Fix blur on large glyphs in runs < SkGlyphCache::max

gm/largeglyphblur.cpp

Index: gm/largeglyphblur.cpp
diff --git a/gm/largeglyphblur.cpp b/gm/largeglyphblur.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..8723824e13707e1ca58d19489ec67ff02dbb3558
--- /dev/null
+++ b/gm/largeglyphblur.cpp
@@ -0,0 +1,69 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "gm.h"
+
+#include "SkBlurMask.h"
+#include "SkBlurMaskFilter.h"
+#include "SkCanvas.h"
+#include "SkTextBlob.h"
+
+// This test ensures that glyphs whose point size is less than the SkGlyphCache's maxmium, but
+// who have a large blur, are still handled correctly
+namespace skiagm {
+class LargeGlyphBlur : public GM {
+public:
+    LargeGlyphBlur() {}
+
+protected:
+    SkString onShortName() override {
+        return SkString("largeglyphblur");
+    }
+
+    SkISize onISize() override {
+        return SkISize::Make(kWidth, kHeight);
+    }
+
+    void onDraw(SkCanvas* canvas) override {
+        const char text[] = "Hamburgefons";
+
+        SkPaint paint;
+        sk_tool_utils::set_portable_typeface(&paint);
+        paint.setTextSize(256);
+        paint.setAntiAlias(true);
+
+        // setup up maskfilter
+        static const SkScalar kSigma = SkBlurMask::ConvertRadiusToSigma(SkIntToScalar(40));
+
+        SkPaint blurPaint(paint);
+        SkAutoTUnref<SkMaskFilter> mf(SkBlurMaskFilter::Create(kNormal_SkBlurStyle, kSigma));
+        blurPaint.setMaskFilter(mf);
+
+        SkTextBlobBuilder builder;
+
+        sk_tool_utils::add_to_text_blob(&builder, text, paint, 0, 0);
+
+        SkAutoTUnref<const SkTextBlob> blob(builder.build());
+        canvas->drawTextBlob(blob.get(), 10, 200, blurPaint);
+        canvas->drawTextBlob(blob.get(), 10, 200, paint);
+
+        size_t len = strlen(text);
+        canvas->drawText(text, len, 10, 500, blurPaint);
+        canvas->drawText(text, len, 10, 500, paint);
+    }
+
+private:
+    static const int kWidth = 1920;
+    static const int kHeight = 600;
+
+    typedef GM INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+DEF_GM( return SkNEW(LargeGlyphBlur); )
+}