Contents

Chapter 1
Introduction

1.1 About ImageMagick

• ImageMagick® is a software suite to create, edit, compose, or convert bitmap (raster) and vector images.
• It runs on Linux, Windows, Mac Os X, iOS, Android OS, and others.
• The functionality of ImageMagick is typically utilized from the command line, although you can use the features from programs written in your favorite language (Perl, C, Ruby and PHP).
• ImageMagick is free software distributed under The Apache 2.0 license.
• There is a forum where you can answer your questions.

1.2 Installed version

1.3 Listing the supported image formats

1.4 Delegates

• Depending on how ImageMagick was configured, there is a collection of delegate programs (for example, to create a MPEG file ImageMagick uses FFMPEG).
  convert −list delegate

1.5 (Local) Help

• All ImageMagick commands has man page:
  man imagemagick
• Each ImageMagick command has a buit-in help:
  convert −help

1.6 Debugging

• Standard debug:
  wget http://www.hpca.ual.es/~vruiz/images/lena.png . 
  convert lena.png lena.jpg
• No debug:
  convert +debug lena.png lena.jpg
• Debug:
  convert −debug lena.png lena.jpg
• More debug:
  convert −verbose lena.png lena.jpg
• Progress information:
  convert −monitor lena.png lena.png

1.7 Commands

1. animage: plays an image sequence.
2. compare: compares images.
3. composite: overlaps images.
4. conjure: performs custom image processing tasks from a script written in the Magick Scripting Language (MSL).
5. convert: resizes, blurs, crops, despeckles, dithers, draws on, flips, joins, re-samples, and much more.
6. display: shows an image.
7. identify: describes the format and characteristics of one or more images.
8. import: captures images from the screen.
9. mogrify: identical to convert, but overwrites the original image file.
10. montage: composites images by combining others.
11. stream: extracts regions directly from disk to disk (without loading the image in the memory).

Chapter 2
Displaying

2.1 Using identify

• Describe the format and characteristics of one or more image files.
  # Basic information about the built−in "rose" image: 
  identify rose: 
   
  # Idem for lena.png: 
  identify lena.png 
   
  # Extremely basic: 
  identify −ping rose: 
   
  # Get extra information: 
  identify −verbose rose:

2.2 Using display

• Display an image or image sequence on any X server.
  # Create an image with the inline image "rose". 
  convert rose: rose.png 
   
  # Display de image using an independent window. 
  display rose.png & 
   
  # Using the root window. 
  display −size 1280x1024 −window root rose.png & 
   
  # Built a preview in a visual image directory. 
  wget http://www.hpca.ual.es/~vruiz/videos/tempete_352x288x30x420x260.avi 
  convert tempete_352x288x30x420x260.avi tempete%03d.png 
  display ’vid:∗.png’ & 
   
  # Using pipes: 
  convert logo: gif:− | display − & 
  #                 ^ ^         ^ 
  #                 | |         | 
  #            stdout pipe    stdin

2.3 Using animate

• Animate an image sequence on any X server.
  # Displays a sequence of independent JPEG images. 
  animate ∗.jpg 
   
  # Displays an animated GIF. 
  animate tempete_animated.gif & 
   
  # or ... 
  firefox tempete_animated.gif &

  # See Section 4.2 to get tempete_animated.gif.

2.4 Using file

Chapter 3
Capturing

• Save 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.

1. Capture a window:
   import window.png
2. Capture a region:
   import −frame region.png
3. Capture the entire screen:
   import −window root screen.png

Chapter 4
Creating & converting

• Convert between image formats as well as resize an image, blur, crop, despeckle, dither, draw on, flip, join, re-sample, and much more.

4.1 Using built-in images

4.2 Creating animated images

1. Using a globbing parameter:
   # Create a sequence of PNG images. 
   wget http://www.hpca.ual.es/~vruiz/videos/tempete_352x288x30x420x260.avi 
   convert tempete_352x288x30x420x260.avi tempete%03d.png 
    
   # Create a GIF animation with a sequence of PNG images. 
   convert −loop 0 −delay 100 tempete∗.png tempete_animated.gif 
   #            ^          ^         ^ 
   #            |          |         | 
   #            |          | filename globbing 
   #            |        delay between images 
   #         Loop forever 
    
   firefox tempete_animated.gif &
2. Using a file with the names of the still images:
   cat << EOF > example_using_references.sh 
   #!/bin/bash 
    
   set −x 
    
   # Empty file. 
   echo −n "" > references.txt 
    
   # Create the "references.txt" file. 
   for (( i=0; i<100; i++ )) 
   do 
     index_i=\‘printf "%02d" \$i\‘ # Be carefully with the ’\‘’! 
     filename=checker−\$index_i.png 
     convert −size 256x256 pattern:checkerboard’[’256x256+\$i+\$i’]’ \$filename 
     echo \$filename >> references.txt 
   done 
    
   # Create the movie using the references file. 
   convert @references.txt movie.gif 
    
   set +x 
   EOF 
    
   chmod +x example_using_references.sh 
   ./example_using_references.sh

4.3 Extracting images from an animated image or video

4.4 Disolving

4.5 Morphing

4.6 Watermarking

1. Visible:
   # No offset: 
   composite −watermark 50% mark.png foreground.jpg output.png 
    
   # Centering the mark: 
   composite −watermarck 40% −gravity center marck.jpg foreground.jpg output.jpg
2. Invisible:
   # Hide ‘‘hidden_mark.png’’ inside of ‘‘foreground.jpg’’: 
   composite −stegano 101 hidden_mark.png foreground.jpg output.jpg 
   #                   ^ 
   #                   | 
   #       offset of the hidden mark 
    
   # Extract the hidden image: 
   display 200x100+101 stegano:output.png 
   #          ^     ^ 
   #          |     | 
   #          | offset of the hidden mark 
   #  size of the hidden marck

4.7 Removing and putting on headers

 # See Section 4.2 to create tempete000.png.

Chapter 5
Comparing

5.1 Compare two images

Chapter 6
Composing

6.1 Overlaping images

6.2 Montaging

• Create a composite image by combining several separate images. The images are tiled on the composite image optionally adorned with a border, frame, image name, and more.
  montage −label %f −frame 10 −shadow −tile 4 ∗.jpg output.jpg 
  #              ^         ^   ^            ^ 
  #              |         |   |            | 
  #              |         |   |  number of images per row 
  #              |         | create a shadow for each image 
  #              |     use a frame os 10 pixels 
  #            filename

Chapter 7
Processing

7.1 Reducing the number of colors

7.2 Chroma subsampling

7.3 Changing the quality

1. In JPEG:
   convert −quality 15% input.png output.jpg
2. In JPEG2000:
   convert −quality 15% input.png −define "jp2:rate=1.0" output.jp2

7.4 Gamma correction

7.5 Transparency

7.6 Scale

Inline (while reading) multiple image processing:

7.7 Crop

7.8 Manipulating contrast

• The contrast is the difference in luminance to make and object distinguishable.
  # Increasing: 
  convert −constrast input.png output.png 
   
  # Decreasing: 
  convert +constrast input.png output.png

7.9 Dithering

• Reduces the number of colors.
  # Using 2 colors: 
  convert −dither −monochrome input.png output.png 
   
  # Using 4 colors: 
  convert −dither −colors 4 input.png output.png

7.10 Equalizing

• Increases the dynamic range of the colors of the image.
  convert −equalize input.png output.png

7.11 Normalizing

• Increases the dynamic range of the colors of the image.
  convert −normalize input.png output.png

7.12 Bluring

• Low pass filtering:
  convert −blur 10 input.png output.png 
  #             ^ 
  #             | 
  #          radius 
   
  conver −blur 7x3 input.opng output.png 
  #             ^ 
  #             | 
  #          size of the convolutional mask

7.13 The charcoal effect

• High pass filtering:
  convert −charcoal 2 input.png output.png 
  #                 ^ 
  #                 | 
  #       thicknes of the boundaries

7.14 The impode effect

• A sink effect:
  convert −implode 2 input.png output.png 
  #                ^ 
  #                | 
  #             factor

7.15 Denoising

• Removes noise:
  convert −noise 3 input.png output.png 
  #              ^ 
  #              | 
  #            radii

7.16 The paint effect

• Simulates oil painting:
  convert −paint 3 input.png output.png 
  #              ^ 
  #              | 
  #            radii

7.17 The radial-blur effect

• Simulates oil painting:
  convert −radial−blur 30 input.png output.png 
  #                     ^ 
  #                     | 
  #                   angle

7.18 Sementing

• Automatic image segmentation:
  convert −segment 1.75x2.0 input.png output.png 
  #                  ^   ^ 
  #                  |   | 
  #                  | smoothing 
  #                clustering

7.19 The sepia-tone effect

• A vintage effect:
  convert −sepia−tone 75% input.png output.png 
  #                    ^ 
  #                    | 
  #                percentage

7.20 The shade effect

• Produces shades:
  convert −shade 0x10 input.png output.png 
  #              ^  ^ 
  #              |  | 
  #              | elevation of the source of light 
  #             azimuth

7.21 Sharpenning

• Using a Gaussian filtering to enhance the color boundaries:
  convert −sharpen 3x6 input.png output.png 
  #                ^  ^ 
  #                |  | 
  #                | standard deviation 
  #               radii

7.22 Negating

• A negative effect:
  convert −negate input.png output.png

7.23 The solarize effect

• Another negative effect:
  convert −solarize 30 input.png output.png 
  #                  ^ 
  #                  | 
  #               factor

7.24 The spread effect

• Swaps pixels randomly:
  convert −spread 7 input.png output.png 
  #               ^ 
  #               | 
  #             radii

7.25 The wave effect

• Shakes the image:
  convert −wave 10x90 input.png output.png 
  #              ^  ^ 
  #              |  | 
  #              | frequency 
  #           amplitude

Chapter 8
Editing

8.1 Annotating

• Put text inside images.
  convert −annotate 0x0+30+40 −stroke blue −fill red ‘‘text’’ input.png output.png 
  #                     ^  ^ 
  #                     |  | 
  #                     | Y offset 
  #                    X offset

8.2 Removing metadata

8.3 Change metadata

8.4 Scaling

1. Absolute size:
   convert −resize 352x288 input.jpg output.jpg
2. Maximum size (not larger than) and conserving the width/height ratio:
   convert −resize 352x288< input.jpg output.jpg
3. Minimum size (not smaller than) and conserving the width/height ratio:
   convert −resize 352x288> input.jpg output.jpg
4. Percentage change:
   convert −resize 25% input.jpg output.jpg
5. Maximun number of pixels:
   convert −resize 25000@ input.jpg output.jpg
6. Sampling (changes both, the resolution and the image size):
   convert −sample 250% input.jpg output.jpg
7. Resampling (in dots per inch). It changes the resolution, but not the size:
   convert −resample 150x150 input.jpg output.jpg
8. Using a faster (but unaccurate) algorithm:
   convert −scale 200% input.jpg output.jpg
9. Thumbnails:
   # Only one image: 
   convert −thumbnail 10% input.jpg output.jpg
   # A group of images (this example does not overwrites the original images): 
   mogrify −format png −thumbnail 15% ∗.jpg

8.5 Rotating

8.6 Flipping

8.7 Shearing

• Put the input image at an angle.
  convert −shear 45x10 input.png output.png 
  #               ^  ^ 
  #               |  | 
  #               | vertical shearing 
  #             horizontal

8.8 Averaging

8.9 Cropping

1. Extract a subregion:
   convert −crop 999x768+100+200 input.png output.png 
   #              ^   ^   ^   ^ 
   #              |   |   |   | 
   #              |   |   | Y offset 
   #              |   | X offset 
   #              | height of the extracted image 
   #            width of the extracted image
2. Remove a border:
   convert −shave 10x10 input.jpg output.jpg
3. Remove the constant border:
   convert −trim input.jpg output.jpg
4. Remove the similar border:
   convert −fuzz 10% input.jpg output.jpg

8.10 Chopping

• Removes columns and rows (both, at the same time) of an image.
  convert −chop 500x600+700+800 input.png output.png 
  #              ^   ^   ^   ^ 
  #              |   |   |   | 
  #              |   |   | Y offset 
  #              |   | X offset 
  #              | height of the removed region 
  #            width of the removed region

8.11 Adding images

8.12 Inserting images

8.13 Deleting images

8.14 Swapping images

8.15 Appending