ignoreRectangles feature

Proposing to add “ignoreRectagles” feature as in node-resemble-js, where options would support an ignoreRectangles property which is as in resemble:

//array of rectangles, each rectangle is defined as (x, y, width, height)
//e.g. [[325, 170, 100, 40]]

Pixels within these rectangles would not be tested. Unsure of best way to represent these in diff image.

[curtw]

Another advantage of including this feature in the package is that the color of the ignore rectangles could be set to black in the diff image, making it clear what had been excluded from the comparison.

if (ignoreHash && ignoreHash[x] && ignoreHash[x][y]) {
    drawPixel(output, pos, 0, 0, 0);
    continue;
}

Setting the color to black in the input images does not produce a diff image that adequately distinguishes ignore rectangles from darker parts of the input images.

You could black-out the resulting diff image as well, but that’s getting a be a lot of extra steps.

[mourner]

No plans for now, to keep it simple. There’s a workaround:

it’s easy enough to just iterate over and null all pixels in desired areas in both input images