Slice up an image in equal slices with ImageMagick or a progress bar in 100 images

Let's assume we need a progress bar in 101 images where each shows a particular percentage form 0 to 100. How to create such image will be explained in the next post (not ready yet at the time of writing). I already prepared the image here.

The easiest way to slice up an image is in a command line using ImageMagick's a crop flag. The first command shows the image file we are going to slice. The second command (which should be in one line) is a simple a bash for loop and in each iteration we create a new slice. The third command just lists files that we created.

 mk@here/$ ls
 progressbar_small.png

 mk@here/$ for((i=0; i<101; i++)) ; do n=$[i*22]; \ 
           convert progressbar_small.png -crop 500x22+0+$n +repage progressbar${i}.png; \
           done

 mk@here/$ ls
 progressbar0.png    progressbar32.png  progressbar56.png  progressbar7.png
 ...
 progressbar2.png    progressbar53.png  progressbar77.png  progressbar_small.png

The -crop flag slices up images 500px wide and 22px high and starts at 0px on the X axis and goes down 22*i where i runs from 0 to 100. The end results are 100 images.

All images are available in this zip file.