Replace edge types with GrEdgeEffect

src/gpu/effects/GrEdgeEffect.h

+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrEdgeEffect_DEFINED
+#define GrEdgeEffect_DEFINED
+
+#include "GrEffect.h"
+
+class GrGLEdgeEffect;
+
+/**
+ * The output of this effect is one of three different edge types: hairlines, quads, 
+ * and hairline quads.
+ *
+ * TODO: Fix the fact that HairLine edge types use y-down coords.

[bsalomon, 2013/03/25 13:35:54]

I think this copied comment is out-of-date. We're using
GrGLShaderBuilder::fragmentPosition() in the code which will be Skia's notion of
device coords.

+ *       (either adjust in VS or use origin_upper_left in GLSL)
+ */
+
+class GrEdgeEffect : public GrEffect {
+public:
+    enum EdgeType {
+        /* 1-pixel wide line
+           2D implicit line eq (a*x + b*y +c = 0). 4th component unused. */
+        kHairLine_EdgeType = 0,
+        /* Quadratic specified by u^2-v canonical coords (only 2
+           components used). Coverage based on signed distance with negative
+           being inside, positive outside. Edge specified in window space
+           (y-down) */
+        kQuad_EdgeType,
+        /* Same as above but for hairline quadratics. Uses unsigned distance.
+           Coverage is min(0, 1-distance). 3rd & 4th component unused. */
+        kHairQuad_EdgeType,
+
+        kLast_EdgeType = kHairQuad_EdgeType
+    };
+    static const int kEdgeTypeCount = kLast_EdgeType + 1;
+
+    static GrEffectRef* Create(EdgeType type) {
+        // we go through this so we only have one copy of each effect (stroked/filled)
+        static SkAutoTUnref<GrEffectRef> gEdgeEffectRef[kEdgeTypeCount] = {
+            SkAutoTUnref<GrEffectRef>(
+                CreateEffectRef(AutoEffectUnref(SkNEW_ARGS(GrEdgeEffect, (kHairLine_EdgeType))))),
+            SkAutoTUnref<GrEffectRef>(
+                CreateEffectRef(AutoEffectUnref(SkNEW_ARGS(GrEdgeEffect, (kQuad_EdgeType))))),
+            SkAutoTUnref<GrEffectRef>(
+                CreateEffectRef(AutoEffectUnref(SkNEW_ARGS(GrEdgeEffect, (kHairQuad_EdgeType)))))
+        };
+
+        gEdgeEffectRef[type].get()->ref();
+        return gEdgeEffectRef[type];
+    }
+
+    virtual ~GrEdgeEffect() {}
+
+    static const char* Name() { return "Edge"; }
+
+    virtual void getConstantColorComponents(GrColor* color, uint32_t* validFlags) const SK_OVERRIDE;
+
+    typedef GrGLEdgeEffect GLEffect;
+
+    virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE;
+
+    inline EdgeType edgeType() const { return fEdgeType; }
+
+private:
+    GrEdgeEffect(EdgeType edgeType);
+
+    virtual bool onIsEqual(const GrEffect& other) const SK_OVERRIDE {
+        const GrEdgeEffect& qee = CastEffect<GrEdgeEffect>(other);
+        return qee.fEdgeType == fEdgeType;
+    }
+
+    EdgeType fEdgeType;
+
+    GR_DECLARE_EFFECT_TEST;
+
+    typedef GrEffect INHERITED;
+};
+
+#endif