QgsMapCanvasItem not position properly if map is rotated

[qgib]

Author Name: Uros Bernik (Uros Bernik)
Original Redmine Issue: 12601
Affected QGIS version: 2.8.1

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Here is the code of my custom QgsMapCanvasItem:

class QgsPositionMarker(QgsMapCanvasItem):
Graphic = QPolygon([QPoint(-20, 0), QPoint(20, 15), QPoint(10, 0), QPoint(20, -15)])

def __init__(self, canvas):
    QgsMapCanvasItem.__init__(self, canvas)
    self.x, self.y, self.r = 0, 0, 0
    
def update_position(self, x, y, r):
    self.x, self.y, self.r = x, y, r

def paint(self, painter, option, widget):
    painter.setPen(QPen(QColor(0, 0, 0), 2))
    painter.setBrush(QColor(255, 0, 0))
    painter.setRenderHint(QPainter.Antialiasing)
    
    point = self.toCanvasCoordinates(QgsPoint(self.x, self.y))
    
    painter.translate(point.x(), point.y())
    painter.rotate(self.r)
    painter.drawPolygon(QgsPositionMarker.Graphic)

I tested, and the transformed points from toCanvasCoordinates method are calculated correctly (ie. i center the position marker in the middle of map canvas, and i get the same resulting point, regardless whether the map is rotated or not) When i update map canvas like this:

    self.map.setRotation(r)
    self.marker.update_position(x, y, r)
            
    self.map.setExtent(myextents)
    self.map.refresh()

Position of the marker is correct only if map rotation is zero, otherwise not, even though the point returned from toCanvasCoordinates is always correct.Error persists if i reverse the order of setRotation and marker.update_position calls.

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Related issue(s): #20120 (duplicates)
Redmine related issue(s): 11910

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[qgib]

Author Name: Uros Bernik (Uros Bernik)

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After checking out #20120, i believe it could be the same issue!

[qgib]

Author Name: Jürgen Fischer (@jef-n)

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• resolution was changed from to duplicate
• status_id was changed from Open to Closed