Add SkTypeface::makeClone.

This adds an method to typeface to allow users to create a copy of the
typeface with different arguments for its parameters. This is far more
efficient when animating a variation font.

Change-Id: Ie41a5b76bef8eaf05b56b65774eaf38aad0dc4cf
Reviewed-on: https://skia-review.googlesource.com/132934
Commit-Queue: Bruce Wang <brucewang@google.com>
Reviewed-by: Bruce Wang <brucewang@google.com>
Reviewed-by: Ben Wagner <bungeman@google.com>

3 files changed, 63 insertions, 5 deletions

diff --git a/gm/fontscalerdistortable.cpp b/gm/fontscalerdistortable.cpp
index 49d254de36..5778ce0200 100644
--- a/gm/fontscalerdistortable.cpp
+++ b/gm/fontscalerdistortable.cpp
@@ -35,8 +35,10 @@ protected:
         paint.setLCDRenderText(true);
         sk_sp<SkFontMgr> fontMgr(SkFontMgr::RefDefault());
 
-        std::unique_ptr<SkStreamAsset> distortable(GetResourceAsStream("fonts/Distortable.ttf"));
-        if (!distortable) {
+        std::unique_ptr<SkStreamAsset> distortableStream(GetResourceAsStream("fonts/Distortable.ttf"));
+        sk_sp<SkTypeface> distortable(MakeResourceAsTypeface("fonts/Distortable.ttf"));
+        
+        if (!distortableStream) {
             return;
         }
         const char* text = "abc";
@@ -48,13 +50,19 @@ protected:
                 SkScalar y = SkIntToScalar(20);
 
                 SkFourByteTag tag = SkSetFourByteTag('w','g','h','t');
-                SkScalar styleValue = SkDoubleToScalar(0.5 + (5*j + i) * ((2.0 - 0.5) / (2 * 5)));
+                SkScalar styleValue = SkDoubleToScalar(0.5 + (5 * j + i) * ((2.0 - 0.5) / (2 * 5)));
                 SkFontArguments::VariationPosition::Coordinate coordinates[] = {{tag, styleValue}};
                 SkFontArguments::VariationPosition position =
                         { coordinates, SK_ARRAY_COUNT(coordinates) };
-                paint.setTypeface(sk_sp<SkTypeface>(fontMgr->makeFromStream(
-                        distortable->duplicate(),
+                if (j == 0 && distortable) {
+                    paint.setTypeface(sk_sp<SkTypeface>(
+                        distortable->makeClone(
+                            SkFontArguments().setVariationDesignPosition(position))));
+                } else {
+                    paint.setTypeface(sk_sp<SkTypeface>(fontMgr->makeFromStream(
+                        distortableStream->duplicate(),
                         SkFontArguments().setVariationDesignPosition(position))));
+                }
 
                 SkAutoCanvasRestore acr(canvas, true);
                 canvas->translate(SkIntToScalar(30 + i * 100), SkIntToScalar(20));
diff --git a/src/ports/SkTypeface_win_dw.cpp b/src/ports/SkTypeface_win_dw.cpp
index 38e68dccca..281355e6a0 100644
--- a/src/ports/SkTypeface_win_dw.cpp
+++ b/src/ports/SkTypeface_win_dw.cpp
@@ -217,6 +217,54 @@ size_t DWriteFontTypeface::onGetTableData(SkFontTableTag tag, size_t offset,
     return size;
 }
 
+sk_sp<SkTypeface> DWriteFontTypeface::onMakeClone(const SkFontArguments& args) const {
+    // Skip if the current face index does not match the ttcIndex
+    if (fDWriteFontFace->GetIndex() != SkTo<UINT32>(args.getCollectionIndex())) {
+        return sk_ref_sp(this);
+    }
+
+#if defined(NTDDI_WIN10_RS3) && NTDDI_VERSION >= NTDDI_WIN10_RS3
+
+    SkTScopedComPtr<IDWriteFontFace5> fontFace5;
+
+    if (SUCCEEDED(fDWriteFontFace->QueryInterface(&fontFace5)) && fontFace5->HasVariations()) {
+        UINT32 fontAxisCount = fontFace5->GetFontAxisValueCount();
+        UINT32 argsCoordCount = args.getVariationDesignPosition().coordinateCount;
+        SkAutoSTMalloc<8, DWRITE_FONT_AXIS_VALUE> fontAxisValue(fontAxisCount);
+        HRN(fontFace5->GetFontAxisValues(fontAxisValue.get(), fontAxisCount));
+
+        for (UINT32 fontIndex = 0; fontIndex < fontAxisCount; ++fontIndex) {
+            for (UINT32 argsIndex = 0; argsIndex < argsCoordCount; ++argsIndex) {
+                if (SkEndian_SwapBE32(fontAxisValue[fontIndex].axisTag) ==
+                    args.getVariationDesignPosition().coordinates[argsIndex].axis) {
+                    fontAxisValue[fontIndex].value =
+                        args.getVariationDesignPosition().coordinates[argsIndex].value;
+                }
+            }
+        }
+        SkTScopedComPtr<IDWriteFontResource> fontResource;
+        HRN(fontFace5->GetFontResource(&fontResource));
+        SkTScopedComPtr<IDWriteFontFace5> newFontFace5;
+        HRN(fontResource->CreateFontFace(fDWriteFont->GetSimulations(),
+                                         fontAxisValue.get(),
+                                         fontAxisCount,
+                                         &newFontFace5));
+
+        SkTScopedComPtr<IDWriteFontFace> newFontFace;
+        HRN(newFontFace5->QueryInterface(&newFontFace));
+        return sk_sp<SkTypeface>(DWriteFontTypeface::Create(fFactory.get(),
+                                                            newFontFace.get(),
+                                                            fDWriteFont.get(),
+                                                            fDWriteFontFamily.get(),
+                                                            fDWriteFontFileLoader.get(),
+                                                            fDWriteFontCollectionLoader.get()));
+    }
+
+#endif
+
+    return sk_ref_sp(this);
+}
+
 SkStreamAsset* DWriteFontTypeface::onOpenStream(int* ttcIndex) const {
     *ttcIndex = fDWriteFontFace->GetIndex();
 
diff --git a/src/ports/SkTypeface_win_dw.h b/src/ports/SkTypeface_win_dw.h
index 75be040fd4..b443c28efe 100644
--- a/src/ports/SkTypeface_win_dw.h
+++ b/src/ports/SkTypeface_win_dw.h
@@ -19,6 +19,7 @@
 #include <dwrite.h>
 #include <dwrite_1.h>
 #include <dwrite_2.h>
+#include <dwrite_3.h>
 
 class SkFontDescriptor;
 struct SkScalerContextRec;
@@ -100,6 +101,7 @@ protected:
         INHERITED::weak_dispose();
     }
 
+    sk_sp<SkTypeface> onMakeClone(const SkFontArguments&) const override;
     SkStreamAsset* onOpenStream(int* ttcIndex) const override;
     SkScalerContext* onCreateScalerContext(const SkScalerContextEffects&,
                                            const SkDescriptor*) const override;