Add gm that tests shaded stroked rectangles.

src/gpu/batches/GrAAStrokeRectBatch.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrAAStrokeRectBatch.h"
 
 #include "GrBatchFlushState.h"
@@ skipping 498 matching lines @@
     for (int i = 0; i < innerVertexNum; ++i) {
         if (tweakAlphaForCoverage) {
             *reinterpret_cast<GrColor*>(verts + i * vertexStride) = scaledColor;
         } else {
             *reinterpret_cast<GrColor*>(verts + i * vertexStride) = color;
             *reinterpret_cast<float*>(verts + i * vertexStride + sizeof(GrColor)) = innerCoverage;
         }
     }
 }
 
-inline static bool is_miter(const SkStrokeRec& stroke) {
+// We support all hairlines, bevels, and miters, but not round joins. Also, check whether the miter
+// limit makes a miter join effectively beveled.
+inline static bool allowed_stroke(const SkStrokeRec& stroke, bool* isMiter) {
+    SkASSERT(stroke.getStyle() == SkStrokeRec::kStroke_Style ||
+             stroke.getStyle() == SkStrokeRec::kHairline_Style);
     // For hairlines, make bevel and round joins appear the same as mitered ones.
-    // small miter limit means right angles show bevel...
-    if ((stroke.getWidth() > 0) && (stroke.getJoin() != SkPaint::kMiter_Join ||
-                                    stroke.getMiter() < SK_ScalarSqrt2)) {
-        return false;
+    if (!stroke.getWidth()) {
+        *isMiter = true;
+        return true;
     }
-    return true;
+    if (stroke.getJoin() == SkPaint::kBevel_Join) {
+        *isMiter = false;
+        return true;
+    }
+    if (stroke.getJoin() == SkPaint::kMiter_Join) {
+        *isMiter = stroke.getMiter() >= SK_ScalarSqrt2;
+        return true;
+    }
+    return false;
 }
 
 static void compute_rects(SkRect* devOutside, SkRect* devOutsideAssist, SkRect* devInside,
                           bool* isDegenerate, const SkMatrix& viewMatrix, const SkRect& rect,
                           SkScalar strokeWidth, bool miterStroke) {
     SkRect devRect;
     viewMatrix.mapRect(&devRect, rect);
 
     SkVector devStrokeSize;
     if (strokeWidth > 0) {
@@ skipping 52 matching lines @@
     AAStrokeRectBatch* batch = AAStrokeRectBatch::Create(viewMatrix, true);
     batch->append(color, devOutside, devOutside, devInside, false);
     batch->init();
     return batch;
 }
 
 GrDrawBatch* Create(GrColor color,
                     const SkMatrix& viewMatrix,
                     const SkRect& rect,
                     const SkStrokeRec& stroke) {
-    bool isMiterStroke = is_miter(stroke);
+    bool isMiterStroke;
+    if (!allowed_stroke(stroke, &isMiterStroke)) {
+        return nullptr;
+    }
     AAStrokeRectBatch* batch = AAStrokeRectBatch::Create(viewMatrix, isMiterStroke);
 
     SkRect devOutside, devOutsideAssist, devInside;
     bool isDegenerate;
     compute_rects(&devOutside, &devOutsideAssist, &devInside, &isDegenerate, viewMatrix,
                   rect, stroke.getWidth(), isMiterStroke);
 
     batch->append(color, devOutside, devOutsideAssist, devInside, isDegenerate);
     batch->init();
     return batch;
 }
 
-bool Append(GrBatch* origBatch,
-            GrColor color,
-            const SkMatrix& viewMatrix,
-            const SkRect& rect,
-            const SkStrokeRec& stroke) {
-    AAStrokeRectBatch* batch = origBatch->cast<AAStrokeRectBatch>();
-
-    // we can't batch across vm changes
-    bool isMiterStroke = is_miter(stroke);
-    if (!batch->canAppend(viewMatrix, isMiterStroke)) {
-        return false;
-    }
-
-    SkRect devOutside, devOutsideAssist, devInside;
-    bool isDegenerate;
-    compute_rects(&devOutside, &devOutsideAssist, &devInside, &isDegenerate, viewMatrix,
-                  rect, stroke.getWidth(), isMiterStroke);
-
-    batch->appendAndUpdateBounds(color, devOutside, devOutsideAssist, devInside, isDegenerate);
-    return true;
-}
-
 };
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 
 #ifdef GR_TEST_UTILS
 
 #include "GrBatchTest.h"
 
 DRAW_BATCH_TEST_DEFINE(AAStrokeRectBatch) {
     bool miterStroke = random->nextBool();
 
     // Create either a empty rect or a non-empty rect.
     SkRect rect = random->nextBool() ? SkRect::MakeXYWH(10, 10, 50, 40) :
                                        SkRect::MakeXYWH(6, 7, 0, 0);
     SkScalar minDim = SkMinScalar(rect.width(), rect.height());
     SkScalar strokeWidth = random->nextUScalar1() * minDim;
 
     GrColor color = GrRandomColor(random);
 
     SkStrokeRec rec(SkStrokeRec::kFill_InitStyle);
     rec.setStrokeStyle(strokeWidth);
     rec.setStrokeParams(SkPaint::kButt_Cap,
                         miterStroke ? SkPaint::kMiter_Join : SkPaint::kBevel_Join,
                         1.f);
     SkMatrix matrix = GrTest::TestMatrixRectStaysRect(random);
     return GrAAStrokeRectBatch::Create(color, matrix, rect, rec);
 }
 
 #endif