ICU layout patches for xetex: support non-OpenType kerning, enable localized forms by default

git-svn-id: svn://tug.org/texlive/trunk@2092 c570f23f-e606-0410-a88d-b1316a301751

4 files changed, 42 insertions, 8 deletions

diff --git a/Build/source/libs/icu-xetex/layout/LEFontInstance.cpp b/Build/source/libs/icu-xetex/layout/LEFontInstance.cpp
index 0bbb627946f..e36c2a0fc68 100644
--- a/Build/source/libs/icu-xetex/layout/LEFontInstance.cpp
+++ b/Build/source/libs/icu-xetex/layout/LEFontInstance.cpp
@@ -81,5 +81,11 @@ LEGlyphID LEFontInstance::mapCharToGlyph(LEUnicode32 ch, const LECharMapper *map
 
     return mapCharToGlyph(mappedChar);
 }
+
+void LEFontInstance::getKernPair(LEGlyphID leftGlyph, LEGlyphID rightGlyph, LEPoint &kern) const
+{
+    kern.fX = kern.fY = 0;
+}
+
 U_NAMESPACE_END
 
diff --git a/Build/source/libs/icu-xetex/layout/LEFontInstance.h b/Build/source/libs/icu-xetex/layout/LEFontInstance.h
index d1b4d77e57c..37a6c98cabc 100644
--- a/Build/source/libs/icu-xetex/layout/LEFontInstance.h
+++ b/Build/source/libs/icu-xetex/layout/LEFontInstance.h
@@ -495,6 +495,11 @@ public:
      * Returns true if writing direction is vertical.
      */
     virtual inline bool getLayoutDirVertical() const;
+
+    /**
+     * Returns kern value for a glyph pair, if the font has a kern pair list.
+     */
+    virtual void getKernPair(LEGlyphID leftGlyph, LEGlyphID rightGlyph, LEPoint &kern) const;
 };
 
 inline le_bool LEFontInstance::canDisplay(LEUnicode32 ch) const
diff --git a/Build/source/libs/icu-xetex/layout/LayoutEngine.cpp b/Build/source/libs/icu-xetex/layout/LayoutEngine.cpp
index 4cd18710d02..eff598cf280 100644
--- a/Build/source/libs/icu-xetex/layout/LayoutEngine.cpp
+++ b/Build/source/libs/icu-xetex/layout/LayoutEngine.cpp
@@ -301,9 +301,25 @@ void LayoutEngine::adjustGlyphPositions(const LEUnicode chars[], le_int32 offset
 
     if (fTypoFlags & 0x1) { /* kerning enabled */
       static const le_uint32 kernTableTag = LE_KERN_TABLE_TAG;
-
-      KernTable kt(fFontInstance, getFontTable(kernTableTag));
-      kt.process(glyphStorage);
+      const void* kernTableData = getFontTable(kernTableTag);
+      if (kernTableData != NULL) {
+        KernTable kt(fFontInstance, getFontTable(kernTableTag));
+        kt.process(glyphStorage);
+      }
+      else { /* no 'kern' table, but the font might know kern pairs from an AFM file, for instance */
+        float xAdjust = 0.0, yAdjust = 0.0;
+        LEGlyphID leftGlyph = glyphStorage.getGlyphID(0, success);
+        for (le_int32 i = 1; i < glyphStorage.getGlyphCount(); ++i) {
+          LEGlyphID rightGlyph = glyphStorage.getGlyphID(i, success);
+          LEPoint   kern;
+          fFontInstance->getKernPair(leftGlyph, rightGlyph, kern);
+          xAdjust += fFontInstance->xUnitsToPoints(kern.fX);
+          yAdjust += fFontInstance->yUnitsToPoints(kern.fY);
+          glyphStorage.adjustPosition(i, xAdjust, yAdjust, success);
+          leftGlyph = rightGlyph;
+        }
+        glyphStorage.adjustPosition(glyphStorage.getGlyphCount(), xAdjust, yAdjust, success);
+      }
     }
 
     // default is no adjustments
diff --git a/Build/source/libs/icu-xetex/layout/OpenTypeLayoutEngine.cpp b/Build/source/libs/icu-xetex/layout/OpenTypeLayoutEngine.cpp
index e87afd98ef9..6df05c19312 100644
--- a/Build/source/libs/icu-xetex/layout/OpenTypeLayoutEngine.cpp
+++ b/Build/source/libs/icu-xetex/layout/OpenTypeLayoutEngine.cpp
@@ -29,6 +29,7 @@ UOBJECT_DEFINE_RTTI_IMPLEMENTATION(OpenTypeLayoutEngine)
 static const LETag emptyTag = 0x00000000;
 
 static const LETag ccmpFeatureTag = LE_CCMP_FEATURE_TAG;
+static const LETag loclFeatureTag = LE_LOCL_FEATURE_TAG;
 static const LETag ligaFeatureTag = LE_LIGA_FEATURE_TAG;
 static const LETag cligFeatureTag = LE_CLIG_FEATURE_TAG;
 static const LETag kernFeatureTag = LE_KERN_FEATURE_TAG;
@@ -39,18 +40,18 @@ static const LETag dligFeatureTag = 0x646C6967; // 'dlig' not used at the moment
 static const LETag paltFeatureTag = 0x70616C74; // 'palt'
 
 // default has no ligatures, that's what java does.  this is the minimal set.
-static const LETag minimalFeatures[] = {ccmpFeatureTag, markFeatureTag, mkmkFeatureTag, emptyTag};
+static const LETag minimalFeatures[] = {ccmpFeatureTag, loclFeatureTag, markFeatureTag, mkmkFeatureTag, emptyTag};
 
 // kerning (kern, palt following adobe recommendation for cjk 'kerning') but no ligatures.
-static const LETag kernFeatures[] = {ccmpFeatureTag, kernFeatureTag, paltFeatureTag, 
+static const LETag kernFeatures[] = {ccmpFeatureTag, loclFeatureTag, kernFeatureTag, paltFeatureTag, 
 				     markFeatureTag, mkmkFeatureTag, emptyTag};
 
 // ligatures (liga, clig) but no kerning.  omit dlig for now.
-static const LETag ligaFeatures[] = {ccmpFeatureTag, ligaFeatureTag, cligFeatureTag, markFeatureTag, 
+static const LETag ligaFeatures[] = {ccmpFeatureTag, loclFeatureTag, ligaFeatureTag, cligFeatureTag, markFeatureTag, 
 				     mkmkFeatureTag, emptyTag};
 
 // kerning and ligatures.
-static const LETag kernAndLigaFeatures[] = {ccmpFeatureTag, ligaFeatureTag, cligFeatureTag, 
+static const LETag kernAndLigaFeatures[] = {ccmpFeatureTag, loclFeatureTag, ligaFeatureTag, cligFeatureTag, 
 					    kernFeatureTag, paltFeatureTag, markFeatureTag, mkmkFeatureTag, emptyTag};
 
 
@@ -241,8 +242,10 @@ void OpenTypeLayoutEngine::adjustGlyphPositions(const LEUnicode chars[], le_int3
     }
 
     le_int32 glyphCount = glyphStorage.getGlyphCount();
+    if (glyphCount == 0)
+        return;
 
-    if (glyphCount > 0 && fGPOSTable != NULL) {
+    if (fGPOSTable != NULL) {
         GlyphPositionAdjustments *adjustments = new GlyphPositionAdjustments(glyphCount);
         le_int32 i;
 
@@ -300,6 +303,10 @@ void OpenTypeLayoutEngine::adjustGlyphPositions(const LEUnicode chars[], le_int3
 
         delete adjustments;
     }
+    else {
+        // if there was no GPOS table, maybe there's non-OpenType kerning we can use
+        LayoutEngine::adjustGlyphPositions(chars, offset, count, reverse, glyphStorage, success);
+    }
 
 #if 0
     // Don't know why this is here...