calib.py

calib.py

import math

from kivy.graphics.transformation import Matrix
from kivy.vector import Vector

CALIBRATION_MATRIX = Matrix()

# Calibration angle: -1.5758043422592645
# Calibration scale: [1.373241596109775, -1.040252303237079]
touches = [
    (181.9474425364121, 1119.759678282034),
    (1694.8342158120147, 1078.1402981296671),
    (1611.2928374331036, 5.0781189019419095),
]


def calibrate(points: list[tuple[float, float]]):
    global CALIBRATION_MATRIX
    window_width, window_height = 1920, 1200

    matrix = Matrix()
    bottom_left, bottom_right, top_right = points

    angle = math.atan2(
        bottom_right[1] - bottom_left[1],
        bottom_right[0] - bottom_left[0],
    )

    # Scale to screen size
    diagonal_vector = Vector(
        top_right[0] - bottom_left[0],
        top_right[1] - bottom_left[1],
    ).rotate(math.degrees(angle))
    scale_vector = (
        Vector(window_width, window_height)
        / Vector(diagonal_vector)
    )
    matrix.scale(scale_vector[0], scale_vector[1], 0)

    # Rotate according to bottom points
    matrix.rotate(angle, 0, 0, 1)

    # Offset in the newly rotated space
    origin = Vector(
        -bottom_left[0],
        2 * window_height - bottom_left[1],
    ).rotate(math.degrees(angle))

    # Translate to new origin
    matrix.translate(origin[0], origin[1], 0)

    CALIBRATION_MATRIX = matrix


calibrate(touches)
calibrated_bottom_left = CALIBRATION_MATRIX.transform_point(*touches[0], 0)[:2]
# Expected: approximately 0.0, 0.0
# Actual: New bottom left: (71.05832720228668, 113.49659082270978)
print('New bottom left:', calibrated_bottom_left)

calibrated_bottom_right = CALIBRATION_MATRIX.transform_point(
    *touches[1],
    0,
)[:2]
# Expected: approximately 1920.0, 0.0
# Actual: New bottom right: (2149.022258748923, 99.6430240209063)
print('New bottom right:', calibrated_bottom_right)

calibrated_top_right = CALIBRATION_MATRIX.transform_point(
    *touches[2],
    0,
)[:2]
# Expected: approximately 1920.0, 1200.0
# Actual: New top right: (2065.039622336423, 1218.6310907894283)
print('New top right:', calibrated_top_right)