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  1. Qt
  2. QTBUG-50093

Qt Quick Anti-aliasing

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    Details

    • Type: Bug
    • Status: Closed
    • Priority: P2: Important
    • Resolution: Invalid
    • Affects Version/s: 5.3.1, 5.3.2
    • Fix Version/s: None
    • Labels:
    • Environment:
      Linux - (Ubuntu 12.04, kernel - 3.13.0-57-generic)

      Description

      Anti-aliasing of Canvas does not work in Qt 5.3. Even after making the
      antialiasing property of Canvas true, the line looks jagged or not smooth.
      Attached images with both anti-aliasing enabled/disabled for you reference.

      Code for your reference:

      import QtQuick 2.0
      
      Rectangle {
          width: 400
          height: 400
      
          Canvas
          {
              id:canvas
              width: 400
              height: 400
              antialiasing: true //false
              onPaint:
              {
                  var ctx = canvas.getContext('2d');
      
                  ctx.save()
      
                  // Make canvas all white
                  ctx.beginPath();
                  ctx.clearRect(0, 0, width, height);
                  ctx.fill();
      
                  var centerX = canvas.width / 2;
                  var centerY = canvas.height / 2;
                  var radius = 140;
      
                  ctx.beginPath();
                  ctx.arc(centerX, centerY, radius, 0, 2 * Math.PI, false);
                  ctx.fillStyle = 'grey';
                  ctx.fill();
                  ctx.lineWidth = 1;
                  ctx.strokeStyle = '#003300';
                  ctx.stroke();
      
                  ctx.beginPath();
                  ctx.moveTo(centerX, centerY);
                  ctx.lineTo(300,180);
                  ctx.stroke();
              }
          }
      }
      
      
      import QtQuick 2.0
      
      Rectangle {
          width: 400
          height: 400
      
          Canvas
          {
              id:canvas
              width: 400
              height: 400
             // antialiasing: true //false
              onPaint:
              {
                  var ctx = canvas.getContext('2d');
      
                  ctx.save()
                  ctx.beginPath();
                  ctx.clearRect(0, 0, width, height);
                  ctx.fill();
      
                  var centerX = canvas.width / 2;
                  var centerY = canvas.height / 2;
                  var radius = 140;
      
      
                  ctx.lineWidth = 1;
                  ctx.strokeStyle = '#003300';
                  ctx.stroke();
      
                  ctx.beginPath();
                  ctx.moveTo(50, 50);
                  ctx.lineTo(300,50);
                  ctx.stroke();
      
                  ctx.beginPath();
                  ctx.moveTo(50, 100);
                  ctx.lineTo(300,100);
                  ctx.stroke();
      
      
                  ctx.beginPath();
                  ctx.moveTo(50, 150);
                  ctx.lineTo(300,250);
                  ctx.stroke();
      
      
              }
          }
      }
      
      

        Attachments

        1. jaggedlines_new.png
          jaggedlines_new.png
          249 kB
        2. line_aliasing_false.png
          line_aliasing_false.png
          178 kB
        3. lines_aliasing_true.png
          lines_aliasing_true.png
          207 kB
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          Activity

            People

            Assignee:
            mitch_curtis Mitch Curtis
            Reporter:
            narayanan_econ narayanan
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            Watchers:
            2 Start watching this issue

              Dates

              Created:
              Updated:
              Resolved:

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