glyphy VS nanovgXC

harfbuzz creator made https://github.com/behdad/glyphy/ which i integrated into GTK a while back (but we don't ship currently, because we still do the bitmap stuff).

the bitmap stuff still has major drawbacks though, like maintaining grid alignments and pixel boundaries where as this stuff (mostly) goes away using glyphy.

still work to be done around hinting though (hence not merged).

You can approximate the Bézier curves with circular arcs and store those in the "SDF" instead. https://github.com/behdad/glyphy

> The only issue with it is that font rendering looks horrific, but that might just be my machine.

This is because GTK4 enables pixel/scaling-independent fractional vertical positioning, even with hinting enabled. There's a long (somewhat ongoing) discussion at https://gitlab.gnome.org/GNOME/gtk/-/issues/3787, though I haven't followed the last few months of discussion.

Even though GTK4 aims to achieve scale-independent layout, the 4 horizontal/vertical positions still produce a bit of judder, and fonts do not scale smoothly (even with bilinear interpolation) with hinting enabled, and (unless fixed) there are rendering issues due to failing to clear the texture atlas properly: https://gitlab.gnome.org/GNOME/gtk/-/issues/4322

Interestingly there's a proposal to switch GTK4 fonts to SDF-style rendering. This is somewhat like what Qt Quick 2 implemented already (and KDE turns off and reverts to FreeType rendering, to make QML apps mimic Qt Widgets font rendering more): https://blogs.gnome.org/chergert/2022/03/20/rendering-text-w... However, I looked at https://github.com/behdad/glyphy and it seems to implement vector-based SDFs, instead of earlier texture-based SDF/MSDFs used by Valve games and Qt Quick.

Nice work. Any plan to add GPU (opengl) support? CPU rendering is OK but the performance using the GPU is likely order of magnitudes better. Here is a library that uses the same antialiasing technique https://github.com/styluslabs/nanovgXC using OpenGL (based on NanoVG).

GPU vector graphics library I released a few years ago: https://github.com/styluslabs/nanovgXC - basically a new backend for nanovg that supports arbitrary paths. Coverage calculation (for analytic antialiasing) is explained a bit here: https://github.com/styluslabs/nanovgXC/blob/master/src/nanov...

Getting sufficient antialiasing quality for 2D graphics is difficult on GPUs. https://github.com/memononen/nanovg accomplishes this with GL2/GLES2 level hardware for most of the stuff one would want to render as part of a GUI. My project https://github.com/styluslabs/nanovgXC supports rendering arbitrary paths with exact coverage antialiasing, but requires GLES3.1 or GL4 level hardware for reasonable performance.