1 2/* 3 * Copyright 2011 Google Inc. 4 * 5 * Use of this source code is governed by a BSD-style license that can be 6 * found in the LICENSE file. 7 */ 8#include "SampleCode.h" 9#include "SkView.h" 10#include "SkCanvas.h" 11#include "Sk64.h" 12#include "SkGradientShader.h" 13 14static void draw_gradient2(SkCanvas* canvas, const SkRect& rect, SkScalar delta) { 15 SkColor colors[] = { SK_ColorRED, SK_ColorGREEN, SK_ColorBLUE, SK_ColorMAGENTA }; 16 SkScalar pos[] = { 0, SkFloatToScalar(0.25f), SkFloatToScalar(0.75f), SK_Scalar1 }; 17 18 SkScalar l = rect.fLeft; 19 SkScalar t = rect.fTop; 20 SkScalar w = rect.width(); 21 SkScalar h = rect.height(); 22 23 SkASSERT(0 == SkScalarMod(w, SK_Scalar1 * 5)); 24 25 SkPoint c0 = { l + 2 * w / 5 + delta, t + h / 2 }; 26 SkPoint c1 = { l + 3 * w / 5, t + h / 2 }; 27 SkScalar r0 = w / 5; 28 SkScalar r1 = 2 * w / 5; 29 SkShader* s = SkGradientShader::CreateTwoPointRadial(c0, r0, c1, r1, colors, 30 pos, SK_ARRAY_COUNT(pos), 31 SkShader::kClamp_TileMode); 32 SkPaint paint; 33 paint.setShader(s)->unref(); 34 35 canvas->drawRect(rect, paint); 36} 37 38 39class DegenerateTwoPtRadialsView : public SampleView { 40 41public: 42 DegenerateTwoPtRadialsView() { 43 fTime = 0; 44 this->setBGColor(0xFFDDDDDD); 45 } 46 47protected: 48 // overrides from SkEventSink 49 virtual bool onQuery(SkEvent* evt) { 50 if (SampleCode::TitleQ(*evt)) { 51 SampleCode::TitleR(evt, "DegenerateTwoPtRadials"); 52 return true; 53 } 54 return this->INHERITED::onQuery(evt); 55 } 56 57 virtual void onDrawContent(SkCanvas* canvas) { 58 fTime += SampleCode::GetAnimSecondsDelta(); 59 SkScalar delta = fTime / 15.f; 60 int intPart = SkScalarFloor(delta); 61 delta = delta - SK_Scalar1 * intPart; 62 if (intPart % 2) { 63 delta = SK_Scalar1 - delta; 64 } 65 delta -= SK_ScalarHalf; 66 static const int DELTA_SCALE = 500; 67 delta /= DELTA_SCALE; 68 69 SkRect rect; 70 SkScalar w = SK_Scalar1 * 500; 71 SkScalar h = SK_Scalar1 * 500; 72 SkScalar l = SK_Scalar1 * 100; 73 SkScalar t = SK_Scalar1 * 100; 74 draw_gradient2(canvas, SkRect::MakeXYWH(l, t, w, h), delta); 75 char txt[512]; 76 sprintf(txt, "gap at \"tangent\" pt = %f", SkScalarToFloat(delta)); 77 SkPaint paint; 78 paint.setAntiAlias(true); 79 paint.setColor(SK_ColorBLACK); 80 canvas->drawText(txt, strlen(txt), l + w/2 + w*DELTA_SCALE*delta, t + h + SK_Scalar1 * 10, paint); 81 this->inval(NULL); 82 } 83 84private: 85 SkScalar fTime; 86 typedef SampleView INHERITED; 87}; 88 89////////////////////////////////////////////////////////////////////////////// 90 91static SkView* MyFactory() { return new DegenerateTwoPtRadialsView; } 92static SkViewRegister reg(MyFactory); 93