cairo_visualize.py

import cairo
import random
import math

# cairo coordinates start in top left, and going down and right is positive


def visualize_path(path, coords, resolution, fname="stringartrender.png"):
    surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, resolution, resolution)
    ctx = cairo.Context(surface)
    # ctx.scale(2*radius, 2*radius)

    # occasionally we want to render at a higher rez than the input picture
    scale = resolution / coords[0][0]
    coords = {
        i: (coords[i][0] * scale, coords[i][1] * scale) for i in range(len(coords))
    }

    # ctx.save()
    ctx.set_source_rgba(1, 1, 1, 1)
    ctx.paint()
    # ctx.restore()

    ctx.set_source_rgba(0, 0, 0, 0.2)
    ctx.set_line_width(2)

    previous_point = coords[0]
    ctx.move_to(*coords[0])
    for point in path:
        x = coords[point][0]
        y = coords[point][1]
        ctx.move_to(*previous_point)
        ctx.line_to(x, y)
        ctx.stroke()
        # print(x)
        previous_point = x, y
    # ctx.close_path()
    # ctx.show_page()
    print("Image built, now saving")
    surface.write_to_png(fname + ".png")
    print("png saved")


"""
# make a random drawing
if __name__ == '__main__':
    NAILS = 300
    THETA_STEP = 2*math.pi / NAILS
    R=800
    STRING_COUNT = 500
    COORDS = {n: (R+R*math.cos(n*THETA_STEP), R+R*math.sin(n*THETA_STEP)) for n in range(NAILS)}
    path = []
    for i in range(STRING_COUNT
                   ):
        path.append(random.randrange(0, NAILS))
    visualize_path(path, COORDS, R)
"""

# draw a specific path
if __name__ == "__main__":
    path = [
        0,
        48,
        76,
        45,
        93,
        33,
        89,
        56,
        12,
        57,
        14,
        64,
        35,
        32,
        35,
        32,
        67,
        24,
        75,
        24,
        75,
        24,
        75,
        24,
        75,
        24,
        75,
        0,
        17,
        82,
        17,
        82,
        17,
        82,
        17,
        82,
        17,
        9,
        68,
        65,
        1,
        98,
        1,
        98,
        1,
        98,
        1,
        98,
        1,
        71,
        28,
        71,
        28,
        50,
        48,
        20,
        55,
        54,
        55,
        23,
        76,
        23,
        76,
        23,
        43,
        39,
        37,
        36,
        37,
        36,
        37,
        36,
        37,
        36,
        63,
        61,
        16,
        10,
        14,
        85,
        89,
        91,
        89,
        88,
        11,
        88,
        11,
        88,
        11,
        88,
        11,
        88,
        11,
        88,
        11,
        50,
        21,
        78,
        21,
        78,
        21,
        78,
        21,
        78,
        21,
        78,
        21,
        78,
        21,
        78,
        21,
        78,
        21,
        78,
        21,
        78,
        21,
        78,
        21,
        78,
        21,
        78,
        21,
        51,
        56,
        59,
        97,
        2,
        68,
        4,
        69,
        30,
        69,
        30,
        69,
        30,
        69,
        30,
        69,
        30,
        69,
        30,
        69,
        30,
        69,
        30,
        69,
        30,
        69,
        30,
        69,
        30,
        69,
        30,
        69,
        30,
        69,
        30,
        69,
        16,
        17,
        82,
        17,
        82,
        17,
        82,
        17,
        82,
        17,
        82,
        17,
        82,
        17,
        82,
        17,
        82,
        17,
        82,
        17,
        82,
        17,
        50,
        48,
        43,
        44,
        43,
        44,
        43,
        39,
        42,
        40,
        41,
        40,
        41,
        40,
        41,
        40,
        41,
        40,
        41,
        40,
        41,
        40,
        41,
        40,
        35,
        32,
        30,
        69,
        30,
        69,
        5,
        61,
        57,
        58,
        57,
        96,
        3,
        96,
        3,
        96,
        3,
        96,
        3,
        96,
        3,
        96,
        3,
        96,
        3,
        96,
        3,
        71,
        28,
        71,
        28,
        71,
        28,
        71,
        28,
        71,
        28,
        71,
        17,
        82,
        17,
        82,
        17,
        82,
        17,
        82,
        17,
        82,
        17,
        82,
        17,
        82,
        17,
        51,
        21,
        78,
        21,
        78,
        21,
        78,
        21,
        78,
        21,
        78,
        21,
        78,
        21,
        78,
        21,
        52,
        22,
        52,
        22,
        17,
        82,
        17,
        82,
        17,
        18,
        81,
        18,
        81,
        18,
        81,
        18,
        81,
        18,
        81,
        18,
        81,
        18,
        81,
        18,
        81,
        18,
        81,
        18,
        81,
        18,
        81,
        18,
        81,
        18,
        81,
        95,
        94,
        95,
        94,
        59,
        56,
        57,
        58,
        57,
        58,
        57,
        58,
        57,
        21,
        78,
        21,
        78,
        21,
        78,
        21,
        78,
        21,
        78,
        21,
        78,
        21,
        18,
        81,
        18,
        81,
        18,
        81,
        18,
        81,
        91,
        95,
        94,
        95,
        94,
        95,
        4,
        21,
        78,
        21,
        78,
        21,
        50,
        25,
        74,
        25,
        74,
        25,
        74,
        25,
        74,
        25,
        74,
        25,
        74,
        25,
        74,
        25,
        74,
        25,
        74,
        25,
        49,
        25,
        74,
        25,
        74,
        25,
        49,
        48,
        43,
        39,
        37,
        36,
        37,
        36,
        37,
        36,
        37,
        36,
        37,
        36,
        63,
        60,
        96,
        3,
        96,
        3,
        96,
        3,
        96,
        3,
        96,
        3,
        96,
        3,
        16,
        10,
        14,
        85,
        14,
        11,
        88,
        11,
        88,
        11,
        88,
        11,
        88,
        11,
        88,
        11,
        88,
        11,
        88,
        11,
        88,
        11,
        88,
        11,
        88,
        11,
        88,
        11,
        88,
        11,
        13,
        12,
        13,
        67,
        1,
        98,
        1,
        98,
        1,
        98,
        1,
        68,
        18,
        81,
        18,
        81,
        18,
        81,
        18,
        81,
        18,
        81,
        18,
        81,
        18,
        81,
        18,
        81,
        18,
        81,
        18,
        81,
        18,
        81,
        18,
        81,
        18,
        81,
        18,
        81,
        18,
        81,
        18,
        81,
        18,
        81,
        18,
        81,
        18,
        81,
        18,
        81,
    ]
    NAILS = 99
    STRING_COUNT = 500
    LINE_DARKNESS = 0.1
    THETA_STEP = 2 * math.pi / NAILS
    R = 1600
    COORDS = {
        n: (R + R * math.cos(n * THETA_STEP), R + R * math.sin(n * THETA_STEP))
        for n in range(NAILS)
    }
    visualize_path(path, COORDS, R)