Wire up Skia axis parameters to HarfBuzz

third_party/WebKit/Source/platform/fonts/shaping/HarfBuzzFace.cpp

 /*
  * Copyright (c) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 369 matching lines @@
   return cacheEntry;
 }
 
 hb_font_t* HarfBuzzFace::getScaledFont(
     PassRefPtr<UnicodeRangeSet> rangeSet) const {
   m_platformData->setupPaint(&m_harfBuzzFontData->m_paint);
   m_harfBuzzFontData->m_paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
   m_harfBuzzFontData->m_rangeSet = rangeSet;
   m_harfBuzzFontData->updateSimpleFontData(m_platformData);
 
-  // TODO crbug.com/674879 - Connect variation axis parameters to future
-  // HarfBuzz API here.
   ASSERT(m_harfBuzzFontData->m_simpleFontData);
   int scale = SkiaScalarToHarfBuzzPosition(m_platformData->size());
   hb_font_set_scale(m_unscaledFont, scale, scale);
+
+// TODO: crbug.com/696570 Remove this conditional
+// once HarfBuzz on CrOS is updated.
+#if HB_VERSION_ATLEAST(1, 4, 2)
+  SkTypeface* typeface = m_harfBuzzFontData->m_paint.getTypeface();
+  int axisCount = typeface->getVariationDesignPosition(nullptr, 0);
+  if (axisCount > 0) {
+    Vector<SkFontArguments::VariationPosition::Coordinate> axisValues;
+    axisValues.resize(axisCount);
+    typeface->getVariationDesignPosition(axisValues.data(), axisValues.size());

[bungeman-skia, 2017/03/01 15:33:10]

Note that you should test that this comes back > 0 also. There are cases where
we can determine how many axes there are, but then fail to retrieve them.

+    Vector<float> axisValuesFloat;

[bungeman-skia, 2017/03/01 15:33:10]

Seems like this should be Vector<hb_variation_t> and call hb_font_set_variations
below instead of hb_font_set_var_coords_design. While it might be the case that
the axisValues are written in the order they are in the font, I can't really
guarantee that all the time (which is why the axis tags are in there).

+    axisValuesFloat.resize(axisCount);
+    for (size_t i = 0; i < axisValues.size(); i++) {
+      axisValuesFloat[i] = axisValues[i].value;
+    }
+    hb_font_set_var_coords_design(m_unscaledFont, axisValuesFloat.data(),
+                                  axisValuesFloat.size());
+  }
+#endif
+
   return m_unscaledFont;
 }
 
 }  // namespace blink