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