
       the size along the same axis of the existing specified image [image].
       'values' can be either a sequence of numbers separated by commas ',', or a mathematical
       expression, as e.g. in the input item '256,256,1,3,if(c==0,x,if(c==1,y,255))' which
       creates a 256x256 RGB color image with a spatial shading on the red and green channels.
    _ '(v1,v2,..)' : Create a new image containing specified prescribed values. Value separators
        inside parentheses can be ',' (column separator), ';' (line separator),
        '/' (slice separator) or '^' (channel separator). For instance, expression
        '(1,2,3;4,5,6;7,8,9)' creates a 3x3 matrix (scalar image), with values from 1 to 9.
  - Special variable assignment string 'label=value' inserts a new labelled element on the
     local stack with a specified value. This actually declares a new local variable.
 ** Command items and selections :
  - A G'MIC item starting by '-' designates a command, most of the time. Mainly, commands
    perform image processing operations on one or several available image(s) of the list.
  - Usual commands may have two equivalent names (regular and short). For instance,
     command names '-resize' and '-r' refer to the same processing action.
  - A G'MIC command may have mandatory or optional arguments. Command arguments must be
     specified in the item next to the command name. Commas ',' are used to separate multiple
     arguments, if any required.
  - The execution of a G'MIC command may be restricted only to a subset of the image list, by
     appending '[subset]' to the command name. Several combinations are possible, such as :
    _ '-com[0,1,3]' : Apply command only on images [0],[1] and [3].
    _ '-com[3-5]' : Apply command only on images [3] to [5] (i.e, [3],[4] and [5]).
    _ '-com[50%-100%]' : Apply command only on the second half of the image list.
    _ '-com[0,-4--1]' : Apply command only on the first image, and the four latest ones.
    _ '-com[0-9:3]' : Apply command only on images [0] to [9], with a step of 3
                        (i.e. [0], [3], [6] and [9]).
    _ '-com[0--1:2]' : Apply command only on images of the list with even indices.
    _ '-com[0,2-4,50%--1]' : Apply command on images [0],[2],[3],[4] and on the second half
                        of the image list.
    _ '-com[^0,1]' : Apply command on all images of the list except the two first ones.
    _ '-com[label1,label2]' : Apply command on labelled images 'label1' and 'label2'.
  - G'MIC commands invoked without '[subset]' are applied by default on all images of the list.
  - A G'MIC command starting with '--' instead of '-' does not act 'in-place' but inserts its
     result as one or several new images, at the end of the image list.
 ** Input/output properties :
  - When dealing with color images, G'MIC reads, writes and displays data using the usual
     RGB color space.
  - G'MIC is able to manage 3d objects that may be read or generated by some commands. These
     objects are stored as regular one-column scalar images containing the object data, in the
     following order { header, sizes, vertices, primitives, colors, opacities }.
     These 3d object representations can be processed as any other regular float-valued images.
  - G'MIC is able to read/write most of the classical image file formats, including :
    _ 2d grayscale/color files : .png, .jpeg, .gif, .pnm, .tif, .bmp, ..
    _ 3d volumetric files : .dcm, .hdr, .nii, .pan, .inr, ..
    _ Image sequences : .mpeg, .avi, .mov, .ogg, .flv, ..
    _ Generic ascii or binary data files : .cimg, .cimgz, .dlm, .asc, .pfm, .raw, .txt, .h.
    _ 3d object files : .off.
  - Classical image file formats may be not always adapted to store 3d multi-spectral datasets,
    resulting in possible loss of pixel informations. Use the .cimg file format (or .cimgz,
    its compressed version) to ensure that all data are preserved during file operations.
  - Options for specific file formats :
    _ For video files : Only sub-frames of an image sequence may be loaded, using the input
       expression 'video.ext,[first_frame[%][,last_frame[%][,step]]]'.
       Output framerate and quality can be also set by using the output expression
       'file.mpg,25,1024' (here, for a 25 fps and 1024k bitrate).
    _ For .raw binary files : Image dimensions must be specified, using the input expression
       'file.raw,width[,height[,depth[,dim]]]]'.
    _ For .yuv files : Image dimensions must be specified, and only sub-frames of an image
       sequence may be loaded, using the input expression
      'file.yuv,width,height[,first_frame[,last_frame[,step]]]'.
    _ For .jpeg files : The output quality may be specified (in %), using the output expression
       'file.jpg,30' (here, to get a 30% quality output).
    _ Filenames with extension '.gmic' are read as G'MIC custom command files.
  - Note that some formats or options may be not supported by your current version of 'gmic',
     depending on how compilation flags have been set for the build of the G'MIC interpreter.
 ** Substitution rules :
  - In G'MIC, items containing '@', '~', '&', '$' or '{}' may be substituted before interpreted.
     Use these expressions to get the current state of the interpreter environment :
    _ '@#' is substituted by the current number of images in the list.
    _ '@%' is substituted by the pid of the current process.
    _ '@|' is substituted by the current value of a millisecond-precision timer.
    _ '@?' is substituted by the current type of image pixels.
    _ '@^' is substituted by the current verbosity level.
    _ '@/' is substituted by the current level of the command scope.
    _ '@{/}' or '@{/,subset}' are substituted by the content of the command scope, or a subset of
       it. If specified subset refers to multiple scope items, they are separated by slash '/'.
    _ '@*' is substituted by the current number of items in the local stack.
    _ '@{*}' or '@{*,subset}' are substituted by the content of the local stack, or a subset of
       it. If specified subset refers to multiple stack items, they are separated by commas ','.
    _ '@>' and '@<' are equivalent. They are both substituted by the number of nested
       'repeat-done' loops that are currently running.
    _ '@{>}' or '@{>,subset}' are substituted by the indice values (or a subset of them) of the
       currently running 'repeat-done' loops, expressed in the ascending order, from 0 to N-1.
       If specified subset refers to multiple loop indices, they appear separated by commas ','.
    _ '@{<}' or '@{<,subset}' do the same but in descending order, from N-1 to 0.
    _ '@indice' or '@{indice,feature}' are substituted by the list of pixel values of the image
       [indice], or by a specific feature (or subset) of it. Requested 'feature' can be one of
       the followings :
         . 'w' : image width (number of image columns).
         . 'h' : image height (number of image lines).
         . 'd' : image depth (number of image slices).
         . 's' : image spectrum (number of image channels).
         . 'wh' : image width x image height.
         . 'whd' : image width x image height x image depth.
         . 'whds' : image width x image height x image depth x image spectrum.
                    (i.e. number of values in the specified image).
         . 'r' : image shared state (1, if the pixel buffer is shared, 0 else).
         . 'n' : image label or filename (if the image has been read from a file).
         . 'b' : image basename (i.e. filename without the folder path nor extension).
         . 'x' : image extension (i.e last characters after the last '.' in the filename).
         . 'f' : image folder name.
         . '#' : number of image values (i.e. width x height x depth x spectrum).
         . '+' : sum of all pixel values.
         . '-' : difference of all pixel values.
         . '*' : product of all pixel values.
         . '/' : quotient of all pixel values.
         . 'm' : minimum pixel value.
         . 'M' : maximum pixel value.
         . 'a' : average pixel value.
         . 'v' : variance of pixel values.
         . 't' : text string built from the image values, regarded as ascii codes.
         . 'c' : (x,y,z,c) coordinates of the minimum value, separated by commas ','.
         . 'C' : (x,y,z,c) coordinates of the maximum value, separated by commas ','.
         . '(x,_y,_z,_c,_borders)' : pixel value at coordinates (x,y,z,c), with specified
            border conditions { 0=dirichlet | 1=neumann | 2=cyclic }.
         . Any other feature is considered as a specified subset of image values. For instance,
            expression '@{-1,0-50%}' is substituted by the sequence of numerical values coming
            from the first half data of the last image, separated by commas ','.
    _ '@!' is substituted by the visibility state of the instant display window [0]
       (can be equal to { 0=closed | 1=visible }).
    _ '@{!,feature}' or '@{!indice,feature}' is substituted by a specific feature of the
       instant display window [0] (or [indice], if specified). The requested feature can be
       one of the followings :
         . 'w' : display width (i.e. width of the display area managed by the window).
         . 'h' : display height (i.e. height of the display area managed by the window).
         . 'wh' : display width x display height.
         . 'd' : window width (i.e. width of the window widget).
         . 'e' : window height (i.e. height of the window widget).
         . 'de' : window width x window height.
         . 'u' : screen width (actually independent on the window size).
         .' v' : screen height (actually independent on the window size).
         . 'uv' : screen width x screen height.
         . 'x' : X-coordinate of the mouse position (or -1, if outside the display area).
         . 'y' : Y-coordinate of the mouse position (or -1, if outside the display area).
         . 'b' : state of the mouse buttons { 1=left-state | 2=right-state | 4=middle-state }.
         . 'o' : state of the mouse wheel.
         . 'k' : decimal code of the pressed key if any, else 0.
         . 'n' : current normalization type of the instant display.
         . 'c' : boolean (0 or 1) telling if the instant display has been closed recently.
         . 'r' : boolean telling if the instant display has been resized recently.
         . 'm' : boolean telling if the instant display has been moved recently.
         . Any other feature stands for a keycode name in capital letter, and is substituted by
            a boolean describing the current key state { 0=pressed | 1=released }.
    _ '@{
       specified command line (see command '-status'). Expression '@{}' stands thus for the
       current status value.
  - '~>' and '~<' are shortcuts respectively for '@{>,-1}' and '@{<,-1}'. They refer to the
     increasing/decreasing indice of the latest (currently) running 'repeat..done' loop.
  - '~ind' and '~{ind}' are shortcuts for '@{*,ind}' where 'ind' is an integer.
     Use them to get the string value of one numbered item [indice] from the local stack.
  - '~label' and '~{label}' refer both to the stack element with the specified label.
  - '&ind' and '&{ind}' are both substituted by the label of the stack element [indice].
  - '&label' and '&{label}' are both substituted by the indice of the local stack element or the
     image with specified 'label' (local stack being prioritary). A label is initially set when
     inserting a new stack element (with commands '-p[label]' or 'label=value') or a new image
     (with commands '-i[label]').
     A labelled insertion is always done at the very end of the local stack or image list.
  - $var and '${var}' are both substituted by the value of the specified variable taken from the
     local stack or as the corresponding OS environment variable (local stack being prioritary).
  - Any other expression inside braces (as in '{expression}') is considered as a mathematical
     expression, and is evaluated, except when expression starts and ends by simple quotes,
     in which case, it is substituted by the sequence of ascii codes that composes the specified
     string, separated by commas ','.
     For instance, item '{3+2}' is substituted by '5', and item '{'foo'}' by '102,111,111'.
  - The last image of the list is always associated to the evaluations of '{expressions}',
     e.g. G'MIC sequence '256,128 -fill {w}' will create a 256x128 image filled with value 256.
  - Item substitution is never done in double-quoted items. One must break double quotes if
    substitution is needed, as eg. in
    substitutions in considered expressions.
  - One can also disable the substitution mechanism outside double-quoted items, by escaping
      the '@','{','}','&','$' and '~' characters, e.g. as in '3+4 doesn't evaluate'.
 ** Mathematical expressions :
  - G'MIC has an embedded mathematical parser. It is used to evaluate formulas inside braces '{}'
     as well as in commands that may take formulas as arguments (e.g. '-fill').
  - When used in commands, a formula is evaluated for each pixel of the selected images.
  - The parser understands the following set of functions, operators and variables :
    _ Usual operators : || (logical or), && (logical and), | (bitwise or), & (bitwise and),
       !=, ==, <=, >=, <, >, << (left bitwise shift), >> (right bitwise shift), -, +, *, /,
       % (modulo), ^ (power), ! (logical not), ~ (bitwise not).
    _ Usual functions : sin(), cos(), tan(), asin(), acos(), atan(), sinh(), cosh(), tanh(),
       log10(), log(), exp(), sign(), abs(), atan2(), round(), narg(), arg(), isval(), isnan(),
       isinf(), isint(), isbool(), rol() (left bit rotation), ror() (right bit rotation),
       min(), max(), sinc(), int().
       Function 'atan2()' is the version of atan() that takes two arguments 'y,x', as in C/C++.
       Function 'narg()' returns the number of specified arguments.
       Function 'arg(i,a1,..,an)' returns the ith argument ai.
       Functions 'min()' and 'max()' can be called with a variable number of arguments.
       Functions 'isval()', 'isnan()', 'isinf()', 'isbool()' can be used to test the type of
       a given number or expression.
    _ These special variable names are pre-defined. They cannot be overloaded :
         . 'w' : width of the associated image, if any (else 0).
         . 'h' : height of the associated image, if any (else 0).
         . 'd' : depth of the associated image, if any (else 0).
         . 's' : spectrum of the associated image, if any (else 0).
         . 'x' : current processed column of the associated image, if any (else 0).
         . 'y' : current processed line of the associated image, if any (else 0).
         . 'z' : current processed slice of the associated image, if any (else 0).
         . 'c' : current processed channel of the associated image, if any (else 0).
         . 'i' : current processed pixel value (i.e. value located at (x,y,z,c)) of the
            associated image, if any (else 0).
         . 'im','iM','ia','iv' : Respectively the minimum, maximum, average values and variance
            of the associated image, if any (else 0).
         . 'xm','ym','zm','cm' : The pixel coordinates of the minimum value in the associated
            image, if any (else 0).
         . 'xM','yM','zM','cM' : The pixel coordinates of the maximum value in the associated,
            image, if any (else 0).
         . 'pi' : value of pi, i.e. 3.1415926..
         . 'e' : value of e, i.e. 2.71828..
         . '?' or 'u' : a random value between [0,1], following an uniform distribution.
         . 'g' : a random value, following a gaussian distribution of variance 1
            (roughly in [-5,5]).
    _ These special operators can be used :
         . ';' : expression separator. The returned value is always the last encountered
            expression. For instance expression '1;2;pi' is evaluated as '3.14159'.
         . '=' : variable assignment. Parser variables can only refer to numerical values.
            Variable names are case-sensitive. Use this operator in conjunction with ';' to
            define complex evaluable expressions, such as 't=cos(x);3*t^2+2*t+1'.
            These variables remain local to the mathematical parser and cannot be accessed
            outside the evaluated expression.
    _ The following specific functions are also defined :
         . 'if(expr_cond,expr_then,expr_else)' : return value of 'expr_then' or 'expr_else',
            depending on the value of 'expr_cond' (0=false, other=true). For instance,
            G'MIC command '-fill if(x%10==0,255,i)' will draw blank vertical lines on every 10th
            column of an image.
         . '?(max)' or '?(min,max)' : return a random value between [0,max] or [min,max],
            following an uniform distribution. 'u(max)' and 'u(min,max)' mean the same.
         . 'i(a,_b,_c,_d,_borders)' : return the value of the pixel located at position
            (a,b,c,d) in the associated image, if any (else 0). Border conditions can be
            { 0=dirichlet | 1=neumann | 2=cyclic }. Omitted coordinates are replaced by their
            default values which are respectively equal to x, y, z, c and 0. For instance,
            command '-fill 0.5*(i(x+1)-i(x-1))' will estimate the X-derivative of an image.
 ** Management of variables :
  - In a G'MIC processing pipeline, management of variables is achieved through the use of
     the local stack (to store variable values), in conjunction with the mathematical parser
     (to update the variable values). For instance, a do..while loop with a custom counter
     would be typically written as : 'X=0 -do -e $X X={$X+1} -while {$X<10}'.
  - Local stack elements (or images) may have a label associated to them. Inserting a new
     labelled element at the end of the local stack is done with command '-push[label] item', or
     more simply by the special assignment command 'label=item'.
  - Overall manipulation of the local stack is done with one of these four commands :
    _ '-push' (eq. to '-p') to insert a new element (opt. labelled) on the local stack.
    _ '-pop' (eq. to '-pp') to remove an existing element on the local stack.
    _ '-push=' (eq. to '-p=') to reassign an existing element on the local stack.
    _ 'label=value' to assign or reassign a labelled item on the local stack.
  - Accessing the content of the local stack is done either through the '@{*,subset}',
     '~ind','~label' or '$label' substituting expressions.
 ** Custom commands :
  - Custom commands can be defined by the user, through the use of G'MIC command files.
  - A command file is a simple ascii text file, where each line starts either by
     'command_name : substitution' or 'substitution (continuation)' or '# comment'.
  - The name of a custom command may contain the characters 'a-z','A-Z','0-9' and '_'.
  - Any '# comment' expression found in a custom command file is discarded by the G'MIC
     interpreter, wherever it is located in a line.
  - A default command file is already provided within the G'MIC package. It is located
     at 'http://gmic.sourceforge.net/gmic_def.xxxx', where 'xxxx' has to be replaced by
     the 4 digits of the current G'MIC version number. Looking at it is a good start to learn
     more on creating your own custom commands. All the commands from this default command file
     are in fact already included by default in the current version of the G'MIC interpreter.
  - The default command file located at 'http://gmic.sourceforge.net/gmic_def.xxxx' may be
     updated/corrected by the G'MIC developers. You can download and include it with the
     '-command' (or -'m') directive to update your default command definitions as well.
  - In custom commands, some expressions starting with '$' are substituted :
    _ '$#' is substituted by the maximum indice of known arguments (either specified by the user
       or set to a default value in the custom command).
    _ '$?' is substituted by a string telling about the command subset restriction (only useful
       when custom commands need to output descriptive messages).
    _ '$i' and '${i}' are both substituted by the i-th specified argument. Negative indices
       such as '$[-j}' are allowed and refer to the j^th latest argument. '$0' is substituted by
       the custom command name.
    _ '${i=default}' is substituted by the value of $i (if defined) or by its new default value
       'default' else ('default' may be a $-expression as well).
    _ '${subset}' is substituted by the arguments values (separated by commas ',') of a specified
       argument subset. For instance expression '${2--2}' is substitued by all
       specified arguments except the first and the last ones. Useful expression '${^0}' is
       substituted by all specified arguments.
  - Specifying arguments may be skipped when invoking a custom command, by replacing them by
     commas ',' as in expression '-flower ,,3'. Omitted arguments are set to their default
     values, which must be thus explicitely defined in the code of the corresponding custom
     command (using default argument expressions as '${1=default}').
 ** Image and data viewers :
  - G'MIC has some very handy embedded visualization modules, for 1d signals (command '-plot'),
     1d/2d/3d images (command '-display') and 3d objects (command '-display3d'). They allow to
     interactively view and explore the selected image datasets.
  - The following keyboard shortcuts are available in the interactive viewers :
    _ CTRL+D : Increase window size.
    _ CTRL+C : Decrease window size.
    _ CTRL+R : Reset window size.
    _ CTRL+F : Toggle fullscreen mode.
    _ CTRL+S : Save current window snapshot as a numbered file 'CImg_xxxx.bmp'.
    _ CTRL+O : Save current instance of the viewed data, as a numbered file 'CImg_xxxx.cimg'.
  - Shortcuts specific to the 1d/2d/3d image viewer :
    _ CTRL+P : Play stack of slices as a movie (for volumetric 3d images).
    _ CTRL+(mousewheel) : Zoom in/out.
    _ SHIFT+(mousewheel) : Go left/right.
    _ ALT+(mousewheel) : Go up/down.
    _ Numeric PAD : Zoom in/out (+/-) and move through zoomed image (digits).
    _ BACKSPACE : Reset zoom scale.
  - Shortcuts specific to the 3d object viewer :
    _ (mouse)+(left mouse button) : Rotate object.
    _ (mouse)+(right mouse button) : Zoom object.
    _ (mouse)+(middle mouse button) : Shift object.
    _ (mousewheel) : Zoom in/out.
    _ CTRL+F1 .. CTRL+F6 : Set 3d rendering mode.
    _ CTRL+Z : Enable/disable z-buffered rendering.
    _ CTRL+A : Show/hide 3d axes.
    _ CTRL+G : Save 3d object, as a numbered file 'CImg_xxxx.off'.
    _ CTRL+T : Switch between single/double-sided modes.
 ** Command reference :
 All recognized G'MIC commands are listed below, classified by themes.
 When several choices of command arguments are possible, they appear separated by '|'.
 An argument specified inside '[]' or starting by '_' is optional except when standing for an
 existing image [image], where 'image' can be either an indice number or an image label.
 In this case, the '[]' characters are mandatory when writing the item. A command marked with
 (*) is available for all image types, else only for the default 'float' pixel datatype.
 Global options
 --------------
    -help _command (*)
        Display help (optionally for specified command only) and quit.
        (eq. to '-h').
    -debug (*)
        Activate debug mode.
        When activated, this mode outputs additionnal log messages describing the
        internal state of the interpreter.
 Mathematical operators and functions
 ------------------------------------
    -add value[%] |
                     [image] |
                     filename |
                     'formula' |
                     (no args)
        Add specified value, image, file or mathematical expression to selected images,
        or compute the pointwise sum of selected images.
        (eq. to '-+').
    -sub value[%] |
                     [image] |
                     filename |
                     'formula' |
                     (no args)
        Subtract specified value, image, file or mathematical expression to selected images,
        or compute the pointwise difference of selected images.
        (eq. to '--').
    -mul value[%] |
                     [image] |
                     filename |
                     'formula' |
                     (no args)
        Multiply selected images by specified value, image, file or mathematical expression,
        or compute the pointwise product of selected images.
        (eq. to '-*').
    -mmul value[%] |
                     [image] |
                     filename |
                     'formula' |
                     (no args)
        Compute the matrix product of selected matrices/vectors by specified value, image, file or
        mathematical expression, or compute the matrix products of selected images.
        (eq. to '-**').
    -div value[%] |
                     [image] |
                     filename |
                     'formula' |
                     (no args)
        Divide selected image by specified value, image, file or mathematical expression,
        or compute the pointwise quotient of selected images.
        (eq. to '-/').
    -pow value[%] |
                     [image] |
                     filename |
                     'formula' |
                     (no args)
        Raise selected image to the power of specified value, image, file or mathematical
        expression, or compute the pointwise sequential powers of selected images.
        (eq. to '-^').
    -min value[%] |
                     [image] |
                     filename |
                     'formula' |
                     (no args)
        Compute the minimum between selected images and specified value, image, file or
        mathematical expression, or compute the pointwise minima between selected images.
    -max value[%] |
                     [image] |
                     filename |
                     'formula' |
                     (no args)
        Compute the maximum between selected images and specified value, image, file or
        mathematical expression, or compute the pointwise maxima between selected images.
    -mod value[%] |
                     [image] |
                     filename |
                     'formula' |
                     (no args)
        Compute the modulo of selected images with specified value, image, file or mathematical
        expression, or compute the pointwise sequential modulo of selected images.
    -and value[%] |
                     [image] |
                     filename |
                     'formula' |
                     (no args)
        Compute the bitwise AND of selected images with specified value, image, file or mathematical
        expression, or compute the pointwise sequential bitwise AND of selected images.
    -or value[%] |
                     [image] |
                     filename |
                     'formula' |
                     (no args)
        Compute the bitwise OR of selected images with specified value, image, file or mathematical
        expression, or compute the pointwise sequential bitwise OR of selected images.
    -xor value[%] |
                     [image] |
                     filename |
                     'formula' |
                     (no args)
        Compute the bitwise XOR of selected images with specified value, image, file or mathematical
        expression, or compute the pointwise sequential bitwise XOR of selected images.
    -bsl value[%] |
                     [image] |
                     filename |
                     'formula' |
                     (no args)
        Compute the bitwise left shift of selected images with specified value, image, file or
        mathematical expression, or compute the pointwise sequential bitwise left shift of
        selected images.
        (eq. to '-<<').
    -bsr value[%] |
                     [image] |
                     filename |
                     'formula' |
                     (no args)
        Compute the bitwise right shift of selected images with specified value, image, file or
        mathematical expression, or compute the pointwise sequential bitwise right shift of
        selected images.
        (eq. to '->>').
    -rol value[%] |
                     [image] |
                     filename |
                     'formula' |
                     (no args)
        Compute the bitwise left rotation of selected images with specified value, image, file or
        mathematical expression, or compute the pointwise sequential bitwise left rotation of
        selected images.
    -ror value[%] |
                     [image] |
                     filename |
                     'formula' |
                     (no args)
        Compute the bitwise right rotation of selected images with specified value, image, file or
        mathematical expression, or compute the pointwise sequential bitwise right rotation of
        selected images.
    -eq value[%] |
                     [image] |
                     filename |
                     'formula' |
                     (no args)
        Compute the boolean equality of selected images with specified value, image, file or
        mathematical expression, or compute the boolean equality of selected images.
        (eq. to '-==').
    -neq value[%] |
                     [image] |
                     filename |
                     'formula' |
                     (no args)
        Compute the boolean inequality of selected images with specified value, image, file or
        mathematical expression, or compute the boolean inequality of selected images.
        (eq. to '-!=').
    -gt value[%] |
                     [image] |
                     filename |
                     'formula' |
                     (no args)
        Compute the boolean 'greater than' of selected images with specified value, image, file or
        mathematical expression, or compute the boolean 'greater than' of selected images.
        (eq. to '->').
    -ge value[%] |
                     [image] |
                     filename |
                     'formula' |
                     (no args)
        Compute the boolean 'greater or equal than' of selected images with specified value, image,
        file or mathematical expression, or compute the boolean 'greater or equal than' of selected
        images.
        (eq. to '->=').
    -lt value[%] |
                     [image] |
                     filename |
                     'formula' |
                     (no args)
        Compute the boolean 'less than' of selected images with specified value, image, file or
        mathematical expression, or compute the boolean 'less than' of selected images.
        (eq. to '-<').
    -le value[%] |
                     [image] |
                     filename |
                     'formula' |
                     (no args)
        Compute the boolean 'less or equl than' of selected images with specified value, image,
        file or mathematical expression, or compute the boolean 'less or equal than' of selected
        images.
        (eq. to '-<=').
    -cos
        Compute the pointwise cosine of selected images.
    -sin
        Compute the pointwise sine of selected images.
    -sinc
        Compute the pointwise sinc function of selected images.
    -tan
        Compute the pointwise tangent of selected images.
    -cosh
        Compute the pointwise hyperbolic cosine of selected images.
    -sinh
        Compute the pointwise hyperbolic sine of selected images.
    -tanh
        Compute the pointwise hyperbolic tangent of selected images.
    -acos
        Compute the pointwise arc-cosine of selected images.
    -asin
        Compute the pointwise arc-sine of selected images.
    -atan
        Compute the pointwise arc-tangent of selected images.
    -atan2 [image]
        Compute the pointwise oriented arc-tangent of selected images.
        Each selected image is regarded as the y-argument of the arc-tangent function, while the
        specified image gives the corresponding x-argument.
    -abs
        Compute the pointwise absolute values of selected images.
    -sign
        Compute the pointwise sign of selected images.
    -sqr
        Compute the pointwise square function of selected images.
    -sqrt
        Compute the pointwise square root of selected images.
    -exp
        Compute the pointwise exponential of selected images.
    -log
        Compute the pointwise logarithm of selected images.
    -log10
        Compute the pointwise logarithm_10 of selected images.
 Basic pixel manipulation
 ------------------------
    -endian (*)
        Reverse data endianness of selected images.
    -set value,_x[%],_y[%],_z[%],_c[%]
        Set pixel value in selected images, at specified coordinates.
        (eq. to '-=').
        If specified coordinates are outside the image bounds, no action is performed.
        Default values for 'x','y','z','c' are '0'.
    -fill value1,_value2,.. |
                     [image] |
                     formula
        Fill selected images with values read from the specified value list, existing image
        or mathematical expression.
        (eq. to '-f').
    -threshold value[%],_soft |
                     (no args)
        Threshold values of selected images.
        (eq. to '-t').
        'soft' can be { 0=hard-thresholding | 1=soft-thresholding }.
        (noargs) runs interactive mode (uses the instant window [0] if opened).
    -cut { value0[%] | [image0] },{ value1[%] | [image1] } |
                     [image] |
                     (no args)
        Cut values of selected images in specified range.
        (eq. to '-c').
        (noargs) runs interactive mode (uses the instant window [0] if opened).
    -normalize { value0[%] | [image0] },{ value1[%] | [image1] } |
                     [image]
        Linearly normalize values of selected images in specified range.
        (eq. to '-n').
    -round rounding_value>=0,_rounding_type
        Round values of selected images.
        'rounding_type' can be { -1=backward | 0=nearest | 1=forward }.
    -equalize nb_levels>0[%],_value0[%],_value1[%]
        Equalize histograms of selected images.
        If value range is specified, the equalization is done only for pixels in the specified
        value range.
    -quantize nb_levels>0[%],_preserve_value_range={ 0 | 1 }
        Uniformly quantize selected images.
    -noise std_variation>=0[%],_noise_type
        Add random noise to selected images.
        'noise_type' can be { 0=gaussian | 1=uniform | 2=salt&pepper | 3=poisson | 4=rice }.
    -rand { value0[%] | [image0] },{ value1[%] | [image1] } |
                     [image]
        Fill selected images with random values uniformly distributed in the specified range.
    -norm
        Compute the pointwise euclidean norm of vector-valued pixels in selected images.
    -orientation
        Compute the pointwise orientation of vector-valued pixels in selected images.
    -map [image] |
                     predefined_palette
        Map specified vector-valued palette to selected indexed scalar images.
        'predefined_palette' can be { 0=default | 1=HSV | 2=lines | 3=hot |
                        4=cool | 5=jet | 6=flag | 7=cube }.
    -index { [image] | predefined_palette },_is_dithered={ 0 | 1 },_map_palette={ 0 | 1 }
        Index selected vector-valued images by specified vector-valued palette.
        'predefined_palette' can be { 0=default | 1=HSV | 2=lines | 3=hot |
                        4=cool | 5=jet | 6=flag | 7=cube }.
 Color base conversion
 ---------------------
    -rgb2hsv
        Convert selected images from RGB to HSV colorbases.
    -rgb2hsl
        Convert selected images from RGB to HSL colorbases.
    -rgb2hsi
        Convert selected images from RGB to HSI colorbases.
    -rgb2yuv
        Convert selected images from RGB to YUV colorbases.
    -rgb2ycbcr
        Convert selected images from RGB to YCbCr colorbases.
    -rgb2xyz
        Convert selected images from RGB to XYZ colorbases.
    -rgb2lab
        Convert selected images from RGB to Lab colorbases.
    -rgb2cmy
        Convert selected images from RGB to CMY colorbases.
    -rgb2cmyk
        Convert selected images from RGB to CMYK colorbases.
    -hsv2rgb
        Convert selected images from HSV to RGB colorbases.
    -hsl2rgb
        Convert selected images from HSL to RGB colorbases.
    -hsi2rgb
        Convert selected images from HSI to RGB colorbases.
    -yuv2rgb
        Convert selected images from YUV to RGB colorbases.
    -ycbcr2rgb
        Convert selected images from YCbCr to RGB colorbases.
    -xyz2rgb
        Convert selected images from XYZ to RGB colorbases.
    -lab2rgb
        Convert selected images from Lab to RGB colorbases.
    -cmy2rgb
        Convert selected images from CMY to RGB colorbases.
    -cmyk2rgb
        Convert selected images from CMYK to RGB colorbases.
 Geometry manipulation
 ---------------------
    -resize [image],_interpolation,_borders,_cx,_cy,_cz,_cc |
                     {[image_w] | width>0[%]},_{[image_h] | height>0[%]},_{[image_d] | depth>0[%]},
                       _{[image_s] | spectrum>0[%]},_interpolation,_borders,_cx,_cy,_cz,_cc |
                     (noargs)
        Resize selected images with specified geometry.
        (eq. to '-r').
        'interpolation' can be { -1=none (memory content) | 0=none | 1=nearest | 2=average |
                        3=linear | 4=grid | 5=bicubic | 6=lanczos }.
        'borders' can be { -1=none | 0=dirichlet | 1=neumann | 2=cyclic }.
        'cx,cy,cz,cc' set the centering mode when 'interpolation=0' (must be in [0,1]).
        Their default values are '0'.
        (noargs) runs interactive mode (uses the instant window [0] if opened).
    -resize2x
        Resize selected images using the Scale2x algorithm.
    -resize3x
        Resize selected images using the Scale3x algorithm.
    -crop x0[%],x1[%],_borders |
                     x0[%],y0[%],x1[%],y1[%],_borders |
                     x0[%],y0[%],z0[%],x1[%],y1[%],z1[%],_borders |
                     x0[%],y0[%],z0[%],c0[%],x1[%],y1[%],z1[%],c1[%],_borders |
                     (noargs)
        Crop selected images with specified region coordinates.
        'borders' can be { 0=dirichlet | 1=neumann }.
        (noargs) runs interactive mode (uses the instant window [0] if opened).
    -autocrop value1,value2,..
        Autocrop selected images by specified vector-valued intensity.
    -channels { [image0] | c0[%] },_{ [image1] | c1[%] }
        Select specified channels of selected images.
    -slices { [image0] | z0[%] },_{ [image1] | z1[%] }
        Select specified slices of selected images.
    -lines { [image0] | y0[%] },_{ [image1] | y1[%] }
        Select specified lines of selected images.
    -columns { [image0] | x0[%] },_{ [image1] | x1[%] }
        Select specified columns of selected images.
    -rotate angle,_borders,_interpolation,_cx[%],_cy[%],_zoom
        Rotate selected images with specified angle (in deg.).
        'borders' can be { 0=dirichlet | 1=neumann | 2=cyclic }.
        'interpolation' can be { 0=none | 1=linear | 2=bicubic }.
        When rotation center ('cx','cy') is specified, the size of the image is preserved.
    -mirror axis={ x | y | z | c }
        Mirror selected images along specified axis.
    -shift vx[%],_vy[%],_vz[%],_vc[%],_borders
        Shift selected images by specified displacement vector.
        'borders' can be { 0=dirichlet | 1=neumann | 2=cyclic }.
    -transpose
        Transpose selected images.
    -invert
        Compute the inverse of the selected matrices.
    -solve [image]
        Solve linear system AX = B for selected B-vectors and specified A-matrix.
    -trisolve [image]
        Solve tridiagonal system AX = B for selected B-vectors and specified tridiagonal A-matrix.
        Tridiagonal matrix must be stored as a 3 column vector, where 2nd column contains the
        diagonal coefficients, while 1st and 3rd columns contain the left and right coefficients.
    -eigen
        Compute the eigenvalues and eigenvectors of specified symmetric matrices.
    -dijkstra starting_node>=0,ending_node>=0
        Compute minimal distances and pathes from specified adjacency matrices by the Dijkstra algorithm.
    -permute permutation
        Permute selected image axes by specified permutation.
        'permutation' is a combination of the character set {x|y|z|c},
        e.g. 'xycz', 'cxyz', ..
    -unroll axis={ x | y | z | c }
        Unroll selected images along specified axis.
    -split axis={ x | y | z | c },_nb_parts |
                     patch_x>0,_patch_y>0,_patch_z>0,_patch_v>0,borders |
                     value,_keep_splitting_values={ + | - }
        Split selected images along specified axis, patch or scalar value.
        (eq. to '-s').
        'nb_parts' can be { 0=maximum split | >0=split in N parts | <0=split in parts of size -N }.
        'borders' can be { 0=dirichlet | 1=neumann }.
    -append axis={ x | y | z | c },_alignment
        Append selected images along specified axis.
        (eq. to '-a').
        'alignment' can be { p=left | c=center | n=right }.
    -warp [image],_is_relative={ 0 | 1 },_interpolation={ 0 | 1 },_borders,_nb_frames>0
        Warp selected image with specified displacement field.
        'borders' can be { 0=dirichlet | 1=neumann | 2=cyclic }.
 Image filtering
 ---------------
    -deriche std_variation>=0[%],order={ 0 | 1 | 2 },axis={ x | y | z | c },_borders
        Apply Deriche recursive filter with specified standard deviation, order, axis and border
        conditions on selected images.
        'borders' can be { 0=dirichlet | 1=neumann }.
    -blur std_variation>=0[%],_borders
        Blur selected images by quasi-gaussian recursive filter.
        'borders' can be { 0=dirichlet | 1=neumann }.
    -bilateral std_variation_s>0[%],std_variation_r>0
        Blur selected images by anisotropic bilateral filtering.
        'borders' can be { 0=dirichlet | 1=neumann }.
    -denoise std_variation_s>=0,_std_variation_p>=0,_patch_size>0,_lookup_size>0,_smoothness,
                      _fast_approx={ 0 | 1 }
        Denoise selected images by non-local patch averaging.
    -smooth amplitude>=0,_sharpness>=0,_anisotropy,_alpha,_sigma,_dl>0,_da>0,_precision>0,
                      interpolation,_fast_approx={ 0 | 1 } |
                     nb_iterations>=0,_sharpness>=0,_anisotropy,_alpha,_sigma,_dt>0,0 |
                     [image],_amplitude>=0,_dl>0,_da>0,_precision>0,_interpolation,_fast_approx={ 0 | 1 } |
                     [image],_nb_iters>=0,_dt>0,0
        Smooth selected images anisotropically using diffusion PDE's, with specified field of
        diffusion tensors.
        'anisotropy' must be in [0,1].
        'interpolation' can be { 0=nearest | 1=linear | 2=runge-kutta }.
    -median radius>=0
        Apply median filter of specified radius on selected images.
    -sharpen amplitude>=0 |
                     amplitude>=0,1,_edge>=0,_alpha,_sigma
        Sharpen selected images by inverse diffusion or shock filters methods.
    -convolve [image],_borders
        Convolve selected images by specified mask.
        'borders' can be { 0=dirichlet | 1=neumann }.
    -correlate [image],_borders
        Correlate selected images by specified mask.
        'borders' can be { 0=dirichlet | 1=neumann }.
    -erode size>=0' |
                     size_x>=0,size_y>=0,_size_z>=0 |
                     [image],_borders
        Erode selected images by a rectangular or the specified structuring element.
        'borders' can be { 0=dirichlet | 1=neumann }.
    -dilate size>=0 |
                     size_x>=0,size_y>=0,size_z>=0 |
                     [image],_borders
        Dilate selected images by a rectangular or the specified structuring element.
        'borders' can be { 0=dirichlet | 1=neumann }.
    -inpaint [image]
        Inpaint selected images by specified mask.
    -gradient { x | y | z }..{ x | y | z },_scheme |
                     (no args)
        Compute the gradient components (first derivatives) of selected images.
        'scheme' can be { -1=backward | 0=centered | 1=forward | 2=sobel |
                        3=rotation-invariant (default) | 4=recursive }.
        (no args) compute all significant 2d/3d components.
    -structuretensors _scheme
        Compute the structure tensor field of selected images.
        'scheme' can be { 0=centered | 1=forward-backward1 | 2=forward-backward2 }.
    -edgetensors sharpness>=0,_anisotropy,_alpha,_sigma,is_sqrt={ 0 | 1 }
        Compute the diffusion tensors of selected images for edge-preserving smoothing algorithms.
        'anisotropy' must be in [0,1].
    -hessian { xx | xy | xz | yy | yz | zz }..{ xx | xy | xz | yy | yz | zz } |
                     (no args)
        Compute the hessian components (second derivatives) of selected images.
        (no args) compute all significant components.
    -haar scale>0
        Compute the direct haar multiscale wavelet transform of selected images.
    -ihaar scale>0
        Compute the inverse haar multiscale wavelet transform of selected images.
    -fft
        Compute the direct fourier transform of selected images.
    -ifft
        Compute the inverse fourier transform of selected images.
 Image creation and drawing
 --------------------------
    -histogram nb_levels>0[%],_val0[%],_val1[%]
        Compute the histogram of selected images.
        If value range is specified, the histogram is estimated only for pixels in the specified
        value range.
    -distance isovalue
        Compute the unsigned distance function to specified isovalue.
    -eikonal nb_iterations>=0,_band_size>=0
        Compute iterations of the eikonal equation (signed distance function) on selected images.
    -watershed [priority_image],_fill_lines={ 0 | 1 }
        Compute the watershed transform of selected images.
    -label
        Label connected components in selected images.
    -displacement [source_image],_smoothness>=0,_precision>0,_nb_scales>=0,iteration_max>=0,
                     is_backward={ 0 | 1 }
        Estimate displacement field between selected images and specified source.
        If 'nbscales'=0, the number of needed scales is estimated from the image size.
    -sort _ordering={ + | - },_axis={ x | y | z | c }
        Sort pixel values of selected images.
    -mse
        Compute MSE (Mean-Squared Error) matrix between selected images.
    -psnr _max_value
        Compute PSNR (Peak Signal-to-Noise Ratio) matrix between selected images.
    -point x[%],y[%],_z[%],_opacity,_color1,..
        Set specified colored pixel on selected images.
        Default color value is '0'.
    -line x0[%],y0[%],x1[%],y1[%],_opacity,_pattern,_color1,..'
        Draw specified colored line on selected images.
        'pattern' is an hexadecimal number starting with '0x' which can be omitted
         even if a color is specified.
        Default color value is '0'.
    -polygon N,x1[%],y1[%],..,xN[%],yN[%],_opacity,_pattern,_color1,..
        Draw specified colored N-vertices polygon on selected images.
        'pattern' is an hexadecimal number starting with '0x' which can be omitted
         even if a color is specified. If a pattern is specified, the polygon is
         drawn outlined instead of filled.
        Default color value is '0'.
    -spline x0[%],y0[%],u0[%],v0[%],x1[%],y1[%],u1[%],v1[%],_opacity,_pattern,_color1,..
        Draw specified colored spline curve on selected images.
        'pattern' is an hexadecimal number starting with '0x' which can be omitted
         even if a color is specified.
        Default color value is '0'.
    -ellipse x[%],y[%],R[%],r[%],_angle,_opacity,_color1,..
        Draw specified colored ellipse on selected images.
        'pattern' is an hexadecimal number starting with '0x' which can be omitted
         even if a color is specified. If a pattern is specified, the ellipse is
         drawn outlined instead of filled.
        Default color value is '0'.
    -text text,_x[%],_y[%],_font_height>0,_opacity,_color1,..
        Draw specified colored text string on selected images.
        Exact pre-defined sizes are '13','24','32' and '57'.
        Default color value is '0'.
        Specifying a target image with a size of 1x1x1x1 resizes it to new
         dimensions such that the image contains the entire text string.
    -graph [function_image],_plot_type,_vertex_type,_ymin,_ymax,_opacity,_pattern,_color1,.. |
                     'formula',_resolution>=0,_plot_type,_vertex_type,_xmin,xmax,_ymin,_ymax,_opacity,_pattern,_color1,..
        Draw specified function graph on selected images.
        'plot_type' can be { 0=none | 1=lines | 2=splines | 3=bar }.
        'vertex_type' can be { 0=none | 1=points | 2,3=crosses | 4,5=circles | 6,7=squares }.
        'pattern' is an hexadecimal number starting with '0x' which can be omitted
         even if a color is specified.
        Default color value is '0'.
    -axes x0,x1,y0,y1,_opacity,_pattern,_color1,..
        Draw xy-axes on selected images.
        'pattern' is an hexadecimal number starting with '0x' which can be omitted
         even if a color is specified.
        Default color value is '0'.
    -grid sizex[%]>=0,sizey[%]>=0,_offsetx[%],_offsety[%],_opacity,_pattern,_color1,..
        Draw xy-grid on selected images.
        'pattern' is an hexadecimal number starting with '0x' which can be omitted
         even if a color is specified.
        Default color value is '0'.
    -quiver [function_image],_sampling>0,_factor,_is_arrow={ 0 | 1 },_opacity,_pattern,_color1,..
        Draw specified 2d vector/orientation field on selected images.
        'pattern' is an hexadecimal number starting with '0x' which can be omitted
         even if a color is specified.
        Default color value is '0'.
    -flood x[%],_y[%],_z[%],_tolerance>=0,_opacity,_color1,..
        Flood-fill selected images using specified value and tolerance.
        Default color value is '0'.
    -image [sprite],_x[%],_y[%],_z[%],_c[%],_opacity,_[sprite_mask]
        Draw specified sprite image on selected images.
    -object3d [object3d],_x[%],_y[%],_z,_opacity,_is_zbuffer={ 0 | 1 }
        Draw specified 3d object on selected images.
    -plasma alpha,_beta,_opacity
        Draw a random colored plasma on selected images.
    -mandelbrot z0r,z0i,z1r,z1i,_iteration_max>=0,_is_julia={ 0 | 1 },_c0r,_c0i,_opacity
        Draw mandelbrot/julia fractal on selected images.
 List manipulation
 -----------------
    -remove (*)
        Remove selected images.
        (eq. to '-rm').
    -keep (*)
        Keep only selected images.
        (eq. to '-k').
    -move position[%] (*)
        Move selected images at specified position.
        (eq. to '-mv').
    -reverse (*)
        Reverse positions of selected images.
        (eq. to '-rv').
    -name name (*)
        Set name of selected images.
        (eq. to '-nm').
 3d rendering
 ------------
    -rotation3d u,v,w,angle
        Create a new 3d rotation matrix with specified axis and angle (in deg).
    -point3d x0,y0,z0
        Create a new 3d point at specified coordinates.
    -line3d x0,y0,z0,x1,y1,z1
        Create a new 3d line at specified coordinates.
    -triangle3d x0,y0,z0,x1,y1,z1,x2,y2,z2
        Create a new 3d triangle at specified coordinates.
    -quadrangle3d x0,y0,z0,x1,y1,z1,x2,y2,z2,x3,y3,z3
        Create a new 3d quadrangle at specified coordinates.
    -circle3d x0,y0,z0,radius>=0
        Create a new 3d circle at specified coordinates.
    -box3d size |
                     size_x,size_y,size_z
        Create a new 3d box at (0,0,0), with specified geometry.
    -cone3d radius,_size_z,_nb_subdivisions>0
        Create a new 3d cone at (0,0,0), with specified geometry.
    -cylinder3d radius,_height,_nb_subdivisions>0
        Create a new 3d cylinder at (0,0,0), with specified geometry.
    -torus3d radius1,_radius2,_nb_subdivisions1>0,_nb_subdivisions2>0
        Create a new 3d torus at (0,0,0), with specified geometry.
    -plane3d size1_size2,_nb_subdivisions1>0,_nb_subdisivions2>0
        Create a new 3d plane at (0,0,0), with specified geometry.
    -sphere3d radius,_nb_recursions>=0
        Create a new 3d sphere at (0,0,0), with specified geometry.
    -elevation3d z-factor |
                     [image] |
                     'formula',_x0,_y0,_x1,y1,_dx[%],_dy[%] |
                     (no args)
        Create 3d elevation of selected images or specified formula, with specified elevation map.
        If a z-factor is specified, each elevation map is computed as the pointwise L2 norm of the
        selected images. Else, elevation values are taken from the specified image or formula.
    -isoline3d isovalue[%] |
                     'formula',value,_x0,_y0,_x1,_y1,_dx>0[%],_dy>0[%]
        Extract 3d isolines with specified value from selected images or from specified formula.
    -isosurface3d isovalue[%] |
                     'formula',value,_x0,_y0,_z0,_x1,_y1,_z1,_size_x>0[%],_size_y>0[%],_size_z>0[%]
        Extract 3d isosurfaces with specified value from selected images or from specified formula.
    -streamline3d x,y,z,_L>=0,_dl>0,_interp,_is_backward={ 0 | 1 },_is_oriented={ 0 | 1 } |
                     'formula',x,y,z,_L>=0,_dl>0,_interp,_is_backward={ 0 | 1 },_is_oriented={ 0 | 1 }
        Extract 3d streamlines from selected vector fields or from specified formula.
        'interp' can be { 0=nearest integer | 1=1st-order | 2=2nd-order | 3=4th-order }.
    -add3d tx,_ty,_tz |
                     [object3d] |
                     (noargs)
        Shift selected 3d objects with specified displacement vector, or merge them with specified
        3d object, or merge all selected 3d objects together.
        (eq. to '-+3d').
    -sub3d tx,_ty,_tz
        Shift selected 3d objects with the opposite of specified displacement vector.
        (eq. to '--3d').
    -mul3d factor |
                     factor_x,factor_y,_factor_z
        Scale selected 3d objects isotropically or anisotropically, with specified factors.
        (eq. to '-*3d').
    -div3d factor |
                     factor_x,factor_y,_factor_z
        Scale selected 3d objects isotropically or anisotropically, with the inverse of specified
        factors.
        (eq. to '-/3d').
    -center3d
        Center selected 3d objects at (0,0,0).
        (eq. to '-c3d').
    -normalize3d
        Normalize selected 3d objects to unit size.
        (eq. to '-n3d').
    -rotate3d u,v,w,angle
        Rotate selected 3d objects around specified axis with specified angle (in deg.).
        (eq. to '-rot3d').
    -color3d R,G,B,_opacity
        Set color and opacity of selected 3d objects.
        (eq. to '-col3d').
    -opacity3d opacity
        Set opacity of selected 3d objects.
        (eq. to '-o3d').
    -reverse3d
        Reverse orientation of selected 3d objects.
        (eq. to '-rv3d').
    -primitives3d mode
        Convert primitives of selected 3d objects.
        (eq. to '-p3d').
        'mode' can be { 0=points | 1=segments | 2=no-textures }.
    -split3d
        Split selected 3d objects into 6 feature vectors :
        { header, sizes, vertices, primitives, colors, opacities }.
        (eq. to '-s3d').
        To recreate the 3d object, append these 6 images along the y-axis.
    -light3d position_x,position_y,position_z |
                     [image] |
                     (no args)
        Set the light coordinates or the light texture for 3d rendering.
        (eq. to '-l3d').
        (noargs) resets the 3d light to default.
    -focale3d focale
        Set 3d focale.
        (eq. to '-f3d').
        Set 'focale' to 0 to enable parallel projection (instead of perspective).
        Set negative 'focale' will disable 3d sprite zooming.
    -pose3d value1,..,value16 |
                     (noargs)
        Set the coefficients of the 3d pose matrix.
        (noargs) resets the 3d pose matrix to default.
    -specl3d value
        Set amount of 3d specular light.
        (eq. to '-sl3d').
    -specs3d value
        Set shininess of 3d specular light.
        (eq. to '-ss3d').
    -double3d is_double={ 0 | 1 }
        Enable/disable double-sided mode for 3d rendering.
        (eq. to '-db3d').
    -mode3d mode
        Set static 3d rendering mode.
        (eq. to '-m3d').
        'mode' can be { -1=bounding-box | 0=pointwise | 1=linear | 2=flat | 3=flat-shaded |
                        4=gouraud-shaded | 5=phong-shaded }.
    -moded3d mode
        Set dynamic 3d rendering mode.
        (eq. to '-md3d').
        'mode' can be { -1=bounding-box | 0=pointwise | 1=linear | 2=flat | 3=flat-shaded |
                        4=gouraud-shaded | 5=phong-shaded }.
    -background3d R,_G,_B |
                     [image] |
                     (no args)
        Define background from specified color or existing image for 3d rendering.
        (eq. to '-b3d').
        (no args) resets the background to default.
 Program control and environment
 -------------------------------
    -skip item (*)
        Do nothing but skip specified item.
    -return (*)
        Return from current custom command.
    -status item | (*)
                     $variable
        Set current status value to the specified item or from the value of the
         specified environment variable.
        (eq. to '-u').
    -exec command (*)
        Execute external command using a system call.
        The status value is then set to the error code returned by the system call.
        (eq. to '-x').
    -do (*)
        Start a 'do..while' block.
    -while boolean | (*)
                     filename
        End a 'do..while' block and go back to associated '-do'
        if specified boolean is true or if specified filename exists.
        'boolean' can be a float number standing for { 0=false | other=true }.
    -repeat nb_iterations (*)
        Start iterations of a 'repeat..done' block.
    -done (*)
        End a 'repeat..done' block, and go to associated '-repeat' position, if iterations remain.
    -break (*)
        Break current 'repeat..done' or 'do..while' block.
        (eq. to '-b').
    -continue (*)
        Continue to next iteration of current 'repeat..done' or 'do..while' block.
    -if boolean | (*)
                     filename
        Start a 'if..[elif]..[else]..endif' block and test if specified boolean is true,
        or if specified filename exists.
        'boolean' can be a float number standing for { 0=false | other=true }.
    -elif boolean | (*)
                     filename
        Start a 'elif..[else]..endif' block if previous '-if' was not verified
        and test if specified boolean is true, or if specified filename exists.
        'boolean' can be a float number standing for { 0=false | other=true }.
    -else (*)
        Execute following commands if previous '-if' or '-elif' conditions failed.
    -endif (*)
        End a 'if..[elif]..[else]..endif' block.
    -local (*)
        Start a 'local..endlocal' block, with selected images.
        (eq. to '-l').
    -endlocal (*)
        End a 'local..endlocal' block.
        (eq. to '-endl').
    -check expression (*)
        Evaluate specified expression and display an error message and quit, if it is evaluated.
        to false.
        If 'expression' is not evaluable, it is regarded as a filename and checked if it exists.
    -quit (*)
        Quit interpreter.
        (eq. to '-q').
    -push item (*)
        Push specified item on the local stack at selected positions.
        (eq. to '-p').
        Command subset (if any) stands for stack indices instead of image indices.
        If no subset is specified, the item is pushed at the end of the local stack.
    -push= item (*)
        Replace item on the local stack by specified item, at selected positions.
        (eq. to '-p=').
        Command subset (if any) stands for stack indices instead of image indices.
    -pop (*)
        Pop items from the local stack at selected positions.
        (eq. to '-pp').
        Command subset (if any) stands for stack indices instead of image indices.
    -error message (*)
        Print specified error message, on the standard output, and quit interpreter.
        Command subset (if any) stands for displayed scope indices instead of image indices.
    -progress 0<=value<=100 | (*)
                     -1
        Set the progress indice of the current processing pipeline.
        This command is useful only when G'MIC is used by an embedding application.
 Input/output
 ------------
    -input filename | (*)
                     [image]x_nb_copies>0 |
                     { width>0[%] | [image_w] },{ _height>0[%] | [image_h] },{ _depth>0[%] | [image_d] },
                     { _spectrum>0[%] | [image_s] },_value1,_value2,.. |
                     (value1{,|;|/|^}value2{,|;|/|^}..)
        Insert a new image taken from a filename or from a copy of an existing image ['indice'],
        or insert new image with specified dimensions and values.
        (eq. to '-i' | (no args)).
    -output filename,_format_options (*)
        Output selected images as one or several numbered file(s).
        (eq. to '-o').
    -verbose level | (*)
                     { + | - }
        Set or increment/decrement the verbosity level.
        (eq. to '-v').
        When 'level'>=0, G'MIC log messages are displayed on the standard output.
        Default value for the verbosity level is 0.
    -print (*)
        Output informations on selected images, on the standard output.
    -echo message (*)
        Output specified message, on the standard output.
        (eq. to '-e').
        Command subset (if any) stands for displayed scope indices instead of image indices.
    -warning message (*)
        Print specified warning message, on the standard output.
        Command subset (if any) stands for displayed scope indices instead of image indices.
    -command filename | (*)
        Import G'MIC custom command(s) from specified file or string.
        (eq. to '-m').
        Imported commands are available directly after the '-command' invokation.
    -type datatype (*)
        Set pixel datatype for all images of the list.
        'datatype' can be { bool | uchar | char | ushort | short | uint |
                        int | float | double }.
    -shell (*)
        Start interactive shell environment, with selected images.
    -shared x0[%],x1[%],y[%],z[%],v[%] | (*)
                     y0[%],y1[%],z[%],v[%] |
                     z0[%],z1[%],v[%] |
                     v0[%],v1[%] |
                     (no args)
        Insert shared buffers from (opt. points/lines/planes/channels of) selected images.
        (eq. to '-sh').
    -camera _camera_index>=-1,_nb_frames>0,_skip_frames>=0,release_camera={ 0 | 1 } (*)
        Insert one or several frames from specified camera, with custom delay between frames (in ms).
        Set 'camera_index' to -1 to use the default camera device.
        When 'release_camera' is set to 1, the camera stream is released and no images are inserted.
    -display
        Display selected images in an interactive viewer (use the instant window [0] if opened).
        (eq. to '-d').
    -display3d
        Display selected 3d objects in an interactive viewer (use the instant window [0] if opened).
        (eq. to '-d3d').
    -plot _plot_type,_vertex_type,_xmin,_xmax,_ymin,_ymax |
                     'formula',_resolution>=0,_plot_type,_vertex_type,_xmin,xmax,_ymin,_ymax
        Display selected image or formula in an interactive viewer (use the instant window [0] if
        opened).
        'plot_type' can be { 0=none | 1=lines | 2=splines | 3=bar }.
        'vertex_type' can be { 0=none | 1=points | 2,3=crosses | 4,5=circles | 6,7=squares }.
        'xmin','xmax','ymin','ymax' set the coordinates of the displayed xy-axes.
    -window _width[%]>=-1,_height[%]>=-1,_normalization,_fullscreen,_title
        Display selected images into an instant window with specified size, normalization type,
        fullscreen mode and title.
        (eq. to '-w').
        If 'width' or 'height' is set to -1, the corresponding dimension is adjusted to the window
        or image size.
        'width'=0 or 'height'=0 closes the instant window.
        'normalization' can be { -1=keep same | 0=none | 1=always | 2=1st-time | 3=auto }.
        'fullscreen' can be { -1=keep same | 0=no | 1=yes }.
        You can manage up to 10 different instant windows by using the numbered variants
        '-w0' (default, eq. to '-w'),'-w1',..,'-w9' of the command '-w'.
    -wait delay |
                     (no args)
        Wait for a given delay (in ms) or for an user event occuring on the selected instant window.
        'delay' can be { <0=delay+flush | 0=event | >0=delay }.
        Command subset (if any) stands for instant window indices instead of image indices.
    -select feature
        Interactively select a feature from selected images (use the instant window [0] if opened).
        'feature' can be { 0=point | 1=segment | 2=rectangle | 3=ellipse }.
        The retrieved feature is returned as a vector containing the feature coordinates.
 Shortcuts for native commands
 -----------------------------
    -h eq. to '-help'. (*)
    -+ eq. to '-add'.
    -- eq. to '-sub'.
    -* eq. to '-mul'.
    -** eq. to '-mmul'.
    -/ eq. to '-div'.
    -^ eq. to '-pow'.
    -<< eq. to '-bsl'.
    ->> eq. to '-bsr'.
    -== eq. to '-eq'.
    -!= eq. to '-neq'.
    -> eq. to '-gt'.
    ->= eq. to '-ge'.
    -< eq. to '-lt'.
    -<= eq. to '-le'.
    -= eq. to '-set'.
    -f eq. to '-fill'.
    -t eq. to '-threshold'.
    -c eq. to '-cut'.
    -n eq. to '-normalize'.
    -r eq. to '-resize'.
    -s eq. to '-split'.
    -a eq. to '-append'.
    -rm eq. to '-remove'. (*)
    -k eq. to '-keep'. (*)
    -mv eq. to '-move'. (*)
    -rv eq. to '-reverse'. (*)
    -nm eq. to '-name'. (*)
    -+3d eq. to '-add3d'.
    --3d eq. to '-sub3d'.
    -*3d eq. to '-mul3d'.
    -/3d eq. to '-div3d'.
    -c3d eq. to '-center3d'.
    -n3d eq. to '-normalize3d'.
    -rot3d eq. to '-rotate3d'.
    -col3d eq. to '-color3d'.
    -o3d eq. to '-opacity3d'.
    -rv3d eq. to '-reverse3d'.
    -p3d eq. to '-primitives3d'.
    -s3d eq. to '-split3d'.
    -l3d eq. to '-light3d'.
    -f3d eq. to '-focale3d'.
    -sl3d eq. to '-specl3d'.
    -ss3d eq. to '-specs3d'.
    -db3d eq. to '-double3d'.
    -m3d eq. to '-mode3d'.
    -md3d eq. to '-moded3d'.
    -b3d eq. to '-background3d'.
    -x eq. to '-exec'. (*)
    -u eq. to '-status'. (*)
    -b eq. to '-break'. (*)
    -l eq. to '-local'. (*)
    -endl eq. to '-endlocal'. (*)
    -q eq. to '-quit'. (*)
    -p eq. to '-push'. (*)
    -p= eq. to '-push='. (*)
    -pp eq. to '-pop'. (*)
    -e eq. to '-echo'. (*)
    -i eq. to '-input'. (*)
    -o eq. to '-output'. (*)
    -sh eq. to '-shared'. (*)
    -v eq. to '-verbose'. (*)
    -m eq. to '-command'. (*)
    -d eq. to '-display'.
    -d3d eq. to '-display3d'.
    -w eq. to '-window'.
 Default custom commands
 -----------------------
 ** Basic pixel manipulation :
    -replace_nan _expression
        Replace all NaN values in selected images by specified expression.
    -replace_inf _expression
        Replace all infinite values in selected images by specified expression.
    -roundify _gamma>=0
        Apply roundify transformation on float-valued data, with specified gamma.
    -complex2polar
        Compute complex to polar transforms of selected images.
    -polar2complex
        Compute polar to complex transforms of selected images.
    -plot2value
        Retrieve values from selected 2d graph plots.
    -transfer_histogram
        Transfer histogram of the last selected image to the other ones.
    -normalize_sum
        Normalize selected images with a unitary sum.
    -apply_gamma gamma
        Apply gamma correction to selected images.
    -apply_curve 0<=smoothness<=1,x0,y0,x1,y1,x2,y2,...,xN,yN
        Apply curve transformation to image values.
    -negative
        Compute negative of selected images.
    -tones N>0
        Get N tones masks from selected images.
    -t2 eq. to '-threshold2'.
    -threshold2 _min,_max
        Threshold selected images between the two given values.
        (eq. to '-t2').
    -chessboard size1>0,_size2>0,_offset1,_offset2,_angle,_opacity,_color1,..,_color2,..
        Draw opaque chessboard on selected images.
 ** Geometric manipulation :
    -split_tiles M!=0,_N!=0,_is_homogeneous={ 0 | 1 }
        Split selected images as a MxN array of tiles.
    -append_tiles M>0,_N>0
        Append MxN selected tiles as a new image.
    -rr2d eq. to '-resize_ratio2d'.
    -resize_ratio2d width>0,height>0,_mode={ 0=inside | 1=outside | 2=padded },0=<_interpolation_type<=6
        Resize selected images while preserving their aspect ratio.
    -r2dx eq. to '-resize2dx'.
    -resize2dx width>0,_interpolation_type={0,1,2,3,4,5}
        Resize selected images along the X-axis, preserving 2d ratio.
        (eq. to '-r2dx').
    -r3dx eq. to '-resize3dx'.
    -resize3dx width>0,_interpolation_type={0,1,2,3,4,5}
        Resize selected images along the X-axis, preserving 3d ratio.
        (eq. to '-r3dx').
    -r2dy eq. to '-resize2dy'.
    -resize2dy height>0,_interpolation_type={0,1,2,3,4,5}
        Resize selected images along the Y-axis, preserving 2d ratio.
        (eq. to '-r2dy').
    -r3dy eq. to '-resize3dy'.
    -resize3dy height>0,_interpolation_type={0,1,2,3,4,5}
        Resize selected images along the Y-axis, preserving 3d ratio.
        (eq. to '-r3dy').
    -r3dz eq. to '-resize3dz'.
    -resize3dz depth>0,_interpolation_type={0,1,2,3,4,5}
        Resize selected images along the Z-axis, preserving 3d ratio.
        (eq. to '-r3dz').
    -upscale_smart width,height,_depth,smoothness>=0,_anisotropy=[0,1],sharpening>=0
        Upscale selected images with an edge-preserving algorithm.
    -expand_x size_x>=0,_borders={ 0=dirichlet | 1=neumann | 2=cyclic }
        Expand selected images along the X-axis.
    -expand_y size_y>=0,_borders={ 0=dirichlet | 1=neumann | 2=cyclic }
        Expand selected images along the Y-axis.
    -expand_z size_z>=0,_borders={ 0=dirichlet | 1=neumann | 2=cyclic }
        Expand selected images along the Z-axis.
    -expand_xy size>=0,_borders={ 0=dirichlet | 1=neumann | 2=cyclic }
        Expand selected images along the XY-axes.
    -expand_xyz size>=0,_borders={ 0=dirichlet | 1=neumann | 2=cyclic }
        Expand selected images along the XYZ-axes.
    -shrink_x size_x>=0
        Shrink selected images along the X-axis.
    -shrink_y size_y>=0
        Shrink selected images along the Y-axis.
    -shrink_z size_z>=0
        Shrink selected images along the Z-axis.
    -shrink_xy size>=0
        Shrink selected images along the XY-axes.
    -elevate _depth,_is_plain,_is_colored
        Elevate selected 2d images into 3d volumes.
 ** Input-Output :
    -ow eq. to '-outputw'.
    -outputw
        Output selected images by overwritting their original location.
        (eq. to '-ow').
    -op eq. to '-outputp'.
    -outputp prefix
        Output selected images as prefixed versions of their original filenames.
        (eq. to '-op').
    -on eq. to '-outputn'.
    -outputn filename
        Output selected images as automatically numbered filenames in repeat..done loops.
        (eq. to '-on').
    -d0 eq. to '-display0'.
    -display0
        Display selected images without value normalization.
        (eq. to '-d0').
    -dfft eq. to '-display_fft'.
    -display_fft
        Display fourier transform of selected images, with centered log-module and argument.
        (eq. to '-dfft').
    -drgba eq. to '-display_rgba'.
    -display_rgba
        Render selected RGBA images over a checkerboard background.
        (eq. to '-drgba').
    -dh eq. to '-display_histogram'.
    -display_histogram _width>0,_height>0,_clusters>0,_max_value>0,_show_axes={ 0 | 1 }
        Render a channel-by-channel histogram.
        (eq. to '-dh').
    -dt eq. to '-display_tensors'.
    -display_tensors _size_factor>0,_ellipse_factor>=0,_opacity,_pattern,_color1,..
        Render field of 2x2 tensors with ellipses.
        (eq. to '-dt').
    -float2int8
        Convert selected float-valued images to 8bits integer representations.
    -int82float
        Convert selected 8bits integer representations to float-valued images.
    -float2fft8
        Convert selected float-valued images to 8bits fourier representations.
    -fft82float
        Convert selected 8bits fourier representations to float-valued images.
    -apply_camera _command,_camera_index>=-1,_skip_frames>=0
        Apply specified command on live camera stream, and display it on display window [0].
 ** Image creation and drawing :
    -ball _R,_G,_B
        Draw a colored RGBA ball sprite on selected images.
    -sierpinski recursion_level>=0
        Draw Sierpinski triangle on selected images.
    -text_outline text,_x[%],_y[%],_font_height>0,_outline>=0,_opacity,_color1,..
        Draw specified colored and outlined text string on selected images.
    -histogram_cumul _nb_levels>0,_is_normalized={ 0 | 1 }
        Compute cumulative histogram of selected images.
    -direction2rgb
        Compute RGB representation of selected 2d direction fields.
    -vector2tensor
        Convert selected vector fields to corresponding diffusion tensor fields.
    -rgb2bayer _start_pattern=0,_color=0
        Transform selected color images to RGB-Bayer sampled images.
    -bayer2rgb _GM_smoothness,_RB_smoothness1,_RB_smoothness2
        Transform selected RGB-Bayer sampled images to color images.
    -lic _amplitude>0,_channels>0
        Generate LIC representation of vector field.
    -gaussian _sigma1[%],_sigma2[%],_angle
        Draw a centered gaussian on selected images, with specified standard deviations and orientation.
    -function1d 0<=smoothness<=1,x0,y0,x1,y1,...,xn,yn
        Generate continuous 1d function from specified list of keypoints (xk,yk)
        in range [0,max(xk)] (xk are integers).
    -pointcloud
        Convert a Nx1, Nx2 or Nx3 image as a point cloud in a 1d/2d or 3d binary image.
 ** Image filtering :
    -blur_x amplitude[%]>=0,_borders={ 0 | 1 }
        Blur selected images along the X-axis.
    -blur_y amplitude[%]>=0,_borders={ 0 | 1 }
        Blur selected images along the Y-axis.
    -blur_z amplitude[%]>=0,_borders={ 0 | 1 }
        Blur selected images along the Z-axis.
    -blur_xy amplitude_x[%],amplitude_y[%],_borders={ 0 | 1 }
        Blur selected images along the X and Y axes.
    -blur_xyz amplitude_x[%],amplitude_y[%],amplitude_z,_borders={ 0 | 1 }
        Blur selected images along the X, Y and Z axes.
    -blur_angular _amplitude[%],_cx,_cy
        Apply angular blur on selected images.
    -blur_radial _amplitude[%],_cx,_cy
        Apply radial blur on selected images.
    -blur_linear _amplitude1[%],_amplitude2[%],_angle=0,_borders={ 0=dirichlet | 1=neumann }
        Apply linear blur on selected images, with specified angle and amplitudes.
    -dog _sigma1>=0[%],_sigma2>=0[%]
        Compute difference of gaussian on selected images.
    -pde_flow _nb_iter>=0,_dt,_velocity_command,_sequence_flag={ 0 | 1 }
        Apply iterations of a generic PDE flow on selected images.
    -heat_flow _nb_iter>=0,_dt,_sequence_flag={ 0 | 1 }
        Apply iterations of the heat flow on selected images.
    -meancurvature_flow _nb_iter>=0,_dt,_sequence_flag={ 0 | 1 }
        Apply iterations of the mean curvature flow on selected images.
    -tv_flow _nb_iter>=0,_dt,_sequence_flag={ 0 | 1 }
        Apply iterations of the total variation flow on selected images.
    -inpaint_flow _nb_iter1>=0,_nb_iter2>=0,_dt>=0,_alpha,_sigma
        Apply iteration of the inpainting flow on selected images.
    -remove_hotpixels _mask_size>0, _threshold[%]>0
        Remove hot pixels in selected images.
    -richardson_lucy amplitude[%]>=0,_nb_iter>=0,_dt>=0,_regul>=0,_regul_type={ 0=Tikhonov | 1=meancurv. | 2=TV }
        Deconvolve image with the iterative Richardson-Lucy algorithm.
    -oriented_richardson_lucy amplitude1[%]>=0,_amplitude2[%]>=0,_angle,_nb_iter>=0,_dt>=0,_regul>=0,_regul_type={ 0=Tikhonov | 1=meancurv. | 2=TV }
        Deconvolve image with the iterative Richardson-Lucy algorithm for oriented kernels.
    -unsharp _radius[%]>=0,_amount>=0,_threshold[%]>=0
        Apply unsharp mask on selected images.
    -unsharp_octave _nb_scales>0,_radius[%]>=0,_amount>=0,threshold[%]>=0
        Apply octave sharpening on selected images.
    -normalize_local _amplitude>=0,_radius>0,_n_smooth>=0[%],_a_smooth>=0[%],_cut={ 0 | 1 },_min=0,_max=255
        Normalize selected images locally.
    -map_tones _threshold>=0,_gamma>=0,_smoothness>=0,iter>=0
        Apply tone mapping operator based on Poisson equation.
    -fftpolar
        Compute fourier transform of selected images, as centered magnitude/phase images.
    -ifftpolar
        Compute inverse fourier transform of selected images, from centered magnitude/phase images.
    -convolve_fft
        Convolve selected images two-by-two through fourier transforms.
    -deconvolve_fft
        Deconvolve selected images two-by-two through fourier transforms.
    -bandpass _min_freq[%],_max_freq[%]
        Apply bandpass filter to selected images.
    -watermark _text
        Add an textual watermark in the frequency domain of selected images.
    -split_freq smoothness>0[%]
        Split selected images into low and high frequency parts.
    -compose_freq
        Compose selected low and high frequency parts into new images.
    -erode_oct _size>=0
        Apply octagonal erosion of selected images by specified size.
    -dilate_oct _size>=0
        Apply octagonal dilation of selected image by specified size.
    -erode_circ _size>=0
        Apply circular erosion of selected images by specified size.
    -dilate_circ _size>=0
        Apply circular dilation of selected image by specified size.
 ** Contours and variations :
    -gradient_norm
        Compute gradient norm of selected images.
    -gradient_orientation _dimension={1,2,3}
        Compute N-D gradient orientation of selected images.
    -gradient2rgb _orientation={ 0 | 1 }
        Compute RGB representation of 2d gradient of selected images.
    -laplacian
        Compute Laplacian of selected images.
    -divergence
        Compute divergence of selected vector fields.
    -inn
        Compute gradient-directed 2nd derivative of image(s).
    -iee
        Compute gradient-orthogonal-directed 2nd derivative of image(s).
    -curvature
        Compute isophote curvatures on selected images.
    -edges _threshold>=0
        Estimate contours of selected images.
    -isophotes _nb_levels>0
        Render isophotes of selected images on a transparent background.
    -topographic_map _nb_levels>0,_smoothness
        Render selected images as topographic maps.
    -segment_watershed _threshold>=0,_edge_threshold>0,_keep_watershed={ 0 | 1 }
        Apply watershed segmentation on selected images.
 ** Arrays and frames :
    -array _M>0,_N>0,_expand_type={0,1,2}
        Create MxN array from selected images.
    -array_fade _M>0,_N>0,0<=_fade_start<=100,0<=_fade_end<=100,_expand_type={0,1,2}
        Create MxN array from selected images.
    -array_mirror _N>=0,_dir={0,1,2},_expand_type={ 0 | 1 }
        Create 2^Nx2^N array from selected images.
    -array_random _Ms>0,_Ns>0,_Md>0,_Nd>0
        Create MdxNd array of tiles from selected MsxNs source arrays.
    -array_pattern _M>0,_N>0,_density>=0,_angle>=0,_zoom>=0,_opacity,_expand_type={0,1,2}
        Create random MxN array from selected images.
    -taquin _M>0,_N>0
        Create MxN taquin puzzle from selected images.
    -imagegrid _M>0,_N>0
        Create MxN image grid from selected images.
    -frame _size_x[%]>=0,_size_y[%]>=0,_col1,...,_colN
        Insert RGBA-colored frame in selected images.
    -frame_fuzzy _size_x>=0,_size_y>=0,_fuzzyness>=0,_smoothness>=0,_R,_G,_B,_A
        Draw RGBA-colored fuzzy frame in selected images.
    -frame_round _sharpness>0,_size>=0,_smoothness,_shade,_R,_G,_B,_A
        Draw RGBA-colored round frame in selected images.
    -frame_blur _sharpness>0,_size>=0,_smoothness,_shade,_blur
        Draw RGBA-colored round frame in selected images.
    -frame_pattern _M>=3,_pattern = { 0=first image | 1=self },_constrain_size = { 0 | 1 }
        Insert selected pattern frame in selected images.
    -rotate_tiles _angle,_M>0,N>0
        Apply MxN tiled-rotation effect on selected images.
    -shift_tiles _M>0,_N>0,_amplitude
        Apply MxN tiled-shift effect on selected images.
    -linearize_tiles _M>0,_N>0
        Linearize MxN tiles on selected images.
    -quadratize_tiles _M>0,_N>0
        Quadratize MxN tiles on selected images.
    -tunnel _level>=0,_factor>0,_cx,_cy,_opacity.
        Apply tunnel effect on selected images.
 ** Artistic effects :
    -polaroid _size1>=0,_size2>=0
        Create polaroid effect in selected images.
    -drop_shadow _offset_x[%],_offset_y[%],_smoothness[%]
        Drop shadow behind selected images.
    -tetris _scale>0
        Apply tetris effect on selected images.
    -mosaic _density>=0,_edges={ 0 | 1 }
        Create random mosaic from selected images.
    -puzzle _scale>=0
        Apply puzzle effect on selected images.
    -sponge _size>0
        Apply sponge effect on selected images.
    -hearts _density>=0
        Apply heart effect on selected images.
    -color_ellipses _count>0,_radius>=0,_opacity>=0
        Add random color ellipses to selected images.
    -ellipsionism _R>0[%],_r>0[%],_smoothness>=0[%],_opacity,_outline>0,_density>0
        Apply ellipsionism filter to selected images.
    -whirls _texture>=0,_smoothness>=0,_darkness>=0,_lightness>=0
        Add random whirl texture to selected images.
    -cartoon _smoothness,_sharpening,_threshold>=0,_thickness>=0,_color>=0,quantization>0
        Apply cartoon effect on selected images.
    -drawing _amplitude>=0
        Apply drawing effect on selected images.
    -draw_whirl _amplitude>=0
        Apply whirl drawing effect on selected images.
    -stencil _radius[%]>=0,_smoothness>=0,_iterations>=0
        Apply stencil filter on selected images.
    -stencilbw _edges>=0,_smoothness>=0
        Apply B&W stencil effect on selected images.
    -pencilbw _size>=0,_amplitude>=0
        Apply B&W pencil effect on selected images.
    -sketchbw
        _nb_orients>0,_start_angle,_angle_range>=0,_length>=0,_threshold>=0,
        _opacity,_bgfactor>=0,_density>0,_sharpness>=0,
        _anisotropy>=0,_smoothness>=0,_coherence>=0,_is_boost={ 0 | 1 },_is_curved={ 0 | 1 }
        Apply sketch effect to selected images.
    -ditheredbw
        Create dithered B&W version of selected images.
    -dotsbw _nb_scales>=0,_resolution>0,_radius>=0
        Apply B&W dots effect on selected images.
    -warhol _M>0,_N>0,_smoothness>=0,_color>=0
        Create MxN Andy Warhol-like artwork from selected images.
    -cubism _nb_iter>=0,_bloc_size>0,_max_angle,_opacity,_smoothness>=0
        Apply cubism effect on selected images.
    -glow _amplitude>=0
        Add soft glow on selected images.
    -old_photo
        Apply old photo effect on selected images.
 ** Spatial warping :
    -euclidean2polar _cx,_cx,_n>0,_borders={ 0=dirichlet | 1=neumann | 2=cyclic }
        Apply euclidean to polar transform on selected images.
    -polar2euclidean _cx,_cy,_n>0,_borders={ 0=dirichlet | 1=neumann | 2=cyclic }
        Apply polar to euclidean transform on selected images.
    -warp_perspective _x-angle,_y-angle,_zoom>0,_x-center,_y-center,_borders={ 0=dirichlet | 1=neumann | 2=cyclic }
        Warp selected images with perspective deformation.
    -water _amplitude>=0,_smoothness>=0
        Apply water deformation on selected images.
    -wave _amplitude>=0,_frequency>=0,_center_x,_center_y
        Apply wave deformation on selected images.
    -twirl _amplitude,_cx,_cy,_borders={ 0=dirichlet | 1=neumann | 2=cyclic }
        Apply twirl deformation on selected images.
    -map_sphere _width>0,_height>0,_radius,_dilation>0
        Map selected images on a sphere.
    -flower _amplitude,_frequency,_offset_r[%],_angle,_cx,_cy,_borders={ 0=dirichlet | 1=neumann | 2=cyclic }
        Apply flower deformation on selected images.
    -zoom _factor,_cx,_cy,_cz,_borders={ 0=dirichlet | 1=neumann | 2=cyclic }
        Apply zoom factor to selected images.
    -deform _amplitude>=0
        Apply random smooth deformation on selected images.
    -fish_eye _x,_y,0<=_radius<=100,_amplitude>=0
        Apply fish-eye deformation on selected images.
    -transform_polar
        Apply user-defined transform on polar representation of selected images.
    -kaleidoscope _cx,_cy,_radius,_angle,_borders={ 0=dirichlet | 1=neumann | 2=cyclic }
        Create kaleidoscope effect from selected images.
    -rotoidoscope _cx,_cy,_tiles>0,_smoothness[%]>=0,_borders={ 0=dirichlet | 1=neumann | 2=cyclic}
        Create rotational kaleidoscope effect from selected images.
 ** Image degradation :
    -spread _dx>=0,_dy>=0,_dz>=0
        Spread pixel values of selected images randomly along x,y and z.
    -shade_stripes _frequency>=0,_direction={ 0 | 1 },_darkness>=0,_lightness>=0
        Add shade stripes to selected images.
    -stripes_y _frequency>=0
        Add vertical stripes to selected images.
    -shadow_patch _opacity>=0
        Add shadow patches to selected images.
    -light_patch _density>0,_darkness>=0,_lightness>=0
        Add light patches to selected images.
    -light_relief _ambient_light,_specular_light,_specular_size,_darkness,_xl,_yl,_zl,_zscale,_opacity_bumpmap={ 0 | 1 }
        Apply relief light to selected images.
    -noise_hurl _amplitude>=0
        Add hurl noise to selected images.
    -pixelize _scale_x>0,_scale_y>0,_scale_z>0
        Pixelize selected images with specified scales.
    -paper
        Add paper texture to selected images.
    -cracks _density>=0,_amplitude,_relief={ 0 | 1 }
        Add random cracks to selected images.
 ** Color-related filters :
    -apply_channels
        Apply specified command on chosen normalized channels of each selected images.
    -to_gray
        Force selected images to be in GRAY mode.
    -to_graya
        Force selected images to be in GRAYA mode.
    -to_rgb
        Force selected images to be in RGB mode.
    -to_rgba
        Force selected images to be in RGBA mode.
    -to_colormode mode={ 0=adaptive | 1=G | 2=GA | 3=RGB | 4=RGBA }
        Force selected images to be in a given color mode.
    -remove_opacity
        Remove opacity channel of selected images.
    -select_color _tolerance[%]>=0,col1,..,colN
        Select pixels with specified color in selected images.
    -replace_color _tolerance[%]>=0,_smoothness[%]>=0,src1,...,srcN,dest1,...,destN
        Replace pixels from/to specified colors in selected images.
    -fc eq. to '-fill_color'.
    -fill_color col1,...,colN
        Fill selected images with specified color.
        (eq. to '-fc').
    -luminance
        Compute luminance of selected images.
    -mix_rgb a11,a12,a13,a21,a22,a23,a31,a32,a33
        Apply 3x3 specified matrix to RGB colors of selected images.
    -mix_channels (a00,...,aMN)
        Apply specified matrix to channels of selected images.
    -solarize
        Solarize selected images.
    -sepia
        Apply sepia tones effect on selected images.
    -split_opacity
        Split color and opacity parts of selected images.
    -red_eye 0<=_threshold<=100,_smoothness>=0,0<=attenuation<=1
        Attenuate red-eye effect in selected images.
    -rgb2lch
        Convert selected images from RGB to Lch color bases.
    -lch2rgb
        Convert selected images from Lch to RGB color bases.
    -lab2lch
        Convert selected images from Lab to Lch color bases.
    -lch2lab
        Convert selected images from Lch to Lab color bases.
 ** Image fading and composition :
    -fade_x 0<=_start<=100,0<=_end<=100
        Create horizontal fading from selected images.
    -fade_y 0<=_start<=100,0<=_end<=100
        Create vertical fading from selected images.
    -fade_z 0<=_start<=100,0<=_end<=100
        Create transversal fading from selected images.
    -fade_radial 0<=_start<=100,0<=_end<=100
        Create radial fading from selected images.
    -fade_diamond 0<=_start<=100,0<=_end<=100
        Create diamond fading from selected images.
    -fade_linear _angle,0<=_start<=100,0<=_end<=100
        Create linear fading from selected images.
    -compose_rgba
        Compose selected RGBA images two-by-two, over RGB background.
    -compose_channels
        Compose all channels of each selected image, using specified arithmetic operator (+,-,or,min,...).
    -compose_average
        Compose selected images two-by-two, using average mode.
    -compose_multiply
        Compose selected images two-by-two, using multiply mode.
    -compose_screen
        Compose selected images two-by-two, using screen mode.
    -compose_darken
        Compose selected images two-by-two, using darken mode.
    -compose_lighten
        Compose selected images two-by-two, using lighten mode.
    -compose_difference
        Compose selected images two-by-two, using difference mode.
    -compose_negation
        Compose selected images two-by-two, using negation mode.
    -compose_exclusion
        Compose selected images two-by-two, using exclusion mode.
    -compose_overlay
        Compose selected images two-by-two, using overlay mode.
    -compose_hardlight
        Compose selected images two-by-two, using hard light mode.
    -compose_softlight
        Compose selected images two-by-two, using soft light mode.
    -compose_dodge
        Compose selected images two-by-two, using dodge mode.
    -compose_colorburn
        Compose selected images two-by-two, using color burn mode.
    -compose_reflect
        Compose selected images two-by-two, using reflect mode.
    -compose_freeze
        Compose selected images two-by-two, using freeze mode.
    -compose_stamp
        Compose selected images two-by-two, using stamp mode.
    -compose_interpolation
        Compose selected images two-by-two, using interpolation mode.
    -compose_xor
        Compose selected images two-by-two, using xor mode.
    -compose_edges _smoothness[%]>=0
        Compose selected images togethers using edge composition.
    -compose_fade
        Compose selected images togethers using a given fading (defined as the latest image).
    -compose_shapeaverage
        Compose selected images two-by-two, using shape average mode.
 ** Motion-related and video processing :
    -cross_correlation
        Compute cross-correlation using two-by-two selected images.
    -normalized_cross_correlation
        Compute normalized cross-correlation using two-by-two selected images.
    -phase_correlation
        Estimate translation vector using two-by-two selected images.
    -morph nb_frames>0,_smoothness>=0,_precision>0
        Create morphing sequence between selected images.
    -register_nonrigid _smoothness>=0,_precision>0,_nb_scale>=0
        Register selected images with non-rigid warp.
    -register_rigid _smoothness>=0
        Register selected images with rigid warp.
    -deinterlace _method={ 0 | 1 }
        Deinterlace selected images ('method' can be { 0=standard or 1=motion-compensated }).
    -animate
        filter_name,(params_start;..;..),(params_end;..;..),nb_frames>=0,_output_frames={ 0 | 1 },_filename |
        delay>0
        Animate filter from starting parameters to ending parameters.
 ** 3d-related filters :
    -empty3d
        Create new empty 3d object.
    -apply_pose3d p1,..,p12
        Apply 3d pose matrix to selected 3d objects.
    -animate3d _width>0,_height>0,_dx,_dy,_dz,_zoom>=0,_filename
        Animate selected 3d objects in a window.
    -balls3d _size>0,_R,_G,_B,_opacity
        Convert selected 3d objects into 3d ball sets.
    -imageplane3d
        Generate 3d mapped planes from selected images.
    -imagesphere3d
        Generate 3d mapped sphere from selected images.
    -imagecube3d
        Generate 3d mapped cubes from selected images.
    -image6cube3d
        Generate 3d mapped cubes from selected sets of 6 selected images.
    -imagepyramid3d
        Generate 3d mapped pyramides from selected images.
    -pyramid3d _width,_height
        Generate 3d pyramid at (0,0,0), with specified geometry.
    -gyroid3d _resolution>0,_zoom
        Generate 3d gyroid at (0,0,0), with specified resolution.
    -weird3d _resolution>0
        Generate 3d weird object at (0,0,0), with specified resolution.
    -text3d text,_font_height>0,_depth>0,_smoothness
        Generate a 3d text object from specified text.
    -gmic3d
        Generate a 3d G'MIC logo.
    -sierpinski3d _recursion_level>=0,_width,_height
        Generate new 3d Sierpinski pyramid.
    -parametric3d _x(a,b),_y(a,b),_z(a,b),_amin,_amax,_bmin,_bmax,_res_a>0,_res_b>0,_res_x>0,_res_y>0,_res_z>0,_smoothness>=0,_isovalue>=0
        Generate new 3d object from specified parametric surface (x(a,b),y(a,b),z(a,b)).
    -snapshot3d _size>0,_zoom>=0,_backgroundR,_backgroundG,_backgroundB
        Create 2d snapshots of selected 3d objects.
        Set 'zoom' to 0 to disable object auto-scaling.
    -texturize3d
        Map selected image texture [0] to all selected 3d objects [1--1].
    -label_points3d _label_size>0,_opacity
        Add a numbered label to all vertices of selected 3d objects.
 ** Interactive demos :
    -x_mandelbrot _julia={ 0 | 1 },_c0r,_c0i
        Launch Mandelbrot/Julia explorer.
    -x_fish_eye
        Launch fish-eye demo.
    -x_spline
        Launch spline curve editor.
    -x_tictactoe
        Launch tic-tac-toe game.
    -x_fourier
        Launch fourier filtering demo.
    -x_life
        Launch the game of life.
    -x_fire
        Launch the fire demo.
    -x_light
        Launch the light demo.
    -x_jawbreaker 0<_width<20,0<_height<20,0<_balls<=8
        Launch the Jawbreaker game.
    -x_paint
        Launch the interactive painter.
 Examples of use
 ---------------
 'gmic' is a generic image processing tool which can be used in a wide variety of situations.
 Here are few examples of possible uses :
  - View a list of images :
     gmic file1.bmp file2.jpeg
  - Convert an image file :
     gmic input.bmp -o output.jpg
  - Create a volumetric image from a movie sequence :
     gmic input.mpg -a z -o output.hdr
  - Compute image gradient norm :
     gmic input.bmp -gradient_norm
  - Denoise a color image :
     gmic image.jpg -denoise 30,10 -o denoised.jpg
  - Compose two images using overlay fading :
     gmic image1.jpg image2.jpg -compose_overlay -o composed.jpg
  - Evaluate a mathematical expression :
     gmic -e
  - Plot a 2d function :
     gmic 1000,1,1,2 -f
  - Plot a 3d elevated function in random colors:
     gmic 128,128,1,3,
  - Plot the isosurface of a 3d volume :
     gmic -m3d 5 -md3d 5 -db3d 0 -isosurface3d
  - Create a G'MIC 3d logo :
     gmic 180,70,1,3 -text G\'MIC,30,5,57,1,1 -blur 2 -n 0,100 --plasma 0.4 -+ -blur 1 -elevation3d -0.1 -md3d 4
  - Create a 3d ring of torii :
     gmic -repeat 20 -torus3d 15,2 -col3d[-1]
  - Create a vase from a 3d isosurface :
     gmic -md3d 4 -isosurface3d
  - Launch a set of G'MIC interactive demos :
     gmic -x_fish_eye -x_fire G\'MIC -x_tictactoe -rm -x_spline -x_mandelbrot 0 -x_life
 ** G'MIC comes with ABSOLUTELY NO WARRANTY; for details visit http://gmic.sourceforge.net **