xref: /third_party/skia/docs/examples/Modulate.cpp (revision cb93a386)
1// Copyright 2019 Google LLC.
2// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
3#include "tools/fiddle/examples.h"
4// HASH=3fdac2b2f48bd227d2e74234c260bc8e
5REG_FIDDLE(Modulate, 256, 256, false, 0) {
6void draw(SkCanvas* canvas) {
7    auto drawSquare = [=](int dx, int dy, SkBlendMode mode, const char* label) -> void {
8        const SkColor colors[] = { SK_ColorBLACK, SK_ColorWHITE };
9        const SkPoint horz[] = { { 0, 0 }, { 128, 0 } };
10        SkPaint paint;
11        paint.setShader(SkGradientShader::MakeLinear(horz, colors, nullptr, SK_ARRAY_COUNT(colors),
12                SkTileMode::kClamp));
13        paint.setBlendMode(mode);
14        canvas->translate(dx, dy);
15        canvas->drawRect({0, 0, 128, 128}, paint);
16        paint.setBlendMode(SkBlendMode::kXor);
17        SkFont font;
18        canvas->drawString(label, 40, 100, font, paint);
19    };
20    drawSquare(0, 0, SkBlendMode::kSrc, "destination");
21    drawSquare(128, 0, SkBlendMode::kSrc, "");
22    drawSquare(0, 128, SkBlendMode::kSrc, "");
23    canvas->translate(-128, -128);
24    canvas->rotate(90, 0, 128);
25    drawSquare(0, 0, SkBlendMode::kSrc, "source");
26    drawSquare(0, -128, SkBlendMode::kModulate, "modulate");
27    drawSquare(-128, 0, SkBlendMode::kMultiply, "multiply");
28}
29}  // END FIDDLE
30