From a4ca275ad1b5edc15474407e2852f8fe9abaac4e Mon Sep 17 00:00:00 2001 From: eunhhu Date: Mon, 28 Sep 2026 15:52:13 +0100 Subject: 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. --- text/layout.h | 37 ++++++++++++++++++++++++++++--------- 1 file changed, 28 insertions(+), 9 deletions(-) (limited to 'text/layout.h') diff --git a/text/layout.h b/text/layout.h index 9282536..f5aeb89 100644 --- a/text/layout.h +++ b/text/layout.h @@ -3,14 +3,16 @@ #include "shape.h" /* A paragraph set into lines (docs/design/004-text.md): its bidi levels - * (UAX #9), lines broken where UAX #14 allows and they fit (spaces at a - * line's end hang past it), and each line's runs (one level, one script) - * shaped and put in visual order. Positions are in the font's units: x - * from the paragraph's left edge, y up from the line's baseline. */ + * (UAX #9), a font for each grapheme cluster, lines broken where UAX #14 + * allows and they fit (spaces at a line's end hang past it), and each + * line's runs (one level, one script, one font) shaped and put in visual + * order. Positions are in the first font's units: x from the paragraph's + * left edge, y up from the line's baseline. */ typedef struct { - uint32_t glyph; /* the font's: its symbol is VEGA_GLYPH_SYMBOLS + glyph */ + uint32_t glyph; /* its font's: its symbol is VEGA_GLYPH_SYMBOLS + glyph */ uint32_t cluster; /* the paragraph index of the first character it came from */ int32_t x, y, advance; + uint32_t font; /* which of the fonts */ } VegaPlaced; typedef struct { size_t first, count; /* its glyphs, left to right */ @@ -29,10 +31,27 @@ typedef struct { size_t work_size, lines_allocated, glyphs_allocated; } VegaLayout; -/* Set count characters in lines of at most width (0: no limit) with the - * font's shaping; direction is VEGA_BIDI_AUTO, _LTR or _RTL. The layout - * holds the result until it is set again; false without memory. */ -bool vega_layout(VegaLayout *, VegaShaper *, const VegaShaping *, const uint32_t *codes, size_t count, int direction, +/* What text is set in: fonts in order of preference, each cluster in the + * first that has all its characters (default ignorables aside: shaping + * hides them), a cluster of Common and Inherited characters (spaces, + * digits, punctuation) in the font before it when that one has them; no + * font having them all, the first that has its first character, else the + * first font. has says whether a font has a character, NULL whether its + * character map does: a font whose glyphs are not all at hand can say it + * lacks the others. */ +enum { VEGA_LAYOUT_FONTS = 16 }; +typedef struct { + const VegaShaping *fonts[VEGA_LAYOUT_FONTS]; + unsigned count; + bool (*has)(void *context, unsigned font, uint32_t code); + void *context; +} VegaFonts; + +/* Set count characters in lines of at most width (0: no limit) in the + * fonts; direction is VEGA_BIDI_AUTO, _LTR or _RTL. The layout holds the + * result until it is set again; false without memory, or when a run's font + * has no plan for its script (nor for Common). */ +bool vega_layout(VegaLayout *, VegaShaper *, const VegaFonts *, const uint32_t *codes, size_t count, int direction, int32_t width); void vega_layout_free(VegaLayout *); #endif -- cgit v1.2.3