gutter_fullscreen.py

#!/usr/bin/env python3

import os
import sys
import argparse
import numpy as np
import cv2 as cv

def draw_pattern(a, grain=1, tiled=False):
	global ix, iy, gx, gy
	h,w = a.shape[:2]

	#ix = np.arange(w)
	#iy = np.arange(h)
	#gx, gy = np.meshgrid(ix, iy, indexing="xy")
	(gy, gx) = np.indices((h,w))

	if not tiled:
		K = 2*grain
		K = 2
		gx //= grain
		gy //= grain
		gx %= 2
		gy %= 2
		a[:,:] = (gx ^ gy) * 255

	else:
		tx = (gx // tiled) & 1
		ty = (gy // tiled) & 1
		tt = ty*2 + tx

		gx //= grain
		gy //= grain
		gx %= 2
		gy %= 2

		#a[tx != ty] = (255 * gx)[tx != ty]
		#a[tx == ty] = (255 * gy)[tx == ty]
		
		a[tt == 0] = (255 * (gx ^ gy))[tt == 0]
		a[tt == 1] = (255 * gx)[tt == 1]
		a[tt == 2] = (255 * gy)[tt == 2]
		a[tt == 3] = 255 * 0.5**(1/2.2)


# https://stackoverflow.com/questions/15008758/parsing-boolean-values-with-argparse
def str2bool(v):
	if isinstance(v, bool):
	   return v
	if v.lower() in ('yes', 'true', 't', 'y', '1'):
		return True
	elif v.lower() in ('no', 'false', 'f', 'n', '0'):
		return False
	else:
		raise argparse.ArgumentTypeError('Boolean value expected.')

# or whatever is hardcoded in window_w32.cpp
parser = argparse.ArgumentParser(description="let's test imshow's gutter and resampling method")
parser.add_argument("--size", metavar="WxH", type=str, default="2560x1440",
	help="assumed resolution")
#parser.set_defaults(size="1920x1080")
parser.add_argument("--fullscreen", metavar="Y/N", type=str2bool, default=True,
	help="fullscreen or resizable window")
parser.add_argument("--gutter", metavar="PIXELS", type=int, default=0,
	help="subtracted from picture size to compensate for imshow() gutter")
parser.add_argument("--opengl", metavar="Y/N", type=str2bool, default=True,
	help="OpenGL uses linear interpolation, \"native\" may be nearest neighbor")

parser.add_argument("--grain", metavar="N", type=int, default=1,
	help="size of checker fields")
parser.add_argument("--tiled", metavar="N", type=int, default=0,
	help="show tiles of gray, horizontal, vertical, and checkered tiles")

args = parser.parse_args()

# pick your display's resolution
# (someone should test this with Windows' DPI scaling because I'm at 100%)
width, height = map(int, args.size.split('x'))
#width, height = 2560, 1440
#width, height = 1920, 1080

print(f"size: {width} x {height}")

#(width, height) = (width + 2*gutter, height + 2*gutter) # (approximately) simulate gutter when no gutter

(width, height) = (width - 2*args.gutter, height - 2*args.gutter) # simulate no gutter when gutter

print(f"size: {width} x {height} adjusted for gutter of {args.gutter} pixels")

checkers = np.zeros((height, width), np.uint8)

draw_pattern(checkers, grain=args.grain, tiled=args.tiled)

cv.imwrite("checkers.png", checkers)

# possible outputs:
# - pixel perfect checker pattern
# - same but cropped (border)
# - resampled nearest neighbor (pixel pattern but with breaks in it, may be hard to see)
# - resampled linearly, blurry but uniform brightness (gamma-aware)
# - resampled linearly, blurry and varying brightness (gamma-oblivious)

windowname = "press a key, any key"

print("namedWindow() with", ("WINDOW_OPENGL" if args.opengl else "WINDOW_NORMAL"))

cv.namedWindow(windowname,
	flags=(cv.WINDOW_OPENGL if args.opengl else cv.WINDOW_NORMAL)
#	flags=cv.WINDOW_NORMAL # WINDOW_NORMAL does nearest neighbor
#	flags=cv.WINDOW_OPENGL # WINDOW_OPENGL does bilinear
)

if args.fullscreen:
	print("setWindowProperty(..., WND_PROP_FULLSCREEN, True)")
	cv.setWindowProperty(windowname,
		prop_id=cv.WND_PROP_FULLSCREEN,
		prop_value=cv.WINDOW_FULLSCREEN) # value is basically "true", is only member of WindowFlags for convenience
else:
	print(f"resizeWindow(..., {width}, {height})")
	cv.resizeWindow(windowname, width, height)

cv.imshow(windowname, checkers)

# 0 should stand for 0 milliseconds (polling), infinity should be strictly < 0
# that's currently not the case...
cv.waitKey(-1)

cv.destroyWindow(windowname)