bug 603879 - part 2 - update harfbuzz integration to support arabic etc shaping. r=jdaggett a=blocking2.0

gfx/thebes/gfxHarfBuzzShaper.cpp

@@ -205,12 +205,13 @@ struct HMetrics {
 };
 
 void
-gfxHarfBuzzShaper::GetGlyphMetrics(gfxContext *aContext,
+gfxHarfBuzzShaper::GetGlyphAdvance(gfxContext *aContext,
                                    hb_codepoint_t glyph,
-                                   hb_glyph_metrics_t *metrics) const
+                                   hb_position_t *x_advance,
+                                   hb_position_t *y_advance) const
 {
     if (mUseHintedWidths) {
-        metrics->x_advance = mFont->GetHintedGlyphWidth(aContext, glyph);
+        *x_advance = mFont->GetHintedGlyphWidth(aContext, glyph);
         return;
     }
 
@@ -229,21 +230,20 @@ gfxHarfBuzzShaper::GetGlyphMetrics(gfxContext *aContext,
     // to contain mNumLongMetrics records
     const HMetrics* hmtx =
         reinterpret_cast<const HMetrics*>(hb_blob_lock(mHmtxTable));
-    metrics->x_advance =
+    *x_advance =
         FloatToFixed(mFont->FUnitsToDevUnitsFactor() *
                      PRUint16(hmtx->metrics[glyph].advanceWidth));
     hb_blob_unlock(mHmtxTable);
-
-    // TODO: set additional metrics if/when harfbuzz needs them
 }
 
 static void
-HBGetGlyphMetrics(hb_font_t *font, hb_face_t *face, const void *user_data,
-                  hb_codepoint_t glyph, hb_glyph_metrics_t *metrics)
+HBGetGlyphAdvance(hb_font_t *font, hb_face_t *face, const void *user_data,
+                  hb_codepoint_t glyph,
+                  hb_position_t *x_advance, hb_position_t *y_advance)
 {
     const FontCallbackData *fcd =
         static_cast<const FontCallbackData*>(user_data);
-    fcd->mShaper->GetGlyphMetrics(fcd->mContext, glyph, metrics);
+    fcd->mShaper->GetGlyphAdvance(fcd->mContext, glyph, x_advance, y_advance);
 }
 
 static hb_bool_t
@@ -711,8 +711,8 @@ gfxHarfBuzzShaper::InitTextRun(gfxContext *aContext,
             // harfbuzz shaper used
             sHBFontFuncs = hb_font_funcs_copy(hb_font_funcs_create());
             hb_font_funcs_set_glyph_func(sHBFontFuncs, HBGetGlyph);
-            hb_font_funcs_set_glyph_metrics_func(sHBFontFuncs,
-                                                 HBGetGlyphMetrics);
+            hb_font_funcs_set_glyph_advance_func(sHBFontFuncs,
+                                                 HBGetGlyphAdvance);
             hb_font_funcs_set_contour_point_func(sHBFontFuncs,
                                                  HBGetContourPoint);
             hb_font_funcs_set_kerning_func(sHBFontFuncs, HBGetKerning);

gfx/thebes/gfxHarfBuzzShaper.h

@@ -64,10 +64,11 @@ public:
     hb_codepoint_t GetGlyph(hb_codepoint_t unicode,
                             hb_codepoint_t variation_selector) const;
 
-    // get harfbuzz glyph metrics, in font design units
-    void GetGlyphMetrics(gfxContext *aContext,
+    // get harfbuzz glyph advance, in font design units
+    void GetGlyphAdvance(gfxContext *aContext,
                          hb_codepoint_t glyph,
-                         hb_glyph_metrics_t *metrics) const;
+                         hb_position_t *x_advance,
+                         hb_position_t *y_advance) const;
 
     hb_position_t GetKerning(PRUint16 aFirstGlyph,
                              PRUint16 aSecondGlyph) const;

gfx/thebes/gfxMacPlatformFontList.mm

@@ -193,7 +193,7 @@ struct ScriptRange {
 };
 
 const ScriptRange gScriptsThatRequireShaping[] = {
-    { eComplexScriptArabic, 0x0600, 0x077F },   // Basic Arabic and Arabic Supplement
+    { eComplexScriptArabic, 0x0600, 0x077F },   // Basic Arabic, Syriac, Arabic Supplement
     { eComplexScriptIndic, 0x0900, 0x0D7F },     // Indic scripts - Devanagari, Bengali, ..., Malayalam
     { eComplexScriptTibetan, 0x0F00, 0x0FFF }     // Tibetan
     // Thai seems to be "renderable" without AAT morphing tables
@@ -261,8 +261,10 @@ MacOSFontEntry::ReadCMAP()
             } else if (whichScript == eComplexScriptArabic) {
                 // special-case for Arabic:
                 // even if there's no morph table, CoreText can shape Arabic
-                // using OpenType layout
-                if (hasOTLayout) {
+                // using OpenType layout; or if it's a downloaded font,
+                // assume the site knows what it's doing (as harfbuzz will
+                // be able to shape even though the font itself lacks tables)
+                if (hasOTLayout || (mIsUserFont && !mIsLocalUserFont)) {
                     // TODO: to be really thorough, we could check that the
                     // GSUB table actually supports the 'arab' script tag.
                     omitRange = PR_FALSE;

gfx/thebes/gfxUnicodeProperties.cpp

@@ -152,23 +152,45 @@ gfxUnicodeProperties::GetScriptCode(PRUint32 aCh)
 // function, is compared to the gfx.font_rendering.harfbuzz.level
 // preference to decide whether to use the harfbuzz shaper.
 //
-// Currently, we only distinguish "simple" (level 1) scripts
-// and "the rest" (level 2), but may subdivide this further in
-// the future.
+// Currently, we only distinguish "simple" (level 1) scripts,
+// Arabic-style cursive scripts (level 2),
+// and "Indic or other complex scripts" (level 3),
+// but may subdivide this further in the future.
 PRInt32
 gfxUnicodeProperties::ScriptShapingLevel(PRInt32 aScriptCode)
 {
     switch (aScriptCode) {
-    case HB_SCRIPT_LATIN:
-    case HB_SCRIPT_CYRILLIC:
-    case HB_SCRIPT_HAN:
-    case HB_SCRIPT_HIRAGANA:
-    case HB_SCRIPT_KATAKANA:
-    case HB_SCRIPT_COMMON:
-    case HB_SCRIPT_INHERITED:
-    case HB_SCRIPT_UNKNOWN:
-        return 1; // level 1: common scripts that can use "generic" shaping
-    }
+    default:
+        return 1; // scripts not explicitly listed here are considered
+                  // level 1: default shaping behavior is adequate
 
-    return 2; // all others are considered level 2
+    case HB_SCRIPT_ARABIC:
+    case HB_SCRIPT_SYRIAC:
+    case HB_SCRIPT_NKO:
+        return 2; // level 2: bidi scripts with Arabic-style shaping
+
+    case HB_SCRIPT_HEBREW:
+    case HB_SCRIPT_HANGUL:
+    case HB_SCRIPT_BENGALI:
+    case HB_SCRIPT_DEVANAGARI:
+    case HB_SCRIPT_GUJARATI:
+    case HB_SCRIPT_GURMUKHI:
+    case HB_SCRIPT_KANNADA:
+    case HB_SCRIPT_MALAYALAM:
+    case HB_SCRIPT_ORIYA:
+    case HB_SCRIPT_TAMIL:
+    case HB_SCRIPT_TELUGU:
+    case HB_SCRIPT_KHMER:
+    case HB_SCRIPT_THAI:
+    case HB_SCRIPT_LAO:
+    case HB_SCRIPT_TIBETAN:
+    case HB_SCRIPT_NEW_TAI_LUE:
+    case HB_SCRIPT_TAI_LE:
+    case HB_SCRIPT_MONGOLIAN:
+    case HB_SCRIPT_MYANMAR:
+    case HB_SCRIPT_PHAGS_PA:
+    case HB_SCRIPT_BATAK:
+    case HB_SCRIPT_BRAHMI:
+        return 3; // scripts that require Indic or other "special" shaping
+    }
 }

modules/libpref/src/init/all.js

@@ -199,7 +199,7 @@ pref("gfx.downloadable_fonts.sanitize.preserve_otl_tables", false);
 pref("gfx.downloadable_fonts.sanitize.preserve_otl_tables", true);
 #endif
 
-pref("gfx.font_rendering.harfbuzz.level", 1);
+pref("gfx.font_rendering.harfbuzz.level", 2);
 
 #ifdef XP_WIN
 #ifndef WINCE