Set text in a stack of fonts: each grapheme cluster in the first that has it

vega_layout takes fonts in order of preference (VegaFonts). A grapheme
cluster goes to the first font that has all its characters (default
ignorables aside: shaping hides them); a cluster of Common and Inherited
characters stays in the font before it when that one has it, so the spaces
between Arabic words stay in the Arabic font; failing that, the first font
with its first character, else the first font. Runs split where the font
changes too. Positions are in the first font's units, a run's pen scaled
as a whole so rounding does not add up. Callers can narrow what a font
has (a symbol file holds only the glyphs its codes reach).

vega_default_ignorable is shape.c's HarfBuzz 10.2 set, now public.

1 files changed, 2 insertions, 1 deletions

diff --git a/symbols/symbols-tool.c b/symbols/symbols-tool.c
index 0682c1c..5b8595f 100644
--- a/symbols/symbols-tool.c
+++ b/symbols/symbols-tool.c
@@ -1178,11 +1178,12 @@ static int paragraph(int argc, char **argv) {
     VegaShaper *shaper = vega_shaper_new();
     VegaGlyphs *glyphs = vega_glyphs_open(&s, (float)(pixels / s.units));
     VegaLayout layouts[16] = {0};
+    VegaFonts fonts = {{&shaping}, 1, NULL, NULL};
     int paragraphs = argc - 6 < 16 ? argc - 6 : 16, height = 2 * margin;
     for (int k = 0; k < paragraphs; ++k) {
         uint32_t codes[4096];
         size_t count = decode_utf8(argv[6 + k], codes, 4096);
-        if (!vega_layout(&layouts[k], shaper, &shaping, codes, count, VEGA_BIDI_AUTO, (int32_t)(width / per_unit)))
+        if (!vega_layout(&layouts[k], shaper, &fonts, codes, count, VEGA_BIDI_AUTO, (int32_t)(width / per_unit)))
             fail("cannot lay out");
         height += (int)layouts[k].line_count * line_height + line_height / 2;
     }