cairo_backend.py 文件源码

def render(self, canvas, transparent=False):

    x0,y0,x1,y1 = canvas.bbox('all')
    self.markers = canvas.markers

    W = int((x1 - x0 + 2*self.padding) * self.scale)
    H = int((y1 - y0 + 2*self.padding) * self.scale)

    ext = os.path.splitext(self.fname)[1].lower()

    if ext == '.svg':
      surf = cairo.SVGSurface(self.fname, W, H)
    elif ext == '.pdf':
      surf = cairo.PDFSurface(self.fname, W, H)
    elif ext in ('.ps', '.eps'):
      surf = cairo.PSSurface(self.fname, W, H)
      if ext == '.eps':
        surf.set_eps(True)
    else: # Bitmap
      surf = cairo.ImageSurface(cairo.FORMAT_ARGB32, W, H)

    self.ctx = cairo.Context(surf)
    ctx = self.ctx

    if not transparent:
      # Fill background
      ctx.rectangle(0,0, W,H)
      ctx.set_source_rgba(1.0,1.0,1.0)
      ctx.fill()

    ctx.scale(self.scale, self.scale)
    ctx.translate(-x0 + self.padding, -y0 + self.padding)

    if self.draw_bbox:
      last = len(canvas.shapes)
      for s in canvas.shapes[:last]:
        bbox = s.bbox
        r = canvas.create_rectangle(*bbox, line_color=(255,0,0, 127), fill=(0,255,0,90))

    for s in canvas.shapes:
      self.draw_shape(s)


    if ext in ('.svg', '.pdf', '.ps', '.eps'):
      surf.show_page()
    else:
      surf.write_to_png(self.fname)