Add buffers for Mask drawing in preparation for bulk API

The next CL will introduce a bulk API between the Painter and
its client code. That CL will uses these buffers to communicate.

Change-Id: I90f78c212db1a3595754e48ab68a41d003ba7003
Reviewed-on: https://skia-review.googlesource.com/c/183920
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Herb Derby <herb@google.com>

src/core/SkGlyphRunPainter.cpp

@@ -117,13 +117,6 @@ bool SkGlyphRunListPainter::ShouldDrawAsPath(
     return SkPaint::TooBigToUseCache(matrix, SkFontPriv::MakeTextMatrix(font), 1024);
 }
 
-void SkGlyphRunListPainter::ensureBitmapBuffers(size_t runSize) {
-    if (runSize > fMaxRunSize) {
-        fPositions.reset(runSize);
-        fMaxRunSize = runSize;
-    }
-}
-
 static bool check_glyph_position(SkPoint position) {
     // Prevent glyphs from being drawn outside of or straddling the edge of device space.
     // Comparisons written a little weirdly so that NaN coordinates are treated safely.
@@ -159,6 +152,8 @@ static SkMask create_mask(const SkGlyph& glyph, SkPoint position, const void* im
 void SkGlyphRunListPainter::drawForBitmapDevice(
         const SkGlyphRunList& glyphRunList, const SkMatrix& deviceMatrix,
         const BitmapDevicePainter* bitmapDevice) {
+    ScopedBuffers _ = this->ensureBuffers(glyphRunList);
+
     const SkPaint& runPaint = glyphRunList.paint();
     // The bitmap blitters can only draw lcd text to a N32 bitmap in srcOver. Otherwise,
     // convert the lcd text into A8 text. The props communicates this to the scaler.
@@ -170,7 +165,6 @@ void SkGlyphRunListPainter::drawForBitmapDevice(
     for (auto& glyphRun : glyphRunList) {
         const SkFont& runFont = glyphRun.font();
         auto runSize = glyphRun.runSize();
-        this->ensureBitmapBuffers(runSize);
 
         if (ShouldDrawAsPath(runPaint, runFont, deviceMatrix)) {
             SkMatrix::MakeTrans(origin.x(), origin.y()).mapPoints(
@@ -379,6 +373,7 @@ void SkGlyphRunListPainter::drawGlyphRunAsBMPWithPathFallback(
         SkGlyphCacheInterface* cache, const SkGlyphRun& glyphRun,
         SkPoint origin, const SkMatrix& deviceMatrix,
         PerEmptyT&& perEmpty, PerGlyphT&& perGlyph, PerPathT&& perPath) {
+    ScopedBuffers _ = this->ensureBuffers(glyphRun);
 
     SkMatrix mapping = deviceMatrix;
     mapping.preTranslate(origin.x(), origin.y());
@@ -386,7 +381,6 @@ void SkGlyphRunListPainter::drawGlyphRunAsBMPWithPathFallback(
     mapping.postTranslate(rounding.x(), rounding.y());
 
     auto runSize = glyphRun.runSize();
-    this->ensureBitmapBuffers(runSize);
     mapping.mapPoints(fPositions, glyphRun.positions().data(), runSize);
     const SkPoint* mappedPtCursor = fPositions;
     for (auto glyphID : glyphRun.glyphsIDs()) {
@@ -459,6 +453,20 @@ void SkGlyphRunListPainter::drawGlyphRunAsSDFWithARGBFallback(
     }
 }
 
+SkGlyphRunListPainter::ScopedBuffers
+SkGlyphRunListPainter::ensureBuffers(const SkGlyphRunList& glyphRunList) {
+    size_t size = 0;
+    for (const SkGlyphRun& run : glyphRunList) {
+        size = std::max(run.runSize(), size);
+    }
+    return ScopedBuffers(this, size);
+}
+
+SkGlyphRunListPainter::ScopedBuffers
+SkGlyphRunListPainter::ensureBuffers(const SkGlyphRun& glyphRun) {
+    return ScopedBuffers(this, glyphRun.runSize());
+}
+
 #if SK_SUPPORT_GPU
 // -- GrTextContext --------------------------------------------------------------------------------
 SkPMColor4f generate_filtered_color(const SkPaint& paint, const GrColorSpaceInfo& colorSpaceInfo) {
@@ -1052,3 +1060,33 @@ bool SkTextBlobCacheDiffCanvas::TrackLayerDevice::maybeProcessGlyphRunForDFT(
     return true;
 }
 #endif
+
+SkGlyphRunListPainter::ScopedBuffers::ScopedBuffers(SkGlyphRunListPainter* painter, int size)
+        : fPainter{painter} {
+    SkASSERT(size >= 0);
+    if (fPainter->fMaxRunSize < size) {
+        fPainter->fMaxRunSize = size;
+
+        fPainter->fPositions.reset(size);
+        fPainter->fMaskGlyphs.reset(size);
+        fPainter->fMaskPositions.reset(size);
+    }
+}
+
+SkGlyphRunListPainter::ScopedBuffers::~ScopedBuffers() {
+    fPainter->fPathGlyphs.clear();
+    fPainter->fPathPositions.clear();
+    fPainter->fARGBGlyphsIDs.clear();
+    fPainter->fARGBPositions.clear();
+
+    if (200 < fPainter->fMaxRunSize) {
+        fPainter->fMaxRunSize = 0;
+        fPainter->fPositions.reset();
+        fPainter->fMaskGlyphs.reset();
+        fPainter->fMaskPositions.reset();
+        fPainter->fPathGlyphs.shrink_to_fit();
+        fPainter->fPathPositions.shrink_to_fit();
+        fPainter->fARGBGlyphsIDs.shrink_to_fit();
+        fPainter->fARGBPositions.shrink_to_fit();
+    }
+}

src/core/SkGlyphRunPainter.h

@@ -111,7 +111,16 @@ public:
     static bool ShouldDrawAsPath(const SkPaint& paint, const SkFont& font, const SkMatrix& matrix);
 
 private:
-    void ensureBitmapBuffers(size_t runSize);
+    struct ScopedBuffers {
+        ScopedBuffers(SkGlyphRunListPainter* painter, int size);
+        ~ScopedBuffers();
+        SkGlyphRunListPainter* fPainter;
+    };
+
+    ScopedBuffers SK_WARN_UNUSED_RESULT ensureBuffers(const SkGlyphRunList& glyphRunList);
+
+    // TODO: Remove once I can hoist ensureBuffers above the list for loop in all cases.
+    ScopedBuffers SK_WARN_UNUSED_RESULT ensureBuffers(const SkGlyphRun& glyphRun);
 
     void processARGBFallback(
             SkScalar maxGlyphDimension, const SkPaint& fallbackPaint, const SkFont& fallbackFont,
@@ -123,8 +132,14 @@ private:
     const SkSurfaceProps fBitmapFallbackProps;
     const SkColorType fColorType;
     const SkScalerContextFlags fScalerContextFlags;
-    size_t fMaxRunSize{0};
+
+    int fMaxRunSize{0};
     SkAutoTMalloc<SkPoint> fPositions;
+    SkAutoTMalloc<const SkGlyph*> fMaskGlyphs;
+    SkAutoTMalloc<SkPoint> fMaskPositions;
+
+    std::vector<const SkGlyph*> fPathGlyphs;
+    std::vector<SkPoint> fPathPositions;
 
     // Vectors for tracking ARGB fallback information.
     std::vector<SkGlyphID> fARGBGlyphsIDs;