"Zoom a window to maximum height."

import re
import sys
import tkinter


class WmInfoGatheringError(Exception):
 pass


class ZoomHeight:
 # Cached values for maximized window dimensions, one for each set
 # of screen dimensions.
 _max_height_and_y_coords = {}

 def __init__(self, editwin):
 self.editwin = editwin
 self.top = self.editwin.top

 def zoom_height_event(self, event=None):
 zoomed = self.zoom_height()

 if zoomed is None:
 self.top.bell()
 else:
 menu_status = 'Restore' if zoomed else 'Zoom'
 self.editwin.update_menu_label(menu='options', index='* Height',
 label=f'{menu_status} Height')

 return "break"

 def zoom_height(self):
 top = self.top

 width, height, x, y = get_window_geometry(top)

 if top.wm_state() != 'normal':
 # Can't zoom/restore window height for windows not in the 'normal'
 # state, e.g. maximized and full-screen windows.
 return None

 try:
 maxheight, maxy = self.get_max_height_and_y_coord()
 except WmInfoGatheringError:
 return None

 if height != maxheight:
 # Maximize the window's height.
 set_window_geometry(top, (width, maxheight, x, maxy))
 return True
 else:
 # Restore the window's height.
 #
 # .wm_geometry('') makes the window revert to the size requested
 # by the widgets it contains.
 top.wm_geometry('')
 return False

 def get_max_height_and_y_coord(self):
 top = self.top

 screen_dimensions = (top.winfo_screenwidth(),
 top.winfo_screenheight())
 if screen_dimensions not in self._max_height_and_y_coords:
 orig_state = top.wm_state()

 # Get window geometry info for maximized windows.
 try:
 top.wm_state('zoomed')
 except tkinter.TclError:
 # The 'zoomed' state is not supported by some esoteric WMs,
 # such as Xvfb.
 raise WmInfoGatheringError(
 'Failed getting geometry of maximized windows, because ' +
 'the "zoomed" window state is unavailable.')
 top.update()
 maxwidth, maxheight, maxx, maxy = get_window_geometry(top)
 if sys.platform == 'win32':
 # On Windows, the returned Y coordinate is the one before
 # maximizing, so we use 0 which is correct unless a user puts
 # their dock on the top of the screen (very rare).
 maxy = 0
 maxrooty = top.winfo_rooty()

 # Get the "root y" coordinate for non-maximized windows with their
 # y coordinate set to that of maximized windows. This is needed
 # to properly handle different title bar heights for non-maximized
 # vs. maximized windows, as seen e.g. in Windows 10.
 top.wm_state('normal')
 top.update()
 orig_geom = get_window_geometry(top)
 max_y_geom = orig_geom[:3] + (maxy,)
 set_window_geometry(top, max_y_geom)
 top.update()
 max_y_geom_rooty = top.winfo_rooty()

 # Adjust the maximum window height to account for the different
 # title bar heights of non-maximized vs. maximized windows.
 maxheight += maxrooty - max_y_geom_rooty

 self._max_height_and_y_coords[screen_dimensions] = maxheight, maxy

 set_window_geometry(top, orig_geom)
 top.wm_state(orig_state)

 return self._max_height_and_y_coords[screen_dimensions]


def get_window_geometry(top):
 geom = top.wm_geometry()
 m = re.match(r"(\d+)x(\d+)\+(-?\d+)\+(-?\d+)", geom)
 return tuple(map(int, m.groups()))


def set_window_geometry(top, geometry):
 top.wm_geometry("{:d}x{:d}+{:d}+{:d}".format(*geometry))


if __name__ == "__main__":
 from unittest import main
 main('idlelib.idle_test.test_zoomheight', verbosity=2, exit=False)

 # Add htest?