* app/gegl/gimpoperationpointlayermode.c: Implement a bunch of
layer modes. Use the exact SVG 1.2 formula for layer modes that
have a counterpart in SVG 1.2. Don't clamp the result to [0..1]
for Dodge and Burn though as we don't need to. Maybe we *should*
clamp from a compositing point of view, I'm not sure. Also
reformat the code a bit for readability.
Keep in mind that we now treat the opacity of all layers the same
indepentant of the layer mode. That is why most of the new
implementations doesn't work the same as the legacy ones when
transparency is involved, only when the layers are completely
opaque. Another important property for all layer modes implemented
below is that compositing onto complete transparency gives the
same result as if the layer would have been in Normal blending
mode.
The status of the new layer mode implementations compared to the
legacy implementations is as follows:
Completely works the same:
o Behind
Works the same for 100% opaque layers:
o Multiply
o Screen
o Difference
o Darken
o Lighten
o Dodge
o Burn
o Hard Light
o Subtract
o Divide
Works different but similar:
o Overlay
Work in progress:
o Soft Light
svn path=/trunk/; revision=27409
cdb3f70184