python - Matplotlib PatchCollection 到图例

Question

目前，我正在尝试通过使用 PatchCollections 创建代理艺术家 (?) 补丁来制作自己的自定义图例处理程序，然后按照 http://matplotlib.org/users/legend_guide.html 进行操作。制作自定义处理程序。

但是，我在尝试将其实现到图例中时遇到了障碍。图例的参数接受补丁，但不接受补丁集合。

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.mlab as mlab
import matplotlib.patches as mpatches
from matplotlib.path import Path
from matplotlib.collections import PatchCollection

fig = plt.figure()
ax = fig.add_subplot(111)

verts1 = [(0.,0.),(0.,1.),(1.,1.),(0.51,0.51),(0.,0.),(0.,0.),]
codes1 = [Path.MOVETO,Path.LINETO,Path.LINETO,Path.LINETO,Path.MOVETO,Path.CLOSEPOLY,]
path1 = Path(verts1,codes1)
patch1 = mpatches.PathPatch(path1,ls='dashed',ec='red',facecolor="none")


verts2 = [(0.49,0.49),(0.,0.),(1.,0.),(1.,1.),(0.5,0.5),(0.,0.),]
codes2 = [Path.MOVETO,Path.LINETO,Path.LINETO,Path.LINETO,Path.MOVETO,Path.CLOSEPOLY,]
path2 = Path(verts2,codes2)
patch2 = mpatches.PathPatch(path2,ls='solid',edgecolor='red', facecolor="none")

patch = PatchCollection([patch1,patch2],match_original=True)

ax.set_xlim(-2,2)
ax.set_ylim(-2,2)

ax.add_collection(patch)

以上是可视化处理程序的代码。基本上是一个矩形，上面的三角形是虚线，下面的三角形是实线

使用，

plt.legend([patch],["hellocello"],loc='upper right')

重现错误。有解决办法吗？

Answer 1

来自此 section 中的示例，看来你需要定义一个对象并用 handle 箱大小来表达所有坐标，

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.mlab as mlab
import matplotlib.patches as mpatches
from matplotlib.path import Path
from matplotlib.collections import PatchCollection

class AnyObject(object):
    pass

class AnyObjectHandler(object):
    def legend_artist(self, legend, orig_handle, fontsize, handlebox):
        x0, y0 = handlebox.xdescent, handlebox.ydescent
        width, height = handlebox.width, handlebox.height
        hw = 0.5*width; hh = 0.5*height
        verts1 = [(x0,y0),(x0,y0+height),(x0+width,y0+height),((x0+hw)*1.01,(y0+hh)*1.01),(x0,y0),(x0,y0),]
        codes1 = [Path.MOVETO,Path.LINETO,Path.LINETO,Path.LINETO,Path.MOVETO,Path.CLOSEPOLY,]
        path1 = Path(verts1,codes1)
        patch1 = mpatches.PathPatch(path1,ls='dashed',ec='red',facecolor="none")

        verts2 = [((x0+hw)*0.99,(y0+hh)*0.99),(x0,y0),(x0+width,y0),(x0+width,y0+height),(x0+hw,y0+hh),(x0,y0),]
        codes2 = [Path.MOVETO,Path.LINETO,Path.LINETO,Path.LINETO,Path.MOVETO,Path.CLOSEPOLY,]
        path2 = Path(verts2,codes2)
        patch2 = mpatches.PathPatch(path2,ls='solid',edgecolor='red', facecolor="none")

        patch = PatchCollection([patch1,patch2],match_original=True)

        handlebox.add_artist(patch)
        return patch


fig = plt.figure()
ax = fig.add_subplot(111)

ax.set_xlim(-2,2)
ax.set_ylim(-2,2)

plt.legend([AnyObject()], ['hellocello'],
           handler_map={AnyObject: AnyObjectHandler()})

plt.show()

这似乎适用于 PatchCollection，至少对我来说在 matplotlib 版本 1.4.3 上是这样。结果看起来像，