Canvas Polyline in QML

saitej

Hi

How to draw a polyline in QML canvas by dynamically adding points to the line path?

Thanks.

? Offline

Hi! You need to make multiple calls to lineTo():

ctx.beginPath()
for (var i=0; i<pts.length-1; ++i) {
  ctx.moveTo(pts[i].x, pts[i].y)
  ctx.lineTo(pts[i+1].x, pts[i+1].y)
}
ctx.stroke()

saitej

@Wieland

Can canvas be added as a Mapquickitem?

I am able to add the the canvas successfully on the map but it does not have the mapquickitem properties like onzoom and pan change etc. I am repainting the canvas onzoomlevelchanged , gesture.onPanStarted and gesture.onPanFinished. But the repaint is not so swift and so the lines can be seen not moving with the map. Is there a way to avoid this?

Note: I am trying to use canvas instead of mappolyline due to bad rendering of the latter and also to add curves to end lines.

Here is the video demonstrating my problem.

Thanks

? Offline

@saitej said in Canvas Polyline in QML:

Can canvas be added as a Mapquickitem?

The manual says:

The MapQuickItem type displays an arbitrary Qt Quick object on a Map.

Regarding the performance related things: I don't know.

saitej

@Wieland

Thanks!! I will give it a shot.