I added a "-s" command line option to both ftview and ftgrid to swap rsvg out with skia and run the same binary twice, one with "-s" and one without, just to look at them side by side. Fixed the pixel positioning discrepancies. Patch posted online below.
I think skia is marginally faster. Also, looking at them side by side, it seems that rsvg+cairo has a tendency of having very pale extra edge pixels compared to Skia's. It is almost as if Skia's svg rendering has a grid-fit/auto-hinting option. As a result, skia-generated color bitmaps has a cleaner look, and often a pixel narrower and shorter too.
The "cleaner" look might be a side-effect of optimization - doing rendering at 1/4 pixels precision or color quantization to 6x6x6 club, for example, can probably go faster than arbitrary precision in color and positioning.
The patch is as below. I don't advertise it, but FontVal-extra/binary-archive on github have rpm's built for fedora 38 I used myself, and have the fontval diff patched in etc. I am thinking of rebuilding my system ftview/frgrid with this patch. If it happens, the rpms will land there.
On Thursday, 13 July 2023 at 04:04:38 BST, Hin-Tak Leung <htl10@users.sourceforge.net> wrote:
> will probably post this up at
> https://github.com/HinTak/harfbuzz-python-demos/ under a new directory "skia-adventure" and write there. Thanks for reading this far :-).
>