SVG过滤线

演示可能与mpl一起使用的SVG过滤效果。

请注意，过滤效果仅在您的svg渲染器支持时才有效。

SVG过滤线示例

输出：

  1. Saving 'svg_filter_line.svg'
  1. import matplotlib.pyplot as plt
  2. import matplotlib.transforms as mtransforms
  4. fig1 = plt.figure()
  5. ax = fig1.add_axes([0.1, 0.1, 0.8, 0.8])
  7. # draw lines
  8. l1, = ax.plot([0.1, 0.5, 0.9], [0.1, 0.9, 0.5], "bo-",
  9.               mec="b", lw=5, ms=10, label="Line 1")
  10. l2, = ax.plot([0.1, 0.5, 0.9], [0.5, 0.2, 0.7], "rs-",
  11.               mec="r", lw=5, ms=10, color="r", label="Line 2")
  14. for l in [l1, l2]:
  16.     # draw shadows with same lines with slight offset and gray colors.
  18.     xx = l.get_xdata()
  19.     yy = l.get_ydata()
  20.     shadow, = ax.plot(xx, yy)
  21.     shadow.update_from(l)
  23.     # adjust color
  24.     shadow.set_color("0.2")
  25.     # adjust zorder of the shadow lines so that it is drawn below the
  26.     # original lines
  27.     shadow.set_zorder(l.get_zorder() - 0.5)
  29.     # offset transform
  30.     ot = mtransforms.offset_copy(l.get_transform(), fig1,
  31.                                  x=4.0, y=-6.0, units='points')
  33.     shadow.set_transform(ot)
  35.     # set the id for a later use
  36.     shadow.set_gid(l.get_label() + "_shadow")
  39. ax.set_xlim(0., 1.)
  40. ax.set_ylim(0., 1.)
  42. # save the figure as a bytes string in the svg format.
  43. from io import BytesIO
  44. f = BytesIO()
  45. plt.savefig(f, format="svg")
  48. import xml.etree.cElementTree as ET
  50. # filter definition for a gaussian blur
  51. filter_def = """
  52.   <defs xmlns='http://www.w3.org/2000/svg' xmlns:xlink='http://www.w3.org/1999/xlink'>
  53.     <filter id='dropshadow' height='1.2' width='1.2'>
  54.       <feGaussianBlur result='blur' stdDeviation='3'/>
  55.     </filter>
  56.   </defs>
  57. """
  60. # read in the saved svg
  61. tree, xmlid = ET.XMLID(f.getvalue())
  63. # insert the filter definition in the svg dom tree.
  64. tree.insert(0, ET.XML(filter_def))
  66. for l in [l1, l2]:
  67.     # pick up the svg element with given id
  68.     shadow = xmlid[l.get_label() + "_shadow"]
  69.     # apply shadow filter
  70.     shadow.set("filter", 'url(#dropshadow)')
  72. fn = "svg_filter_line.svg"
  73. print("Saving '%s'" % fn)
  74. ET.ElementTree(tree).write(fn)

下载这个示例