Convert SkGlyphIDs to SkPaths

Change-Id: I26893e4055a5fa44914f5e7b8702b0c280d5866b
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/558916
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Herb Derby <herb@google.com>

src/core/SkScalerCache.cpp

@@ -14,6 +14,7 @@
 #include "src/core/SkEnumerate.h"
 #include "src/core/SkGlyphBuffer.h"
 #include "src/core/SkScalerContext.h"
+#include "src/text/StrikeForGPU.h"
 
 static SkFontMetrics use_or_generate_metrics(
         const SkFontMetrics* metrics, SkScalerContext* context) {
@@ -173,6 +174,18 @@ std::tuple<SkSpan<const SkGlyph*>, size_t> SkScalerCache::preparePaths(
     return {glyphs, delta};
 }
 
+size_t SkScalerCache::glyphIDsToPaths(SkSpan<sktext::IDOrPath> idsOrPaths) {
+    size_t increase = 0;
+    SkAutoMutexExclusive lock{fMu};
+    for (sktext::IDOrPath& idOrPath : idsOrPaths) {
+        auto [glyph, size] = this->glyph(SkPackedGlyphID{idOrPath.fGlyphID});
+        increase += size;
+        increase += this->preparePath(glyph);
+        new (&idOrPath.fPath) SkPath{*glyph->path()};
+    }
+    return increase;
+}
+
 std::tuple<SkSpan<const SkGlyph*>, size_t> SkScalerCache::prepareImages(
         SkSpan<const SkPackedGlyphID> glyphIDs, const SkGlyph* results[]) {
     const SkGlyph** cursor = results;

src/core/SkScalerCache.h

@@ -16,9 +16,13 @@
 #include "src/core/SkDescriptor.h"
 #include "src/core/SkGlyph.h"
 #include "src/core/SkGlyphRunPainter.h"
+
 #include <memory>
 
 class SkScalerContext;
+namespace sktext {
+union IDOrPath;
+}  // namespace sktext
 
 // This class represents a strike: a specific combination of typeface, size, matrix, etc., and
 // holds the glyphs for that strike.
@@ -86,6 +90,9 @@ public:
     size_t prepareForDrawableDrawing(
             SkDrawableGlyphBuffer* accepted, SkSourceGlyphBuffer* rejected) SK_EXCLUDES(fMu);
 
+    // Convert all the IDs into SkPaths in the span.
+    size_t glyphIDsToPaths(SkSpan<sktext::IDOrPath> idsOrPaths) SK_EXCLUDES(fMu);
+
     std::tuple<SkScalar, size_t>
             findMaximumGlyphDimension(SkSpan<const SkGlyphID> glyphs) SK_EXCLUDES(fMu);
 

src/core/SkStrikeCache.h

@@ -157,6 +157,11 @@ public:
         this->updateDelta(increase);
     }
 
+    void glyphIDsToPaths(SkSpan<sktext::IDOrPath> idsOrPaths) {
+        size_t increase = fScalerCache.glyphIDsToPaths(idsOrPaths);
+        this->updateDelta(increase);
+    }
+
     void prepareForDrawableDrawing(
             SkDrawableGlyphBuffer* accepted, SkSourceGlyphBuffer* rejected) override {
         size_t increase = fScalerCache.prepareForDrawableDrawing(accepted, rejected);

src/text/StrikeForGPU.h

@@ -69,6 +69,15 @@ public:
 // -- ScopedStrikeForGPU ---------------------------------------------------------------------------
 using ScopedStrikeForGPU = std::unique_ptr<StrikeForGPU, StrikeForGPU::Deleter>;
 
+// prepareForPathDrawing uses this union to convert glyph ids to paths.
+union IDOrPath {
+    SkGlyphID fGlyphID;
+    SkPath fPath;
+
+    // PathOpSubmitter takes care of destroying the paths.
+    ~IDOrPath() {}
+};
+
 // -- StrikeRef ------------------------------------------------------------------------------------
 // Hold a ref to either a RemoteStrike or an SkStrike. Use either to flatten a descriptor, but
 // when MakeFromBuffer runs look up the SkStrike associated with the descriptor.