#!/usr/bin/env python2.7
""" pygame.examples.prevent_display_stretching

Prevent display stretching on Windows.

On some computers, the display environment can be configured to stretch
all windows so that they will not appear too small on the screen for
the user. This configuration is especially common on high-DPI displays.
pygame graphics appear distorted when automatically stretched by the
display environment. This script demonstrates a technique for preventing
this stretching and distortion.

Limitations:
This script makes an API call that is only available on Windows (versions
Vista and newer).

"""

# Ensure that the computer is running Windows Vista or newer
import os
import sys

if os.name != "nt" or sys.getwindowsversion()[0] < 6:
    raise NotImplementedError("this script requires Windows Vista or newer")

import pygame as pg

import ctypes

# Determine whether or not the user would like to prevent stretching
if os.path.basename(sys.executable) == "pythonw.exe":
    selection = "y"
else:
    from pygame.compat import raw_input_

    selection = None
    while selection not in ("y", "n"):
        selection = raw_input_("Prevent stretching? (y/n): ").strip().lower()

if selection == "y":
    msg = "Stretching is prevented."
else:
    msg = "Stretching is not prevented."

# Prevent stretching
if selection == "y":
    user32 = ctypes.windll.user32
    user32.SetProcessDPIAware()

# Show screen
pg.display.init()
RESOLUTION = (350, 350)
screen = pg.display.set_mode(RESOLUTION)

# Render message onto a surface
pg.font.init()
font = pg.font.Font(None, 36)
msg_surf = font.render(msg, 1, pg.Color("green"))
res_surf = font.render("Intended resolution: %ix%i" % RESOLUTION, 1, pg.Color("green"))

# Control loop
running = True
clock = pg.time.Clock()
counter = 0
while running:

    for event in pg.event.get():
        if event.type == pg.QUIT:
            running = False

    screen.fill(pg.Color("black"))

    # Draw lines which will be blurry if the window is stretched
    # or clear if the window is not stretched.
    pg.draw.line(screen, pg.Color("white"), (0, counter), (RESOLUTION[0] - 1, counter))
    pg.draw.line(screen, pg.Color("white"), (counter, 0), (counter, RESOLUTION[1] - 1))

    # Blit message onto screen surface
    msg_blit_rect = screen.blit(msg_surf, (0, 0))
    screen.blit(res_surf, (0, msg_blit_rect.bottom))

    clock.tick(10)

    pg.display.flip()

    counter += 1
    if counter == RESOLUTION[0]:
        counter = 0
