How to create a map tool with QgsMapToolEmitPoint that has snapping functionality?

Question

I'm developing a plugin for creating points and lines, but I noticed that when using QgsMapToolEmitPoint the cursor doesn't have snapping functionality

canvas = iface.mapCanvas()
addPoint = QgsMapToolEmitPoint(canvas)
canvas.setMapTool(addPoint)

I noticed that the created tool does not have snapping functionality. Is it possible to create a MapTool with QgsMapToolEmitPoint that has snapping functionality?

Answer 1

You need to sub-class QgsMapToolEmitPoint instead of using the default implementation. Here is a basic example:

class CustomMapTool(QgsMapToolEmitPoint):

    def __init__(self, canvas):
        self.canvas = canvas
        super(CustomMapTool, self).__init__(self.canvas)
        self.layer = iface.activeLayer()
        self.snap_indicator = QgsSnapIndicator(self.canvas)
        self.snap_utils = self.canvas.snappingUtils()

    def canvasMoveEvent(self, e):
        snap_match = self.snap_utils.snapToMap(e.pos())
        self.snap_indicator.setMatch(snap_match)

    def canvasPressEvent(self, e):
        point = e.mapPoint()
        if self.snap_indicator.match().type():
            snapped_point = self.snap_indicator.match().point()


canvas = iface.mapCanvas()
map_tool = CustomMapTool(canvas)
canvas.setMapTool(map_tool)