GPU Gradients

gm/gradients_no_texture.cpp

+/*
+ * Copyright 2013 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 "SkGradientShader.h"
+
+using namespace skiagm;
+
+struct GradData {
+    int             fCount;
+    const SkColor*  fColors;
+    const SkScalar* fPos;
+};
+
+static const SkColor gColors[] = {
+    SK_ColorRED, SK_ColorGREEN, SK_ColorBLUE, SK_ColorWHITE,
+};
+
+static const GradData gGradData[] = {
+    { 1, gColors, NULL },
+    { 2, gColors, NULL },
+    { 3, gColors, NULL },
+    { 4, gColors, NULL },
+};
+
+static SkShader* MakeLinear(const SkPoint pts[2], const GradData& data,
+                            SkShader::TileMode tm, SkUnitMapper* mapper) {
+    return SkGradientShader::CreateLinear(pts, data.fColors, data.fPos,
+                                          data.fCount, tm, mapper);
+}
+
+static SkShader* MakeRadial(const SkPoint pts[2], const GradData& data,
+                            SkShader::TileMode tm, SkUnitMapper* mapper) {
+    SkPoint center;
+    center.set(SkScalarAve(pts[0].fX, pts[1].fX),
+               SkScalarAve(pts[0].fY, pts[1].fY));
+    return SkGradientShader::CreateRadial(center, center.fX, data.fColors,
+                                          data.fPos, data.fCount, tm, mapper);
+}
+
+static SkShader* MakeSweep(const SkPoint pts[2], const GradData& data,
+                           SkShader::TileMode, SkUnitMapper* mapper) {
+    SkPoint center;
+    center.set(SkScalarAve(pts[0].fX, pts[1].fX),
+               SkScalarAve(pts[0].fY, pts[1].fY));
+    return SkGradientShader::CreateSweep(center.fX, center.fY, data.fColors,
+                                         data.fPos, data.fCount, mapper);
+}
+
+static SkShader* Make2Radial(const SkPoint pts[2], const GradData& data,
+                             SkShader::TileMode tm, SkUnitMapper* mapper) {
+    SkPoint center0, center1;
+    center0.set(SkScalarAve(pts[0].fX, pts[1].fX),
+                SkScalarAve(pts[0].fY, pts[1].fY));
+    center1.set(SkScalarInterp(pts[0].fX, pts[1].fX, SkIntToScalar(3)/5),
+                SkScalarInterp(pts[0].fY, pts[1].fY, SkIntToScalar(1)/4));
+    return SkGradientShader::CreateTwoPointRadial(
+        center1, (pts[1].fX - pts[0].fX) / 7,
+        center0, (pts[1].fX - pts[0].fX) / 2,
+        data.fColors, data.fPos, data.fCount, tm, mapper);
+}
+
+static SkShader* Make2Conical(const SkPoint pts[2], const GradData& data,
+                              SkShader::TileMode tm, SkUnitMapper* mapper) {
+    SkPoint center0, center1;
+    SkScalar radius0 = SkScalarDiv(pts[1].fX - pts[0].fX, 10);
+    SkScalar radius1 = SkScalarDiv(pts[1].fX - pts[0].fX, 3);
+    center0.set(pts[0].fX + radius0, pts[0].fY + radius0);
+    center1.set(pts[1].fX - radius1, pts[1].fY - radius1);
+    return SkGradientShader::CreateTwoPointConical(center1, radius1,
+                                                   center0, radius0,
+                                                   data.fColors, data.fPos,
+                                                   data.fCount, tm, mapper);
+}
+
+
+typedef SkShader* (*GradMaker)(const SkPoint pts[2], const GradData& data,
+                               SkShader::TileMode tm, SkUnitMapper* mapper);
+static const GradMaker gGradMakers[] = {
+    MakeLinear, MakeRadial, MakeSweep, Make2Radial, Make2Conical,
+};
+
+///////////////////////////////////////////////////////////////////////////////
+
+class GradientsNoTextureGM : public GM {
+public:
+    GradientsNoTextureGM() {
+        this->setBGColor(0xFFDDDDDD);
+    }
+
+protected:
+    SkString onShortName() SK_OVERRIDE { return SkString("gradients_no_texture"); }
+    virtual SkISize onISize() SK_OVERRIDE { return make_isize(640, 615); }
+
+    virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
+        static const SkPoint kPts[2] = { { 0, 0 },
+                                         { SkIntToScalar(50), SkIntToScalar(50) } };
+        static const SkShader::TileMode kTM = SkShader::kClamp_TileMode;
+        SkRect kRect = { 0, 0, SkIntToScalar(50), SkIntToScalar(50) };
+        SkPaint paint;
+        paint.setAntiAlias(true);
+
+        canvas->translate(SkIntToScalar(20), SkIntToScalar(20));
+        static const uint8_t kAlphas[] = { 0xff, 0x40 };
+        for (size_t a = 0; a < SK_ARRAY_COUNT(kAlphas); ++a) {
+            for (size_t i = 0; i < SK_ARRAY_COUNT(gGradData); ++i) {
+                canvas->save();
+                for (size_t j = 0; j < SK_ARRAY_COUNT(gGradMakers); ++j) {
+                    SkShader* shader = gGradMakers[j](kPts, gGradData[i], kTM, NULL);
+                    paint.setShader(shader)->unref();
+                    paint.setAlpha(kAlphas[a]);
+                    canvas->drawRect(kRect, paint);
+                    canvas->translate(0, SkIntToScalar(kRect.height() + 20));
+                }
+                canvas->restore();
+                canvas->translate(SkIntToScalar(kRect.width() + 20), 0);
+            }
+        }
+    }
+
+private:
+    typedef GM INHERITED;
+};
+
+///////////////////////////////////////////////////////////////////////////////
+
+DEF_GM( return SkNEW(GradientsNoTextureGM));