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- /*
- * Copyright 2013 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
- #include "include/core/SkCanvas.h"
- #include "include/core/SkPaint.h"
- #include "include/core/SkPath.h"
- #include "include/utils/SkRandom.h"
- #include "samplecode/Sample.h"
- // Generates y values for the chart plots.
- static void gen_data(SkScalar yAvg, SkScalar ySpread, int count, SkTDArray<SkScalar>* dataPts) {
- dataPts->setCount(count);
- static SkRandom gRandom;
- for (int i = 0; i < count; ++i) {
- (*dataPts)[i] = gRandom.nextRangeScalar(yAvg - SkScalarHalf(ySpread),
- yAvg + SkScalarHalf(ySpread));
- }
- }
- // Generates a path to stroke along the top of each plot and a fill path for the area below each
- // plot. The fill path is bounded below by the bottomData plot points or a horizontal line at
- // yBase if bottomData == nullptr.
- // The plots are animated by rotating the data points by leftShift.
- static void gen_paths(const SkTDArray<SkScalar>& topData,
- const SkTDArray<SkScalar>* bottomData,
- SkScalar yBase,
- SkScalar xLeft, SkScalar xDelta,
- int leftShift,
- SkPath* plot, SkPath* fill) {
- plot->rewind();
- fill->rewind();
- plot->incReserve(topData.count());
- if (nullptr == bottomData) {
- fill->incReserve(topData.count() + 2);
- } else {
- fill->incReserve(2 * topData.count());
- }
- leftShift %= topData.count();
- SkScalar x = xLeft;
- // Account for the leftShift using two loops
- int shiftToEndCount = topData.count() - leftShift;
- plot->moveTo(x, topData[leftShift]);
- fill->moveTo(x, topData[leftShift]);
- for (int i = 1; i < shiftToEndCount; ++i) {
- plot->lineTo(x, topData[i + leftShift]);
- fill->lineTo(x, topData[i + leftShift]);
- x += xDelta;
- }
- for (int i = 0; i < leftShift; ++i) {
- plot->lineTo(x, topData[i]);
- fill->lineTo(x, topData[i]);
- x += xDelta;
- }
- if (bottomData) {
- SkASSERT(bottomData->count() == topData.count());
- // iterate backwards over the previous graph's data to generate the bottom of the filled
- // area (and account for leftShift).
- for (int i = 0; i < leftShift; ++i) {
- x -= xDelta;
- fill->lineTo(x, (*bottomData)[leftShift - 1 - i]);
- }
- for (int i = 0; i < shiftToEndCount; ++i) {
- x -= xDelta;
- fill->lineTo(x, (*bottomData)[bottomData->count() - 1 - i]);
- }
- } else {
- fill->lineTo(x - xDelta, yBase);
- fill->lineTo(xLeft, yBase);
- }
- }
- // A set of scrolling line plots with the area between each plot filled. Stresses out GPU path
- // filling
- class ChartView : public Sample {
- static constexpr int kNumGraphs = 5;
- static constexpr int kPixelsPerTick = 3;
- static constexpr int kShiftPerFrame = 1;
- int fShift = 0;
- SkISize fSize = {-1, -1};
- SkTDArray<SkScalar> fData[kNumGraphs];
- SkString name() override { return SkString("Chart"); }
- void onDrawContent(SkCanvas* canvas) override {
- bool sizeChanged = false;
- if (canvas->getBaseLayerSize() != fSize) {
- fSize = canvas->getBaseLayerSize();
- sizeChanged = true;
- }
- SkScalar ySpread = SkIntToScalar(fSize.fHeight / 20);
- SkScalar height = SkIntToScalar(fSize.fHeight);
- if (sizeChanged) {
- int dataPointCount = SkMax32(fSize.fWidth / kPixelsPerTick + 1, 2);
- for (int i = 0; i < kNumGraphs; ++i) {
- SkScalar y = (kNumGraphs - i) * (height - ySpread) / (kNumGraphs + 1);
- fData[i].reset();
- gen_data(y, ySpread, dataPointCount, fData + i);
- }
- }
- canvas->clear(0xFFE0F0E0);
- static SkRandom colorRand;
- static SkColor gColors[kNumGraphs] = { 0x0 };
- if (0 == gColors[0]) {
- for (int i = 0; i < kNumGraphs; ++i) {
- gColors[i] = colorRand.nextU() | 0xff000000;
- }
- }
- SkPath plotPath;
- SkPath fillPath;
- static const SkScalar kStrokeWidth = SkIntToScalar(2);
- SkPaint plotPaint;
- SkPaint fillPaint;
- plotPaint.setAntiAlias(true);
- plotPaint.setStyle(SkPaint::kStroke_Style);
- plotPaint.setStrokeWidth(kStrokeWidth);
- plotPaint.setStrokeCap(SkPaint::kRound_Cap);
- plotPaint.setStrokeJoin(SkPaint::kRound_Join);
- fillPaint.setAntiAlias(true);
- fillPaint.setStyle(SkPaint::kFill_Style);
- SkTDArray<SkScalar>* prevData = nullptr;
- for (int i = 0; i < kNumGraphs; ++i) {
- gen_paths(fData[i],
- prevData,
- height,
- 0,
- SkIntToScalar(kPixelsPerTick),
- fShift,
- &plotPath,
- &fillPath);
- // Make the fills partially transparent
- fillPaint.setColor((gColors[i] & 0x00ffffff) | 0x80000000);
- canvas->drawPath(fillPath, fillPaint);
- plotPaint.setColor(gColors[i]);
- canvas->drawPath(plotPath, plotPaint);
- prevData = fData + i;
- }
- fShift += kShiftPerFrame;
- }
- };
- DEF_SAMPLE( return new ChartView(); )
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