(mflt_find): Prototype adjusted.

(mflt_name): Extern it.

diff --git a/src/m17n-flt.h b/src/m17n-flt.h
index 12d2840..f8aa48d 100644 (file)
--- a/src/m17n-flt.h
+++ b/src/m17n-flt.h
@@ -74,14 +74,16 @@ struct _MFLTGlyph
   /***en Horizontal and vertical adjustments for the glyph positioning
       expressed in 26.6 fractional pixel format.  */
   int xoff, yoff;
-  /***en Flag to tell if the member <code> is encoded into a glyph ID
-      of a font.  */
+  /***en Flag to tell if the member <code> is already encoded into a
+      glyph ID of a font.  */
   unsigned encoded : 1;
   /***en Flag to tell if the metrics of the glyph (members <xadv> thru
       <rbearing>) are already calculated.  */
   unsigned measured : 1;
   /***en For m17n-lib's internal use only.  */
   unsigned internal : 30;
+
+  /* Arbitrary data can follow.  */
 };
 
 /***en
@@ -167,11 +169,39 @@ typedef struct _MFLTFont MFLTFont;
 
 struct _MFLTFont
 {
+  /* Family name of the font.  It may be #Mnil if the family name is
+     not important in finding a Font Layout Table suitable for the
+     font (for instance, in the case that the font is an OpenType
+     font).  */
+  MSymbol family;
+
+  /* Horizontal and vertical font sizes in pixel per EM.  */
   int x_ppem, y_ppem;
+
+  /* If the font is an OpenType font, MFLTFont->otf.sym must be #Mt,
+     and the other members must describe available GSUB/GPOS features
+     of the specific script and language system for which the font is
+     used.  Otherwise, MFLTFont->spec.sym must be #Mnil.  */
+  MFLTOtfSpec otf;
+
+  /* Callback function to get glyph IDs for glyphs between FROM
+     (inclusive) and TO (exclusive) of GSTRING.  If <encoded> member
+     of a glyph is zero, the <code> member of the glyph is a character
+     code.  The function must convert it to the glyph ID of FONT.  */
   int (*get_glyph_id) (MFLTFont *font, MFLTGlyphString *gstring,
                       int form, int to);
-  int (*get_metric) (MFLTFont *font, MFLTGlyphString *gstring, int form, int to);
-  int (*suitable_p) (MFLTFont *font, MSymbol family, MFLTOtfSpec *spec);
+
+  /* Callback function to get metrics of glyphs between FROM
+     (inclusive) and TO (exclusive) of GSTRING.  If <measured> member
+     of a glyph is zero, the function must set members <xadv>, <yadv>,
+     <ascent>, <descent>, <lbearing>, and <rbearing> of the glyph.  */
+  int (*get_metrics) (MFLTFont *font, MFLTGlyphString *gstring,
+                    int form, int to);
+
+  /* Callback function to apply OpenType features in SPEC to glyphs
+     between FROM (inclusive) and TO (exclusive) of IN.  The resulting
+     glyphs should be appended to the tail of OUT.  If OUT doesn't
+     have a room to store all resulting glyphs, it must return -2.  */
   int (*drive_otf) (MFLTFont *font, MFLTOtfSpec *spec,
                    MFLTGlyphString *in, int from, int to,
                    MFLTGlyphString *out, MFLTGlyphAdjustment *adjustment);
@@ -182,7 +212,9 @@ typedef struct _MFLT MFLT;
 
 extern MFLT *mflt_get (char *name);
 
-extern MFLT *mflt_find (MFLTGlyphString *gstring, int pos, MFLTFont *font);
+extern MFLT *mflt_find (int c, MFLTFont *font);
+
+extern char *mflt_name (MFLT *flt);
 
 extern MCharTable *mflt_coverage (MFLT *flt);