User Guide

GNU Image Manipulation Program
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Figure 8.23: Example for layer mode ‘Darken only’
(a) Mask 1 is used as upper layer with 100% opac-
ity.
(b) Mask 2 is used as upper layer with 100% opac-
ity.
Darken only mode compares each component of each pixel in the upper layer with the corresponding one in the lower
layer and uses the smaller value in the resulting image. Completely white layers have no effect on the final image and
completely black layers result in a black image.
The equation is:
E = min(M,I)
EQUATION 8.18: Equation for layer mode Darken only
The mode is commutative; the order of the two layers doesn’t matter.
Lighten only
Figure 8.24: Example for layer mode ‘Lighten only’
(a) Mask 1 is used as upper layer with 100% opac-
ity.
(b) Mask 2 is used as upper layer with 100% opac-
ity.
Lighten only mode compares each component of each pixel in the upper layer with the corresponding one in the lower layer
and uses the larger value in the resulting image. Completely black layers have no effect on the final image and completely
white layers result in a white image.