Expose API for gx font variation axes.

src/ports/SkFontMgr_fontconfig.cpp

 /*
  * 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 "SkDataTable.h"
 #include "SkFixed.h"
 #include "SkFontDescriptor.h"
@@ skipping 816 matching lines @@
         SkFontStyle style;
         bool isFixedWidth = false;
         if (!fScanner.scanFont(stream, ttcIndex, nullptr, &style, &isFixedWidth, nullptr)) {
             return nullptr;
         }
 
         return new SkTypeface_stream(new SkFontData(stream.detach(), ttcIndex, nullptr, 0), style,
                                      isFixedWidth);
     }
 
+    SkTypeface* onCreateFromStream(SkStreamAsset* s, const FontParameters& params) const override {
+        using Scanner = SkTypeface_FreeType::Scanner;
+        SkAutoTDelete<SkStreamAsset> stream(s);
+        bool isFixedPitch;
+        SkFontStyle style;
+        SkString name;
+        Scanner::AxisDefinitions axisDefinitions;
+        if (!fScanner.scanFont(stream, params.getCollectionIndex(), &name, &style, &isFixedPitch,
+                               &axisDefinitions))
+        {
+            return nullptr;
+        }
+
+        int paramAxisCount;
+        const FontParameters::Axis* paramAxes = params.getAxes(&paramAxisCount);
+        SkAutoSTMalloc<4, SkFixed> axisValues(axisDefinitions.count());
+        Scanner::computeAxisValues(axisDefinitions, paramAxes, paramAxisCount, axisValues, name);
+
+        SkFontData* data(new SkFontData(stream.detach(), params.getCollectionIndex(),
+                                        axisValues.get(), axisDefinitions.count()));
+        return new SkTypeface_stream(data, style, isFixedPitch);
+    }
+
     SkTypeface* onCreateFromData(SkData* data, int ttcIndex) const override {
         return this->createFromStream(new SkMemoryStream(data), ttcIndex);
     }
 
     SkTypeface* onCreateFromFile(const char path[], int ttcIndex) const override {
         return this->createFromStream(SkStream::NewFromFile(path), ttcIndex);
     }
 
     SkTypeface* onCreateFromFontData(SkFontData* fontData) const override {
         SkStreamAsset* stream(fontData->getStream());
@@ skipping 26 matching lines @@
             return typeface.detach();
         }
 
         return this->matchFamilyStyle(nullptr, style);
     }
 };
 
 SK_API SkFontMgr* SkFontMgr_New_FontConfig(FcConfig* fc) {
     return new SkFontMgr_fontconfig(fc);
 }