Getting screen coordinates from canvas coordinate using PyQGIS

Question

I'm trying to set the initial position of my QGIS plugin dialog. I'm using .setGeometry() but the problem is that I don't know how to get coordinates. I want to set the initial position in the top corner of the canvas in QGIS (like the image below). I've tried this but it does not work.

self.dlg = SetZoomDialog()
canvasCenter = iface.mapCanvas().extent().center()
canvasToGlobal = iface.mapCanvas().mapToGlobal(QPoint(int(canvasCenter.x())/2, int(canvasCenter.y())/2))
x= canvasToGlobal.x()
y= canvasToGlobal.y()
self.dlg.setGeometry(x,y,width,height)

I tried also this canvasToGlobal = QgsMapTool(iface.mapCanvas()).toCanvasCoordinates(canvasCenter) but still I don't understand how to convert canvas coordinates to screen coordinates.

Answer 1

It is not very difficult to do that. That position in Map Canvas corresponds to QPoint(0,0), so you only need 'mapToGlobal' QgsMapCanvas method to find screen coordinates. I used a test plugin for testing my approach. It can be observed in following code snippet.

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from PyQt5.QtCore import QSettings, QTranslator, qVersion, QCoreApplication, QVariant, QPoint
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    def run(self):
        """Run method that performs all the real work"""
        # show the dialog
        self.dlg.show()
        mapcanvas = self.iface.mapCanvas()
        point = mapcanvas.mapToGlobal(QPoint(0,0))
        self.dlg.move(point.x(), point.y())
        # Run the dialog event loop
        result = self.dlg.exec_()
        # See if OK was pressed
        if result:
            # Do something useful here - delete the line containing pass and
            # substitute with your code.
            pass

When I launch my plugin by clicking in corresponding icon, it appears in desired position; as it can be observed in following image: