introduce Props to surface

include/core/SkSurfaceProps.h

+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkSurfaceProps_DEFINED
+#define SkSurfaceProps_DEFINED
+
+#include "SkPoint.h"
+
+/**
+ *  Description of how the LCD strips are arranged for each pixel. If this is unknown, or the
+ *  pixels are meant to be "portable" and/or transformed before showing (e.g. rotated, scaled)
+ *  then use kUnknown_SkPixelGeometry.
+ */
+enum SkPixelGeometry {
+    kUnknown_SkPixelGeometry,
+    kRGB_H_SkPixelGeometry,
+    kBGR_H_SkPixelGeometry,
+    kRGB_V_SkPixelGeometry,
+    kBGR_V_SkPixelGeometry,
+};
+
+/**
+ *  Describes properties and constraints of a given SkSurface. The rendering engine can parse these
+ *  during drawing, and can sometimes optimized its performance (e.g. disabling an expensive
+ *  feature).
+ */
+class SkSurfaceProps {
+public:
+    enum Flags {
+        kDisallowAntiAlias_Flag     = 1 << 0,
+        kDisallowDither_Flag        = 1 << 1,
+        kUseDistanceFieldFonts_Flag = 1 << 2,
+    };
+private:
+    SkSurfaceProps();
+public:
+    // uses kLegacyLCD_SkPixelGeometry
+    enum InitType {
+        kLegacyFontHost_InitType
+    };
+    SkSurfaceProps(InitType);
+
+    // pixel geometry cannot be kLegacyLCD_SkPixelGeometry
+    SkSurfaceProps(uint32_t flags, SkPixelGeometry);
+
+    uint32_t flags() const { return fFlags; }
+    SkPixelGeometry pixelGeometry() const { return fPixelGeometry; }
+
+    bool disallowAA() const { return SkToBool(fFlags & kDisallowAntiAlias_Flag); }
+    bool disallowDither() const { return SkToBool(fFlags & kDisallowDither_Flag); }
+    bool useDistanceFieldFonts() const { return SkToBool(fFlags & kUseDistanceFieldFonts_Flag); }
+
+private:
+    uint32_t        fFlags;
+    SkPixelGeometry fPixelGeometry;
+};
+
+#endif