Animated the PathUtils Sample to show path contours

gm/nate_gradients.cpp

+
+/*
+ * Copyright 2011 Google Inc.

[scroggo, 2013/07/08 19:11:31]

2013

+ *
+ * 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, SK_ColorBLACK,
+    SK_ColorRED, SK_ColorGREEN, SK_ColorBLUE, SK_ColorWHITE, SK_ColorBLACK,
+    SK_ColorRED, SK_ColorGREEN, SK_ColorBLUE, SK_ColorWHITE, SK_ColorBLACK,
+    SK_ColorRED, SK_ColorGREEN, SK_ColorBLUE, SK_ColorWHITE, SK_ColorBLACK,
+};
+static const SkScalar gPos0[] = { 0, SK_Scalar1 };
+static const SkScalar gPos1[] = { SK_Scalar1/4, SK_Scalar1*3/4 };
+static const SkScalar gPos2[] = {
+    0, SK_Scalar1/8, SK_Scalar1/2, SK_Scalar1*7/8, SK_Scalar1
+};
+
+static const GradData gGradData[] = {
+    { 20, 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 GradientsGM : public GM {

[scroggo, 2013/07/08 19:11:31]

What is this new GM demonstrating that isn't covered by our other gradient GMs?

+public:
+    GradientsGM() {
+        this->setBGColor(0xFFDDDDDD);
+    }
+
+protected:
+    SkString onShortName() { return SkString("nate_gradients"); }
+
+    virtual SkISize onISize() { return make_isize(640, 615); }
+
+    virtual void onDraw(SkCanvas* canvas) {
+
+        SkPoint pts[2] = {
+            { 0, 0 },
+            { SkIntToScalar(100), SkIntToScalar(100) }
+        };
+        SkShader::TileMode tm = SkShader::kClamp_TileMode;
+        SkRect r = { 0, 0, SkIntToScalar(100), SkIntToScalar(100) };
+        SkPaint paint;
+        paint.setAntiAlias(true);
+
+        canvas->translate(SkIntToScalar(20), SkIntToScalar(20));
+        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](pts, gGradData[i], tm, NULL);
+                paint.setShader(shader);
+                canvas->drawRect(r, paint);
+                shader->unref();
+                canvas->translate(0, SkIntToScalar(120));
+            }
+            canvas->restore();
+            canvas->translate(SkIntToScalar(120), 0);
+        }
+    }
+
+private:
+    typedef GM INHERITED;
+};
+
+
+
+///////////////////////////////////////////////////////////////////////////////
+
+static GM* MyFactory(void*) { return new GradientsGM; }
+static GMRegistry reg(MyFactory);
+
+