Update PDF backend to support fallback fonts on Android.

src/ports/SkFontConfigInterface_android.cpp

 
 /*
  * Copyright 2013 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkFontConfigInterface.h"
 #include "SkTypeface_android.h"
@@ skipping 85 matching lines @@
      *  contains the specified chararacter. if no font is found, returns false.
      */
     bool getFallbackFamilyNameForChar(SkUnichar uni, const char* lang, SkString* name);
     /**
      *
      */
     SkTypeface* getTypefaceForChar(SkUnichar uni, SkTypeface::Style style,
                                    SkPaintOptionsAndroid::FontVariant fontVariant);
     SkTypeface* nextLogicalTypeface(SkFontID currFontID, SkFontID origFontID,
                                     const SkPaintOptionsAndroid& options);
+    SkTypeface* getTypefaceForGlyphID(uint16_t glyphID, const SkTypeface* origTypeface,
+                                      const SkPaintOptionsAndroid& options,
+                                      int* lowerBounds, int* upperBounds);
 
 private:
     void addFallbackFamily(FamilyRecID fontRecID);
     SkTypeface* getTypefaceForFontRec(FontRecID fontRecID);
     FallbackFontList* getCurrentLocaleFallbackFontList();
     FallbackFontList* findFallbackFontList(const SkLanguage& lang, bool isOriginal = true);
 
     SkTArray<FontRec> fFonts;
     SkTArray<FamilyRec> fFontFamilies;
     SkTDict<FamilyRecID> fFamilyNameDict;
@@ skipping 547 matching lines @@
     }
 
     DEBUG_FONT(("---- nextLogicalFont: currFontID=%d, origFontID=%d, currRecID=%d, "
                 "lang=%s, variant=%d, nextFallbackIndex[%d,%d] => nextLogicalTypeface=%d",
                 currFontID, origFontID, currFontRecID, opts.getLanguage().getTag().c_str(),
                 variant, nextFallbackFontIndex, currentFallbackList->getAt(nextFallbackFontIndex),
                 (nextLogicalTypeface) ? nextLogicalTypeface->uniqueID() : 0));
     return SkSafeRef(nextLogicalTypeface);
 }
 
+SkTypeface* SkFontConfigInterfaceAndroid::getTypefaceForGlyphID(uint16_t glyphID,
+                                                                const SkTypeface* origTypeface,
+                                                                const SkPaintOptionsAndroid& opts,
+                                                                int* lBounds, int* uBounds) {
+    // Skia does not support font fallback by default. This enables clients such
+    // as WebKit to customize their font selection. In any case, clients can use
+    // GetFallbackFamilyNameForChar() to get the fallback font for individual
+    // characters.
+    if (!opts.isUsingFontFallbacks()) {
+        return NULL;
+    }
+
+    SkTypeface* currentTypeface = NULL;
+    int lowerBounds = 0; //inclusive
+    int upperBounds = origTypeface->countGlyphs(); //exclusive
+
+    // check to see if the glyph is in the bounds of the origTypeface
+    if (glyphID < upperBounds) {
+        currentTypeface = const_cast<SkTypeface*>(origTypeface);

[scroggo, 2013/10/01 21:00:14]

It appears you do not modify currentTypeface. It seems weird to do this cast
here.

[djsollen, 2013/10/02 16:16:41]

But I do return that value and I can't return a const SkTypeface*

+    } else {
+        FallbackFontList* currentFallbackList = findFallbackFontList(opts.getLanguage());
+        SkASSERT(currentFallbackList);
+
+        // If an object is set to prefer "kDefault_Variant" it means they have no preference
+        // In this case, we set the value to "kCompact_Variant"
+        SkPaintOptionsAndroid::FontVariant variant = opts.getFontVariant();
+        if (variant == SkPaintOptionsAndroid::kDefault_Variant) {
+            variant = SkPaintOptionsAndroid::kCompact_Variant;
+        }
+
+        int32_t acceptedVariants = SkPaintOptionsAndroid::kDefault_Variant | variant;
+        SkTypeface::Style origStyle = origTypeface->style();
+
+        for (int x = 0; x < currentFallbackList->count(); ++x) {
+            FamilyRecID familyRecID = currentFallbackList->getAt(x);
+            if ((fFontFamilies[familyRecID].fPaintOptions.getFontVariant() & acceptedVariants) != 0) {

[scroggo, 2013/10/01 21:00:14]

100 chars

+                FontRecID matchedFont = find_best_style(fFontFamilies[familyRecID], origStyle);
+                currentTypeface = this->getTypefaceForFontRec(matchedFont);
+                lowerBounds = upperBounds;
+                upperBounds += currentTypeface->countGlyphs();
+                if (glyphID < upperBounds) {
+                    break;
+                }
+            }
+        }
+    }
+
+    if (currentTypeface) {

[scroggo, 2013/10/01 21:00:14]

nit: explicit NULL check.

+        if (lBounds) {
+            *lBounds = lowerBounds;
+        }
+        if (uBounds) {
+            *uBounds = upperBounds;
+        }
+    }
+    return SkSafeRef(currentTypeface);

[scroggo, 2013/10/01 21:00:14]

Why not return SkRef(currentTypeface) inside the if block, and return NULL here?

Also, it doesn't look like it gets unreffed?

+}
+
 ///////////////////////////////////////////////////////////////////////////////
 
 bool SkGetFallbackFamilyNameForChar(SkUnichar uni, SkString* name) {
     SkString locale = SkFontConfigParser::GetLocale();
     SkFontConfigInterfaceAndroid* fontConfig = getSingletonInterface();
     return fontConfig->getFallbackFamilyNameForChar(uni, locale.c_str(), name);
 }
 
 bool SkGetFallbackFamilyNameForChar(SkUnichar uni, const char* lang, SkString* name) {
     SkFontConfigInterfaceAndroid* fontConfig = getSingletonInterface();
@@ skipping 12 matching lines @@
               gTestMainConfigFile, gTestFallbackConfigFile, gTestFontFilePrefix));
 }
 
 SkTypeface* SkAndroidNextLogicalTypeface(SkFontID currFontID, SkFontID origFontID,
                                          const SkPaintOptionsAndroid& options) {
     SkFontConfigInterfaceAndroid* fontConfig = getSingletonInterface();
     return fontConfig->nextLogicalTypeface(currFontID, origFontID, options);
 
 }
 
+SkTypeface* SkGetTypefaceForGlyphID(uint16_t glyphID, const SkTypeface* origTypeface,
+                                    const SkPaintOptionsAndroid& options,
+                                    int* lowerBounds, int* upperBounds) {
+    SkFontConfigInterfaceAndroid* fontConfig = getSingletonInterface();
+    return fontConfig->getTypefaceForGlyphID(glyphID, origTypeface, options,
+                                             lowerBounds, upperBounds);
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 
 #ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
 
 struct HB_UnicodeMapping {
     // TODO: when the WebView no longer needs harfbuzz_old, remove
     HB_Script script_old;
     hb_script_t script;
     const SkUnichar unicode;
 };
@@ skipping 136 matching lines @@
     return SkCreateTypefaceForScriptNG(getHBScriptFromHBScriptOld(script), style, fontVariant);
 }
 
 #endif
 
 ///////////////////////////////////////////////////////////////////////////////
 
 SkFontMgr* SkFontMgr::Factory() {
     return NULL;
 }