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pythonpyqt5pyqtgraph

Smaller QPolygon in PyQt than 1 not drawing

So im trying to use the drawPolygon() function to draw some shapes in a plot. After a lot of trouble I tried painting this two polygons, the first one does not work and the second one yes:

points1 = QPolygon([
                    QPoint(0,0),
                    QPoint(0,0.5),
                    QPoint(0.5,0.5),
                    QPoint(0.5,0)])
points2 = QPolygon([
                    QPoint(0,0),
                    QPoint(0,1),
                    QPoint(1,1),
                    QPoint(1,0)])
p.drawPolygon(points1)
#p.drawPolygon(points2)
p.end()

Is something with the drawPolygon function that cant draw a smaller polygon than 1 unit?

I tried to draw a polygon with Qpolygon function. I came up with the problem of not being able to draw a smaller polygon than 1 unit

Solution

  • QPolygon and QPoint have integer precision

    So QPoint(0, 0.5) is actually QPoint(0, 0), and your polygon results in 4 congruent points

    What should be used are their floating-point versions: QPolygonF and QPointF

    For reference: Qpoint, QPolygon, QPointF, QPolygonF