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, 3 insertions, 0 deletions

diff --git a/text/shape.h b/text/shape.h
index 9381754..cafa9b4 100644
--- a/text/shape.h
+++ b/text/shape.h
@@ -128,6 +128,9 @@ bool vega_shaping_open(VegaShaping *, const unsigned char *bytes, size_t size, c
 void vega_shaping_close(VegaShaping *);
 /* The font's glyph for a character, or 0. */
 uint32_t vega_shaping_glyph(const VegaShaping *, uint32_t code);
+/* Default_Ignorable_Code_Point as HarfBuzz 10.2 has it: what shaping hides
+ * (a zero-width space in its place, or nothing). */
+bool vega_default_ignorable(uint32_t code);
 
 /* A shaped glyph, as HarfBuzz gives it: in visual order (left to right),
  * cluster the index of the first character it came from; each glyph is