With GTK4, the Cairo context we get is always in logical pixels, and isautomatically scaled to the right size, without any worry aboutblurriness. So in that case, we can ignore all scale factor changes, andassume it's always 1.The remaining effect of tracking scale factor changes is to trigger are-draw, but GTK will send a resize event to go along with it, whichwill do that for us.Fixesmatplotlib#25847Replacesmatplotlib#25861

With GTK3, the Cairo surface we get is for the whole window, which meansthe automatic size inference frommatplotlib#22004 gets the wrong size. For theGtkDrawingArea, the Cairo context is aligned and clipped to the widget,so nothing goes out-of-bounds. However, since the Cairo renderer flipsthe origin using the height in the calculation (which is, for thewindow, bigger than the drawing widget), everything is drawn lower thanit should.