Zooming QCanvas: QCanvasLine problem

[Pieter from Belgium]

Hi,

When zooming a canvas view holding a canvas with a single canvas line, the line is rendered incorrectly:

QCanvas* canvas = new QCanvas(4000,4000);
QCanvasView* canvasView = new QCanvasView(canvas);
QCanvasLine* line = new QCanvasLine(canvas);
line->setPoints(5,5,3995,3995);
line->show();
canvasView->setWorldMatrix(QWMatrix(canvasView->worldMatrix()).scale(10,10));
canvasView->show();

QCanvas* canvas = new QCanvas(4000,4000);
QCanvasView* canvasView = new QCanvasView(canvas);
QCanvasLine* line = new QCanvasLine(canvas);
line->setPoints(5,5,3995,3995);
line->show();
canvasView->setWorldMatrix(QWMatrix(canvasView->worldMatrix()).scale(10,10));
canvasView->show();

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While the line should be rendered along almost the entire diagonal, only a small upper-left part is rendered. Moreover when scrolling, small artefacts are shown.

Is there anything that can be done about this?
[I am using Qt 3.3.3/Linux]

Pieter