bsalomon@google.com | 9053c2e | 2013-02-13 21:22:13 +0000 | [diff] [blame] | 1 | |
| 2 | /* |
| 3 | * Copyright 2013 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 "SkCanvas.h" |
| 10 | #include "SkPaint.h" |
| 11 | #include "SkRandom.h" |
| 12 | #include "SkView.h" |
| 13 | |
| 14 | namespace { |
| 15 | |
| 16 | // Generates y values for the chart plots. |
| 17 | void gen_data(SkScalar yAvg, SkScalar ySpread, int count, SkTDArray<SkScalar>* dataPts) { |
| 18 | dataPts->setCount(count); |
| 19 | static SkMWCRandom gRandom; |
| 20 | for (int i = 0; i < count; ++i) { |
| 21 | (*dataPts)[i] = gRandom.nextRangeScalar(yAvg - SkScalarHalf(ySpread), |
| 22 | yAvg + SkScalarHalf(ySpread)); |
| 23 | } |
| 24 | } |
| 25 | |
| 26 | // Generates a path to stroke along the top of each plot and a fill path for the area below each |
| 27 | // plot. The fill path is bounded below by the bottomData plot points or a horizontal line at |
| 28 | // yBase if bottomData == NULL. |
| 29 | // The plots are animated by rotating the data points by leftShift. |
| 30 | void gen_paths(const SkTDArray<SkScalar>& topData, |
| 31 | const SkTDArray<SkScalar>* bottomData, |
| 32 | SkScalar yBase, |
| 33 | SkScalar xLeft, SkScalar xDelta, |
| 34 | int leftShift, |
| 35 | SkPath* plot, SkPath* fill) { |
| 36 | plot->rewind(); |
| 37 | fill->rewind(); |
| 38 | plot->incReserve(topData.count()); |
| 39 | if (NULL == bottomData) { |
| 40 | fill->incReserve(topData.count() + 2); |
| 41 | } else { |
| 42 | fill->incReserve(2 * topData.count()); |
| 43 | } |
| 44 | |
| 45 | leftShift %= topData.count(); |
| 46 | SkScalar x = xLeft; |
| 47 | |
| 48 | // Account for the leftShift using two loops |
| 49 | int shiftToEndCount = topData.count() - leftShift; |
| 50 | plot->moveTo(x, topData[leftShift]); |
| 51 | fill->moveTo(x, topData[leftShift]); |
| 52 | |
| 53 | for (int i = 1; i < shiftToEndCount; ++i) { |
| 54 | plot->lineTo(x, topData[i + leftShift]); |
| 55 | fill->lineTo(x, topData[i + leftShift]); |
| 56 | x += xDelta; |
| 57 | } |
| 58 | |
| 59 | for (int i = 0; i < leftShift; ++i) { |
| 60 | plot->lineTo(x, topData[i]); |
| 61 | fill->lineTo(x, topData[i]); |
| 62 | x += xDelta; |
| 63 | } |
| 64 | |
| 65 | if (NULL != bottomData) { |
| 66 | SkASSERT(bottomData->count() == topData.count()); |
| 67 | // iterate backwards over the previous graph's data to generate the bottom of the filled |
| 68 | // area (and account for leftShift). |
| 69 | for (int i = 0; i < leftShift; ++i) { |
| 70 | x -= xDelta; |
| 71 | fill->lineTo(x, (*bottomData)[leftShift - 1 - i]); |
| 72 | } |
| 73 | for (int i = 0; i < shiftToEndCount; ++i) { |
| 74 | x -= xDelta; |
| 75 | fill->lineTo(x, (*bottomData)[bottomData->count() - 1 - i]); |
| 76 | } |
| 77 | } else { |
| 78 | fill->lineTo(x - xDelta, yBase); |
| 79 | fill->lineTo(xLeft, yBase); |
| 80 | } |
| 81 | } |
| 82 | |
| 83 | } |
| 84 | |
| 85 | // A set of scrolling line plots with the area between each plot filled. Stresses out GPU path |
| 86 | // filling |
| 87 | class ChartView : public SampleView { |
| 88 | public: |
| 89 | ChartView() { |
| 90 | fShift = 0; |
| 91 | fSize.set(-1, -1); |
| 92 | } |
| 93 | |
| 94 | protected: |
| 95 | virtual bool onQuery(SkEvent* evt) SK_OVERRIDE { |
| 96 | if (SampleCode::TitleQ(*evt)) { |
| 97 | SampleCode::TitleR(evt, "Chart"); |
| 98 | return true; |
| 99 | } |
| 100 | return this->INHERITED::onQuery(evt); |
| 101 | } |
| 102 | |
| 103 | virtual void onDrawContent(SkCanvas* canvas) SK_OVERRIDE { |
| 104 | bool sizeChanged = false; |
| 105 | if (canvas->getDeviceSize() != fSize) { |
| 106 | fSize = canvas->getDeviceSize(); |
| 107 | sizeChanged = true; |
| 108 | } |
| 109 | |
| 110 | SkScalar ySpread = SkIntToScalar(fSize.fHeight / 20); |
| 111 | |
| 112 | SkScalar height = SkIntToScalar(fSize.fHeight); |
| 113 | |
| 114 | if (sizeChanged) { |
| 115 | int dataPointCount = SkMax32(fSize.fWidth / kPixelsPerTick + 1, 2); |
| 116 | |
| 117 | for (int i = 0; i < kNumGraphs; ++i) { |
| 118 | SkScalar y = (kNumGraphs - i) * (height - ySpread) / (kNumGraphs + 1); |
| 119 | fData[i].reset(); |
| 120 | gen_data(y, ySpread, dataPointCount, fData + i); |
| 121 | } |
| 122 | } |
| 123 | |
| 124 | canvas->clear(0xFFE0F0E0); |
| 125 | |
| 126 | static SkMWCRandom colorRand; |
| 127 | static SkColor gColors[kNumGraphs] = { 0x0 }; |
| 128 | if (0 == gColors[0]) { |
| 129 | for (int i = 0; i < kNumGraphs; ++i) { |
| 130 | gColors[i] = colorRand.nextU() | 0xff000000; |
| 131 | } |
| 132 | } |
| 133 | |
| 134 | SkPath plotPath; |
| 135 | SkPath fillPath; |
| 136 | |
| 137 | static const SkScalar kStrokeWidth = SkIntToScalar(2); |
| 138 | SkPaint plotPaint; |
| 139 | SkPaint fillPaint; |
| 140 | plotPaint.setAntiAlias(true); |
| 141 | plotPaint.setStyle(SkPaint::kStroke_Style); |
| 142 | plotPaint.setStrokeWidth(kStrokeWidth); |
| 143 | plotPaint.setStrokeCap(SkPaint::kRound_Cap); |
| 144 | plotPaint.setStrokeJoin(SkPaint::kRound_Join); |
| 145 | fillPaint.setAntiAlias(true); |
| 146 | fillPaint.setStyle(SkPaint::kFill_Style); |
| 147 | |
| 148 | SkTDArray<SkScalar>* prevData = NULL; |
| 149 | for (int i = 0; i < kNumGraphs; ++i) { |
| 150 | gen_paths(fData[i], |
| 151 | prevData, |
| 152 | height, |
| 153 | 0, |
| 154 | SkIntToScalar(kPixelsPerTick), |
| 155 | fShift, |
| 156 | &plotPath, |
| 157 | &fillPath); |
| 158 | |
| 159 | // Make the fills partially transparent |
| 160 | fillPaint.setColor((gColors[i] & 0x00ffffff) | 0x80000000); |
| 161 | canvas->drawPath(fillPath, fillPaint); |
| 162 | |
| 163 | plotPaint.setColor(gColors[i]); |
| 164 | canvas->drawPath(plotPath, plotPaint); |
| 165 | |
| 166 | prevData = fData + i; |
| 167 | } |
| 168 | |
| 169 | fShift += kShiftPerFrame; |
| 170 | this->inval(NULL); |
| 171 | } |
| 172 | |
| 173 | private: |
| 174 | enum { |
| 175 | kNumGraphs = 5, |
| 176 | kPixelsPerTick = 3, |
| 177 | kShiftPerFrame = 1, |
| 178 | }; |
| 179 | int fShift; |
| 180 | SkISize fSize; |
| 181 | SkTDArray<SkScalar> fData[kNumGraphs]; |
| 182 | typedef SampleView INHERITED; |
| 183 | }; |
| 184 | |
| 185 | ////////////////////////////////////////////////////////////////////////////// |
| 186 | |
| 187 | static SkView* MyFactory() { return new ChartView; } |
| 188 | static SkViewRegister reg(MyFactory); |