Spinel Antialiasing — Text

Quality antialiasing of small glyphs requires precise pixel coverage information.

Spinel achieves high-quality antialiasing by retaining the subpixel geometry of paths throughout its pipeline. This enables both high-resolution pixel coverage calculation and is one gateway to efficient subpixel-aware rendering.

In the comparison below, the capture on the left was produced by NVIDIA’s NV Path OpenGL extension with MSAA 8x antialiasing.

The Spinel text capture is on the right. Note the capture in this post is not demonstrating subpixel-aware antialiasing.

Slide the divider back and forth to see the difference between precise coverage antialiasing and low-sample count MSAA 8x.

Spinel:

NVPR 8x:

If you look closely, you’ll see that Spinel’s antialiasing is consistent across all of the glyphs while the MSAA capture demonstrates uneven coverage and overly dark and light “pixel popping” in many of the letter forms.

One example of MSAA’s uneven coverage and pixel popping is in the last line of the first paragraph.

Using MSAA 8x for antialiasing vector graphics might be practical but it’s an indisputable step backwards.

A vector graphics pipeline running on a teraflop GPU should at least meet — or beat — the antialiasing quality of existing CPU-powered rasterizers.