Processing comic images for e-reader

First, this post probably falls into the category of “just because you can do it doesn’t mean you should” with Mathematica.

Here is the job: the comic is in cbz/cbr format, and images are too large for the e-reader usually with 800 by 600 resolutions (the actual usable space is even smaller). So you like to do three things with these images: 1.cut white margins, 2. resize, 3. increase contrast if image is not clear enough. It can be done with three Mathematica commands: ImageCrop, ImageResize and ImageAdjust.

One line example:

Export[#,
  ImageAdjust[
    ImageResize[
    ImageCrop[Import["test.cbz", {"ZIP", #}]], {584, 714}],
    0.2]] & /@ (Import["test.cbz", "ZIP"])

If it is in cbr format, it has to be unpacked first.

Actually under  the certain situation, this may come in handy. There are more and more comics in epub format made for iPad. And epub is basically a zip file contains html/css and images. The following line returns the image file names inside epub. 

Select[Import["test.epub","ZIP"], StringMatchQ[#,__~~".jpg", IgnoreCase->True]&]

Then the images can be changed into grayscale if necessary and re-formatted for e-reader. Just dump the images back into epub afterward.