layer modes: add soft light blend mode
authorAndrew Chadwick <andrewc-git@piffle.org>
Wed, 31 Oct 2012 19:08:58 +0000 (19:08 +0000)
committerAndrew Chadwick <andrewc-git@piffle.org>
Wed, 31 Oct 2012 19:18:35 +0000 (19:18 +0000)
commit3d1f3be947c8cb8424c36d5d3a8029bd88b062f0
tree3d76c8ff4883859b014ca55542365e74e5b6b147
parent978dbb541d01bf128edebf4aa25046c7327c27ce
layer modes: add soft light blend mode

Add the svg:soft-light operator, specified as being the W3C SVG one(s)
by the OpenRaster specification.

    http://www.w3.org/TR/SVGCompositing/#comp-op-soft-light
    https://dvcs.w3.org/hg/FXTF/rawfile/tip/compositing/index.html#blendingsoftlight

The current SVGCompositing reference has an incorrect derivation for
working in premultiplied alpha, so let's not implement that for now. The
nonpremult math is correct and matches the current FXTF one.
lib/composite_rgbx.hpp
lib/layer.py
lib/pixops.hpp
lib/tiledsurface.py