A very quick introductory course on ImageMagick. Part of our standard training courses for offshore software developers at Zeropoint.IT

1. Introduction
The absolute basics
Let’s get a little more advanced
Introduction to ImageMagick
Bart Van Loon
2nd February 2012
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2. Introduction
The absolute basics
Let’s get a little more advanced
1 Introduction
2 The absolute basics
3 Let’s get a little more advanced
2 / 13 Bart Van Loon Introduction to ImageMagick

3. Introduction
The absolute basics
Let’s get a little more advanced
Introduction
ImageMagick®
ImageMagick is an Open Source software suite to create, edit,
compose, or convert bitmap images.
ImageMagick: mind the spelling, and camel-case
Open Source: Apache 2.0 license (GPLv3 compatible)
software suite: more than ten binaries
create, edit, compsose or convert: extremely versatile tools
bitmap images: over 100 formats supported, but all bitmaps
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4. Introduction
The absolute basics
Let’s get a little more advanced
Did I mention extremely versatile?
features : translate, flip, mirror, rotate, scale, shear and
transform images, adjust image colors, apply various
special effects, or draw text, lines, polygons, ellipses
and Bezier curves, . . .
bindings : MagickCore (C), MagickWand (C), ChMagick
(Ch), Magick++ (C++), JMagick (Java), L-Magick
(Lisp), PascalMagick (Pascal), PerlMagick (Perl),
MagickWand for PHP (PHP), PythonMagick
(Python), RMagick (Ruby), TclMagick (Tcl/TK),
...
platforms : runs on all major operating systems
We will focus on simple command line usage.
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5. Introduction
The absolute basics
Let’s get a little more advanced
Overview of some of the binaries
animate : animates an image or image sequence
compare : annotates the difference between images
composite : overlaps one image over another
conjure : executes scripts in the Magick Scripting Language
convert : converts between image formats and much more
display : displays an image or image sequence
identify : describes the characteristics of image files
import : saves any visible area and outputs it as an image file
mogrify : is like convert but works on the original image file
montage : creates an image by combining several images
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6. Introduction
The absolute basics
Let’s get a little more advanced
Conversion of file formats
Binary to use is convert. Example:
$ convert image.png image.jpg
It guesses the required format from the target filename extension.
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7. Introduction
The absolute basics
Let’s get a little more advanced
Identifying images
Binary to use is identify. Examples:
$ identify pic.jpg
pic.jpg JPEG 170x100 170x100+0+0 8-bit DirectClass
7.75KB 0.000u 0:00.000
$ identify pic.png
pic.png PNG 960x191 960x191+0+0 8-bit DirectClass
104KB 0.000u 0:00.000
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8. Introduction
The absolute basics
Let’s get a little more advanced
Changing the size of an image
Binary to use is convert or mogrify. The switch is -scale:
$ convert -scale 100x250 pic.png png small.png
or
$ mogrify -scale 100x250 pic.png
The -scale switch takes a “geometry” as argument. A simple
“geometry” looks like <W>x<H> where
<W> is a width; and
<H> is a height.
One of both can be ommitted!
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9. Introduction
The absolute basics
Let’s get a little more advanced
Adding a frame to an image
Again, convert (or mogrify) can take care of this. Example:
$ convert -border 2 -bordercolor black pic.png frame.png
More sexy example:
$ convert -caption "My latest Polaroid" pic.png
-gravity center -background black +polaroid polaroid.png
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10. Introduction
The absolute basics
Let’s get a little more advanced
Making a screenshot
For making screenshots, import is a great tool. Example uses:
$ import window.jpg
# now click on a window with your mouse
$ import -rotate 30 area.png
# now draw a rectangle with your mouse
$ sleep 5; import -window root all.tiff
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11. Introduction
The absolute basics
Let’s get a little more advanced
A real story
For a project, we needed drawings of various pieces of clothing.
Our script expected a bunch of .png-files like
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12. Introduction
The absolute basics
Let’s get a little more advanced
A real story
But we only had .pdf-documents that looked like
Hundreds of them. . .
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13. Introduction
The absolute basics
Let’s get a little more advanced
A real story
So for each .pdf-file we had to:
convert the .pdf-files to the .png-format;
cut the original images in two to separate the drawings of the
front side from those of the back side of the clothing;
set all the images on a transparent background; and
fix the filenames of the resulting .png images.
We did this with a simple ImageMagick script (the loop and file
renaming was taken care of by bash) which saved both a developer
and a designer a day of boring, repetitive work.
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14. Introduction
The absolute basics
Let’s get a little more advanced
The time saving script
Now what would this script have looked like, you think?
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15. Introduction
The absolute basics
Let’s get a little more advanced
References
http://imagemagick.org
http://www.soton.ac.uk/~fangohr/computing/imagemagick.html
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