在python matplotlib中用多种颜色填充多边形 [英] Fill polygons with multiple colors in python matplotlib

问题描述

我正在使用matplotlib绘制多边形补丁，并想表示每个多边形要用特定颜色填充的部分，即制作饼形图，但为三角形，正方形或六边形.有没有办法改变饼图的形状或为多边形表示多种填充颜色?

I am using matplotlib to plot polygon patches and would like to denote sections of each polygon to be filled with a particular color, i.e. make a pie chart but triangle or square or hexagonal shaped. Is there a way to change the shape of a pie chart or denote multiple fill colors for polygons?

谢谢！

更新:这是我意思的模拟:

Update: Here is mock up of what I mean:

推荐答案

您可以创建 Matplotlib集合，然后传递颜色数组/列表以用于绘图.

You can create a Matplotlib collection, and then pass a array/list of colors to use for plotting.

考虑以下示例.首先得到一些虚拟形状.

Consider the following example. First get some dummy-shapes.

import matplotlib.path as mpath
import matplotlib.pyplot as plt
import matplotlib as mpl
import numpy as np

def get_tri(xoff=0, yoff=0, up=1):

    verts = [(0.0 + xoff, 0.0 + yoff),
             (0.5 + xoff, 1.0 * up + yoff),
             (1.0 + xoff, 0.0 + yoff),
             (0.0 + xoff, 0.0 + yoff)]

    p = mpath.Path(verts, [mpath.Path.MOVETO] + (len(verts)-1)*[mpath.Path.LINETO])

    return p

shapes = [get_tri(xoff=x, yoff=y, up=o) for x,y,o in [(0.0, 0,  1),
                                                    (1.0, 0,  1),
                                                    (0.5, 1,  1),
                                                    (0.5, 1, -1)]]

从颜色图中获取颜色:

cmap = plt.cm.RdYlBu_r
colors = cmap(np.linspace(0,1, len(shapes)))

并绘制形状:

fig, ax = plt.subplots(subplot_kw={'aspect': 1.0})

coll = mpl.collections.PathCollection(shapes, facecolor=colors, linewidth=3)

ax.add_collection(coll)
ax.autoscale_view()

请注意，由于我为形状使用了 Paths ，因此我也使用了 PathCollection .如果您使用 Polygons(或其他东西)，您还应该使用适当类型的集合，例如 PolyCollection.

Note that since I'm using Paths for my shapes, I'm also using a PathCollection. If you use Polygons (or something else) you should also use the appropriate type of collection, like a PolyCollection.

因此，绘制不同的颜色非常容易，棘手的部分可能是获取路径/多边形.如果已经有了它们，则可以将它们放在列表中以创建集合.

So the plotting of different colors is very easy, the tricky part is probably to get the Paths/Polygons. If you already have them, you can put them in a list to create the collection.

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