Add new spacing value FC_DUAL (dual-width, as some CJK fonts). (bug #111)

When checking for monospace and dual-width fonts, allow roughly a 3%
    variance in the advances.

ChangeLog

@@ -1,3 +1,16 @@
+2003-09-06  Noah Levitt  <nlevitt@columbia.edu>
+
+	* doc/fontconfig-devel.sgml:
+	* doc/fontconfig-user.sgml:
+	* fontconfig/fontconfig.h:
+	* src/fcname.c:
+	* src/fcfreetype.c (FcFreeTypeCharSetAndSpacing): Add new spacing
+	value FC_DUAL (dual-width, as some CJK fonts). (bug #111)
+
+	* src/fcfreetype.c (FcFreeTypeCharSetAndSpacing): When checking for
+	monospace and dual-width fonts, allow roughly a 3% variance in the
+	advances.
+
 2003-08-31  Manish Singh  <yosh@gimp.org>
 
 	* src/fccfg.c (FcConfigAppFontClear): Support passing NULL to

doc/fontconfig-devel.sgml

@@ -139,8 +139,8 @@ convenience for the applications rendering mechanism.
     aspect         FC_ASPECT            Double  Stretches glyphs horizontally
                                                 before hinting
     pixelsize      FC_PIXEL_SIZE        Double  Pixel size
-    spacing        FC_SPACING           Int     Proportional, monospace or
+    spacing        FC_SPACING           Int     Proportional, dual-width,
-                                                charcell
+                                                monospace or charcell
     foundry        FC_FOUNDRY           String  Font foundry name
     antialias      FC_ANTIALIAS         Bool    Whether glyphs can be
                                                 antialiased

doc/fontconfig-user.sgml

@@ -98,7 +98,7 @@ convenience for the applications rendering mechanism.
   size            Double  Point size
   aspect          Double  Stretches glyphs horizontally before hinting
   pixelsize       Double  Pixel size
-  spacing         Int     Proportional, monospace or charcell
+  spacing         Int     Proportional, dual-width, monospace or charcell
   foundry         String  Font foundry name
   antialias       Bool    Whether glyphs can be antialiased
   hinting         Bool    Whether the rasterizer should use hinting
@@ -349,6 +349,7 @@ symbolic names for common font values:
   italic          slant           100
   oblique         slant           110
   proportional    spacing         0
+  dual            spacing         90
   mono            spacing         100
   charcell        spacing         110
   unknown         rgba            0

fontconfig/fontconfig.h

@@ -128,6 +128,7 @@ typedef int		FcBool;
 #define FC_WIDTH_ULTRAEXPANDED	    200
 
 #define FC_PROPORTIONAL		    0
+#define FC_DUAL			    90
 #define FC_MONO			    100
 #define FC_CHARCELL		    110
 

src/fcfreetype.c

@@ -1807,6 +1807,8 @@ FcFreeTypeCheckGlyph (FT_Face face, FcChar32 ucs4,
     return FcFalse;
 }
 
+#define APPROXIMATELY_EQUAL(x,y) (ABS ((x) - (y)) <= MAX (ABS (x), ABS (y)) / 33)
+
 FcCharSet *
 FcFreeTypeCharSetAndSpacing (FT_Face face, FcBlanks *blanks, int *spacing)
 {
@@ -1820,8 +1822,8 @@ FcFreeTypeCharSetAndSpacing (FT_Face face, FcBlanks *blanks, int *spacing)
     int		    o;
     int		    i;
     FT_UInt	    glyph;
-    FT_Pos	    advance, all_advance = 0;
+    FT_Pos	    advance, advance_one = 0, advance_two = 0;
-    FcBool	    has_advance = FcFalse, fixed_advance = FcTrue;
+    FcBool	    has_advance = FcFalse, fixed_advance = FcTrue, dual_advance = FcFalse;
 
     fcs = FcCharSetCreate ();
     if (!fcs)
@@ -1851,10 +1853,20 @@ FcFreeTypeCharSetAndSpacing (FT_Face face, FcBlanks *blanks, int *spacing)
 		    if (!has_advance)
 		    {
 			has_advance = FcTrue;
-			all_advance = advance;
+			advance_one = advance;
 		    }
-		    else if (advance != all_advance)
+		    else if (!APPROXIMATELY_EQUAL (advance, advance_one))
-			fixed_advance = FcFalse;
+                    {
+                        if (fixed_advance)
+                        {
+                            dual_advance = FcTrue;
+                            fixed_advance = FcFalse;
+                            advance_two = advance;
+                        }
+                        else if (!APPROXIMATELY_EQUAL (advance, advance_two))
+                            dual_advance = FcFalse;
+                    }
+
 		    leaf = FcCharSetFindLeafCreate (fcs, ucs4);
 		    if (!leaf)
 			goto bail1;
@@ -1899,10 +1911,20 @@ FcFreeTypeCharSetAndSpacing (FT_Face face, FcBlanks *blanks, int *spacing)
 			if (!has_advance)
 			{
 			    has_advance = FcTrue;
-			    all_advance = advance;
+			    advance_one = advance;
 			}
-			else if (advance != all_advance)
+		        else if (!APPROXIMATELY_EQUAL (advance, advance_one))
-			    fixed_advance = FcFalse;
+                        {
+                            if (fixed_advance)
+                            {
+                                dual_advance = FcTrue;
+                                fixed_advance = FcFalse;
+                                advance_two = advance;
+                            }
+                            else if (!APPROXIMATELY_EQUAL (advance, advance_two))
+                                dual_advance = FcFalse;
+                        }
+
 			if (!leaf)
 			{
 			    leaf = FcCharSetFindLeafCreate (fcs, ucs4);
@@ -1956,10 +1978,19 @@ FcFreeTypeCharSetAndSpacing (FT_Face face, FcBlanks *blanks, int *spacing)
 		    if (!has_advance)
 		    {
 			has_advance = FcTrue;
-			all_advance = advance;
+			advance_one = advance;
 		    }
-		    else if (advance != all_advance)
+		    else if (!APPROXIMATELY_EQUAL (advance, advance_one))
-			fixed_advance = FcFalse;
+                    {
+                        if (fixed_advance)
+                        {
+                            dual_advance = FcTrue;
+                            fixed_advance = FcFalse;
+                            advance_two = advance;
+                        }
+                        else if (!APPROXIMATELY_EQUAL (advance, advance_two))
+                            dual_advance = FcFalse;
+                    }
 		    leaf = FcCharSetFindLeafCreate (fcs, ucs4);
 		    if (!leaf)
 			goto bail1;
@@ -1993,6 +2024,8 @@ FcFreeTypeCharSetAndSpacing (FT_Face face, FcBlanks *blanks, int *spacing)
 #endif
     if (fixed_advance)
 	*spacing = FC_MONO;
+    else if (dual_advance && APPROXIMATELY_EQUAL (2 * MIN (advance_one, advance_two), MAX (advance_one, advance_two)))
+        *spacing = FC_DUAL;
     else
 	*spacing = FC_PROPORTIONAL;
     return fcs;

src/fcname.c

@@ -167,6 +167,7 @@ static const FcConstant _FcBaseConstants[] = {
     { (FcChar8 *) "ultraexpanded",  "width",	FC_WIDTH_ULTRAEXPANDED },
     
     { (FcChar8 *) "proportional",   "spacing",  FC_PROPORTIONAL, },
+    { (FcChar8 *) "dual",	    "spacing",  FC_DUAL, },
     { (FcChar8 *) "mono",	    "spacing",  FC_MONO, },
     { (FcChar8 *) "charcell",	    "spacing",  FC_CHARCELL, },