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How can I get the coordinates of generated labels on Canvas? Or is there a way to make static labels for each feature? I want the labels to not move when the canvas changes scale or moves.

My situation: my plugin loads the pipelines (LineString) into memory layer. Label for the pipelines must be parallel and above the line. After first rendering of the canvas I need to remember the position of these labels. The ideal variant would be to get the x, y coordinates and angle of rotation of each labels and put them into additional fields of layer.

I'm interested in only stage of extraction of coordinates.

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For me in a simple:

mc = self.iface.mapCanvas()
lr = mc.labelingResults()
extent = mc.extent()

labellayer.startEditing()

for lrl in lr.labelsWithinRect(extent):
    if lrl.layerID == labellayer.id():
        angle = 90 - QgsPoint(lrl.cornerPoints[0]).azimuth(QgsPoint(lrl.cornerPoints[1]))
        fieldIdx = labellayerpr.fields().indexFromName('xpos')
        fieldIdy = labellayerpr.fields().indexFromName('ypos')
        fieldIdr = labellayerpr.fields().indexFromName('rpos')
        xlabel = lrl.cornerPoints[0][0]
        ylabel = lrl.cornerPoints[0][1]
        rlabel = angle
        labellayer.changeAttributeValue(lrl.featureId, fieldIdx, xlabel)
        labellayer.changeAttributeValue(lrl.featureId, fieldIdy, ylabel)
        labellayer.changeAttributeValue(lrl.featureId, fieldIdr, rlabel)
labellayer.commitChanges()

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