Fix Ganesh drawAtlas bug with quad colors

gm/drawatlascolor.cpp

Index: gm/drawatlascolor.cpp
diff --git a/gm/drawatlascolor.cpp b/gm/drawatlascolor.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..ad0ec502657786b3a537737f221cffffc43f8582
--- /dev/null
+++ b/gm/drawatlascolor.cpp
@@ -0,0 +1,177 @@
+/*
+ * 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 "gm.h"
+#include "SkCanvas.h"
+#include "SkRSXform.h"
+#include "SkSurface.h"
+
+// Create a square atlas of:
+//   opaque white  |     opaque red
+//  ------------------------------------
+//   opaque green  |  transparent black
+//
+static SkImage* make_atlas(SkCanvas* caller, int atlasSize) {
+    const int kBlockSize = atlasSize/2;
+
+    SkImageInfo info = SkImageInfo::MakeN32Premul(atlasSize, atlasSize);
+    SkAutoTUnref<SkSurface> surface(caller->newSurface(info));
+    if (NULL == surface) {
+        surface.reset(SkSurface::NewRaster(info));
+    }
+    SkCanvas* canvas = surface->getCanvas();
+
+    SkPaint paint;
+    paint.setXfermode(SkXfermode::Create(SkXfermode::kSrc_Mode));
+
+    paint.setColor(SK_ColorWHITE);
+    SkRect r = SkRect::MakeXYWH(0, 0, 
+                                SkIntToScalar(kBlockSize), SkIntToScalar(kBlockSize));
+    canvas->drawRect(r, paint);
+
+    paint.setColor(SK_ColorRED);
+    r = SkRect::MakeXYWH(SkIntToScalar(kBlockSize), 0, 
+                         SkIntToScalar(kBlockSize), SkIntToScalar(kBlockSize));
+    canvas->drawRect(r, paint);
+
+    paint.setColor(SK_ColorGREEN);
+    r = SkRect::MakeXYWH(0, SkIntToScalar(kBlockSize), 
+                         SkIntToScalar(kBlockSize), SkIntToScalar(kBlockSize));
+    canvas->drawRect(r, paint);
+
+    paint.setColor(SK_ColorTRANSPARENT);
+    r = SkRect::MakeXYWH(SkIntToScalar(kBlockSize), SkIntToScalar(kBlockSize), 
+                         SkIntToScalar(kBlockSize), SkIntToScalar(kBlockSize));
+    canvas->drawRect(r, paint);
+
+    return surface->newImageSnapshot();
+}
+
+// This GM tests the drawAtlas API with colors, different xfer modes
+// and transparency in the atlas image
+class DrawAtlasColorsGM : public skiagm::GM {
+public:
+    DrawAtlasColorsGM() {
+        this->setBGColor(sk_tool_utils::color_to_565(0xFFCCCCCC));
+    }
+    
+protected:
+    SkString onShortName() override {
+        return SkString("draw-atlas-colors");
+    }
+    
+    SkISize onISize() override {
+        return SkISize::Make(kNumXferModes * (kAtlasSize + kPad) + kPad,
+                             2 * kNumColors * (kAtlasSize + kPad) + kTextPad + kPad);
+    }
+    
+    void onDraw(SkCanvas* canvas) override {
+        const SkRect target = SkRect::MakeWH(SkIntToScalar(kAtlasSize), SkIntToScalar(kAtlasSize));
+
+        if (NULL == fAtlas) {
+            fAtlas.reset(make_atlas(canvas, kAtlasSize));
+        }
+
+        const struct {
+            SkXfermode::Mode fMode;
+            const char*      fLabel;
+        } gModes[] = {
+            { SkXfermode::kClear_Mode,      "Clear"     },
+            { SkXfermode::kSrc_Mode,        "Src"       },
+            { SkXfermode::kDst_Mode,        "Dst"       },
+            { SkXfermode::kSrcOver_Mode,    "SrcOver"   },
+            { SkXfermode::kDstOver_Mode,    "DstOver"   },
+            { SkXfermode::kSrcIn_Mode,      "SrcIn"     },
+            { SkXfermode::kDstIn_Mode,      "DstIn"     },
+            { SkXfermode::kSrcOut_Mode,     "SrcOut"    },
+            { SkXfermode::kDstOut_Mode,     "DstOut"    },
+            { SkXfermode::kSrcATop_Mode,    "SrcATop"   },
+            { SkXfermode::kDstATop_Mode,    "DstATop"   },
+            { SkXfermode::kXor_Mode,        "Xor"       },
+            { SkXfermode::kPlus_Mode,       "Plus"      },
+            { SkXfermode::kModulate_Mode,   "Mod"       },
+            { SkXfermode::kScreen_Mode,     "Screen"    },
+            { SkXfermode::kOverlay_Mode,    "Overlay"   },
+            { SkXfermode::kDarken_Mode,     "Darken"    },
+            { SkXfermode::kLighten_Mode,    "Lighten"   },
+            { SkXfermode::kColorDodge_Mode, "Dodge"     },
+            { SkXfermode::kColorBurn_Mode,  "Burn"      },
+            { SkXfermode::kHardLight_Mode,  "Hard"      },
+            { SkXfermode::kSoftLight_Mode,  "Soft"      },
+            { SkXfermode::kDifference_Mode, "Diff"      },
+            { SkXfermode::kExclusion_Mode,  "Exclusion" },
+            { SkXfermode::kMultiply_Mode,   "Multiply"  },
+            { SkXfermode::kHue_Mode,        "Hue"       },
+            { SkXfermode::kSaturation_Mode, "Sat"       },
+            { SkXfermode::kColor_Mode,      "Color"     },
+            { SkXfermode::kLuminosity_Mode, "Luminosity"},
+        };
+
+        SkColor gColors[] = {
+            SK_ColorWHITE,
+            SK_ColorRED,
+            0x88888888,         // transparent grey
+            0x88000088          // transparent blue
+        };
+
+        const int numModes = SK_ARRAY_COUNT(gModes);
+        SkASSERT(numModes == kNumXferModes);
+        const int numColors = SK_ARRAY_COUNT(gColors);
+        SkASSERT(numColors == kNumColors);
+        SkRSXform xforms[numColors];
+        SkRect rects[numColors];
+        SkColor quadColors[numColors];
+
+        SkPaint paint;
+        paint.setAntiAlias(true);
+
+        for (int i = 0; i < numColors; ++i) {
+            xforms[i].set(1.0f, 0.0f, SkIntToScalar(kPad), i*(target.width()+kPad));
+            rects[i] = target;
+            quadColors[i] = gColors[i];
+        }
+
+        SkPaint textP;
+        textP.setTextSize(SkIntToScalar(kTextPad));
+        textP.setAntiAlias(true);
+        sk_tool_utils::set_portable_typeface_always(&textP, NULL);
+
+        for (int i = 0; i < numModes; ++i) {
+            canvas->drawText(gModes[i].fLabel, strlen(gModes[i].fLabel),
+                             i*(target.width()+kPad)+kPad, SkIntToScalar(kTextPad),
+                             textP);
+        }
+
+        for (int i = 0; i < numModes; ++i) {
+            canvas->save();            
+            canvas->translate(SkIntToScalar(i*(target.height()+kPad)),
+                              SkIntToScalar(kTextPad+kPad));
+            // w/o a paint
+            canvas->drawAtlas(fAtlas, xforms, rects, quadColors, numColors, 
+                              gModes[i].fMode, NULL, NULL);
+            canvas->translate(0.0f, numColors*(target.height()+kPad));
+            // w a paint
+            canvas->drawAtlas(fAtlas, xforms, rects, quadColors, numColors, 
+                              gModes[i].fMode, NULL, &paint);
+            canvas->restore();        
+        }
+    }
+    
+private:
+    static const int kNumXferModes = 29;
+    static const int kNumColors = 4;
+    static const int kAtlasSize = 30;
+    static const int kPad = 2;
+    static const int kTextPad = 8;
+
+
+    SkAutoTUnref<SkImage> fAtlas;
+
+    typedef GM INHERITED;
+};
+DEF_GM( return new DrawAtlasColorsGM; )
+