add right click drag to pan to matplotlib imshow. Now available via https://github.com/ianhi/mpl-interactions

imshow_panhandler.py

class panhandler:
    """
    enable click to pan image.
    button determines which button will be used (default right click)
    Left: 1
    Middle: 2
    Right: 3
    """
    def __init__(self, fig, button=3):
        self.fig = fig
        self._id_drag = None
        self.button = 2
        self.fig.canvas.mpl_connect('button_press_event', self.press)
        self.fig.canvas.mpl_connect('button_release_event', self.release)

    def _cancel_action(self):
        self._xypress = []
        if self._id_drag:
            self.fig.canvas.mpl_disconnect(self._id_drag)
            self._id_drag = None
        
    def press(self, event):
        if event.button != self.button:
            self._cancel_action()
            return

        x, y = event.x, event.y

        self._xypress = []
        for i, a in enumerate(self.fig.get_axes()):
            if (x is not None and y is not None and a.in_axes(event) and
                    a.get_navigate() and a.can_pan()):
                a.start_pan(x, y, event.button)
                self._xypress.append((a, i))
                self._id_drag = self.fig.canvas.mpl_connect(
                    'motion_notify_event', self._mouse_move)
    def release(self, event):
        self._cancel_action()
        self.fig.canvas.mpl_disconnect(self._id_drag)


        for a, _ind in self._xypress:
            a.end_pan()
        if not self._xypress:
            self._cancel_action()
            return
        self._cancel_action()

    def _mouse_move(self, event):
        for a, _ind in self._xypress:
            # safer to use the recorded button at the _press than current
            # button: # multiple button can get pressed during motion...
            a.drag_pan(1, event.key, event.x, event.y)
        self.fig.canvas.draw_idle()

Pairs well with https://gist.github.com/ianhi/b638e09fa7a00764ea539940a0519af9

Good portions of this are taken from the panning option from the toolbar https://github.com/matplotlib/matplotlib/blob/1b12cd5651283ea49665a95308d0bb6a430f62e8/lib/matplotlib/backend_bases.py#L3046