Redo drawTextRSXForm for glyph runs

Change-Id: Iec9ad6a2c91b16c4e25150902b433fc7aae68a33
Reviewed-on: https://skia-review.googlesource.com/142171
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Herb Derby <herb@google.com>

5 files changed, 95 insertions, 49 deletions

diff --git a/src/core/SkCanvas.cpp b/src/core/SkCanvas.cpp
index cb98b09b37..8fc431864d 100644
--- a/src/core/SkCanvas.cpp
+++ b/src/core/SkCanvas.cpp
@@ -2478,7 +2478,7 @@ void SkCanvas::onDrawTextOnPath(const void* text, size_t byteLength, const SkPat
     LOOPER_END
 }
 
-void SkCanvas::onDrawTextRSXform(const void* text, size_t byteLength, const SkRSXform xform[],
+void SkCanvas::onDrawTextRSXform(const void* text, size_t len, const SkRSXform xform[],
                                  const SkRect* cullRect, const SkPaint& paint) {
     if (cullRect && this->quickReject(*cullRect)) {
         return;
@@ -2487,7 +2487,12 @@ void SkCanvas::onDrawTextRSXform(const void* text, size_t byteLength, const SkRS
     LOOPER_BEGIN(paint, nullptr)
 
     while (iter.next()) {
-        iter.fDevice->drawTextRSXform(text, byteLength, xform, looper.paint());
+        fScratchGlyphRunBuilder->drawTextAtOrigin(paint, text, len);
+        auto list = fScratchGlyphRunBuilder->useGlyphRunList();
+        if (!list->empty()) {
+            auto glyphRun = (*list)[0];
+            iter.fDevice->drawGlyphRunRSXform(&glyphRun, xform);
+        }
     }
 
     LOOPER_END
diff --git a/src/core/SkDevice.cpp b/src/core/SkDevice.cpp
index 2296d359da..60f8cd861f 100644
--- a/src/core/SkDevice.cpp
+++ b/src/core/SkDevice.cpp
@@ -476,55 +476,34 @@ void SkBaseDevice::drawTextOnPath(const void* text, size_t byteLength,
 
 #include "SkUtils.h"
 
-void SkBaseDevice::drawTextRSXform(const void* text, size_t len,
-                                   const SkRSXform xform[], const SkPaint& paint) {
-    SkPaint::TextEncoding textEncoding = paint.getTextEncoding();
-    const char* end = (const char*)text + len;
-    SkPaint localPaint(paint);
-    SkShader* shader = paint.getShader();
-    SkScalar pos[2] = {0.0f, 0.0f};
-    SkPoint origin = SkPoint::Make(0, 0);
-
-    SkMatrix localM, currM;
-    const void* stopText = (const char*)text + len;
-    while ((const char*)text < (const char*)stopText) {
-        localM.setRSXform(*xform++);
-        currM.setConcat(this->ctm(), localM);
-        SkAutoDeviceCTMRestore adc(this, currM);
+void SkBaseDevice::drawGlyphRunRSXform(SkGlyphRun* run, const SkRSXform* xform) {
+    const SkMatrix originalCTM = this->ctm();
+    sk_sp<SkShader> shader = sk_ref_sp(run->mutablePaint()->getShader());
+    auto perGlyph = [this, &xform, &originalCTM, shader] (
+            SkGlyphRun* glyphRun, SkPaint* runPaint) {
+        SkMatrix ctm;
+        ctm.setRSXform(*xform++);
 
         // We want to rotate each glyph by the rsxform, but we don't want to rotate "space"
         // (i.e. the shader that cares about the ctm) so we have to undo our little ctm trick
         // with a localmatrixshader so that the shader draws as if there was no change to the ctm.
         if (shader) {
             SkMatrix inverse;
-            if (localM.invert(&inverse)) {
-                localPaint.setShader(shader->makeWithLocalMatrix(inverse));
+            if (ctm.invert(&inverse)) {
+                runPaint->setShader(shader->makeWithLocalMatrix(inverse));
             } else {
-                localPaint.setShader(nullptr);  // can't handle this xform
+                runPaint->setShader(nullptr);  // can't handle this xform
             }
         }
-        int subLen = 0;
-        switch (textEncoding) {
-            case SkPaint::kUTF8_TextEncoding:
-                subLen = SkUTF8_CountUTF8Bytes((const char*)text);
-                break;
-            case SkPaint::kUTF16_TextEncoding:
-                {
-                    const uint16_t* ptr = (const uint16_t*)text;
-                    (void)SkUTF16_NextUnichar(&ptr, (const uint16_t*)end);
-                    subLen = SkToInt((const char*)ptr - (const char*)text);
-                };
-                break;
-            case SkPaint::kUTF32_TextEncoding:
-                subLen = 4;
-                break;
-            case SkPaint::kGlyphID_TextEncoding:
-                subLen = 2;
-                break;
-        }
-        this->drawPosText(text, subLen, pos, 2, origin, localPaint);
-        text = (const char*)text + subLen;
-    }
+
+        ctm.setConcat(originalCTM, ctm);
+        this->setCTM(ctm);
+        SkGlyphRunList glyphRunList{glyphRun};
+        this->drawGlyphRunList(&glyphRunList);
+    };
+    run->eachGlyphToGlyphRun(perGlyph);
+    run->mutablePaint()->setShader(shader);
+    this->setCTM(originalCTM);
 }
 
 //////////////////////////////////////////////////////////////////////////////////////////
diff --git a/src/core/SkDevice.h b/src/core/SkDevice.h
index 345b90548b..bd327a65c3 100644
--- a/src/core/SkDevice.h
+++ b/src/core/SkDevice.h
@@ -16,8 +16,8 @@
 
 class SkBitmap;
 struct SkDrawShadowRec;
+class SkGlyphRun;
 class SkGlyphRunList;
-class SkGlyphRunBuilder;
 class SkImageFilterCache;
 struct SkIRect;
 class SkMatrix;
@@ -242,8 +242,7 @@ protected:
 
     virtual void drawTextOnPath(const void* text, size_t len, const SkPath&,
                                 const SkMatrix*, const SkPaint&);
-    virtual void drawTextRSXform(const void* text, size_t len, const SkRSXform[],
-                                 const SkPaint&);
+    void drawGlyphRunRSXform(SkGlyphRun* run, const SkRSXform* xform);
 
     virtual void drawSpecial(SkSpecialImage*, int x, int y, const SkPaint&,
                              SkImage* clipImage, const SkMatrix& clipMatrix);
diff --git a/src/core/SkGlyphRun.cpp b/src/core/SkGlyphRun.cpp
index 3548dfa203..e587dc55c6 100644
--- a/src/core/SkGlyphRun.cpp
+++ b/src/core/SkGlyphRun.cpp
@@ -51,6 +51,31 @@ SkGlyphRun::SkGlyphRun(SkPaint&& runPaint,
         , fClusters{clusters}
         , fRunPaint{std::move(runPaint)} {}
 
+
+void SkGlyphRun::eachGlyphToGlyphRun(SkGlyphRun::PerGlyph perGlyph) {
+    SkPaint paint{fRunPaint};
+    SkPoint point;
+    SkGlyphID glyphID;
+    SkGlyphRun run{
+        std::move(paint),
+        SkSpan<const uint16_t>{},  // No dense indices for now.
+        SkSpan<const SkPoint>{&point, 1},
+        SkSpan<const SkGlyphID>{&glyphID, 1},
+        SkSpan<const SkGlyphID>{},
+        SkSpan<const char>{},
+        SkSpan<const uint32_t>{}
+    };
+
+    auto runSize = fTemporaryShuntGlyphIDs.size();
+    auto runPaint = run.mutablePaint();
+    for (size_t i = 0; i < runSize; i++) {
+        glyphID = fTemporaryShuntGlyphIDs[i];
+        point = fPositions[i];
+        perGlyph(&run, runPaint);
+    }
+
+}
+
 void SkGlyphRun::temporaryShuntToDrawPosText(SkBaseDevice* device, SkPoint origin) {
 
     auto pos = (const SkScalar*) this->positions().data();
@@ -74,6 +99,7 @@ void SkGlyphRun::filloutGlyphsAndPositions(SkGlyphID* glyphIDs, SkPoint* positio
 }
 
 // -- SkGlyphRunList -------------------------------------------------------------------------------
+SkGlyphRunList::SkGlyphRunList() = default;
 SkGlyphRunList::SkGlyphRunList(
         const SkPaint& paint,
         const SkTextBlob* blob,
@@ -84,6 +110,12 @@ SkGlyphRunList::SkGlyphRunList(
         , fOrigin{origin}
         , fGlyphRuns{glyphRunList} { }
 
+SkGlyphRunList::SkGlyphRunList(SkGlyphRun* glyphRun)
+        : fOriginalPaint{nullptr}
+        , fOriginalTextBlob{nullptr}
+        , fOrigin{SkPoint::Make(0, 0)}
+        , fGlyphRuns{SkSpan<SkGlyphRun>{glyphRun, 1}} {}
+
 uint64_t SkGlyphRunList::uniqueID() const {
     return fOriginalTextBlob != nullptr ? fOriginalTextBlob->uniqueID()
                                         : SK_InvalidUniqueID;
@@ -166,6 +198,29 @@ SkSpan<const SkGlyphID> SkGlyphIDSet::uniquifyGlyphIDs(
 }
 
 // -- SkGlyphRunBuilder ----------------------------------------------------------------------------
+void SkGlyphRunBuilder::drawTextAtOrigin(
+        const SkPaint& paint, const void* bytes, size_t byteLength) {
+    auto glyphIDs = textToGlyphIDs(paint, bytes, byteLength);
+    if (!glyphIDs.empty()) {
+        this->initialize(glyphIDs.size());
+    }
+
+    auto positions = SkSpan<const SkPoint>{fPositions, glyphIDs.size()};
+
+    // Every glyph is at the origin.
+    sk_bzero((void *)positions.data(), positions.size_bytes());
+
+    this->makeGlyphRun(
+            paint,
+            glyphIDs,
+            positions,
+            SkSpan<const uint16_t>{},  // no dense indices for now.,
+            SkSpan<const SkGlyphID>{},
+            SkSpan<const char>{},
+            SkSpan<const uint32_t>{});
+    this->makeGlyphRunList(paint, nullptr, SkPoint::Make(0, 0));
+}
+
 void SkGlyphRunBuilder::drawText(
         const SkPaint& paint, const void* bytes, size_t byteLength, SkPoint origin) {
     auto glyphIDs = textToGlyphIDs(paint, bytes, byteLength);
diff --git a/src/core/SkGlyphRun.h b/src/core/SkGlyphRun.h
index 001c3c4548..6de4cdc40f 100644
--- a/src/core/SkGlyphRun.h
+++ b/src/core/SkGlyphRun.h
@@ -19,6 +19,7 @@
 #include "SkTypes.h"
 
 class SkBaseDevice;
+class SkGlyphRunList;
 
 template <typename T>
 class SkSpan {
@@ -55,6 +56,10 @@ public:
                SkSpan<const char> text,
                SkSpan<const uint32_t> clusters);
 
+    // A function that turns an SkGlyphRun into an SkGlyphRun for each glyph.
+    using PerGlyph = std::function<void (SkGlyphRun*, SkPaint*)>;
+    void eachGlyphToGlyphRun(PerGlyph perGlyph);
+
     // The temporaryShunt calls are to allow inter-operating with existing code while glyph runs
     // are developed.
     void temporaryShuntToDrawPosText(SkBaseDevice* device, SkPoint origin);
@@ -65,6 +70,7 @@ public:
     size_t runSize() const { return fTemporaryShuntGlyphIDs.size(); }
     SkSpan<const SkPoint> positions() const { return fPositions; }
     const SkPaint& paint() const { return fRunPaint; }
+    SkPaint* mutablePaint() { return &fRunPaint; }
 
 private:
     //
@@ -80,11 +86,11 @@ private:
     // Original clusters from SkTextBlob if present. Will be empty if not present.
     const SkSpan<const uint32_t>   fClusters;
     // Paint for this run modified to have glyph encoding and left alignment.
-    const SkPaint fRunPaint;
+    SkPaint fRunPaint;
 };
 
 class SkGlyphRunList {
-    const SkPaint* fOriginalPaint{nullptr};
+    const SkPaint* fOriginalPaint{nullptr};  // This should be deleted soon.
     // The text blob is needed to hookup the call back that the SkTextBlob destructor calls. It
     // should be used for nothing else
     const SkTextBlob*  fOriginalTextBlob{nullptr};
@@ -92,7 +98,7 @@ class SkGlyphRunList {
     SkSpan<SkGlyphRun> fGlyphRuns;
 
 public:
-    SkGlyphRunList() = default;
+    SkGlyphRunList();
     // Blob maybe null.
     SkGlyphRunList(
             const SkPaint& paint,
@@ -100,6 +106,8 @@ public:
             SkPoint origin,
             SkSpan<SkGlyphRun> glyphRunList);
 
+    SkGlyphRunList(SkGlyphRun* glyphRun);
+
     uint64_t uniqueID() const;
     bool anyRunsLCD() const;
     void temporaryShuntBlobNotifyAddedToCache(uint32_t cacheID) const;
@@ -143,6 +151,7 @@ private:
 
 class SkGlyphRunBuilder {
 public:
+    void drawTextAtOrigin(const SkPaint& paint, const void* bytes, size_t byteLength);
     void drawText(
             const SkPaint& paint, const void* bytes, size_t byteLength, SkPoint origin);
     void drawPosTextH(
@@ -152,7 +161,6 @@ public:
             const SkPaint& paint, const void* bytes, size_t byteLength, const SkPoint* pos);
     void drawTextBlob(const SkPaint& paint, const SkTextBlob& blob, SkPoint origin);
 
-    SkGlyphRun* useGlyphRun();
     SkGlyphRunList* useGlyphRunList();
 
 private: