Font variations.

src/ports/SkFontHost_mac.cpp

Index: src/ports/SkFontHost_mac.cpp
diff --git a/src/ports/SkFontHost_mac.cpp b/src/ports/SkFontHost_mac.cpp
index 3c7be463643b7ceb73a1bcac141777be8bf6428a..ff23b99905117c486e4c682bfbe3339aee5d4ad7 100755
--- a/src/ports/SkFontHost_mac.cpp
+++ b/src/ports/SkFontHost_mac.cpp
@@ -428,10 +428,12 @@ static const uint32_t SkCTFontColorGlyphsTrait = (1 << 13);
 class SkTypeface_Mac : public SkTypeface {
 public:
     SkTypeface_Mac(const SkFontStyle& fs, bool isFixedPitch,
-                   CTFontRef fontRef, const char requestedName[], bool isLocalStream)
+                   CTFontRef fontRef, const char requestedName[], bool isLocalStream,
+                   CGFontRef originatingCGFontRef = NULL)
         : SkTypeface(fs, SkTypefaceCache::NewFontID(), isFixedPitch)
         , fRequestedName(requestedName)
         , fFontRef(fontRef) // caller has already called CFRetain for us
+        , fOriginatingCGFontRef(originatingCGFontRef)
         , fHasColorGlyphs(SkToBool(CTFontGetSymbolicTraits(fFontRef) & SkCTFontColorGlyphsTrait))
         , fIsLocalStream(isLocalStream)
     {
@@ -440,11 +442,13 @@ public:
 
     SkString fRequestedName;
     AutoCFRelease<CTFontRef> fFontRef;
+    AutoCFRelease<CGFontRef> fOriginatingCGFontRef;
     const bool fHasColorGlyphs;
 
 protected:
     int onGetUPEM() const override;
     SkStreamAsset* onOpenStream(int* ttcIndex) const override;
+    SkFontData* onCreateFontData() const override;
     void onGetFamilyName(SkString* familyName) const override;
     SkTypeface::LocalizedStrings* onCreateFamilyNameIterator() const override;
     int onGetTableTags(SkFontTableTag tags[]) const override;
@@ -467,12 +471,15 @@ private:
 };
 
 /** Creates a typeface without searching the cache. Takes ownership of the CTFontRef. */
-static SkTypeface* NewFromFontRef(CTFontRef fontRef, const char name[], bool isLocalStream) {
+static SkTypeface* NewFromFontRef(CTFontRef fontRef, const char name[], bool isLocalStream,
+                                  CGFontRef originatingCGFontRef = NULL)
+{
     SkASSERT(fontRef);
     bool isFixedPitch;
     SkFontStyle style = SkFontStyle(computeStyleBits(fontRef, &isFixedPitch));
 
-    return new SkTypeface_Mac(style, isFixedPitch, fontRef, name, isLocalStream);
+    return new SkTypeface_Mac(style, isFixedPitch, fontRef, name, isLocalStream,
+                              originatingCGFontRef);
 }
 
 static bool find_by_CTFontRef(SkTypeface* cached, const SkFontStyle&, void* context) {
@@ -1752,6 +1759,115 @@ SkStreamAsset* SkTypeface_Mac::onOpenStream(int* ttcIndex) const {
     return stream;
 }
 
+struct NonDefaultAxesContext {
+    SkFixed* axisValue;
+    CFArrayRef cgAxes;
+};
+static void set_non_default_axes(CFTypeRef key, CFTypeRef value, void* context) {
+    NonDefaultAxesContext* self = static_cast<NonDefaultAxesContext*>(context);
+
+    if (CFGetTypeID(key) != CFStringGetTypeID() || CFGetTypeID(value) != CFNumberGetTypeID()) {
+        return;
+    }
+
+    // The key is a CFString which is a string from the 'name' table.
+    // Search the cgAxes for an axis with this name, and use its index to store the value.
+    CFIndex keyIndex = -1;
+    CFStringRef keyString = static_cast<CFStringRef>(key);
+    for (CFIndex i = 0; i < CFArrayGetCount(self->cgAxes); ++i) {
+        CFTypeRef cgAxis = CFArrayGetValueAtIndex(self->cgAxes, i);
+        if (CFGetTypeID(cgAxis) != CFDictionaryGetTypeID()) {
+            continue;
+        }
+
+        CFDictionaryRef cgAxisDict = static_cast<CFDictionaryRef>(cgAxis);
+        CFTypeRef cgAxisName = CFDictionaryGetValue(cgAxisDict, kCGFontVariationAxisName);
+        if (!cgAxisName || CFGetTypeID(cgAxisName) != CFStringGetTypeID()) {
+            continue;
+        }
+        CFStringRef cgAxisNameString = static_cast<CFStringRef>(cgAxisName);
+        if (CFStringCompare(keyString, cgAxisNameString, 0) == kCFCompareEqualTo) {
+            keyIndex = i;
+            break;
+        }
+    }
+    if (keyIndex == -1) {
+        return;
+    }
+
+    CFNumberRef valueNumber = static_cast<CFNumberRef>(value);
+    double valueDouble;
+    if (!CFNumberGetValue(valueNumber, kCFNumberDoubleType, &valueDouble) ||
+        valueDouble < SkFixedToDouble(SK_FixedMin) || SkFixedToDouble(SK_FixedMax) < valueDouble)
+    {
+        return;
+    }
+    self->axisValue[keyIndex] = SkDoubleToFixed(valueDouble);
+}
+static bool get_variations(CTFontRef fFontRef, CFIndex* cgAxisCount,
+                           SkAutoSTMalloc<4, SkFixed>* axisValues)
+{
+    // CTFontCopyVariationAxes and CTFontCopyVariation do not work when applied to fonts which
+    // started life with CGFontCreateWithDataProvider (they simply always return NULL).
+    // As a result, we are limited to CGFontCopyVariationAxes and CGFontCopyVariations.
+    AutoCFRelease<CGFontRef> cgFont(CTFontCopyGraphicsFont(fFontRef, NULL));
+
+    AutoCFRelease<CFDictionaryRef> cgVariations(CGFontCopyVariations(cgFont));
+    // If a font has no variations CGFontCopyVariations returns NULL (instead of an empty dict).
+    if (!cgVariations.get()) {
+        return false;
+    }
+
+    AutoCFRelease<CFArrayRef> cgAxes(CGFontCopyVariationAxes(cgFont));
+    *cgAxisCount = CFArrayGetCount(cgAxes);
+    axisValues->reset(*cgAxisCount);
+
+    // Set all of the axes to their default values.
+    // Fail if any default value cannot be determined.
+    for (CFIndex i = 0; i < *cgAxisCount; ++i) {
+        CFTypeRef cgAxis = CFArrayGetValueAtIndex(cgAxes, i);
+        if (CFGetTypeID(cgAxis) != CFDictionaryGetTypeID()) {
+            return false;
+        }
+
+        CFDictionaryRef cgAxisDict = static_cast<CFDictionaryRef>(cgAxis);
+        CFTypeRef axisDefaultValue = CFDictionaryGetValue(cgAxisDict,
+                                                          kCGFontVariationAxisDefaultValue);
+        if (!axisDefaultValue || CFGetTypeID(axisDefaultValue) != CFNumberGetTypeID()) {
+            return false;
+        }
+        CFNumberRef axisDefaultValueNumber = static_cast<CFNumberRef>(axisDefaultValue);
+        double axisDefaultValueDouble;
+        if (!CFNumberGetValue(axisDefaultValueNumber, kCFNumberDoubleType, &axisDefaultValueDouble))
+        {
+            return false;
+        }
+        if (axisDefaultValueDouble < SkFixedToDouble(SK_FixedMin) ||
+                                     SkFixedToDouble(SK_FixedMax) < axisDefaultValueDouble)
+        {
+            return false;
+        }
+        (*axisValues)[(int)i] = SkDoubleToFixed(axisDefaultValueDouble);
+    }
+
+    // Override the default values with the given font's stated axis values.
+    NonDefaultAxesContext c = { axisValues->get(), cgAxes.get() };
+    CFDictionaryApplyFunction(cgVariations, set_non_default_axes, &c);
+
+    return true;
+}
+SkFontData* SkTypeface_Mac::onCreateFontData() const {
+    int index;
+    SkAutoTDelete<SkStreamAsset> stream(this->onOpenStream(&index));
+
+    CFIndex cgAxisCount;
+    SkAutoSTMalloc<4, SkFixed> axisValues;
+    if (get_variations(fFontRef, &cgAxisCount, &axisValues)) {
+        return new SkFontData(stream.detach(), index, axisValues.get(), cgAxisCount);
+    }
+    return new SkFontData(stream.detach(), index, NULL, 0);
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 ///////////////////////////////////////////////////////////////////////////////
 
@@ -2247,6 +2363,89 @@ protected:
         return create_from_dataProvider(pr);
     }
 
+    static CFDictionaryRef get_axes(CGFontRef cg, SkFontData* fontData) {
+        AutoCFRelease<CFArrayRef> cgAxes(CGFontCopyVariationAxes(cg));
+        if (!cgAxes) {
+            return NULL;
+        }
+
+        CFIndex axisCount = CFArrayGetCount(cgAxes);
+        if (0 == axisCount || axisCount != fontData->getAxisCount()) {
+            return NULL;
+        }
+
+        CFMutableDictionaryRef dict = CFDictionaryCreateMutable(kCFAllocatorDefault, axisCount,
+                                                                &kCFTypeDictionaryKeyCallBacks,
+                                                                &kCFTypeDictionaryValueCallBacks);
+        for (int i = 0; i < fontData->getAxisCount(); ++i) {
+            CFTypeRef axisInfo = CFArrayGetValueAtIndex(cgAxes, i);
+            if (CFDictionaryGetTypeID() != CFGetTypeID(axisInfo)) {
+                return NULL;
+            }
+            CFDictionaryRef axisInfoDict = static_cast<CFDictionaryRef>(axisInfo);
+
+            CFTypeRef axisName = CFDictionaryGetValue(axisInfoDict, kCGFontVariationAxisName);
+            if (!axisName || CFGetTypeID(axisName) != CFStringGetTypeID()) {
+                return NULL;
+            }
+
+            // The variation axes can be set to any value, but cg will effectively pin them.
+            // Pin them here to normalize.
+            CFTypeRef min = CFDictionaryGetValue(axisInfoDict, kCGFontVariationAxisMinValue);
+            CFTypeRef max = CFDictionaryGetValue(axisInfoDict, kCGFontVariationAxisMaxValue);
+            if (!min || CFGetTypeID(min) != CFNumberGetTypeID() ||
+                !max || CFGetTypeID(max) != CFNumberGetTypeID())
+            {
+                return NULL;
+            }
+            CFNumberRef minNumber = static_cast<CFNumberRef>(min);
+            CFNumberRef maxNumber = static_cast<CFNumberRef>(max);
+            double minDouble;
+            double maxDouble;
+            if (!CFNumberGetValue(minNumber, kCFNumberDoubleType, &minDouble) ||
+                !CFNumberGetValue(maxNumber, kCFNumberDoubleType, &maxDouble))
+            {
+                return NULL;
+            }
+            double value = SkTPin(SkFixedToDouble(fontData->getAxis()[i]), minDouble, maxDouble);
+            CFNumberRef valueNumber = CFNumberCreate(kCFAllocatorDefault, kCFNumberDoubleType,
+                                                     &value);
+
+            CFDictionaryAddValue(dict, axisName, valueNumber);
+            CFRelease(valueNumber);
+        }
+        return dict;
+    }
+    SkTypeface* onCreateFromFontData(SkFontData* data) const override {
+        SkAutoTDelete<SkFontData> fontData(data);
+        SkStreamAsset* stream = fontData->detachStream();
+        AutoCFRelease<CGDataProviderRef> provider(SkCreateDataProviderFromStream(stream));
+        if (NULL == provider) {
+            return NULL;
+        }
+        AutoCFRelease<CGFontRef> cg(CGFontCreateWithDataProvider(provider));
+        if (NULL == cg) {
+            return NULL;
+        }
+
+        AutoCFRelease<CFDictionaryRef> cgVariations(get_axes(cg, fontData));
+        // The CGFontRef returned by CGFontCreateCopyWithVariations when the passed CGFontRef was
+        // created from a data provider does not appear to have any ownership of the underlying
+        // data. The original CGFontRef must be kept alive until the copy will no longer be used.
+        AutoCFRelease<CGFontRef> cgVariant;
+        if (cgVariations) {
+            cgVariant.reset(CGFontCreateCopyWithVariations(cg, cgVariations));
+        } else {
+            cgVariant.reset(cg.detach());
+        }
+
+        CTFontRef ct = CTFontCreateWithGraphicsFont(cgVariant, 0, NULL, NULL);
+        if (!ct) {
+            return NULL;
+        }
+        return NewFromFontRef(ct, NULL, true, cg.detach());
+    }
+
     SkTypeface* onCreateFromFile(const char path[], int ttcIndex) const override {
         AutoCFRelease<CGDataProviderRef> pr(CGDataProviderCreateWithFilename(path));
         if (NULL == pr) {