skia2/gm/gaussianedge.cpp

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/*
* Copyright 2016 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "gm.h"
#include "SkColorFilter.h"
#include "SkGaussianEdgeShader.h"
#include "SkRRect.h"
//#define VIZ 1
#ifdef VIZ
#include "SkStroke.h"
static void draw_stroke(SkCanvas* canvas, const SkRRect& rr, const SkPaint& p, SkColor color) {
SkPath output;
if (SkPaint::kFill_Style == p.getStyle()) {
output.addRRect(rr);
} else {
SkPath input;
input.addRRect(rr);
SkStroke stroke(p);
stroke.strokePath(input, &output);
}
SkPaint paint;
paint.setStyle(SkPaint::kStroke_Style);
paint.setColor(color);
canvas->drawPath(output, paint);
}
static void extract_pts(const SkBitmap& bm, SkTDArray<SkPoint>* pts,
int xOff, int width) {
pts->rewind();
for (int x = 0; x < width; ++x) {
SkColor color = bm.getColor(xOff+x, 0);
pts->append()->set(SkIntToScalar(x), 255.0f-SkColorGetB(color));
if (x > 0 && x < width-1) {
pts->append()->set(SkIntToScalar(x), 255.0f-SkColorGetB(color));
}
}
}
static void draw_row(SkCanvas* canvas, int row, int width) {
SkPaint paint;
paint.setAntiAlias(true);
SkBitmap readback;
if (!canvas->readPixels(SkIRect::MakeXYWH(0, row, width, 1), &readback)) {
return;
}
SkTDArray<SkPoint> pts;
pts.setReserve(width/3);
extract_pts(readback, &pts, 0, width/3);
paint.setColor(SK_ColorRED);
canvas->drawPoints(SkCanvas::kLines_PointMode, pts.count(), pts.begin(), paint);
extract_pts(readback, &pts, width/3, width/3);
paint.setColor(SK_ColorGREEN);
canvas->drawPoints(SkCanvas::kLines_PointMode, pts.count(), pts.begin(), paint);
extract_pts(readback, &pts, 2*width/3, width/3);
paint.setColor(SK_ColorBLUE);
canvas->drawPoints(SkCanvas::kLines_PointMode, pts.count(), pts.begin(), paint);
}
#endif
namespace skiagm {
// This GM exercises the SkGaussianEdgeShader.
// It draws three columns showing filled, stroked, and stroke and filled rendering.
// It draws three rows showing a blur radius smaller than, equal to
// and, finally, double the RRect's corner radius
// In VIZ mode an extra column is drawn showing the blur ramps (they should all line up).
class GaussianEdgeGM : public GM {
public:
GaussianEdgeGM() {
this->setBGColor(SK_ColorWHITE);
}
protected:
SkString onShortName() override {
return SkString("gaussianedge");
}
SkISize onISize() override {
int numCols = kNumBaseCols;
#ifdef VIZ
numCols++;
#endif
return SkISize::Make(kPad + numCols*(kCellWidth+kPad),
kPad + kNumRows*(kCellWidth+kPad));
}
static void DrawRow(SkCanvas* canvas, int blurRad, int midLine) {
SkAutoCanvasRestore acr(canvas, true);
SkRRect rrects[kNumBaseCols];
SkPaint paints[kNumBaseCols];
{
const SkRect r = SkRect::MakeIWH(kRRSize, kRRSize);
const SkRRect baseRR = SkRRect::MakeRectXY(r,
SkIntToScalar(kRRRad),
SkIntToScalar(kRRRad));
SkPaint basePaint;
basePaint.setAntiAlias(true);
basePaint.setColor(SkColorSetARGB(255, (4 * blurRad) >> 8, (4 * blurRad) & 0xff, 0));
basePaint.setShader(SkGaussianEdgeShader::Make());
basePaint.setColorFilter(SkColorFilter::MakeModeFilter(SK_ColorRED,
SkBlendMode::kModulate));
//----
paints[0] = basePaint;
rrects[0] = baseRR;
//----
paints[1] = basePaint;
paints[1].setStyle(SkPaint::kStroke_Style);
rrects[1] = baseRR;
if (blurRad/2.0f < kRRRad) {
rrects[1].inset(blurRad/2.0f, blurRad/2.0f);
paints[1].setStrokeWidth(SkIntToScalar(blurRad));
} else {
SkScalar inset = kRRRad - 0.5f;
rrects[1].inset(inset, inset);
SkScalar pad = blurRad/2.0f - inset;
paints[1].setStrokeWidth(blurRad + 2.0f * pad);
paints[1].setColor(SkColorSetARGB(255, (4 * blurRad) >> 8, (4 * blurRad) & 0xff,
(int)(4.0f*pad)));
}
//----
paints[2] = basePaint;
paints[2].setStyle(SkPaint::kStrokeAndFill_Style);
rrects[2] = baseRR;
if (blurRad/2.0f < kRRRad) {
rrects[2].inset(blurRad/2.0f, blurRad/2.0f);
paints[2].setStrokeWidth(SkIntToScalar(blurRad));
} else {
SkScalar inset = kRRRad - 0.5f;
rrects[2].inset(inset, inset);
SkScalar pad = blurRad/2.0f - inset;
paints[2].setStrokeWidth(blurRad + 2.0f * pad);
paints[2].setColor(SkColorSetARGB(255, (4 * blurRad) >> 8, (4 * blurRad) & 0xff,
(int)(4.0f*pad)));
}
}
//----
canvas->save();
// draw the shadows
for (int i = 0; i < kNumBaseCols; ++i) {
canvas->drawRRect(rrects[i], paints[i]);
canvas->translate(SkIntToScalar(kCellWidth+kPad), 0.0f);
}
#ifdef VIZ
// draw the visualization of the shadow ramps
draw_row(canvas, midLine, 3*(kRRSize+kPad));
#endif
canvas->restore();
#ifdef VIZ
const SkColor colors[kNumBaseCols] = { SK_ColorRED, SK_ColorGREEN, SK_ColorBLUE };
// circle back and draw the stroked geometry (they would mess up the viz otherwise)
for (int i = 0; i < kNumBaseCols; ++i) {
draw_stroke(canvas, rrects[i], paints[i], colors[i]);
canvas->translate(SkIntToScalar(kCellWidth+kPad), 0.0f);
}
#endif
}
void onDraw(SkCanvas* canvas) override {
GrRenderTargetContext* renderTargetContext =
canvas->internal_private_accessTopLayerRenderTargetContext();
if (!renderTargetContext) {
skiagm::GM::DrawGpuOnlyMessage(canvas);
return;
}
const int blurRadii[kNumRows] = { kRRRad/2, kRRRad, 2*kRRRad };
canvas->translate(SkIntToScalar(kPad), SkIntToScalar(kPad));
for (int i = 0; i < kNumRows; ++i) {
DrawRow(canvas, blurRadii[i], kPad+(i*kRRSize)+kRRSize/2);
canvas->translate(0.0f, SkIntToScalar(kCellWidth+kPad));
}
}
private:
static const int kNumRows = 3;
static const int kNumBaseCols = 3;
static const int kPad = 5;
static const int kRRSize = 256;
static const int kRRRad = 64;
static const int kCellWidth = kRRSize;
typedef GM INHERITED;
};
//////////////////////////////////////////////////////////////////////////////
DEF_GM(return new GaussianEdgeGM;)
}