Matplotlib savefig与情节外的传奇

Question

阅读下面的文章,我设法将一个传奇放在外面.

• 如何将传说从情节中删除

码:

import matplotlib.pyplot as pyplot

x = [0, 1, 2, 3, 4]
y = [xx*xx for xx in x]

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

box = ax.get_position()
ax.set_position([box.x0, box.y0, box.width*0.8, box.height])

ax.plot(x, y)
leg = ax.legend(['abc'], loc = 'center left', bbox_to_anchor = (1.0, 0.5))
#pyplot.show()

fig.savefig('aaa.png', bbox_inches='tight')

pyplot.show()显示正确的情节,外面有一个图例.但是当我将其保存为文件时fig.savefig(),图例会被截断.

一些谷歌搜索显示我作为变通方法添加这样bbox_extra_artists=[leg.legendPatch]或bbox_extra_artists=[leg]至savefig(),但既不工作.

这样做的正确方法是什么？Matplotlib版本为0.99.3.

谢谢.

Answer 1

问题是,当您动态绘制时,会matplotlib自动确定边框以适合所有对象.保存文件时,事情不会自动完成,因此您需要指定图形的大小,然后指定轴对象的边界框.以下是更正代码的方法:

import matplotlib.pyplot as pyplot

x = [0, 1, 2, 3, 4]
y = [xx*xx for xx in x]

fig = pyplot.figure(figsize=(3,3))
ax  = fig.add_subplot(111)

#box = ax.get_position()
#ax.set_position([0.3, 0.4, box.width*0.3, box.height])
# you can set the position manually, with setting left,buttom, witdh, hight of the axis
# object
ax.set_position([0.1,0.1,0.5,0.8])
ax.plot(x, y)
leg = ax.legend(['abc'], loc = 'center left', bbox_to_anchor = (1.0, 0.5))

fig.savefig('aaa.png')

Answer 2

对于大多数情况，一个简单的修复案例是修改命令plt.savefig()：

plt.savefig('your_figure.png', bbox_inches='tight')

这个解决方案已经在问题下面的评论中建议，但我忽略了这些，并在GitHub上的 matplotlib issues 中找到了它。为未阅读顶部评论的其他人保留此答案。

Answer 3

虽然这种方法适用于图例,但是当有多个子图并且我们想要一个整体图例时,它似乎不能与figlegend一起使用.当savefig时,figlegend仍会被裁剪.我刚刚粘贴了我的临时解决方案,以防有人遇到这种情况.

import matplotlib.pyplot as plt

para = {
    ## this parameter will indicate the position of
    ## subplot within figure, but will not be shown
    ## if using bbox_inches='tight' when saving
    'figure.subplot.top': 0.5
}
#plt.rcParams.update(para)

fig = plt.figure()

ax=fig.add_subplot(221)
## only needed when what to manually control
## subplot ration
#ax.set_position([0.1,0.6,0.5, 0.4])
ax.plot([1,1,1])


ax=fig.add_subplot(222)
#ax.set_position([0.7,0.6,0.5, 0.4])
ax.plot([2,2,2])

ax=fig.add_subplot(223)
#ax.set_position([0.1,0.1,0.5, 0.4])
ax.plot([3,3,3])


ax=fig.add_subplot(224)
#ax.set_position([0.7,0.1,0.5, 0.4])
p1, = ax.plot([4,4,4])
p2, = ax.plot([2,3,2])

## figlegend does not work fine with tight bbox
## the legend always get cropped by this option
## even add bbox extra will not help
## had to use legend, and manually adjust it to
## arbitary position such as (0.3, 2.5)

## http://matplotlib.org/users/tight_layout_guide.html
## according to this link, tight layout is only
## an experimental feature, might not support figlegend

#lgd = plt.figlend(
lgd = plt.legend(
    [p1,p2],
    ['a', 'b'],
    ## by default, legend anchor to axis, but can
    ## also be anchored to arbitary position
    ## positions within [1,1] would be within the figure
    ## all numbers are ratio by default

    bbox_to_anchor=(-0.1, 2.5),

    ## loc indicates the position within the figure
    ## it is defined consistent to the same Matlab function 
    loc='center',

    ncol=2
    #mode="expand",
    #borderaxespad=0.
    )



#plt.show()

plt.savefig('temp.png', bbox_inches='tight')#, bbox_extra_artist=[lgd])