Add GM that tests bmp filter qualities with repeat mode

gm/bmpfilterqualityrepeat.cpp

Index: gm/bmpfilterqualityrepeat.cpp
diff --git a/gm/bmpfilterqualityrepeat.cpp b/gm/bmpfilterqualityrepeat.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..f53386020147a1c0bd7339fa9ee65712a2ee5fda
--- /dev/null
+++ b/gm/bmpfilterqualityrepeat.cpp
@@ -0,0 +1,79 @@
+/*
+ * 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 "SkShader.h"
+
+// Inspired by svg/as-border-image/svg-as-border-image.html. Draws a four-color checker board bitmap
+// such that it is stretched and repeat tiled with different filter qualities. It is testing whether
+// the bmp filter respects the repeat mode at the tile seams.
+class BmpFilterQualityRepeat : public skiagm::GM {
+public:
+    BmpFilterQualityRepeat() { this->setBGColor(0xFFCCBBAA); }
+
+protected:
+
+    void onOnceBeforeDraw() override {
+        fBmp.allocN32Pixels(40, 40, true);
+        SkCanvas canvas(fBmp);
+        SkBitmap colorBmp;
+        colorBmp.allocN32Pixels(20, 20, true);
+        colorBmp.eraseColor(0xFFFF0000);
+        canvas.drawBitmap(colorBmp, 0, 0);
+        colorBmp.eraseColor(0xFF008200);
+        canvas.drawBitmap(colorBmp, 20, 0);
+        colorBmp.eraseColor(0xFFFF9000);
+        canvas.drawBitmap(colorBmp, 0, 20);
+        colorBmp.eraseColor(0xFF2000FF);
+        canvas.drawBitmap(colorBmp, 20, 20);
+    }
+
+    SkString onShortName() override { return SkString("bmp_filter_quality_repeat"); }
+
+    SkISize onISize() override { return SkISize::Make(810, 235); }
+
+    void onDraw(SkCanvas* canvas) override {
+
+        static const struct { 
+            SkFilterQuality fQuality;
+            const char* fName;
+        } kQualities[] = {
+            {kNone_SkFilterQuality, "none"},
+            {kLow_SkFilterQuality, "low"},
+            {kMedium_SkFilterQuality, "medium"},
+            {kHigh_SkFilterQuality, "high"},
+        };
+
+        for (size_t q = 0; q < SK_ARRAY_COUNT(kQualities); ++q) {
+            SkPaint paint;
+            paint.setFilterQuality(kQualities[q].fQuality);
+            SkPaint bmpPaint(paint);
+            SkMatrix lm = SkMatrix::I();
+            lm.setScaleX(2.5);
+            lm.setTranslateX(423);
+            lm.setTranslateY(330);
+
+            static const SkShader::TileMode kTM = SkShader::kRepeat_TileMode;
+            bmpPaint.setShader(SkShader::CreateBitmapShader(fBmp, kTM, kTM, &lm))->unref();
+            SkRect rect = SkRect::MakeLTRB(20, 60, 220, 210);
+            canvas->drawRect(rect, bmpPaint);
+            paint.setAntiAlias(true);
+            canvas->drawText(kQualities[q].fName, strlen(kQualities[q].fName), 20, 40, paint);
+            canvas->translate(250, 0);
+        }
+    }
+
+private:
+    SkBitmap    fBmp;
+
+    typedef skiagm::GM INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+DEF_GM( return SkNEW(BmpFilterQualityRepeat); )