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# GraphicsMagick Tools

# Animate: animate a sequence of images

Animate displays a sequence of images or an animation on any display running an X server.

# Compare: compare two images using statistics and/or visual differencing

Compare compares two images using either a specified standard statistical metric (MAE, MSE, PAE, PSNR, RMSE), or a specified visual differencing method (assign, threshold, tint, xor). The statistical comparison produces a textual display of metric values while the visual differencing method writes a difference image with the differences annotated using the specified algorithm. For example:

    % gm convert input.jpg -blur 0x1.5 output.jpg
    % gm compare -metric MSE input.jpg output.jpg
    Image Difference (MeanSquaredError):
               Normalized    Absolute
              ============  ==========
         Red: 0.0014374614       94.2
       Green: 0.0014396270       94.3
        Blue: 0.0014464548       94.8
       Total: 0.0014411811       94.4

# Composite: composite images together

Composite blends and merges images to create new images.

# Conjure: execute a Magick Scripting Language (MSL) XML script

Conjure interprets and executes scripts in the Magick Scripting Language (MSL). The interpreter is called conjure and here is an example script:

    <?xml version="1.0" encoding="UTF-8"?>
    <image size="400x400" >
      <read filename="image.gif" />
      <get width="base-width" height="base-height" />
      <resize geometry="%[dimensions]" />
      <get width="width" height="height" />
      <print output=
        "Image sized from %[base-width]x%[base-height]
         to %[width]x%[height].\n" />
      <write filename="image.png" />
    </image>

which is invoked like

    conjure -dimensions 400x400 incantation.msl

All operations closely follow the key/value pairs defined in the PerlMagick documentation, unless otherwise noted.

# Convert: convert an image or sequence of images

Convert converts an input file using one image format to an output file with using any of the supported writeable image formats. A large number of image processing operations may be performed on the image before it is written. By default, the input image format is determined by its magic number. To specify a particular image format, precede the filename with an image format name and a colon (i.e. ps:image) or specify the image type as the filename suffix (i.e. image.ps). Specify file as - for standard input or output. If file has the extension .Z, the file is decoded with uncompress. For example:

    % gm convert input.jpg -rotate 90 rotated.tiff

# Display: display an image on a workstation running X

Display is a machine architecture independent image processing and display program. It can display an image on any workstation display running an X server. The image can be displayed as background image of any window.

# Identify: describe an image or image sequence

Identify describes the format and characteristics of one or more image files. It will also report if an image is incomplete or corrupt. The information displayed includes the scene number, the file name, the width and height of the image, whether the image is colormapped or not, the number of colors in the image, the number of bytes in the image, the format of the image (JPEG, PNM, etc.), and finally the number of seconds it took to read and process the image. For example:

    % gm identify tiger-1200-rgb16.tiff
    tiger-1200-rgb16.tiff TIFF 9083x9450+0+0 DirectClass 16-bit 491.2M 0.000u 0:01

# Import: capture an application or X server screen

Import reads an image from any visible window on an X server and outputs it as an image file. You can capture a single window, the entire screen, or any rectangular portion of the screen.

The target window can be specified by id, name, or may be selected by clicking the mouse in the desired window. If you press a button and then drag, a rectangle will form which expands and contracts as the mouse moves. To save the portion of the screen defined by the rectangle, just release the button. The keyboard bell is rung once at the beginning of the screen capture and twice when it completes. For example:

    % gm import capture.tiff

# Mogrify: transform an image or sequence of images

Mogrify transforms an image or a sequence of images "in place". These transforms include image scaling, image rotation, color reduction, and others. The transmogrified image overwrites the original image. Mogrify is very similar to Convert except that it can operate on many images at once, and overwrites the input files by default. However, Mogrify may also be used to convert file formats, and send modified files to another directory. For example, the following reads several JPEG files and writes a rotated version of them in TIFF format:

    % gm mogrify -rotate 90 -format tiff image1.jpg image2.jpg image3.jpg

# Montage: create a composite image (in a grid) from separate images

Montage creates a composite by combining several separate images. The images are tiled on a composite image with the name of the image and its properties optionally appearing just below the individual tile.

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