render.py 文件源码

def circles(self, x1, y1, x2, y2, r, nmin=2):

    arc = self.ctx.arc
    fill = self.ctx.fill

    dx = x1-x2
    dy = y1-y2
    dd = sqrt(dx*dx+dy*dy)

    n = int(dd/self.pix)
    n = n if n>nmin else nmin

    a = arctan2(dy, dx)

    scale = linspace(0, dd, n)

    xp = x1-scale*cos(a)
    yp = y1-scale*sin(a)

    for x, y in zip(xp, yp):
      arc(x, y, r, 0, pi*2.)
      fill()