I work on a QGIS Plugin in python. This plugin import in QGIS project several print layout (A4/A3/Landscape/Portait format) from a directoty of my laptop to the layout manager. The plugin add also a vector layer in my QGIS project. I would like that when I open a layout from the layout manager, the map of this layout is centered on the extent of the layer in my project. I have tried the code below but it does not zoom in correctly on the layer.

project = QgsProject.instance()

zip_layer = QgsVectorLayer("C:/Users/Thysma/Documents/Stage/Data/zip.shp", "Aire d'étude",'ogr')                   

composition = QgsPrintLayout(project)
document = QDomDocument()
template_file = open('C:/Users/Thysma/Documents/Stage/Composeurs/A3 Paysage.qpt')
template_content = template_file.read()
composition.loadFromTemplate(document, QgsReadWriteContext()) 

layout = project.layoutManager().layoutByName('A3 Paysage')        
map = layout.itemById("map")      
map.attemptMove(QgsLayoutPoint(0.150, 21.610, QgsUnitTypes.LayoutMillimeters))
map.attemptResize(QgsLayoutSize(342.235, 275.240,QgsUnitTypes.LayoutMillimeters))

The zoom made gives me the following rendering (the map is not zoomed in on the total extent of the layer): enter image description here


Instead of setExtent() you should use zoomToExtent() method.


layer_extent = zip_layer.extent()

If you wish too zoom out very slightly from the layer extent you can use the grow() method on the QgsRectangle layer_extent object.


layer_extent = zip_layer.extent()
layer_extent.grow(0.1)#pass a sensible value depending on crs used and map scale

The value you pass to the grow() method will depend on size/scale of your layer and whether you are working with meter or geographic degree units etc.

  • 1
    Thank you ! This code perfectly answers my question :) – Mathys WOHL Apr 13 at 14:36

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