Qt 5.6 | Qt Quick | Qt Quick Examples - Canvas | bezierCurve.qml Example File

Qt 5.6.3 Reference Documentation

# bezierCurve.qml Example File

canvas/bezierCurve/bezierCurve.qml

      /****************************************************************************
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      ** Contact: http://www.qt.io/licensing/
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      ** This file is part of the examples of the Qt Toolkit.
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      ** $QT_BEGIN_LICENSE:BSD$
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      import QtQuick 2.0
      import "../contents"
      import "../../shared"

      Item {
          id:container
          width: 320
          height: 480

          Column {
              spacing:5
              anchors.fill: parent
              anchors.topMargin: 12

              Text {
                  font.pointSize: 24
                  font.bold: true
                  text: "Bezier Curve"
                  anchors.horizontalCenter: parent.horizontalCenter
                  color: "#777"
              }

              Canvas {
                  id:canvas
                  width:320
                  height:280
                  property color strokeStyle:  Qt.darker(fillStyle, 1.4)
                  property color fillStyle: "#b40000" // red
                  property int lineWidth: lineWidthCtrl.value
                  property bool fill: true
                  property bool stroke: true
                  property real alpha: 1.0
                  property real scale : scaleCtrl.value
                  property real rotate : rotateCtrl.value
                  antialiasing: true

                  onLineWidthChanged:requestPaint();
                  onFillChanged:requestPaint();
                  onStrokeChanged:requestPaint();
                  onScaleChanged:requestPaint();
                  onRotateChanged:requestPaint();

                  onPaint: {
                      var ctx = canvas.getContext('2d');
                      var originX = 85
                      var originY = 75
                      ctx.save();
                      ctx.clearRect(0, 0, canvas.width, canvas.height);
                      ctx.translate(originX, originX);
                      ctx.globalAlpha = canvas.alpha;
                      ctx.strokeStyle = canvas.strokeStyle;
                      ctx.fillStyle = canvas.fillStyle;
                      ctx.lineWidth = canvas.lineWidth;

                      ctx.translate(originX, originY)
                      ctx.scale(canvas.scale, canvas.scale);
                      ctx.rotate(canvas.rotate);
                      ctx.translate(-originX, -originY)

                      ctx.beginPath();
                      ctx.moveTo(75,40);
                      ctx.bezierCurveTo(75,37,70,25,50,25);
                      ctx.bezierCurveTo(20,25,20,62.5,20,62.5);
                      ctx.bezierCurveTo(20,80,40,102,75,120);
                      ctx.bezierCurveTo(110,102,130,80,130,62.5);
                      ctx.bezierCurveTo(130,62.5,130,25,100,25);
                      ctx.bezierCurveTo(85,25,75,37,75,40);
                      ctx.closePath();
                      if (canvas.fill)
                          ctx.fill();
                      if (canvas.stroke)
                          ctx.stroke();
                      ctx.restore();
                  }
              }
          }
          Column {
              id: controls
              anchors.bottom: parent.bottom
              anchors.bottomMargin: 12
              Slider {id: lineWidthCtrl; min: 1; max: 10; init: 2; name: "Outline"}
              Slider {id: scaleCtrl; min: 0.1; max: 10; init: 1; name: "Scale"}
              Slider {id: rotateCtrl; min: 0; max: Math.PI*2; init: 0; name: "Rotate"}
          }
      }