Add geometry-based rotated AA rect drawing path

src/gpu/GrAARectRenderer.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrAARectRenderer.h"
 #include "GrRefCnt.h"
 #include "GrGpu.h"
@@ skipping 343 matching lines @@
             fAAStrokeRectIndexBuffer->updateData(gStrokeAARectIdx,
                                                  sizeof(gStrokeAARectIdx));
             GR_DEBUGASSERT(updated);
         }
     }
     return fAAStrokeRectIndexBuffer;
 }
 
 void GrAARectRenderer::geometryFillAARect(GrGpu* gpu,
                                           GrDrawTarget* target,
+                                          const GrRect& rect,
+                                          const SkMatrix& combinedMatrix,
                                           const GrRect& devRect,
                                           bool useVertexCoverage) {
     GrDrawState* drawState = target->drawState();
 
     set_aa_rect_vertex_attributes(drawState, useVertexCoverage);
 
     GrDrawTarget::AutoReleaseGeometry geo(target, 8, 0);
     if (!geo.succeeded()) {
         GrPrintf("Failed to get space for vertices!\n");
         return;
     }
 
     GrIndexBuffer* indexBuffer = this->aaFillRectIndexBuffer(gpu);
     if (NULL == indexBuffer) {
         GrPrintf("Failed to create index buffer!\n");
         return;
     }
 
     intptr_t verts = reinterpret_cast<intptr_t>(geo.vertices());
     size_t vsize = drawState->getVertexSize();
     GrAssert(sizeof(GrPoint) + sizeof(GrColor) == vsize);
 
     GrPoint* fan0Pos = reinterpret_cast<GrPoint*>(verts);
     GrPoint* fan1Pos = reinterpret_cast<GrPoint*>(verts + 4 * vsize);
 
-    set_inset_fan(fan0Pos, vsize, devRect, -SK_ScalarHalf, -SK_ScalarHalf);
-    set_inset_fan(fan1Pos, vsize, devRect,  SK_ScalarHalf,  SK_ScalarHalf);
+    if (combinedMatrix.rectStaysRect()) {
+        set_inset_fan(fan0Pos, vsize, devRect, -SK_ScalarHalf, -SK_ScalarHalf);
+        set_inset_fan(fan1Pos, vsize, devRect,  SK_ScalarHalf,  SK_ScalarHalf);
+    } else {
+        // compute transformed (1, 0) and (0, 1) vectors
+        SkVector vec[2] = {
+          { combinedMatrix[SkMatrix::kMScaleX], combinedMatrix[SkMatrix::kMSkewY] },
+          { combinedMatrix[SkMatrix::kMSkewX],  combinedMatrix[SkMatrix::kMScaleY] }
+        };
+
+        vec[0].normalize();
+        vec[0].scale(SK_ScalarHalf);
+        vec[1].normalize();
+        vec[1].scale(SK_ScalarHalf);
+
+        fan0Pos->setRectFan(rect.fLeft, rect.fTop,
+                            rect.fRight, rect.fBottom, vsize);
+        combinedMatrix.mapPointsWithStride(fan0Pos, vsize, 4);
+
+        // TL
+        *((SkPoint*)((intptr_t)fan1Pos + 0 * vsize)) = 
+            *((SkPoint*)((intptr_t)fan0Pos + 0 * vsize)) + vec[0] + vec[1];
+        *((SkPoint*)((intptr_t)fan0Pos + 0 * vsize)) -= vec[0] + vec[1];
+        // BL
+        *((SkPoint*)((intptr_t)fan1Pos + 1 * vsize)) = 
+            *((SkPoint*)((intptr_t)fan0Pos + 1 * vsize)) + vec[0] - vec[1];
+        *((SkPoint*)((intptr_t)fan0Pos + 1 * vsize)) -= vec[0] - vec[1];
+        // BR
+        *((SkPoint*)((intptr_t)fan1Pos + 2 * vsize)) = 
+            *((SkPoint*)((intptr_t)fan0Pos + 2 * vsize)) - vec[0] - vec[1];
+        *((SkPoint*)((intptr_t)fan0Pos + 2 * vsize)) += vec[0] + vec[1];
+        // TR
+        *((SkPoint*)((intptr_t)fan1Pos + 3 * vsize)) = 
+            *((SkPoint*)((intptr_t)fan0Pos + 3 * vsize)) - vec[0] + vec[1];
+        *((SkPoint*)((intptr_t)fan0Pos + 3 * vsize)) += vec[0] - vec[1];
+    }
 
     verts += sizeof(GrPoint);
     for (int i = 0; i < 4; ++i) {
         *reinterpret_cast<GrColor*>(verts + i * vsize) = 0;
     }
 
     GrColor innerColor;
-    if (useVertexCoverage) {
+    if (useVertexCoverage) { 
         innerColor = 0xffffffff;
     } else {
         innerColor = target->getDrawState().getColor();
     }
 
     verts += 4 * vsize;
     for (int i = 0; i < 4; ++i) {
         *reinterpret_cast<GrColor*>(verts + i * vsize) = innerColor;
     }
 
@@ skipping 249 matching lines @@
     // The innermost rect has full coverage
     verts += 8 * vsize;
     for (int i = 0; i < 4; ++i) {
         *reinterpret_cast<GrColor*>(verts + i * vsize) = 0;
     }
 
     target->setIndexSourceToBuffer(indexBuffer);
     target->drawIndexed(kTriangles_GrPrimitiveType,
                         0, 0, 16, aaStrokeRectIndexCount());
 }