Expose API for gx font variation axes.

include/ports/SkFontMgr.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkFontMgr_DEFINED
 #define SkFontMgr_DEFINED
 
+#include "SkFontStyle.h"
 #include "SkRefCnt.h"
-#include "SkFontStyle.h"
+#include "SkScalar.h"
+#include "SkTypes.h"
 
 class SkData;
 class SkFontData;
 class SkStreamAsset;
 class SkString;
 class SkTypeface;
 
 class SK_API SkFontStyleSet : public SkRefCnt {
 public:
     virtual int count() = 0;
@@ skipping 70 matching lines @@
      */
     SkTypeface* createFromData(SkData*, int ttcIndex = 0) const;
 
     /**
      *  Create a typeface for the specified stream and TTC index
      *  (pass 0 for none) or NULL if the stream is not recognized. The caller
      *  must call unref() on the returned object if it is not null.
      */
     SkTypeface* createFromStream(SkStreamAsset*, int ttcIndex = 0) const;
 
+    struct FontParameters {
+        struct Axis {
+            SkFourByteTag fTag;
+            SkScalar fStyleValue;
+        };
+
+        FontParameters() : fCollectionIndex(0), fAxisCount(0), fAxes(nullptr) {}
+
+        /** Specify the index of the desired font.
+         *
+         *  Font formats like ttc, dfont, cff, cid, pfr, t42, t1, and fon may actually be indexed
+         *  collections of fonts.
+         */
+        FontParameters& setCollectionIndex(int collectionIndex) {
+            fCollectionIndex = collectionIndex;
+            return *this;
+        }
+
+        /** Specify the GX variation axis values.
+         *
+         *  Any axes not specified will use the default value. Specified axes not present in the
+         *  font will be ignored.
+         *
+         *  @param axes not copied. This pointer must remain valid for life of FontParameters.
+         */
+        FontParameters& setAxes(const Axis* axes, int axisCount) {
+            fAxisCount = axisCount;
+            fAxes = axes;
+            return *this;
+        }
+
+        int getCollectionIndex() const {
+            return fCollectionIndex;
+        }
+        const Axis* getAxes(int* axisCount) const {
+            *axisCount = fAxisCount;
+            return fAxes;
+        }
+    private:
+        int fCollectionIndex;
+        int fAxisCount;
+        const Axis* fAxes;
+    };
+    /* Experimental, API subject to change. */
+    SkTypeface* createFromStream(SkStreamAsset*, const FontParameters&) const;
+
     /**
      *  Create a typeface from the specified font data.
      *  Takes ownership of the font data, so the caller should not reference it again.
      *  Will return NULL if the typeface could not be created.
      *  The caller must call unref() on the returned object if it is not null.
      */
     SkTypeface* createFromFontData(SkFontData*) const;
 
     /**
      *  Create a typeface for the specified fileName and TTC index
@@ skipping 24 matching lines @@
                                            const SkFontStyle&) const = 0;
     virtual SkTypeface* onMatchFamilyStyleCharacter(const char familyName[], const SkFontStyle&,
                                                     const char* bcp47[], int bcp47Count,
                                                     SkUnichar character) const = 0;
     virtual SkTypeface* onMatchFaceStyle(const SkTypeface*,
                                          const SkFontStyle&) const = 0;
 
     virtual SkTypeface* onCreateFromData(SkData*, int ttcIndex) const = 0;
     virtual SkTypeface* onCreateFromStream(SkStreamAsset*, int ttcIndex) const = 0;
     // TODO: make pure virtual.
+    virtual SkTypeface* onCreateFromStream(SkStreamAsset*, const FontParameters&) const;
     virtual SkTypeface* onCreateFromFontData(SkFontData*) const;
     virtual SkTypeface* onCreateFromFile(const char path[], int ttcIndex) const = 0;
 
     virtual SkTypeface* onLegacyCreateTypeface(const char familyName[],
                                                unsigned styleBits) const = 0;
 private:
     static SkFontMgr* Factory();    // implemented by porting layer
     friend SkFontMgr* sk_fontmgr_create_default();
 
     typedef SkRefCnt INHERITED;
 };
 
 #endif