Getting label geometry using PyQGIS 3

Question

We need to get LabelGeometry from a feature. There is such a class QgsLabelPosition, it sets parameters. I need to get the parameters of the bounding box label.

Version QGIS 3.16.4

Answer 1

You need the labelRect attribute. My way of getting the value of the labelReсt attribute is as follows.

Take a point that intersects with some label(s). In my case, this point is the last position of the mouse cursor:

point = iface.mapCanvas().mouseLastXY()
point = iface.mapCanvas().getCoordinateTransform().toMapCoordinates(point)

Since several labels can intersect with our point at once, labelsAtPosition returns a list of QgsLabelPosition objects:

labels = iface.mapCanvas().labelingResults().labelsAtPosition(QgsPointXY(point))

Get the attributes we need (for example, LabelRect) of each QgsLabelPosition object (of each label).

for l in labels:
    print(l.labelRect)

In the same way, we can get all other QgsLabelPosition attributes: cornerPoints, featureId, height, isDiagram, isPinned, isUnplaced, labelFont, labelGeometry, labelRect, labelText, layerID, providerID, rotation, upsideDown, width.

Answer 2

Add 2 fields to the featureclass: label_x,label_y (Type: real) and set the placement in the label options to those fields:

Do NOT check the "Store Data in the project" option!

layer=QgsProject.instance().mapLayersByName('xxx')[0]
for feat in layer.getSelectedFeatures():
    x=feat['label_x']
    y=feat['label_y']
    p1=QgsPointXY(x,y)
    buffer=1
    rec=QgsRectangle.fromCenterAndSize(p1,buffer,buffer)
    labels=iface.mapCanvas().labelingResults ().labelsWithinRect(rec)
    if len(labels)>0:
        label_rec=labels[0].labelRect
        print(label_rec)

Tested in QGIS 3.16.10

Answer 3

This will return all label geometries of the labels in current map extent:

extent = iface.mapCanvas().extent()
labelresults = iface.mapCanvas().labelingResults()
labelsinextent = labelresults.labelsWithinRect(extent) #Find the labels in current map extent

for lbl in labelsinextent:
    h = lbl.height
    w = lbl.width
    labelrect = lbl.labelRect
    labelgeom = lbl.labelGeometry

#labelrect
#<QgsRectangle: 527101.23714807606302202 6882549.52799519244581461, 527175.66743653104640543 6882609.07222595624625683>