Apply font variations when drawing text with Skia

Set variations on the Skia font since now we allow the user to set font
variations, and they can be different from the variations the font was
created with. Previously we only supported named instances and these got
their variations set by the platform font API.

Change-Id: I2cda0409273a8ae00f40dacb1deb166af65ebbe5
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/200673
Reviewed-by: Khaled Hosny <khaled@libreoffice.org>
Tested-by: Jenkins

vcl/CppunitTest_vcl_skia.mk

@@ -37,6 +37,7 @@ $(eval $(call gb_CppunitTest_use_libraries,vcl_skia, \
 $(eval $(call gb_CppunitTest_use_externals,vcl_skia, \
 	boost_headers \
 	$(if $(filter SKIA,$(BUILD_TYPE)),skia) \
+	harfbuzz \
 ))
 
 $(eval $(call gb_CppunitTest_use_sdk_api,vcl_skia))

vcl/inc/skia/utils.hxx

@@ -27,12 +27,14 @@
 #include <driverblocklist.hxx>
 #include <vcl/bitmap.hxx>
 #include <vcl/salgtype.hxx>
+#include <font/LogicalFontInstance.hxx>
 
 #include <test/GraphicsRenderTests.hxx>
 
 #include <premac.h>
 #include <SkRegion.h>
 #include <SkSurface.h>
+#include <SkTypeface.h>
 #if defined __GNUC__ && !defined __clang__
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wattributes"
@@ -138,6 +140,9 @@ VCL_DLLPUBLIC const SkSurfaceProps* surfaceProps();
 // Set pixel geometry to be used by SkSurfaceProps.
 VCL_DLLPUBLIC void setPixelGeometry(SkPixelGeometry pixelGeometry);
 
+VCL_DLLPUBLIC sk_sp<SkTypeface> applyVariations(const sk_sp<SkTypeface>& skTypeface,
+                                                const LogicalFontInstance& font);
+
 inline bool isUnitTestRunning(const char* name = nullptr)
 {
     if (name == nullptr)

vcl/skia/SkiaHelper.cxx

@@ -57,6 +57,8 @@ bool isAlphaMaskBlendingEnabled() { return false; }
 #include <SkRuntimeEffect.h>
 #include <SkStream.h>
 #include <SkTileMode.h>
+#include <SkTypeface.h>
+#include <SkFontArguments.h>
 #include <skia_compiler.hxx>
 #include <skia_opts.hxx>
 #if defined(MACOSX)
@@ -909,6 +911,29 @@ void dump(const sk_sp<SkImage>& image, const char* file)
     ostream.write(static_cast<const char*>(data->data()), data->size());
 }
 
+sk_sp<SkTypeface> applyVariations(const sk_sp<SkTypeface>& skTypeface,
+                                  const LogicalFontInstance& font)
+{
+    const auto& variations = font.GetVariations();
+    if (variations.empty() || !skTypeface)
+        return skTypeface;
+
+    std::vector<SkFontArguments::VariationPosition::Coordinate> skCoords;
+    skCoords.reserve(variations.size());
+    for (const auto& var : variations)
+        skCoords.push_back({ var.tag, var.value });
+
+    SkFontArguments fontArgs;
+    SkFontArguments::VariationPosition varPosition
+        = { skCoords.data(), static_cast<int>(skCoords.size()) };
+    fontArgs.setVariationDesignPosition(varPosition);
+
+    sk_sp<SkTypeface> variationFace = skTypeface->makeClone(fontArgs);
+    if (variationFace)
+        return variationFace;
+    return skTypeface;
+}
+
 #ifdef DBG_UTIL
 void prefillSurface(const sk_sp<SkSurface>& surface)
 {

vcl/skia/osx/gdiimpl.cxx

@@ -381,7 +381,8 @@ void AquaSkiaSalGraphicsImpl::drawTextLayout(const GenericSalLayout& rLayout)
         }
     }
 
-    sk_sp<SkTypeface> typeface = SkMakeTypefaceFromCTFont(rFont.GetCTFont());
+    sk_sp<SkTypeface> typeface
+        = SkiaHelper::applyVariations(SkMakeTypefaceFromCTFont(rFont.GetCTFont()), rFont);
     SkFont font(typeface);
     font.setSize(nHeight);
     //    font.setScaleX(rFont.mfFontStretch); TODO

vcl/skia/win/gdiimpl.cxx

@@ -268,6 +268,7 @@ bool WinSkiaSalGraphicsImpl::DrawTextLayout(const GenericSalLayout& rLayout)
             if (!typeface)
                 return false;
         }
+        typeface = SkiaHelper::applyVariations(typeface, rWinFont);
         // Cache the typeface.
         rWinFont.SetSkiaTypeface(typeface, dwrite);
     }

vcl/skia/x11/textrender.cxx

@@ -64,8 +64,9 @@ void SkiaTextRender::DrawTextLayout(const GenericSalLayout& rLayout, const SalGr
         fontManager
             = SkFontMgr_New_FontConfig(FcConfigReference(nullptr), SkFontScanner_Make_FreeType());
     }
-    sk_sp<SkTypeface> typeface
-        = SkFontMgr_createTypefaceFromFcPattern(fontManager, rFont.GetFontOptions()->GetPattern());
+    sk_sp<SkTypeface> typeface = SkiaHelper::applyVariations(
+        SkFontMgr_createTypefaceFromFcPattern(fontManager, rFont.GetFontOptions()->GetPattern()),
+        rInstance);
     SkFont font(typeface);
     font.setSize(nHeight);
     font.setScaleX(nWidth / nHeight);