542818 - Avoid converting to a fixed point representation in cairo

Status: NEW

(Core :: Graphics, defect)

Description

[Jeff Muizelaar [:jrmuizel]]

Make it possible for cairo to use floating point internally instead of fixed point. Currently the cairo choices for number representation are not that great.
Quartz on 32-bit and Direct2d both use float for there external api and quartz 64b-bit uses double. Cairo uses double and then converts that to float

Comment 1

[Jeff Muizelaar [:jrmuizel]]

In a profile of stroking a bunch of really short lines we spend about 43.5% in _cairo_path_fixed_interpret a bunch of this time is doing number representation conversion.

Comment 2

[Jeff Muizelaar [:jrmuizel]]

The easiest way to get this working would probably be for it to be a compile time option. Having cairo use different representations for different backends would be trickier.

Comment 3

[Jeff Muizelaar [:jrmuizel]]

Attachment: a proof of concept

This seems to work on the simple test that I did. I've not done any other experimentation yet.