I am using draw_line to draw a line across the screen. The color of the line, although fed Color.black, draws as white.
export (Color) var window_color : Color = Color8(0, 0, 0, 255)
for i in 128:
draw_rect(Rect2(Vector2(window_1_memory[i*2], i), Vector2(window_1_memory[i*2 + 1], 1.0)), window_color, true)