Fix scaling issue with distance field text.

gm/dftext.cpp

Index: gm/dftext.cpp
diff --git a/gm/dftext.cpp b/gm/dftext.cpp
new file mode 100755
index 0000000000000000000000000000000000000000..ecc91d02425291dd09fbba4f91ed81a9ca28ed72
--- /dev/null
+++ b/gm/dftext.cpp
@@ -0,0 +1,132 @@
+/*
+ * 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 "gm.h"
+#include "SkTypeface.h"
+
+namespace skiagm {
+
+class DFTextGM : public GM {
+public:
+    DFTextGM() {
+        this->setBGColor(0xFFFFFFFF);
+    }
+
+    virtual ~DFTextGM() {
+    }
+
+protected:
+    virtual uint32_t onGetFlags() const SK_OVERRIDE {
+        return kSkipTiled_Flag | kGPUOnly_Flag;

[bsalomon, 2014/09/15 13:33:19]

why the skip tile?

Have you checked that it draws similar to the raster or non-DF code path?

[jvanverth1, 2014/09/15 13:43:53]

I copied another GM that had it. I can remove it.
Yes, it looks similar.

+    }
+
+    virtual SkString onShortName() {
+        return SkString("dftext");
+    }
+
+    virtual SkISize onISize() {
+        return SkISize::Make(1024, 768);
+    }
+
+    static void rotate_about(SkCanvas* canvas,
+        SkScalar degrees,
+        SkScalar px, SkScalar py) {
+        canvas->translate(px, py);
+        canvas->rotate(degrees);
+        canvas->translate(-px, -py);
+    }
+
+    virtual void onDraw(SkCanvas* canvas) {
+        SkScalar textSizes[] = { 11.0f, 11.0f*2.0f, 11.0f*5.0f, 11.0f*2.0f*5.0f };
+        SkScalar scales[] = { 2.0f*5.0f, 5.0f, 2.0f, 1.0f };
+
+        SkPaint paint;
+
+        paint.setAntiAlias(true);
+        paint.setSubpixelText(true);
+        paint.setDistanceFieldTextTEMP(true);

[bsalomon, 2014/09/15 13:33:19]

Is the surface method of triggering DF more permanent? If so, maybe make a
surface, draw to it, snap and draw it back to canvas?

[jvanverth1, 2014/09/15 13:43:53]

Will do.

+
+        sk_tool_utils::set_portable_typeface(&paint, "Times New Roman", SkTypeface::kNormal);
+
+        const char* text = "Hamburgefons";
+        const size_t textLen = strlen(text);
+
+        // check a variety of scales
+        SkScalar x = SkIntToScalar(0);
+        SkScalar y = SkIntToScalar(78);
+        for (int i = 0; i < SK_ARRAY_COUNT(textSizes); ++i) {
+            SkAutoCanvasRestore acr(canvas, true);
+            canvas->translate(x, y);
+            canvas->scale(scales[i], scales[i]);
+            paint.setTextSize(textSizes[i]);
+            canvas->drawText(text, textLen, 0, 0, paint);
+            y += paint.getFontMetrics(NULL)*scales[i];
+        }
+
+        // check rotation
+        for (int i = 0; i < 5; ++i) {
+            SkScalar rotX = SkIntToScalar(10);
+            SkScalar rotY = y;
+
+            SkAutoCanvasRestore acr(canvas, true);
+            canvas->translate(SkIntToScalar(10 + i * 200), -80);
+            rotate_about(canvas, SkIntToScalar(i * 5), rotX, rotY);
+            for (int ps = 6; ps <= 32; ps += 3) {
+                paint.setTextSize(SkIntToScalar(ps));
+                canvas->drawText(text, textLen, rotX, rotY, paint);
+                rotY += paint.getFontMetrics(NULL);
+            }
+        }
+
+        // check gamma-corrected blending
+        const SkColor fg[] = {
+            0xFFFFFFFF,
+            0xFFFFFF00, 0xFFFF00FF, 0xFF00FFFF,
+            0xFFFF0000, 0xFF00FF00, 0xFF0000FF,
+            0xFF000000,
+        };
+
+        paint.setLCDRenderText(true);
+        paint.setColor(0xFFF1F1F1);
+        SkRect r = SkRect::MakeLTRB(690, 20, 840, 230);
+        canvas->drawRect(r, paint);
+
+        x = 700;
+        y = 40;
+        paint.setTextSize(SkIntToScalar(22));
+        for (size_t i = 0; i < SK_ARRAY_COUNT(fg); ++i) {
+            paint.setColor(fg[i]);
+
+            canvas->drawText(text, textLen, x, y, paint);
+            y += paint.getFontMetrics(NULL);
+        }
+
+        paint.setColor(0xFF1F1F1F);
+        r = SkRect::MakeLTRB(840, 20, 990, 230);
+        canvas->drawRect(r, paint);
+
+        x = 850;
+        y = 40;
+        paint.setTextSize(SkIntToScalar(22));
+        for (size_t i = 0; i < SK_ARRAY_COUNT(fg); ++i) {
+            paint.setColor(fg[i]);
+
+            canvas->drawText(text, textLen, x, y, paint);
+            y += paint.getFontMetrics(NULL);
+        }
+
+    }
+
+private:
+    typedef GM INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+static GM* MyFactory(void*) { return new DFTextGM; }
+static GMRegistry reg(MyFactory);
+
+}