visgrep is a program that greps for image in another image.
All .pat files are created using
png2pat(1) or
rgb2pat(1) c . The image.png is scanned for detect.pat starting from X,Y given in parameters.
When detect.pat is found, then all the match.pat files are scanned at an offset of
x,y given in parameters. If a match is found, then
visgrep prints the x,y and index of the item.
For example, image.png is a screenshot and match1.pat .. match5.pat are images of
letters a to e. Each of these letters is enclosed in a blue box, so detect.pat is
an image of the upper left corner of the box. This box is not included in the
match*.pat files, so they are actually offset 5 pixels down and 4 pixels to the left.
You might run it like this then:
