Implement canvas zoom

rendercanvas/base.py

@@ -550,6 +550,25 @@ def get_pixel_ratio(self) -> float:
         """
         return self.__size_info["total_pixel_ratio"]
 
+    def get_zoom(self) -> float:
+        """Get the zoom factor.
+
+        The zoom factor is similar to the zoom setting in browsers; it's a
+        fraction (in browsers it's a percentage) that can be used to enlarge
+        rendered objects that are sized in logical pixels. Increasing the zoom
+        factor reduces the logical size of the canvas.
+
+        More technically, the zoom factor represents a canvas-specific
+        pixel-ratio, which is multiplied with the backend-specified pixel-ratio
+        (which usually matches the OS pixel ratio).
+        """
+        return self.__size_info["canvas_pixel_ratio"]
+
+    def set_zoom(self, zoom: float) -> None:
+        """Set the zoom factor."""
+        self.__size_info["canvas_pixel_ratio"] = float(zoom)
+        self.__resolve_total_pixel_ratio_and_logical_size()
+
     def close(self) -> None:
         """Close the canvas."""
         # Clear the draw-function, to avoid it holding onto e.g. wgpu objects.