xref: /third_party/skia/docs/examples/pathops.cpp (revision cb93a386)
1// Copyright 2020 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"
4REG_FIDDLE(pathops, 1000, 600, false, 0) {
5void makePaint(SkPaint * paint, SkColor color) {
6    paint->setAntiAlias(true);
7    paint->setStyle(SkPaint::kFill_Style);
8    paint->setColor(color);
9}
10
11SkColor blend(SkColor one, SkColor two) {
12    SkBitmap temp;
13    temp.allocN32Pixels(1, 1);
14    SkCanvas canvas(temp);
15    canvas.drawColor(one);
16    canvas.drawColor(two);
17    void* pixels = temp.getPixels();
18    return *(SkColor*)pixels;
19}
20
21void draw(SkCanvas* canvas) {
22    SkPaint fOnePaint;
23    SkPaint fTwoPaint;
24    SkPaint fOutlinePaint;
25    SkPaint fOpPaint[kReverseDifference_SkPathOp - kDifference_SkPathOp + 1];
26
27    const unsigned oneColor = 0xFF8080FF;
28    const unsigned twoColor = 0x807F1f1f;
29    SkColor blendColor = blend(oneColor, twoColor);
30    makePaint(&fOnePaint, oneColor);
31    makePaint(&fTwoPaint, twoColor);
32    makePaint(&fOpPaint[kDifference_SkPathOp], oneColor);
33    makePaint(&fOpPaint[kIntersect_SkPathOp], blendColor);
34    makePaint(&fOpPaint[kUnion_SkPathOp], 0xFFc0FFc0);
35    makePaint(&fOpPaint[kReverseDifference_SkPathOp], twoColor);
36    makePaint(&fOpPaint[kXOR_SkPathOp], 0xFFa0FFe0);
37    makePaint(&fOutlinePaint, 0xFF000000);
38    fOutlinePaint.setStyle(SkPaint::kStroke_Style);
39
40    SkPath one, two;
41    int yPos = 0;
42    for (int oneFill = 0; oneFill <= 1; ++oneFill) {
43        SkPathFillType oneF =
44                oneFill ? SkPathFillType::kInverseEvenOdd : SkPathFillType::kEvenOdd;
45        for (int twoFill = 0; twoFill <= 1; ++twoFill) {
46            SkPathFillType twoF =
47                    twoFill ? SkPathFillType::kInverseEvenOdd : SkPathFillType::kEvenOdd;
48            one.reset();
49            one.setFillType(oneF);
50
51            one.moveTo(10, 10);
52            one.conicTo(0, 90, 50, 50, 3);
53            one.conicTo(90, 0, 90, 90, 2);
54            one.close();
55
56            two.reset();
57            two.setFillType(twoF);
58            two.addRect(40, 40, 100, 100);
59            canvas->save();
60            canvas->translate(0, SkIntToScalar(yPos));
61            canvas->clipRect(SkRect::MakeWH(110, 110), SkClipOp::kIntersect, true);
62            canvas->drawPath(one, fOnePaint);
63            canvas->drawPath(one, fOutlinePaint);
64            canvas->drawPath(two, fTwoPaint);
65            canvas->drawPath(two, fOutlinePaint);
66            canvas->restore();
67            int xPos = 150;
68            for (int op = kDifference_SkPathOp; op <= kReverseDifference_SkPathOp; ++op) {
69                SkPath result;
70                Op(one, two, (SkPathOp)op, &result);
71                canvas->save();
72                canvas->translate(SkIntToScalar(xPos), SkIntToScalar(yPos));
73                canvas->clipRect(SkRect::MakeWH(110, 110), SkClipOp::kIntersect, true);
74                canvas->drawPath(result, fOpPaint[op]);
75                canvas->drawPath(result, fOutlinePaint);
76                canvas->restore();
77                xPos += 150;
78            }
79            yPos += 150;
80        }
81    }
82}
83
84}  // END FIDDLE
85