skia2/docs/examples/BlendModes.cpp
Hal Canary 6c8422c671 add more docs/examples from named fiddles.
ignore offscreen, srgb, and animated fiddles for now.

Change-Id: I923131b684865698e6cda138b004930e11f504d5
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/263713
Commit-Queue: Hal Canary <halcanary@google.com>
Reviewed-by: Ben Wagner <bungeman@google.com>
2020-01-14 19:22:26 +00:00

74 lines
2.5 KiB
C++

// Copyright 2020 Google LLC.
// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
#include "tools/fiddle/examples.h"
REG_FIDDLE(BlendModes, 256, 4352, false, 0) {
void drawBG(SkCanvas* canvas) {
SkColor radColors[] = {0xFFFFFFFF, 0xFFFFFFFF, 0x00FFFFFF};
auto rad = SkGradientShader::MakeRadial(SkPoint::Make(128, 128), 128, radColors, nullptr, 3,
SkTileMode::kClamp);
SkMatrix rotMtx;
rotMtx.setRotate(-90, 128, 128);
SkColor sweepColors[] = {0xFFFF00FF, 0xFFFF0000, 0xFFFFFF00, 0xFF00FF00,
0xFF00FFFF, 0xFF0000FF, 0xFFFF00FF};
auto sweep = SkGradientShader::MakeSweep(128, 128, sweepColors, nullptr, 7, 0, &rotMtx);
auto comp = SkShaders::Blend(SkBlendMode::kModulate, std::move(rad), std::move(sweep));
SkPaint p;
p.setShader(std::move(comp));
canvas->drawPaint(p);
}
void draw(SkCanvas* canvas) {
SkBlendMode blendModes[] = {
SkBlendMode::kDst,
SkBlendMode::kSrc,
SkBlendMode::kSrcOver,
SkBlendMode::kDstOver,
SkBlendMode::kSrcIn,
SkBlendMode::kDstIn,
SkBlendMode::kSrcOut,
SkBlendMode::kDstOut,
SkBlendMode::kSrcATop,
SkBlendMode::kDstATop,
SkBlendMode::kXor,
SkBlendMode::kPlus,
SkBlendMode::kModulate,
SkBlendMode::kScreen,
SkBlendMode::kOverlay,
SkBlendMode::kDarken,
SkBlendMode::kLighten,
};
SkPaint labelPaint;
labelPaint.setAntiAlias(true);
SkFont font(nullptr, 12);
for (auto mode : blendModes) {
SkPaint layerPaint;
layerPaint.setBlendMode(mode);
canvas->save();
canvas->clipRect(SkRect::MakeWH(256, 256));
drawBG(canvas);
canvas->saveLayer(nullptr, &layerPaint);
const SkScalar r = 80;
SkPaint discP;
discP.setAntiAlias(true);
discP.setBlendMode(SkBlendMode::kPlus);
discP.setColor(SK_ColorGREEN); canvas->drawCircle(128, r, r, discP);
discP.setColor(SK_ColorRED); canvas->drawCircle(r, 256 - r, r, discP);
discP.setColor(SK_ColorBLUE); canvas->drawCircle(256 - r, 256 - r, r, discP);
canvas->restore();
canvas->drawSimpleText(SkBlendMode_Name(mode), strlen(SkBlendMode_Name(mode)),
SkTextEncoding::kUTF8, 10, 10, font, labelPaint);
canvas->restore();
canvas->translate(0, 256);
}
}
} // END FIDDLE