1/*
2 * Copyright 2015 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#include "gm.h"
9#include "SkPath.h"
10
11DEF_SIMPLE_GM(PlusMergesAA, canvas, 256, 256) {
12    SkPaint p;
13    p.setColor(SK_ColorRED);
14    p.setAntiAlias(true);  //  <-- crucial to the test that we use AA
15
16    // Draw a two red squares.
17    canvas->drawRect(SkRect::MakeWH(100, 100), p);
18    canvas->drawRect(SkRect::MakeXYWH(150, 0, 100, 100), p);
19
20    p.setColor(0xf000ff00);
21
22    // We'll draw a green square on top of each using two triangles.
23    SkPath upperLeft;
24    upperLeft.lineTo(100, 0);
25    upperLeft.lineTo(0, 100);
26    upperLeft.lineTo(0, 0);
27
28    SkPath bottomRight;
29    bottomRight.moveTo(100, 0);
30    bottomRight.lineTo(100, 100);
31    bottomRight.lineTo(0, 100);
32    bottomRight.lineTo(100, 0);
33
34    // The left square is drawn simply with SrcOver.  It will show a red seam.
35    canvas->drawPath(upperLeft, p);
36    canvas->drawPath(bottomRight, p);
37
38    // Using Plus on the right should merge the AA of seam together completely covering the red.
39    canvas->saveLayer(nullptr, nullptr);
40      p.setXfermodeMode(SkXfermode::kPlus_Mode);
41      canvas->translate(150, 0);
42      canvas->drawPath(upperLeft, p);
43      canvas->drawPath(bottomRight, p);
44    canvas->restore();
45}
46