1 /*
2 * Copyright 2013 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 "include/core/SkCanvas.h"
9 #include "include/core/SkPaint.h"
10 #include "include/core/SkPathBuilder.h"
11 #include "include/private/base/SkTDArray.h"
12 #include "src/base/SkRandom.h"
13 #include "tools/viewer/Slide.h"
14
15 // Generates y values for the chart plots.
gen_data(SkScalar yAvg,SkScalar ySpread,int count,SkTDArray<SkScalar> * dataPts)16 static void gen_data(SkScalar yAvg, SkScalar ySpread, int count, SkTDArray<SkScalar>* dataPts) {
17 dataPts->resize(count);
18 static SkRandom gRandom;
19 for (int i = 0; i < count; ++i) {
20 (*dataPts)[i] = gRandom.nextRangeScalar(yAvg - SkScalarHalf(ySpread),
21 yAvg + SkScalarHalf(ySpread));
22 }
23 }
24
25 // Generates a path to stroke along the top of each plot and a fill path for the area below each
26 // plot. The fill path is bounded below by the bottomData plot points or a horizontal line at
27 // yBase if bottomData == nullptr.
28 // The plots are animated by rotating the data points by leftShift.
gen_paths(const SkTDArray<SkScalar> & topData,const SkTDArray<SkScalar> * bottomData,SkScalar yBase,SkScalar xLeft,SkScalar xDelta,int leftShift,SkPathBuilder * plot,SkPathBuilder * fill)29 static void gen_paths(const SkTDArray<SkScalar>& topData,
30 const SkTDArray<SkScalar>* bottomData,
31 SkScalar yBase,
32 SkScalar xLeft, SkScalar xDelta,
33 int leftShift,
34 SkPathBuilder* plot, SkPathBuilder* fill) {
35 plot->incReserve(topData.size());
36 if (nullptr == bottomData) {
37 fill->incReserve(topData.size() + 2);
38 } else {
39 fill->incReserve(2 * topData.size());
40 }
41
42 leftShift %= topData.size();
43 SkScalar x = xLeft;
44
45 // Account for the leftShift using two loops
46 int shiftToEndCount = topData.size() - leftShift;
47 plot->moveTo(x, topData[leftShift]);
48 fill->moveTo(x, topData[leftShift]);
49
50 for (int i = 1; i < shiftToEndCount; ++i) {
51 plot->lineTo(x, topData[i + leftShift]);
52 fill->lineTo(x, topData[i + leftShift]);
53 x += xDelta;
54 }
55
56 for (int i = 0; i < leftShift; ++i) {
57 plot->lineTo(x, topData[i]);
58 fill->lineTo(x, topData[i]);
59 x += xDelta;
60 }
61
62 if (bottomData) {
63 SkASSERT(bottomData->size() == topData.size());
64 // iterate backwards over the previous graph's data to generate the bottom of the filled
65 // area (and account for leftShift).
66 for (int i = 0; i < leftShift; ++i) {
67 x -= xDelta;
68 fill->lineTo(x, (*bottomData)[leftShift - 1 - i]);
69 }
70 for (int i = 0; i < shiftToEndCount; ++i) {
71 x -= xDelta;
72 fill->lineTo(x, (*bottomData)[bottomData->size() - 1 - i]);
73 }
74 } else {
75 fill->lineTo(x - xDelta, yBase);
76 fill->lineTo(xLeft, yBase);
77 }
78 }
79
80 // A set of scrolling line plots with the area between each plot filled. Stresses out GPU path
81 // filling
82 class ChartSlide : public Slide {
83 inline static constexpr int kNumGraphs = 5;
84 inline static constexpr int kPixelsPerTick = 3;
85 inline static constexpr int kShiftPerFrame = 1;
86 int fShift = 0;
87 SkISize fSize = {-1, -1};
88 SkTDArray<SkScalar> fData[kNumGraphs];
89
90 public:
ChartSlide()91 ChartSlide() { fName = "Chart"; }
92
draw(SkCanvas * canvas)93 void draw(SkCanvas* canvas) override {
94 bool sizeChanged = false;
95 if (canvas->getBaseLayerSize() != fSize) {
96 fSize = canvas->getBaseLayerSize();
97 sizeChanged = true;
98 }
99
100 SkScalar ySpread = SkIntToScalar(fSize.fHeight / 20);
101
102 SkScalar height = SkIntToScalar(fSize.fHeight);
103
104 if (sizeChanged) {
105 int dataPointCount = std::max(fSize.fWidth / kPixelsPerTick + 1, 2);
106
107 for (int i = 0; i < kNumGraphs; ++i) {
108 SkScalar y = (kNumGraphs - i) * (height - ySpread) / (kNumGraphs + 1);
109 fData[i].reset();
110 gen_data(y, ySpread, dataPointCount, fData + i);
111 }
112 }
113
114 canvas->clear(0xFFE0F0E0);
115
116 static SkRandom colorRand;
117 static SkColor gColors[kNumGraphs] = { 0x0 };
118 if (0 == gColors[0]) {
119 for (int i = 0; i < kNumGraphs; ++i) {
120 gColors[i] = colorRand.nextU() | 0xff000000;
121 }
122 }
123
124 static const SkScalar kStrokeWidth = SkIntToScalar(2);
125 SkPaint plotPaint;
126 SkPaint fillPaint;
127 plotPaint.setAntiAlias(true);
128 plotPaint.setStyle(SkPaint::kStroke_Style);
129 plotPaint.setStrokeWidth(kStrokeWidth);
130 plotPaint.setStrokeCap(SkPaint::kRound_Cap);
131 plotPaint.setStrokeJoin(SkPaint::kRound_Join);
132 fillPaint.setAntiAlias(true);
133 fillPaint.setStyle(SkPaint::kFill_Style);
134
135 SkPathBuilder plotPath, fillPath;
136 SkTDArray<SkScalar>* prevData = nullptr;
137
138 for (int i = 0; i < kNumGraphs; ++i) {
139 gen_paths(fData[i],
140 prevData,
141 height,
142 0,
143 SkIntToScalar(kPixelsPerTick),
144 fShift,
145 &plotPath,
146 &fillPath);
147
148 // Make the fills partially transparent
149 fillPaint.setColor((gColors[i] & 0x00ffffff) | 0x80000000);
150 canvas->drawPath(fillPath.detach(), fillPaint);
151
152 plotPaint.setColor(gColors[i]);
153 canvas->drawPath(plotPath.detach(), plotPaint);
154
155 prevData = fData + i;
156 }
157
158 fShift += kShiftPerFrame;
159 }
160 };
161
162 DEF_SLIDE( return new ChartSlide(); )
163