Fix the rendering error of SkDraw::drawVertices in gpu path for solid color

src/gpu/SkGpuDevice.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkGpuDevice.h"
 
 #include "effects/GrBicubicEffect.h"
@@ skipping 16 matching lines @@
 #include "SkImageFilter.h"
 #include "SkMaskFilter.h"
 #include "SkPathEffect.h"
 #include "SkPicture.h"
 #include "SkPicturePlayback.h"
 #include "SkRRect.h"
 #include "SkStroke.h"
 #include "SkSurface.h"
 #include "SkTLazy.h"
 #include "SkUtils.h"
+#include "SkVertState.h"
 #include "SkErrorInternals.h"
 
 #define CACHE_COMPATIBLE_DEVICE_TEXTURES 1
 
 #if 0
     extern bool (*gShouldDrawProc)();
     #define CHECK_SHOULD_DRAW(draw, forceI)                     \
         do {                                                    \
             if (gShouldDrawProc && !gShouldDrawProc()) return;  \
             this->prepareDraw(draw, forceI);                    \
@@ skipping 1574 matching lines @@
 };
 
 void SkGpuDevice::drawVertices(const SkDraw& draw, SkCanvas::VertexMode vmode,
                               int vertexCount, const SkPoint vertices[],
                               const SkPoint texs[], const SkColor colors[],
                               SkXfermode* xmode,
                               const uint16_t indices[], int indexCount,
                               const SkPaint& paint) {
     CHECK_SHOULD_DRAW(draw, false);
 
+    // If both textures and vertex-colors are NULL, strokes hairlines with the paint's color.
+    if ((NULL == texs || NULL == paint.getShader()) && NULL == colors) {
+        texs = NULL;
+        SkPaint copy(paint);
+        copy.setStyle(SkPaint::kStroke_Style);
+        copy.setStrokeWidth(0);
+
+        VertState       state(vertexCount, indices, indexCount);
+        VertState::Proc vertProc = state.chooseProc(vmode);
+
+        SkPoint* pts = new SkPoint[vertexCount * 6];
+        int i = 0;
+        while (vertProc(&state)) {
+            pts[i] = vertices[state.f0];
+            pts[i + 1] = vertices[state.f1];
+            pts[i + 2] = vertices[state.f1];
+            pts[i + 3] = vertices[state.f2];
+            pts[i + 4] = vertices[state.f2];
+            pts[i + 5] = vertices[state.f0];
+            i += 6;
+        }
+        draw.drawPoints(SkCanvas::kLines_PointMode, i, pts, copy, true);
+        return;
+    }
+
     GrPaint grPaint;
     // we ignore the shader if texs is null.
     if (NULL == texs) {
         SkPaint2GrPaintNoShader(this->context(), paint, false, NULL == colors, &grPaint);
     } else {
         SkPaint2GrPaintShader(this->context(), paint, NULL == colors, &grPaint);
     }
 
     if (NULL != xmode && NULL != texs && NULL != colors) {
         if (!SkXfermode::IsMode(xmode, SkXfermode::kModulate_Mode)) {
@@ skipping 350 matching lines @@
         GrCachedLayer* layer = fContext->getLayerCache()->findLayerOrCreate(picture, i);
 
         if (NULL != layer->getTexture()) {
             fContext->unlockScratchTexture(layer->getTexture());
             layer->setTexture(NULL);
         }
     }
 
     return true;
 }