Lomiri
Circle.qml
1 /*
2  * Copyright (C) 2013, 2016 Canonical Ltd.
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation; version 3.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11  * GNU General Public License for more details.
12  *
13  * You should have received a copy of the GNU General Public License
14  * along with this program. If not, see <http://www.gnu.org/licenses/>.
15  */
16 
17 import QtQuick 2.12
18 
19 Canvas {
20  id: root
21  property color color
22  property real circleScale
23  property var centerCircle
24 
25  onColorChanged: requestPaint()
26  onCircleScaleChanged: requestPaint()
27  onCenterCircleChanged: requestPaint()
28 
29  onPaint: {
30  if (circleScale <= 0 || width <= 0 || height <= 0) {
31  return;
32  }
33 
34  var ctx = getContext("2d");
35 
36  // draw big circle
37  ctx.save();
38  ctx.fillStyle = color;
39  ctx.beginPath();
40  ctx.arc(width / 2, height / 2, circleScale * width / 2, 0, 2 * Math.PI, false);
41  ctx.fill();
42  ctx.restore();
43 
44  // chop out inner infographics circle
45  if (centerCircle) {
46  var circleMiddle = mapFromItem(centerCircle,
47  centerCircle.width / 2,
48  centerCircle.height / 2);
49  ctx.save();
50  ctx.globalCompositeOperation = "destination-out";
51  ctx.beginPath();
52  ctx.arc(circleMiddle.x, circleMiddle.y, centerCircle.width / 2, 0, 2 * Math.PI, false);
53  ctx.fill();
54  ctx.restore();
55  }
56  }
57 }