1 /*
2 * Copyright 2011 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8 #include "SampleCode.h"
9 #include "SkView.h"
10 #include "SkCanvas.h"
11 #include "SkGradientShader.h"
12 #include "SkString.h"
13
draw_gradient2(SkCanvas * canvas,const SkRect & rect,SkScalar delta)14 static 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, 0.25f, 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::CreateTwoPointConical(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
39 class DegenerateTwoPtRadialsView : public SampleView {
40
41 public:
DegenerateTwoPtRadialsView()42 DegenerateTwoPtRadialsView() {
43 fTime = 0;
44 this->setBGColor(0xFFDDDDDD);
45 }
46
47 protected:
48 // overrides from SkEventSink
onQuery(SkEvent * evt)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
onDrawContent(SkCanvas * canvas)57 virtual void onDrawContent(SkCanvas* canvas) {
58 fTime += SampleCode::GetAnimSecondsDelta();
59 SkScalar delta = fTime / 15.f;
60 int intPart = SkScalarFloorToInt(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 SkScalar w = SK_Scalar1 * 500;
70 SkScalar h = SK_Scalar1 * 500;
71 SkScalar l = SK_Scalar1 * 100;
72 SkScalar t = SK_Scalar1 * 100;
73 draw_gradient2(canvas, SkRect::MakeXYWH(l, t, w, h), delta);
74 SkString txt;
75 txt.appendf("gap at \"tangent\" pt = %f", SkScalarToFloat(delta));
76 SkPaint paint;
77 paint.setAntiAlias(true);
78 paint.setColor(SK_ColorBLACK);
79 canvas->drawText(txt.c_str(), txt.size(), l + w/2 + w*DELTA_SCALE*delta, t + h + SK_Scalar1 * 10, paint);
80 this->inval(NULL);
81 }
82
83 private:
84 SkScalar fTime;
85 typedef SampleView INHERITED;
86 };
87
88 //////////////////////////////////////////////////////////////////////////////
89
MyFactory()90 static SkView* MyFactory() { return new DegenerateTwoPtRadialsView; }
91 static SkViewRegister reg(MyFactory);
92