Improve the method used for Anti-Aliasing Lines and Texts over raster images.

When lines and text are anti-aliased the background color is used as the basis for the anti-aliasing.
When there is a raster image behind the lines the anti-aliased edges become more prominent and interfere with the proper appearance of the line work.
Black BG anti-alias OFF

Black BG anti-alias ON

White BG anti-alias OFF