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| author | Glenn Morris <rgm@gnu.org> | 2021-06-08 07:50:36 -0700 |
|---|---|---|
| committer | Glenn Morris <rgm@gnu.org> | 2021-06-08 07:50:36 -0700 |
| commit | bef3070ab8dfbb8b68c08f0f0aa03532311f3dd5 (patch) | |
| tree | ee17d21741f4b14425e44ea13b2e4b76e8915f7d /src/composite.h | |
| parent | 6456a67b5d62fb2682bf163ade8ca1f65554a2aa (diff) | |
| parent | 37f44579946380ec13f7929360f8f552334362d4 (diff) | |
| download | emacs-bef3070ab8dfbb8b68c08f0f0aa03532311f3dd5.tar.gz emacs-bef3070ab8dfbb8b68c08f0f0aa03532311f3dd5.tar.bz2 emacs-bef3070ab8dfbb8b68c08f0f0aa03532311f3dd5.zip | |
Merge from origin/emacs-27
37f4457994 (origin/emacs-27) ; Fix typo in dynamic module functions d...
f7d4bbceee ; * src/composite.h: Improve comments for LGSTRING and LGL...
Diffstat (limited to 'src/composite.h')
| -rw-r--r-- | src/composite.h | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/src/composite.h b/src/composite.h index 660b1fa1b9e..67e87201bf2 100644 --- a/src/composite.h +++ b/src/composite.h @@ -246,6 +246,11 @@ composition_valid_p (ptrdiff_t start, ptrdiff_t end, Lisp_Object prop) /* Macros for lispy glyph-string. This is completely different from struct glyph_string. */ +/* LGSTRING is a string of font glyphs, LGLYPHs. It is represented as + a Lisp vector, with components shown below. Once LGSTRING was + processed by a shaping engine, it holds font glyphs for one or more + grapheme clusters. */ + #define LGSTRING_HEADER(lgs) AREF (lgs, 0) #define LGSTRING_SET_HEADER(lgs, header) ASET (lgs, 0, header) @@ -259,6 +264,10 @@ composition_valid_p (ptrdiff_t start, ptrdiff_t end, Lisp_Object prop) #define LGSTRING_ID(lgs) AREF (lgs, 1) #define LGSTRING_SET_ID(lgs, id) ASET (lgs, 1, id) +/* LGSTRING_GLYPH_LEN is the maximum number of LGLYPHs that the + LGSTRING can hold. This is NOT the actual number of valid LGLYPHs; + to find the latter, walk the glyphs returned by LGSTRING_GLYPH + until the first one that is nil. */ #define LGSTRING_GLYPH_LEN(lgs) (ASIZE ((lgs)) - 2) #define LGSTRING_GLYPH(lgs, idx) AREF ((lgs), (idx) + 2) #define LGSTRING_SET_GLYPH(lgs, idx, val) ASET ((lgs), (idx) + 2, (val)) @@ -278,6 +287,14 @@ enum lglyph_indices LGLYPH_SIZE }; +/* Each LGLYPH is a single font glyph, whose font code is in + LGLYPH_CODE. + LGLYPH_FROM and LGLYPH_TO are indices into LGSTRING; all the + LGLYPHs that share the same values of LGLYPH_FROM and LGLYPH_TO + belong to the same grapheme cluster. + LGLYPH_CHAR is one of the characters, usually the first one, that + contributed to the glyph (since there isn't a 1:1 correspondence + between composed characters and the font glyphs). */ #define LGLYPH_NEW() make_nil_vector (LGLYPH_SIZE) #define LGLYPH_FROM(g) XFIXNUM (AREF ((g), LGLYPH_IX_FROM)) #define LGLYPH_TO(g) XFIXNUM (AREF ((g), LGLYPH_IX_TO)) |