Dashes

from std.math import cos, pi, sin

from canvas.color import Color
from canvas.buffer import Canvas
from canvas.geometry import Point
from canvas.shapes.lines import (
    draw_line,
    draw_line_aa,
    draw_polygon,
    draw_polygon_aa,
)
from canvas.io.bmp import write_bmp
from canvas.io.png import write_png


def main() raises:
    var c = Canvas(1080, 900, Color(255, 255, 255))
    var dashes: List[Float64] = [48.0, 24.0]

    draw_line(c, 60, 120, 1020, 120, Color(120, 120, 120), dashes)
    draw_line_aa(c, 60, 210, 1020, 210, Color(120, 120, 120), dashes=dashes)

    # A pentagon outline, large enough and with a short enough dash
    # period per edge that a phase reset at any vertex would show as
    # two dashes back-to-back, or a doubled gap, right at the corner.
    var cx = 540.0
    var cy = 585.0
    var r = 330.0
    var points = List[Point]()
    for i in range(5):
        var angle = -pi / 2.0 + Float64(i) * (2.0 * pi / 5.0)
        var x = cx + r * cos(angle)
        var y = cy + r * sin(angle)
        points.append(Point(Int(x), Int(y)))
    draw_polygon_aa(c, points, Color(40, 100, 200), dashes=dashes)

    write_bmp(c, "examples/out_dashes.bmp")
    write_png(c, "examples/out_dashes.png")
    print("wrote examples/out_dashes.bmp and .png")