add sample for gradients

git-svn-id: http://skia.googlecode.com/svn/trunk@144 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 114 insertions, 0 deletions

diff --git a/samplecode/SampleGradients.cpp b/samplecode/SampleGradients.cpp
new file mode 100644
index 0000000000..c80d653747
--- /dev/null
+++ b/samplecode/SampleGradients.cpp
@@ -0,0 +1,114 @@
+#include "SampleCode.h"
+#include "SkView.h"
+#include "SkCanvas.h"
+#include "SkGradientShader.h"
+
+struct GradData {
+    int             fCount;
+    const SkColor*  fColors;
+    const SkScalar* fPos;
+};
+
+static const SkColor gColors[] = {
+    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[] = {
+    { 2, gColors, NULL },
+    { 2, gColors, gPos0 },
+    { 2, gColors, gPos1 },
+    { 5, gColors, NULL },
+    { 5, gColors, gPos2 }
+};
+
+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 tm, 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);
+}
+
+typedef SkShader* (*GradMaker)(const SkPoint pts[2], const GradData& data,
+                     SkShader::TileMode tm, SkUnitMapper* mapper);
+static const GradMaker gGradMakers[] = {
+    MakeLinear, MakeRadial, MakeSweep
+};
+
+///////////////////////////////////////////////////////////////////////////////
+
+class GradientsView : public SkView {
+public:
+	GradientsView() {}
+    
+protected:
+    // overrides from SkEventSink
+    virtual bool onQuery(SkEvent* evt) {
+        if (SampleCode::TitleQ(*evt)) {
+            SampleCode::TitleR(evt, "Gradients");
+            return true;
+        }
+        return this->INHERITED::onQuery(evt);
+    }
+
+    void drawBG(SkCanvas* canvas) {
+        canvas->drawColor(0xFFDDDDDD);
+    }
+    
+    virtual void onDraw(SkCanvas* canvas) {
+        this->drawBG(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 SkView INHERITED;
+};
+
+///////////////////////////////////////////////////////////////////////////////
+
+static SkView* MyFactory() { return new GradientsView; }
+static SkViewRegister reg(MyFactory);
+