SkFontMgr for Android.

src/ports/SkFontMgr_android.cpp

Index: src/ports/SkFontMgr_android.cpp
diff --git a/src/ports/SkFontMgr_android.cpp b/src/ports/SkFontMgr_android.cpp
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+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkFontConfigParser_android.h"
+#include "SkFontDescriptor.h"
+#include "SkFontHost_FreeType_common.h"
+#include "SkFontMgr.h"
+#include "SkFontStyle.h"
+#include "SkStream.h"
+#include "SkTDArray.h"
+#include "SkTSearch.h"
+#include "SkTypeface.h"
+#include "SkTypefaceCache.h"
+
+#include <limits>
+#include <stdlib.h>
+
+#ifndef SK_FONT_FILE_PREFIX
+#    define SK_FONT_FILE_PREFIX "/fonts/"
+#endif
+
+#ifndef SK_DEBUG_FONTS
+    #define SK_DEBUG_FONTS 0
+#endif
+
+#if SK_DEBUG_FONTS
+#    define DEBUG_FONT(args) SkDebugf args
+#else
+#    define DEBUG_FONT(args)
+#endif
+
+class SkTypeface_Android : public SkTypeface_FreeType {
+public:
+    SkTypeface_Android(int index,
+                       Style style,
+                       bool isFixedPitch,
+                       const SkString familyName)
+        : INHERITED(style, SkTypefaceCache::NewFontID(), isFixedPitch)
+        , fIndex(index)
+        , fFamilyName(familyName)
+    { }
+
+    const SkString& name() const { return fFamilyName; }
+
+protected:
+    int fIndex;
+    SkString fFamilyName;
+
+private:
+    typedef SkTypeface_FreeType INHERITED;
+};
+
+class SkTypeface_AndroidSystem : public SkTypeface_Android {
+public:
+    SkTypeface_AndroidSystem(const SkString pathName,
+                             int index,
+                             Style style,
+                             bool isFixedPitch,
+                             const SkString familyName)
+        : INHERITED(index, style, isFixedPitch, familyName)
+        , fPathName(pathName)
+    { }
+
+    virtual void onGetFontDescriptor(SkFontDescriptor* desc,
+                                     bool* serialize) const SK_OVERRIDE
+    {
+        SkASSERT(desc);
+        SkASSERT(serialize);
+        desc->setFamilyName(fFamilyName.c_str());
+        desc->setFontFileName(fPathName.c_str());
+        *serialize = false;
+    }
+    virtual SkStream* onOpenStream(int* ttcIndex) const SK_OVERRIDE {
+        *ttcIndex = fIndex;
+        return SkStream::NewFromFile(fPathName.c_str());
+    }
+
+private:
+    SkString fPathName;
+
+    typedef SkTypeface_Android INHERITED;
+};
+
+class SkTypeface_AndroidStream : public SkTypeface_Android {
+public:
+    SkTypeface_AndroidStream(SkStream* stream,
+                             int index,
+                             Style style,
+                             bool isFixedPitch,
+                             const SkString familyName)
+        : INHERITED(index, style, isFixedPitch, familyName)
+        , fStream(stream)
+    { }
+
+    virtual void onGetFontDescriptor(SkFontDescriptor* desc,
+                                     bool* serialize) const SK_OVERRIDE {
+        SkASSERT(desc);
+        SkASSERT(serialize);
+        desc->setFamilyName(fFamilyName.c_str());
+        desc->setFontFileName(NULL);
+        *serialize = true;
+    }
+
+    virtual SkStream* onOpenStream(int* ttcIndex) const SK_OVERRIDE {
+        *ttcIndex = fIndex;
+        return fStream->duplicate();
+    }
+
+private:
+    SkAutoTUnref<SkStream> fStream;
+
+    typedef SkTypeface_Android INHERITED;
+};
+
+void get_path_for_sys_fonts(SkString* full, const SkString& name) {
+    full->set(getenv("ANDROID_ROOT"));
+    full->append(SK_FONT_FILE_PREFIX);
+    full->append(name);
+}
+
+class SkFontStyleSet_Android : public SkFontStyleSet {
+public:
+    explicit SkFontStyleSet_Android(FontFamily* family) : fFontFamily(family) {
+        // TODO? make this lazy
+        for (int i = 0; i < family->fFontFiles.count(); ++i) {
+            const SkString& fileName = family->fFontFiles[i].fFileName;
+
+            SkString pathName;
+            get_path_for_sys_fonts(&pathName, fileName);
+
+            SkAutoTUnref<SkStream> stream(SkStream::NewFromFile(pathName.c_str()));
+            if (!stream.get()) {
+                DEBUG_FONT(("---- SystemFonts[%d] file=%s (NOT EXIST)", i, filename.c_str()));
+                continue;
+            }
+
+            SkString fontName;
+            SkTypeface::Style style;
+            bool isFixedWidth;
+            if (!SkTypeface_FreeType::ScanFont(stream.get(), family->fFontFiles[i].fIndex,
+                                               &fontName, &style, &isFixedWidth))
+            {
+                DEBUG_FONT(("---- SystemFonts[%d] file=%s (INVALID)", i, filename.c_str()));
+                continue;
+            }
+
+            fStyles.push_back().reset(SkNEW_ARGS(SkTypeface_AndroidSystem,
+                                                 (pathName, 0,
+                                                  style, isFixedWidth, fontName)));
+        }
+    }
+
+    virtual int count() SK_OVERRIDE {
+        return fStyles.count();
+    }
+    virtual void getStyle(int index, SkFontStyle* style, SkString* name) SK_OVERRIDE {
+        if (index < 0 || fStyles.count() <= index) {
+            return;
+        }
+        if (style) {
+            *style = this->style(index);
+        }
+        if (name) {
+            name->reset();
+        }
+    }
+    virtual SkTypeface* createTypeface(int index) SK_OVERRIDE {
+        if (index < 0 || fStyles.count() <= index) {
+            return NULL;
+        }
+        return SkRef(fStyles[index].get());
+    }
+
+    /** Find the typeface in this style set that most closely matches the given pattern.
+     *  TODO: consider replacing with SkStyleSet_Indirect::matchStyle();
+     *  this simpler version using match_score() passes all our tests.
+     */
+    virtual SkTypeface* matchStyle(const SkFontStyle& pattern) SK_OVERRIDE {
+        if (0 == fStyles.count()) {
+            return NULL;
+        }
+        SkTypeface* closest = fStyles[0];
+        int minScore = std::numeric_limits<int>::max();
+        for (int i = 0; i < fStyles.count(); ++i) {
+            SkFontStyle style = this->style(i);
+            int score = match_score(pattern, style);
+            if (score < minScore) {
+                closest = fStyles[i];
+                minScore = score;
+            }
+        }
+        return SkRef(closest);
+    }
+
+private:
+    SkFontStyle style(int index) {
+        return SkFontStyle(this->weight(index), SkFontStyle::kNormal_Width,
+                           this->slant(index));
+    }
+    SkFontStyle::Weight weight(int index) {
+        if (fStyles[index]->isBold()) return SkFontStyle::kBold_Weight;
+        return SkFontStyle::kNormal_Weight;
+    }
+    SkFontStyle::Slant slant(int index) {
+        if (fStyles[index]->isItalic()) return SkFontStyle::kItalic_Slant;
+        return SkFontStyle::kUpright_Slant;
+    }
+    static int match_score(const SkFontStyle& pattern, const SkFontStyle& candidate) {
+        int score = 0;
+        score += abs((pattern.width() - candidate.width()) * 100);
+        score += abs((pattern.isItalic() == candidate.isItalic()) ? 0 : 1000);
+        score += abs(pattern.weight() - candidate.weight());
+        return score;
+    }
+
+
+    FontFamily* fFontFamily;
+    SkTArray<SkAutoTUnref<SkTypeface>, true> fStyles;
+
+    friend struct NameToFamily;
+    friend class SkFontMgr_Android;
+
+    typedef SkFontStyleSet INHERITED;
+};
+
+/** On Android a single family can have many names, but our API assumes unique names.
+ *  Map names to the back end so that all names for a given family refer to the same
+ *  (non-replicated) set of typefaces.
+ *  SkTDict<> doesn't let us do index-based lookup, so we write our own mapping.
+ */
+struct NameToFamily {
+    SkString name;
+    SkFontStyleSet_Android* styleSet;
+};
+
+class SkFontMgr_Android : public SkFontMgr {
+public:
+    SkFontMgr_Android() {
+        SkTDArray<FontFamily*> fontFamilies;
+        SkFontConfigParser::GetFontFamilies(fontFamilies);
+        this->buildNameToFamilyMap(fontFamilies);
+        this->findDefaultFont();
+    }
+
+protected:
+    /** Returns not how many families we have, but how many unique names
+     *  exist among the families.
+     */
+    virtual int onCountFamilies() const SK_OVERRIDE {
+        return fNameToFamilyMap.count();
+    }
+
+    virtual void onGetFamilyName(int index, SkString* familyName) const SK_OVERRIDE {
+        if (index < 0 || fNameToFamilyMap.count() <= index) {
+            familyName->reset();
+            return;
+        }
+        familyName->set(fNameToFamilyMap[index].name);
+    }
+
+    virtual SkFontStyleSet* onCreateStyleSet(int index) const SK_OVERRIDE {
+        if (index < 0 || fNameToFamilyMap.count() <= index) {
+            return NULL;
+        }
+        return SkRef(fNameToFamilyMap[index].styleSet);
+    }
+
+    virtual SkFontStyleSet* onMatchFamily(const char familyName[]) const SK_OVERRIDE {
+        if (!familyName) {
+            return NULL;
+        }
+        SkAutoAsciiToLC tolc(familyName);
+        for (int i = 0; i < fNameToFamilyMap.count(); ++i) {
+            if (fNameToFamilyMap[i].name.equals(tolc.lc())) {
+                return SkRef(fNameToFamilyMap[i].styleSet);
+            }
+        }
+        return NULL;
+    }
+
+    virtual SkTypeface* onMatchFamilyStyle(const char familyName[],
+                                           const SkFontStyle& style) const SK_OVERRIDE {
+        SkAutoTUnref<SkFontStyleSet> sset(this->matchFamily(familyName));
+        return sset->matchStyle(style);
+    }
+
+    virtual SkTypeface* onMatchFaceStyle(const SkTypeface* typeface,
+                                         const SkFontStyle& style) const SK_OVERRIDE {
+        for (int i = 0; i < fFontStyleSets.count(); ++i) {
+            for (int j = 0; j < fFontStyleSets[i]->fStyles.count(); ++j) {
+                if (fFontStyleSets[i]->fStyles[j] == typeface) {
+                    return fFontStyleSets[i]->matchStyle(style);
+                }
+            }
+        }
+        return NULL;
+    }
+
+    virtual SkTypeface* onCreateFromData(SkData* data, int ttcIndex) const SK_OVERRIDE {
+        SkAutoTUnref<SkStream> stream(new SkMemoryStream(data));
+        return this->createFromStream(stream, ttcIndex);
+    }
+
+    virtual SkTypeface* onCreateFromFile(const char path[], int ttcIndex) const SK_OVERRIDE {
+        SkAutoTUnref<SkStream> stream(SkStream::NewFromFile(path));
+        return stream.get() ? this->createFromStream(stream, ttcIndex) : NULL;
+    }
+
+    virtual SkTypeface* onCreateFromStream(SkStream* s, int ttcIndex) const SK_OVERRIDE {
+        SkAutoTUnref<SkStream> stream(s);
+
+        bool isFixedPitch;
+        SkTypeface::Style style;
+        SkString name;
+        if (!SkTypeface_FreeType::ScanFont(stream, ttcIndex, &name, &style, &isFixedPitch)) {
+            return NULL;
+        }
+        return SkNEW_ARGS(SkTypeface_AndroidStream, (stream.detach(), ttcIndex,
+                                                     style, isFixedPitch, name));
+    }
+
+
+    virtual SkTypeface* onLegacyCreateTypeface(const char familyName[],
+                                               unsigned styleBits) const SK_OVERRIDE {
+        SkTypeface::Style oldStyle = (SkTypeface::Style)styleBits;
+        SkFontStyle style = SkFontStyle(oldStyle & SkTypeface::kBold
+                                                 ? SkFontStyle::kBold_Weight
+                                                 : SkFontStyle::kNormal_Weight,
+                                        SkFontStyle::kNormal_Width,
+                                        oldStyle & SkTypeface::kItalic
+                                                 ? SkFontStyle::kItalic_Slant
+                                                 : SkFontStyle::kUpright_Slant);
+        SkTypeface* tf = NULL;
+
+        if (NULL != familyName) {
+            // On Android, we must return NULL when we can't find the requested
+            // named typeface so that the system/app can provide their own recovery
+            // mechanism. On other platforms we'd provide a typeface from the
+            // default family instead.
+            tf = this->onMatchFamilyStyle(familyName, style);
+        } else {
+            tf = fDefaultFamily->matchStyle(style);
+        }
+
+        // TODO: double ref? qv matchStyle()
+        return SkSafeRef(tf);
+    }
+
+
+private:
+
+    SkTArray<SkAutoTUnref<SkFontStyleSet_Android>, true> fFontStyleSets;
+    SkFontStyleSet* fDefaultFamily;
+    SkTypeface* fDefaultTypeface;
+
+    SkTDArray<NameToFamily> fNameToFamilyMap;
+
+    void buildNameToFamilyMap(SkTDArray<FontFamily*> families) {
+        for (int i = 0; i < families.count(); i++) {
+            fFontStyleSets.push_back().reset(
+                SkNEW_ARGS(SkFontStyleSet_Android, (families[i])));
+            for (int j = 0; j < families[i]->fNames.count(); j++) {
+                NameToFamily* nextEntry = fNameToFamilyMap.append();
+                SkNEW_PLACEMENT_ARGS(&nextEntry->name, SkString, (families[i]->fNames[j]));
+                nextEntry->styleSet = fFontStyleSets.back().get();
+            }
+        }
+    }
+
+    void findDefaultFont() {
+        SkASSERT(!fFontStyleSets.empty());
+
+        static const char* gDefaultNames[] = { "sans-serif" };
+        for (size_t i = 0; i < SK_ARRAY_COUNT(gDefaultNames); ++i) {
+            SkFontStyleSet* set = this->onMatchFamily(gDefaultNames[i]);
+            if (NULL == set) {
+                continue;
+            }
+            SkTypeface* tf = set->matchStyle(SkFontStyle());
+            if (NULL == tf) {
+                continue;
+            }
+            fDefaultFamily = set;
+            fDefaultTypeface = tf;
+            break;
+        }
+        if (NULL == fDefaultTypeface) {
+            fDefaultFamily = fFontStyleSets[0];
+            fDefaultTypeface = fDefaultFamily->createTypeface(0);
+        }
+        SkASSERT(fDefaultFamily);
+        SkASSERT(fDefaultTypeface);
+    }
+
+    typedef SkFontMgr INHERITED;
+};
+
+///////////////////////////////////////////////////////////////////////////////
+
+SkFontMgr* SkFontMgr::Factory() {
+    return SkNEW(SkFontMgr_Android);
+}