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import struct
from typing import NamedTuple, Tuple
from tests.support.asserts import assert_png
inch_in_cm = 2.54
inch_in_pixel = 96
inch_in_point = 72
def cm_to_px(cm: float) -> float:
return round(cm * inch_in_pixel / inch_in_cm)
def px_to_cm(px: float) -> float:
return px * inch_in_cm / inch_in_pixel
def pt_to_cm(pt: float) -> float:
return pt * inch_in_cm / inch_in_point
def png_dimensions(screenshot) -> Tuple[int, int]:
image = assert_png(screenshot)
width, height = struct.unpack(">LL", image[16:24])
return int(width), int(height)
class ImageDifference(NamedTuple):
"""Summary of the pixel-level differences between two images."""
"""The total number of pixel differences between the images"""
total_pixels: int
"""The maximum difference between any corresponding color channels across all pixels of the image"""
max_difference: int
def equal(self) -> bool:
return self.total_pixels == 0