drawing.py 文件源码

def crosshair(ctx, x, y, length, color=None):
    if not color:
        color = (1, 0, 0)
    ctx.save()
    ctx.set_source_rgb(*color)
    ctx.set_line_width(2.0)
    ctx.set_line_cap(cairo.LINE_CAP_BUTT)
    ctx.new_path()
    ctx.move_to(x, y + length)
    ctx.line_to(x, y - length)
    ctx.move_to(x + length, y)
    ctx.line_to(x - length, y)
    ctx.stroke()
    ctx.restore()