[OpenJDK 2D-Dev] Pisces AA renderer performance improvement.

[Roman Kennke]

Hi Denis,


> The version in the webrev is the fastest yet, and it uses
> a class similar to the ScanlineIterator for the sorting
> (but now it iterates through pixel rows, not scanlines).
> Unfortunately this means that there still are two levels
> of intermediate storage (edges and crossings, analogous
> to edges and RLE elements in the old version), but the
> only way I can think of how to get rid of one of them
> and still take use an average linear time sort is if we
> start outputting alphas pixelrow by pixelrow, rather than
> in 32x32 tiles.

- What speaks against doing that? E.g. outputting pixelrow by pixelrow?
I was implementing a pure Java AA scanline converter for GNU Classpath
some years ago and this is exactly what I did. I found that useful
because drawing horizontal lines is often very cheap (i.e. filling
adjacent bits/bytes in framebuffers).
- What about writing 32 pixelrows into an intermediate buffer and then
outputting those in 32x32 blocks when done? Or is this what you are
currently doing?

Cheers, Roman