The basic image merging operations defined by Porter and Duff in their 1984 paper, with a couple of additions.  All these operations are methods of Image and return a new Image instance.

Each of the following operations is illustrated with these foreground and background images:

ice.Image Over(fg)

The image being operated on is the background image.

Parameters

fg

Foreground image (ice.Image).

Example

fg = ice.Load('teapot.tif')
bg = ice.Load('tinbox.tif')
result = bg.Over(fg) 

ice.Image Cover(fg)

Correlated Over operation.  Similar to Over, but works better for correlated subpixel coverage.

Parameters

fg

Foreground image (ice.Image).

Example

fg = ice.Load('teapot.tif')
bg = ice.Load('tinbox.tif')
result = bg.Cover(fg)

ice.Image MergeAtop(fg)

Merge "atop".

Parameters

fg

Foreground image (ice.Image).

Example

fg = ice.Load('teapot.tif')
bg = ice.Load('tinbox.tif')
result = bg.MergeAtop(fg)

ice.Image In(fg)

Merge "in".

Parameters

fg

Foreground image (ice.Image).

Example

fg = ice.Load('teapot.tif')
bg = ice.Load('tinbox.tif')
result = bg.MergeXOR(fg) 

ice.Image MergeXOR(fg)

Merge XOR operation.

Parameters

Example

fg = ice.Load('teapot.tif')
bg = ice.Load('tinbox.tif')
result = bg.MergeXOR(fg) 
				

ice.Image Out(fg)

Merge out operation.

Parameters

fg

Foreground image (ice.Image).

Example

fg = ice.Load('teapot.tif')
bg = ice.Load('tinbox.tif')
result = bg.Out(fg) 

ice.Image TransmissionFilter(fg)

In this operation, the foreground acts as a color filter for the background.

Parameter

fg

Foreground image (ice.Image).

Example

fg = ice.Load('teapot.tif')
bg = ice.Load('tinbox.tif')
result = bg.TransmissionFilter(fg) 

ice.Image AlphaDivide()

Divide image by alpha channel.

ice.Image AlphaMultiply()

Multiply image by alpha channel.