graph.py 文件源码

def generate_thumbnail(self, dotcode):
        #size = self.tree.allocation.width
        size = self.side_hb.get_allocated_width()
        tmp_dot = tempfile.NamedTemporaryFile(delete = False)
        tmp_dot.write(dotcode)
        tmp_dot.close()

        cmd = "dot -Tpng " + tmp_dot.name + " > " + tmp_dot.name + ".png" 
        os.system(cmd)

        im = Image.open(tmp_dot.name + ".png")
        im.convert('RGBA')
        im.thumbnail([size,size], Image.ANTIALIAS)
        #im.save(tmp_dot.name + ".png.thumbnail", "JPEG")

        # Add white backgound as image is transparent
        offset_tuple = (im.size[0], im.size[1])
        final_thumb = Image.new(mode='RGBA',size=offset_tuple, color=(255,255,255,0))
        final_thumb.paste(im)
        final_thumb.save(tmp_dot.name + ".png.thumbnail", "PNG")

        self.fill_preview(tmp_dot.name + ".png.thumbnail")

        os.remove(tmp_dot.name)
        os.remove(tmp_dot.name + ".png")
        os.remove(tmp_dot.name + ".png.thumbnail")