The ImageChops module contains a number of arithmetical image operations, called channel operations ("chops"). These can be used for various purposes, including special effects, image compositions, algorithmic painting, and more.
At this time, channel operations are only implemented for 8-bit images (e.g. "L" and "RGB").
Most channel operations take one or two image arguments and returns a new image. Unless otherwise noted, the result of a channel operation is always clipped to the range 0 to MAX (which is 255 for all modes supported by the operations in this module).
Add images ((image1 + image2) / scale + offset).
Adds two images, dividing the result by scale and adding the offset. If omitted, scale defaults to 1.0, and offset to 0.0.
Add images without clipping ((image1 + image2) % MAX).
Adds two images, without clipping the result.
Blend images using constant transparency weight.
Same as the blend function in the Image module.
Create composite using transparency mask.
Same as the composite function in the Image module.
Compare images, and return darker pixel value (min(image1, image2)).
Compares the two images, pixel by pixel, and returns a new image containing the darker values.
Calculate absolute difference (abs(image1 - image2)).
Returns the absolute value of the difference between the two images.
Compare images, and return lighter pixel value (max(image1, image2)).
Compares the two images, pixel by pixel, and returns a new image containing the lighter values.
Superimpose positive images (image1 * image2 / MAX).
Superimposes two images on top of each other. If you multiply an image with a solid black image, the result is black. If you multiply with a solid white image, the image is unaffected.
Offset image data.
Returns a copy of the image where data has been offset by the given distances. Data wraps around the edges. If yoffset is omitted, it is assumed to be equal to xoffset.
Superimpose negative images (MAX - ((MAX - image1) * (MAX - image2) / MAX)).
Superimposes two inverted images on top of each other.
Subtract images ((image1 - image2) / scale + offset).
Subtracts two images, dividing the result by scale and adding the offset. If omitted, scale defaults to 1.0, and offset to 0.0.
Subtract images without clipping ((image1 - image2) % MAX).
Subtracts two images, without clipping the result.