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  1. Qt
  2. QTBUG-34339

QML Canvas wrong length of drawing lines

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    Details

    • Type: Bug
    • Status: Closed
    • Priority: Not Evaluated
    • Resolution: Invalid
    • Affects Version/s: 5.1.0 , 5.1.1, 5.2.0 Beta1
    • Fix Version/s: None
    • Labels:
    • Environment:
      Windows7+ Qt5.1.0 or Qt5.1.1 or Qt5.2.0beta1

      Description

      Drawing a vertical line or horizontal line in Canvas, the canvas will lengthen the size of the line if next point goes back.
      eg.

      import QtQuick 2.0
      
      Item {
          Canvas {
              id: canvas
              smooth: true
              width: 800; height: 600
      
              onPaint: {
                  var ctx = canvas.getContext('2d');
                  ctx.clearRect(0, 0, canvas.width, canvas.height);
                  ctx.rotate(canvas.rotate);
                  ctx.lineWidth = 5;
                  ctx.strokeStyle = ctx.createPattern("red", Qt.SolidPattern);
      
                  ctx.beginPath()
                  ctx.moveTo(10, 10)
                  ctx.lineTo(30, 10)
                  ctx.stroke()
      
                  ctx.beginPath()
                  ctx.moveTo(10, 20)
                  ctx.lineTo(30, 20)
                  ctx.lineTo(20, 20) //goes back 10 horizontally, and the line will be resized
                  ctx.stroke()
      
                  ctx.restore()
              } //end of onPaint
          } //end of Canvas
      }
      

      the lengths of the two lines should be same, but they are not.
      the same problem also happens for vertical lines.
      please check the screen shot(in Attachment)

        Attachments

        1. Capture.PNG
          Capture.PNG
          7 kB
        2. main.qml
          0.7 kB
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          Activity

            People

            Assignee:
            sletta Gunnar Sletta
            Reporter:
            realfan realfan
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            Watchers:
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              Dates

              Created:
              Updated:
              Resolved:

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