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-rw-r--r--src/composite.h21
1 files changed, 21 insertions, 0 deletions
diff --git a/src/composite.h b/src/composite.h
index c5d3c0faabb..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))
@@ -320,6 +337,10 @@ extern bool composition_gstring_p (Lisp_Object);
extern int composition_gstring_width (Lisp_Object, ptrdiff_t, ptrdiff_t,
struct font_metrics *);
+extern bool find_automatic_composition (ptrdiff_t, ptrdiff_t, ptrdiff_t,
+ ptrdiff_t *, ptrdiff_t *,
+ Lisp_Object *, Lisp_Object);
+
extern void composition_compute_stop_pos (struct composition_it *,
ptrdiff_t, ptrdiff_t, ptrdiff_t,
Lisp_Object);