xref: /third_party/skia/bench/ChartBench.cpp (revision cb93a386) 
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 "bench/Benchmark.h"
9#include "include/core/SkCanvas.h"
10#include "include/core/SkPaint.h"
11#include "include/core/SkPath.h"
12#include "include/private/SkTDArray.h"
13#include "include/utils/SkRandom.h"
14
15/**
16 * This is a conversion of samplecode/SampleChart.cpp into a bench. It sure would be nice to be able
17 * to write one subclass that can be a GM, bench, and/or Sample.
18 */
19
20// Generates y values for the chart plots.
21static void gen_data(SkScalar yAvg, SkScalar ySpread, int count,
22                     SkRandom* random, SkTDArray<SkScalar>* dataPts) {
23    dataPts->setCount(count);
24    for (int i = 0; i < count; ++i) {
25        (*dataPts)[i] = random->nextRangeScalar(yAvg - SkScalarHalf(ySpread),
26                                                yAvg + SkScalarHalf(ySpread));
27    }
28}
29
30// Generates a path to stroke along the top of each plot and a fill path for the area below each
31// plot. The fill path is bounded below by the bottomData plot points or a horizontal line at
32// yBase if bottomData == nullptr.
33// The plots are animated by rotating the data points by leftShift.
34static void gen_paths(const SkTDArray<SkScalar>& topData,
35                      const SkTDArray<SkScalar>* bottomData,
36                      SkScalar yBase,
37                      SkScalar xLeft, SkScalar xDelta,
38                      int leftShift,
39                      SkPath* plot, SkPath* fill) {
40    plot->rewind();
41    fill->rewind();
42    plot->incReserve(topData.count());
43    if (nullptr == bottomData) {
44        fill->incReserve(topData.count() + 2);
45    } else {
46        fill->incReserve(2 * topData.count());
47    }
48
49    leftShift %= topData.count();
50    SkScalar x = xLeft;
51
52    // Account for the leftShift using two loops
53    int shiftToEndCount = topData.count() - leftShift;
54    plot->moveTo(x, topData[leftShift]);
55    fill->moveTo(x, topData[leftShift]);
56
57    for (int i = 1; i < shiftToEndCount; ++i) {
58        plot->lineTo(x, topData[i + leftShift]);
59        fill->lineTo(x, topData[i + leftShift]);
60        x += xDelta;
61    }
62
63    for (int i = 0; i < leftShift; ++i) {
64        plot->lineTo(x, topData[i]);
65        fill->lineTo(x, topData[i]);
66        x += xDelta;
67    }
68
69    if (bottomData) {
70        SkASSERT(bottomData->count() == topData.count());
71        // iterate backwards over the previous graph's data to generate the bottom of the filled
72        // area (and account for leftShift).
73        for (int i = 0; i < leftShift; ++i) {
74            x -= xDelta;
75            fill->lineTo(x, (*bottomData)[leftShift - 1 - i]);
76        }
77        for (int i = 0; i < shiftToEndCount; ++i) {
78            x -= xDelta;
79            fill->lineTo(x, (*bottomData)[bottomData->count() - 1 - i]);
80        }
81    } else {
82        fill->lineTo(x - xDelta, yBase);
83        fill->lineTo(xLeft, yBase);
84    }
85}
86
87// A set of scrolling line plots with the area between each plot filled. Stresses out GPU path
88// filling
89class ChartBench : public Benchmark {
90public:
91    ChartBench(bool aa) {
92        fShift = 0;
93        fAA = aa;
94        fSize.fWidth = -1;
95        fSize.fHeight = -1;
96    }
97
98protected:
99    const char* onGetName() override {
100        if (fAA) {
101            return "chart_aa";
102        } else {
103            return "chart_bw";
104        }
105    }
106
107    void onDraw(int loops, SkCanvas* canvas) override {
108        bool sizeChanged = false;
109        if (canvas->getBaseLayerSize() != fSize) {
110            fSize = canvas->getBaseLayerSize();
111            sizeChanged = true;
112        }
113
114        SkScalar ySpread = SkIntToScalar(fSize.fHeight / 20);
115
116        SkScalar height = SkIntToScalar(fSize.fHeight);
117        if (sizeChanged) {
118            int dataPointCount = std::max(fSize.fWidth / kPixelsPerTick + 1, 2);
119
120            SkRandom random;
121            for (int i = 0; i < kNumGraphs; ++i) {
122                SkScalar y = (kNumGraphs - i) * (height - ySpread) / (kNumGraphs + 1);
123                fData[i].reset();
124                gen_data(y, ySpread, dataPointCount, &random, fData + i);
125            }
126        }
127
128        SkRandom colorRand;
129        SkColor colors[kNumGraphs];
130        for (int i = 0; i < kNumGraphs; ++i) {
131            colors[i] = colorRand.nextU() | 0xff000000;
132        }
133
134        for (int frame = 0; frame < loops; ++frame) {
135            SkPath plotPath;
136            SkPath fillPath;
137
138            static const SkScalar kStrokeWidth = SkIntToScalar(2);
139            SkPaint plotPaint;
140            SkPaint fillPaint;
141            plotPaint.setAntiAlias(fAA);
142            plotPaint.setStyle(SkPaint::kStroke_Style);
143            plotPaint.setStrokeWidth(kStrokeWidth);
144            plotPaint.setStrokeCap(SkPaint::kRound_Cap);
145            plotPaint.setStrokeJoin(SkPaint::kRound_Join);
146            fillPaint.setAntiAlias(fAA);
147            fillPaint.setStyle(SkPaint::kFill_Style);
148
149            SkTDArray<SkScalar>* prevData = nullptr;
150            for (int i = 0; i < kNumGraphs; ++i) {
151                gen_paths(fData[i],
152                          prevData,
153                          height,
154                          0,
155                          SkIntToScalar(kPixelsPerTick),
156                          fShift,
157                          &plotPath,
158                          &fillPath);
159
160                // Make the fills partially transparent
161                fillPaint.setColor((colors[i] & 0x00ffffff) | 0x80000000);
162                canvas->drawPath(fillPath, fillPaint);
163
164                plotPaint.setColor(colors[i]);
165                canvas->drawPath(plotPath, plotPaint);
166
167                prevData = fData + i;
168            }
169
170            fShift += kShiftPerFrame;
171        }
172    }
173
174private:
175    enum {
176        kNumGraphs = 5,
177        kPixelsPerTick = 3,
178        kShiftPerFrame = 1,
179    };
180    int                 fShift;
181    SkISize             fSize;
182    SkTDArray<SkScalar> fData[kNumGraphs];
183    bool                fAA;
184
185    using INHERITED = Benchmark;
186};
187
188//////////////////////////////////////////////////////////////////////////////
189
190DEF_BENCH( return new ChartBench(true); )
191DEF_BENCH( return new ChartBench(false); )
192