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