The ImageChops Module

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").

Functions

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).

constant

ImageChops.constant(image, value) => image

Return a layer with the same size as the given image, but filled with the given pixel value.

duplicate

ImageChops.duplicate(image) => image

Return a copy of the given image.

invert

ImageChops.invert(image) => image

Inverts an image.

    out = MAX - image

lighter

ImageChops.lighter(image1, image2) => image

Compares the two images, pixel by pixel, and returns a new image containing the lighter values.

    out = max(image1, image2)

darker

ImageChops.darker(image1, image2) => image

Compares the two images, pixel by pixel, and returns a new image containing the darker values.

    out = min(image1, image2)

difference

ImageChops.difference(image1, image2) => image

Returns the absolute value of the difference between the two images.

    out = abs(image1 - image2)

multiply

ImageChops.multiply(image1, image2) => image

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.

    out = image1 * image2 / MAX

screen

ImageChops.screen(image1, image2) => image

Superimposes two inverted images on top of each other.

    out = MAX - ((MAX - image1) * (MAX - image2) / MAX)

add

ImageChops.add(image1, image2, scale, offset) => image

Adds two images, dividing the result by scale and adding the offset. If omitted, scale defaults to 1.0, and offset to 0.0.

    out = (image1 + image2) / scale + offset

subtract

ImageChops.subtract(image1, image2, scale, offset) => image

Subtracts two images, dividing the result by scale and adding the offset. If omitted, scale defaults to 1.0, and offset to 0.0.

    out = (image1 - image2) / scale + offset

blend

ImageChops.blend(image1, image2, alpha) => image

Same as the blend function in the Image module.

composite

ImageChops.composite(image1, image2, mask) => image

Same as the composite function in the Image module.

offset

ImageChops.offset(xoffset, yoffset) => image

ImageChops.offset(offset) => image

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.