artemp/trac2github — Issue #732: AGG nearest neighbour scaling broken for semi-transparent images
Author: artemp
Created: 2011-10-09 20:48:42+00:00
State: open
Labels: Symbolizers

Use RasterSymbolizer to render a source image that contains areas of <255 alpha using nearest neighbour scaling.

Weird colours happen because byte overflow happens in all the saturated areas for each channel.

i.e. FFFFFF --> black, FF1234 --> 001234.

My bad, this was a bug in my AGG blending stuff.

Fix is here: https://github.com/craigds/mapnik2/commit/f134694d8e9cb12d61072b6e0092949b11989c06