blocks|key|649592|text|我是从matehat,+here那里学到这个技巧的|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|649593|import+matplotlib.pyplot+as+plt
import+numpy+as+np

def+make_image(data,+outputname,+size=(1,+1),+dpi=80):
++++fig+=+plt.figure()
++++fig.set_size_inches(size)
++++ax+=+plt.Axes(fig,+[0.,+0.,+1.,+1.])
++++ax.set_axis_off()
++++fig.add_axes(ax)
++++plt.set_cmap('hot')
++++ax.imshow(data,+aspect='equal')
++++plt.savefig(outputname,+dpi=dpi)

#+data+=+mpimg.imread(inputname)[:,:,0]
data+=+np.arange(1,10).reshape((3,+3))

make_image(data,+'/tmp/out.png')|code-block|syntax|javascript|649594|收益率|649595|​|649596|📷|atomic|649597|649598|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/q/8218887/190597|1|IMAGE|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/14d1986105b77e8e40113ee745947cd1.png|imageAlt^0|3|D|0|0|0|0|0|0|1|1|0|0^^$0|@$1|2|3|4|5|6|7|14|8|@]|9|@$A|15|B|16|1|17]]|C|$]]|$1|D|3|E|5|F|7|18|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|19|8|@]|9|@]|C|$]]|$1|K|3|L|5|6|7|1A|8|@]|9|@]|C|$]]|$1|M|3|N|5|O|7|1B|8|@]|9|@$A|1C|B|1D|1|1E]]|C|$]]|$1|P|3|L|5|6|7|1F|8|@]|9|@]|C|$]]|$1|Q|3|-4|5|6|7|1G|8|@]|9|@]|C|$]]]|R|$S|$5|T|U|V|C|$W|X]]|Y|$5|Z|U|10|C|$11|12|13|-4]]]]

I learned this trick from <a href="https://stackoverflow.com/q/8218887/190597">matehat, here</a>:

<pre><code>import matplotlib.pyplot as plt
import numpy as np

def make_image(data, outputname, size=(1, 1), dpi=80):
 fig = plt.figure()
 fig.set_size_inches(size)
 ax = plt.Axes(fig, [0., 0., 1., 1.])
 ax.set_axis_off()
 fig.add_axes(ax)
 plt.set_cmap('hot')
 ax.imshow(data, aspect='equal')
 plt.savefig(outputname, dpi=dpi)

# data = mpimg.imread(inputname)[:,:,0]
data = np.arange(1,10).reshape((3, 3))

make_image(data, '/tmp/out.png')
</code></pre>

yields

<img src="https://i.stack.imgur.com/dyCKl.png" alt="enter image description here">

blocks|key|435299|text|我认为命令axis('off')处理其中一个问题比单独更改每个轴和边界更简洁。但是，它仍然会留下边界周围的空白。在savefig命令中添加bbox_inches='tight'几乎就可以实现这一点，您可以在下面的示例中看到，留出的空格要小得多，但仍然存在。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|435300|请注意，更新版本的matplotlib可能需要bbox_inches=0而不是字符串'tight'+(通过@episodeyang和@kadrach)|435301|from+numpy+import+random
import+matplotlib.pyplot+as+plt

data+=+random.random((5,5))
img+=+plt.imshow(data,+interpolation='nearest')
img.set_cmap('hot')
plt.axis('off')
plt.savefig("test.png",+bbox_inches='tight')|code-block|syntax|javascript|435302|​|435303|📷|atomic|435304|435305|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/8a1f638c0c05f3b6736e453085fa8f71.png|imageAlt^0|5|B|1L|7|1X|J|0|N|D|16|7|0|0|0|0|1|0|0|0^^$0|@$1|2|3|4|5|6|7|11|8|@$9|12|A|13|B|C]|$9|14|A|15|B|C]|$9|16|A|17|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|18|8|@$9|19|A|1A|B|C]|$9|1B|A|1C|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|1D|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|1E|8|@]|D|@]|E|$]]|$1|O|3|P|5|Q|7|1F|8|@]|D|@$9|1G|A|1H|1|1I]]|E|$]]|$1|R|3|N|5|6|7|1J|8|@]|D|@]|E|$]]|$1|S|3|-4|5|6|7|1K|8|@]|D|@]|E|$]]]|T|$U|$5|V|W|X|E|$Y|Z|10|-4]]]]

I think that the command <code>axis('off')</code> takes care of one of the problems more succinctly than changing each axis and the border separately. It still leaves the white space around the border however. Adding <code>bbox_inches='tight'</code> to the <code>savefig</code> command almost gets you there, you can see in the example below that the white space left is much smaller, but still present.

Note that newer versions of matplotlib may require <code>bbox_inches=0</code> instead of the string <code>'tight'</code> (via @episodeyang and @kadrach) 

<pre><code>from numpy import random
import matplotlib.pyplot as plt

data = random.random((5,5))
img = plt.imshow(data, interpolation='nearest')
img.set_cmap('hot')
plt.axis('off')
plt.savefig("test.png", bbox_inches='tight')
</code></pre>

<img src="https://i.stack.imgur.com/4ZMuW.png" alt="enter image description here">

blocks|key|435356|text|您还可以为bbox_inches参数指定地物的范围。这将消除图形周围的白色填充。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|435357|def+make_image(inputname,outputname):
++++data+=+mpimg.imread(inputname)[:,:,0]
++++fig+=+plt.imshow(data)
++++fig.set_cmap('hot')
++++ax+=+fig.gca()
++++ax.set_axis_off()
++++ax.autoscale(False)
++++extent+=+ax.get_window_extent().transformed(plt.gcf().dpi_scale_trans.inverted())
++++plt.savefig(outputname,+bbox_inches=extent)|code-block|syntax|javascript|435358|entityMap^0|5|B|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

You can also specify the extent of the figure to the <code>bbox_inches</code> argument. This would get rid of the white padding around the figure.

<pre><code>def make_image(inputname,outputname):
 data = mpimg.imread(inputname)[:,:,0]
 fig = plt.imshow(data)
 fig.set_cmap('hot')
 ax = fig.gca()
 ax.set_axis_off()
 ax.autoscale(False)
 extent = ax.get_window_extent().transformed(plt.gcf().dpi_scale_trans.inverted())
 plt.savefig(outputname, bbox_inches=extent)
</code></pre>

blocks|key|435424|text|可能最简单的解决方案：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|435425|我简单地结合了问题中描述的方法和钩子答案中的方法。|435426|fig+=+plt.imshow(my_data)
plt.axis('off')
fig.axes.get_xaxis().set_visible(False)
fig.axes.get_yaxis().set_visible(False)
plt.savefig('pict.png',+bbox_inches='tight',+pad_inches+=+0)|code-block|syntax|javascript|435427|在这段代码之后，没有空格和框架。|435428|​|435429|📷|atomic|offset|length|435430|435431|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/ed8f4f64bd6402cf37a99c57d29cccc5.png|imageAlt^0|0|0|0|0|0|0|1|0|0|0^^$0|@$1|2|3|4|5|6|7|11|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|12|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|13|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|14|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|15|8|@]|9|@]|A|$]]|$1|M|3|N|5|O|7|16|8|@]|9|@$P|17|Q|18|1|19]]|A|$]]|$1|R|3|L|5|6|7|1A|8|@]|9|@]|A|$]]|$1|S|3|-4|5|6|7|1B|8|@]|9|@]|A|$]]]|T|$U|$5|V|W|X|A|$Y|Z|10|-4]]]]

Possible simplest solution:

I simply combined the method described in the question and the method from the answer by Hooked.

<pre><code>fig = plt.imshow(my_data)
plt.axis('off')
fig.axes.get_xaxis().set_visible(False)
fig.axes.get_yaxis().set_visible(False)
plt.savefig('pict.png', bbox_inches='tight', pad_inches = 0)
</code></pre>

After this code there is no whitespaces and no frame.

<img src="https://i.stack.imgur.com/kzrdo.png" alt="No whitespaces, axes or frame">

blocks|key|435484|text|还没有人提到imsave，这使得这只是一句话：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|435485|import+matplotlib.pyplot+as+plt
import+numpy+as+np

data+=+np.arange(10000).reshape((100,+100))
plt.imsave("/tmp/foo.png",+data,+format="png",+cmap="hot")|code-block|syntax|javascript|435486|它直接按原样存储图像，即不添加任何轴或边框/填充。|435487|​|435488|📷|atomic|435489|435490|entityMap|0|LINK|mutability|MUTABLE|url|https://matplotlib.org/devdocs/api/_as_gen/matplotlib.pyplot.imsave.html|1|IMAGE|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/fc50d283c7c11aa74af4bcafb918dfd5.png|imageAlt^0|6|6|6|6|0|0|0|0|0|0|1|1|0|0^^$0|@$1|2|3|4|5|6|7|16|8|@$9|17|A|18|B|C]]|D|@$9|19|A|1A|1|1B]]|E|$]]|$1|F|3|G|5|H|7|1C|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|1D|8|@]|D|@]|E|$]]|$1|M|3|N|5|6|7|1E|8|@]|D|@]|E|$]]|$1|O|3|P|5|Q|7|1F|8|@]|D|@$9|1G|A|1H|1|1I]]|E|$]]|$1|R|3|N|5|6|7|1J|8|@]|D|@]|E|$]]|$1|S|3|-4|5|6|7|1K|8|@]|D|@]|E|$]]]|T|$U|$5|V|W|X|E|$Y|Z]]|10|$5|11|W|12|E|$13|14|15|-4]]]]

No one mentioned <a href="https://matplotlib.org/devdocs/api/_as_gen/matplotlib.pyplot.imsave.html" rel="noreferrer"><code>imsave</code></a> yet, which makes this a one-liner:

<pre><code>import matplotlib.pyplot as plt
import numpy as np

data = np.arange(10000).reshape((100, 100))
plt.imsave("/tmp/foo.png", data, format="png", cmap="hot")
</code></pre>

It directly stores the image as it is, i.e. does not add any axes or border/padding.

<a href="https://i.stack.imgur.com/NQv8Z.png" rel="noreferrer"><img src="https://i.stack.imgur.com/NQv8Z.png" alt="enter image description here"></a>

blocks|key|649965|text|首先，对于某些图像格式(即TIFF)，您实际上可以将色彩映射表保存在标题中，并且大多数查看器将使用色彩映射表显示您的数据。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|649966|为了保存实际的matplotlib图像，这对于向图像添加注释或其他数据很有用，我使用了以下解决方案：|style|CODE|649967|fig,+ax+=+plt.subplots(figsize=inches)
ax.matshow(data)++#+or+you+can+use+also+imshow
#+add+annotations+or+anything+else
#+The+code+below+essentially+moves+your+plot+so+that+the+upper
#+left+hand+corner+coincides+with+the+upper+left+hand+corner
#+of+the+artist
fig.subplots_adjust(left=0,+right=1,+top=1,+bottom=0,+wspace=0,+hspace=0)
#+now+generate+a+Bbox+instance+that+is+the+same+size+as+your
#+single+axis+size+(this+bbox+will+only+encompass+your+figure)
bbox+=+matplotlib.transforms.Bbox(((0,+0),+inches))
#+now+you+can+save+only+the+part+of+the+figure+with+data
fig.savefig(savename,+bbox_inches=bbox,+**kwargs)|code-block|syntax|javascript|649968|entityMap|0|LINK|mutability|MUTABLE|url|https://en.wikipedia.org/wiki/TIFF^0|D|4|0|0|7|A|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@$A|V|B|W|1|X]]|C|$]]|$1|D|3|E|5|6|7|Y|8|@$A|Z|B|10|F|G]]|9|@]|C|$]]|$1|H|3|I|5|J|7|11|8|@]|9|@]|C|$K|L]]|$1|M|3|-4|5|6|7|12|8|@]|9|@]|C|$]]]|N|$O|$5|P|Q|R|C|$S|T]]]]

First, for certain image formats (i.e. <a href="https://en.wikipedia.org/wiki/TIFF" rel="nofollow noreferrer">TIFF</a>) you can actually save the colormap in the header and most viewers will show your data with the colormap.

For saving an actual <code>matplotlib</code> image, which can be useful for adding annotations or other data to images, I've used the following solution:

<pre><code>fig, ax = plt.subplots(figsize=inches)
ax.matshow(data) # or you can use also imshow
# add annotations or anything else
# The code below essentially moves your plot so that the upper
# left hand corner coincides with the upper left hand corner
# of the artist
fig.subplots_adjust(left=0, right=1, top=1, bottom=0, wspace=0, hspace=0)
# now generate a Bbox instance that is the same size as your
# single axis size (this bbox will only encompass your figure)
bbox = matplotlib.transforms.Bbox(((0, 0), inches))
# now you can save only the part of the figure with data
fig.savefig(savename, bbox_inches=bbox, **kwargs)
</code></pre>

blocks|key|435717|text|我喜欢ubuntu's+answer，但它没有明确显示如何设置非正方形图像的开箱即用大小，所以我修改了它以便于复制-粘贴：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|435718|import+matplotlib.pyplot+as+plt
import+matplotlib.image+as+mpimg
import+numpy+as+np

def+save_image_fix_dpi(data,+dpi=100):
++++shape=np.shape(data)[0:2][::-1]
++++size+=+[float(i)/dpi+for+i+in+shape]

++++fig+=+plt.figure()
++++fig.set_size_inches(size)
++++ax+=+plt.Axes(fig,[0,0,1,1])
++++ax.set_axis_off()
++++fig.add_axes(ax)
++++ax.imshow(data)
++++fig.savefig('out.png',+dpi=dpi)
++++plt.show()|code-block|syntax|javascript|435719|如果保留pixel_size/+dpi+=size，则无论您选择什么dpi，保存无边框的图像都很容易。|435720|data+=+mpimg.imread('test.png')
save_image_fix_dpi(data,+dpi=100)|435721|​|435722|📷|atomic|435723|435724|然而，显示是可怕的。如果您选择小dpi，您的图像大小可以大于您的屏幕，并在显示期间获得边框。然而，这并不影响储蓄。|435725|所以对于|435726|save_image_fix_dpi(data,+dpi=20)|435727|显示变得有边框(但保存有效)：|435728|435729|435730|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/users/190597/unutbu|1|IMAGE|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/8a9bf6c7cb8330d753b26efbeb172a06.png|imageAlt|2|https://ask.qcloudimg.com/http-save/yehe-900000/fc9e88c8af7e7ffd6b9dc50521f27378.png^0|3|8|0|0|0|0|0|0|0|1|1|0|0|0|0|0|0|0|1|2|0|0^^$0|@$1|2|3|4|5|6|7|1I|8|@]|9|@$A|1J|B|1K|1|1L]]|C|$]]|$1|D|3|E|5|F|7|1M|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|1N|8|@]|9|@]|C|$]]|$1|K|3|L|5|F|7|1O|8|@]|9|@]|C|$G|H]]|$1|M|3|N|5|6|7|1P|8|@]|9|@]|C|$]]|$1|O|3|P|5|Q|7|1Q|8|@]|9|@$A|1R|B|1S|1|1T]]|C|$]]|$1|R|3|N|5|6|7|1U|8|@]|9|@]|C|$]]|$1|S|3|T|5|6|7|1V|8|@]|9|@]|C|$]]|$1|U|3|V|5|6|7|1W|8|@]|9|@]|C|$]]|$1|W|3|X|5|F|7|1X|8|@]|9|@]|C|$G|H]]|$1|Y|3|Z|5|6|7|1Y|8|@]|9|@]|C|$]]|$1|10|3|P|5|Q|7|1Z|8|@]|9|@$A|20|B|21|1|22]]|C|$]]|$1|11|3|N|5|6|7|23|8|@]|9|@]|C|$]]|$1|12|3|-4|5|6|7|24|8|@]|9|@]|C|$]]]|13|$14|$5|15|16|17|C|$18|19]]|1A|$5|1B|16|1C|C|$1D|1E|1F|-4]]|1G|$5|1B|16|1C|C|$1D|1H|1F|-4]]]]

I liked <a href="https://stackoverflow.com/users/190597/unutbu">ubuntu's</a> answer, but it was not showing explicitly how to set the size for non-square images out-of-the-box, so I modified it for easy copy-paste:

<pre><code>import matplotlib.pyplot as plt
import matplotlib.image as mpimg
import numpy as np

def save_image_fix_dpi(data, dpi=100):
 shape=np.shape(data)[0:2][::-1]
 size = [float(i)/dpi for i in shape]

 fig = plt.figure()
 fig.set_size_inches(size)
 ax = plt.Axes(fig,[0,0,1,1])
 ax.set_axis_off()
 fig.add_axes(ax)
 ax.imshow(data)
 fig.savefig('out.png', dpi=dpi)
 plt.show()
</code></pre>

Saving images without border is easy whatever dpi you choose if pixel_size/dpi=size is kept. 

<pre><code>data = mpimg.imread('test.png')
save_image_fix_dpi(data, dpi=100)
</code></pre>

<a href="https://i.stack.imgur.com/viokB.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/viokB.png" alt="enter image description here"></a>

However displaying is spooky. If you choose small dpi, your image size can be larger than your screen and you get border during display. Nevertheless, this does not affect saving.

So for

<pre><code>save_image_fix_dpi(data, dpi=20)
</code></pre>

The display becomes bordered (but saving works):
<a href="https://i.stack.imgur.com/jtkq2.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/jtkq2.png" alt="enter image description here"></a>

blocks|key|650180|text|这应该会删除所有的填充和边框：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|650181|from+matplotlib+import+pyplot+as+plt

fig+=+plt.figure()
fig.patch.set_visible(False)

ax+=+fig.add_subplot(111)

plt.axis('off')
plt.imshow(data)

extent+=+ax.get_window_extent().transformed(fig.dpi_scale_trans.inverted())
plt.savefig("../images/test.png",+bbox_inches=extent)|code-block|syntax|javascript|650182|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This should remove all padding and borders:

<pre><code>from matplotlib import pyplot as plt

fig = plt.figure()
fig.patch.set_visible(False)

ax = fig.add_subplot(111)

plt.axis('off')
plt.imshow(data)

extent = ax.get_window_extent().transformed(fig.dpi_scale_trans.inverted())
plt.savefig("../images/test.png", bbox_inches=extent)
</code></pre>

blocks|key|435894|text|积极的答案不再起作用了。为了让它工作，你需要手动添加一个设置为0，0，1，1的轴，或者删除figure下的面片。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|435895|import+matplotlib.pyplot+as+plt

fig+=+plt.figure(figsize=(5,+5),+dpi=20)
ax+=+plt.Axes(fig,+[0.,+0.,+1.,+1.])
fig.add_axes(ax)
plt.imshow([[0,+1],+[0.5,+0]],+interpolation="nearest")
plt.axis('off')++++++++++++++++++++++++++++++++#+same+as:+ax.set_axis_off()

plt.savefig("test.png")|code-block|syntax|javascript|435896|或者，您可以只删除补丁。您不需要为了删除填充而添加子图。这是从Vlady's+answer+below简化的|offset|length|435897|fig+=+plt.figure(figsize=(5,+5))
fig.patch.set_visible(False)+++++++++++++++++++#+turn+off+the+patch

plt.imshow([[0,+1],+[0.5,+0]],+interpolation="nearest")
plt.axis('off')

plt.savefig("test.png",+cmap='hot')|435898|这是在2019/06/19使用3.0.3版本测试的。图片如下：|style|CODE|435899|​|435900|📷|atomic|435901|435902|更简单的方法是使用pyplot.imsave。有关详情，请访问see+luator's+answer+bellow|435903|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/51573601/1560241|1|IMAGE|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/ea3c4425701171ce4d0fbdbb44e2da70.png|imageAlt|2|https://stackoverflow.com/a/45214623/1560241^0|0|0|V|K|0|0|0|F|5|0|0|0|1|1|0|0|9|D|V|Q|2|0^^$0|@$1|2|3|4|5|6|7|1E|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|1F|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|1G|8|@]|9|@$I|1H|J|1I|1|1J]]|A|$]]|$1|K|3|L|5|D|7|1K|8|@]|9|@]|A|$E|F]]|$1|M|3|N|5|6|7|1L|8|@$I|1M|J|1N|O|P]]|9|@]|A|$]]|$1|Q|3|R|5|6|7|1O|8|@]|9|@]|A|$]]|$1|S|3|T|5|U|7|1P|8|@]|9|@$I|1Q|J|1R|1|1S]]|A|$]]|$1|V|3|R|5|6|7|1T|8|@]|9|@]|A|$]]|$1|W|3|X|5|6|7|1U|8|@$I|1V|J|1W|O|P]]|9|@$I|1X|J|1Y|1|1Z]]|A|$]]|$1|Y|3|-4|5|6|7|20|8|@]|9|@]|A|$]]]|Z|$10|$5|11|12|13|A|$14|15]]|16|$5|17|12|18|A|$19|1A|1B|-4]]|1C|$5|11|12|13|A|$14|1D]]]]

The upvoted answer does not work anymore. To get it to work you need 
to manually add an axis set to [0, 0, 1, 1], or remove the patch under figure.

<pre><code>import matplotlib.pyplot as plt

fig = plt.figure(figsize=(5, 5), dpi=20)
ax = plt.Axes(fig, [0., 0., 1., 1.])
fig.add_axes(ax)
plt.imshow([[0, 1], [0.5, 0]], interpolation="nearest")
plt.axis('off') # same as: ax.set_axis_off()

plt.savefig("test.png")

</code></pre>

Alternatively, you could just remove the patch. You don't need to add a subplot in order to remove the paddings. This is simplified from <a href="https://stackoverflow.com/a/51573601/1560241">Vlady's answer below</a>

<pre><code>fig = plt.figure(figsize=(5, 5))
fig.patch.set_visible(False) # turn off the patch

plt.imshow([[0, 1], [0.5, 0]], interpolation="nearest")
plt.axis('off')

plt.savefig("test.png", cmap='hot')
</code></pre>

This is tested with version <code>3.0.3</code> on 2019/06/19. Image see bellow:

<a href="https://i.stack.imgur.com/tFV46.png" rel="noreferrer"><img src="https://i.stack.imgur.com/tFV46.png" alt="enter image description here"></a>

A much simpler thing to do is to use <code>pyplot.imsave</code>. For details, <a href="https://stackoverflow.com/a/45214623/1560241">see luator's answer bellow</a>

blocks|key|650389|text|感谢每个人的精彩回答，...I有完全相同的问题，只想绘制一个图像，没有额外的填充/空间等，所以非常高兴能在这里找到每个人的想法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|650390|除了没有填充的图像之外，我还希望能够轻松地添加注释等，而不仅仅是简单的图像绘图。|650391|所以我最终做的就是将David's+answer和csnemes'结合起来，在图形创建时创建一个简单的包装器。当您使用它时，您不需要在以后使用imsave()或其他任何东西进行任何更改：|offset|length|650392|def+get_img_figure(image,+dpi):
++++"""
++++Create+a+matplotlib+(figure,axes)+for+an+image+(numpy+array)+setup+so+that
++++++++a)+axes+will+span+the+entire+figure+(when+saved+no+whitespace)
++++++++b)+when+saved+the+figure+will+have+the+same+x/y+resolution+as+the+array,+
+++++++++++with+the+dpi+value+you+pass+in.

++++Arguments:
++++++++image+--+numpy+2d+array
++++++++dpi+--+dpi+value+that+the+figure+should+use

++++Returns:+(figure,+ax)+tuple+from+plt.subplots
++++"""

++++#+get+required+figure+size+in+inches+(reversed+row/column+order)
++++inches+=+image.shape[1]/dpi,+image.shape[0]/dpi

++++#+make+figure+with+that+size+and+a+single+axes
++++fig,+ax+=+plt.subplots(figsize=inches,+dpi=dpi)

++++#+move+axes+to+span+entire+figure+area
++++fig.subplots_adjust(left=0,+right=1,+top=1,+bottom=0,+wspace=0,+hspace=0)

++++return+fig,+ax|code-block|syntax|javascript|650393|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/47999122/9423009|1|https://stackoverflow.com/a/49194852/9423009^0|0|0|A|E|0|P|8|1|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|X|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|Y|8|@]|9|@$F|Z|G|10|1|11]|$F|12|G|13|1|14]]|A|$]]|$1|H|3|I|5|J|7|15|8|@]|9|@]|A|$K|L]]|$1|M|3|-4|5|6|7|16|8|@]|9|@]|A|$]]]|N|$O|$5|P|Q|R|A|$S|T]]|U|$5|P|Q|R|A|$S|V]]]]

Thanks for the awesome answers from everyone ...I had exactly the same problem with wanting to plot just an image with no extra padding/space etc, so was super happy to find everyone's ideas here.

Apart from image with no padding, I also wanted to be able to easily add annotations etc, beyond just a simple image plot.

So what I ended up doing was combining <a href="https://stackoverflow.com/a/47999122/9423009">David's answer</a> with <a href="https://stackoverflow.com/a/49194852/9423009">csnemes'</a> to make a simple wrapper at the figure creation time. When you use that, you don't need any changes later with imsave() or anything else:

<pre><code>def get_img_figure(image, dpi):
 """
 Create a matplotlib (figure,axes) for an image (numpy array) setup so that
 a) axes will span the entire figure (when saved no whitespace)
 b) when saved the figure will have the same x/y resolution as the array, 
 with the dpi value you pass in.

 Arguments:
 image -- numpy 2d array
 dpi -- dpi value that the figure should use

 Returns: (figure, ax) tuple from plt.subplots
 """

 # get required figure size in inches (reversed row/column order)
 inches = image.shape[1]/dpi, image.shape[0]/dpi

 # make figure with that size and a single axes
 fig, ax = plt.subplots(figsize=inches, dpi=dpi)

 # move axes to span entire figure area
 fig.subplots_adjust(left=0, right=1, top=1, bottom=0, wspace=0, hspace=0)

 return fig, ax
</code></pre>

blocks|key|650479|text|我发现这都是有记录的..。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|650480|https://matplotlib.org/3.1.1/api/_as_gen/matplotlib.axes.Axes.axis.html#matplotlib.axes.Axes.axis|offset|length|650481|我的代码…。"bcK“是一张512x512的图片|650482|plt.figure()
plt.imshow(bck)
plt.axis("off")+++#+turns+off+axes
plt.axis("tight")++#+gets+rid+of+white+border
plt.axis("image")++#+square+up+the+image+instead+of+filling+the+"figure"+space
plt.show()|code-block|syntax|javascript|650483|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|2P|0|0|0|0^^$0|@$1|2|3|4|5|6|7|T|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|U|8|@]|9|@$D|V|E|W|1|X]]|A|$]]|$1|F|3|G|5|6|7|Y|8|@]|9|@]|A|$]]|$1|H|3|I|5|J|7|Z|8|@]|9|@]|A|$K|L]]|$1|M|3|-4|5|6|7|10|8|@]|9|@]|A|$]]]|N|$O|$5|P|Q|R|A|$S|C]]]]

I found that it is all documented...

<a href="https://matplotlib.org/3.1.1/api/_as_gen/matplotlib.axes.Axes.axis.html#matplotlib.axes.Axes.axis" rel="noreferrer">https://matplotlib.org/3.1.1/api/_as_gen/matplotlib.axes.Axes.axis.html#matplotlib.axes.Axes.axis</a>

My code…. "bcK" is a 512x512 image

<pre><code>plt.figure()
plt.imshow(bck)
plt.axis("off") # turns off axes
plt.axis("tight") # gets rid of white border
plt.axis("image") # square up the image instead of filling the "figure" space
plt.show()
</code></pre>

blocks|key|436168|text|我一直在寻找几个代码来解决这个问题，这个question的验证答案是唯一对我有帮助的代码。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|436169|这对于散点图和三线图非常有用。你所要做的就是把页边距改成零，然后你就全部完成了。|436170|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/46844963/python-matplotlib-print-to-resolution-and-without-white-space-borders-mar^0|K|8|0|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@$A|O|B|P|1|Q]]|C|$]]|$1|D|3|E|5|6|7|R|8|@]|9|@]|C|$]]|$1|F|3|-4|5|6|7|S|8|@]|9|@]|C|$]]]|G|$H|$5|I|J|K|C|$L|M]]]]

I have been looking for several codes to solve this problem and the verified answer to this <a href="https://stackoverflow.com/questions/46844963/python-matplotlib-print-to-resolution-and-without-white-space-borders-mar">question</a> is the only code that helped me.
This is useful for scatter plots and triplots. All you have to do is change the margins to zero and you are all done.

blocks|key|650620|text|plt.axis('off')|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|650621|plt.savefig('example.png',bbox_inches='tight',pad_inches+=+0)|unstyled|offset|length|style|CODE|650622|给我无边界的图像。|650623|entityMap^0|0|0|1P|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|P|8|@$G|Q|H|R|I|J]]|9|@]|A|$]]|$1|K|3|L|5|F|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|F|7|T|8|@]|9|@]|A|$]]]|N|$]]

<pre><code>plt.axis('off')
</code></pre>
<code>plt.savefig('example.png',bbox_inches='tight',pad_inches = 0)</code>
gets me the borderless image.

blocks|key|436267|text|这就是最终对我有效的方法：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|436268|ax.margins(x=0，y=0，tight=True)是主线。|436269|++++fig+=+plt.figure(figsize=(8,+8))
++++ax+=+plt.Axes(fig,+[0.,+0.,+1.,+1.])
++++ax.set_axis_off()
++++ax.margins(x=0,+y=0,+tight=True)
++++fig.add_axes(ax)
++++for+triangle+in+list_of_triangles:
++++++++x_points+=+[point[0]+for+point+in+triangle]
++++++++y_points+=+[point[1]+for+point+in+triangle]
++++++++plt.fill(x_points,+y_points,+'k',+edgecolor='k')
++++plt.savefig("test.png",+bbox_inches=0,+pad_inches=0)
++++plt.show()|code-block|syntax|javascript|436270|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

This is what finally worked for me:
ax.margins(x=0, y=0, tight=True) was the key line.
<pre><code> fig = plt.figure(figsize=(8, 8))
 ax = plt.Axes(fig, [0., 0., 1., 1.])
 ax.set_axis_off()
 ax.margins(x=0, y=0, tight=True)
 fig.add_axes(ax)
 for triangle in list_of_triangles:
 x_points = [point[0] for point in triangle]
 y_points = [point[1] for point in triangle]
 plt.fill(x_points, y_points, 'k', edgecolor='k')
 plt.savefig(&quot;test.png&quot;, bbox_inches=0, pad_inches=0)
 plt.show()
</code></pre>

I'm new to Python and Matplotlib, I would like to simply apply colormap to an image and write the resulting image, without using axes, labels, titles or anything usually automatically added by matplotlib. Here is what I did:

<pre><code>def make_image(inputname,outputname):
 data = mpimg.imread(inputname)[:,:,0]
 fig = plt.imshow(data)
 fig.set_cmap('hot')
 fig.axes.get_xaxis().set_visible(False)
 fig.axes.get_yaxis().set_visible(False)
 plt.savefig(outputname)
</code></pre>

It successfully removes the axis of the figure, but the figure saved presents a white padding and a frame around the actual image.
How can I remove them (at least the white padding)? Thanks

Matplotlib plots: removing axis, legends and white spaces

Python

我是Python和Matplotlib的新手，我想简单地将colormap应用于图像并编写结果图像，而不使用轴、标签、标题或通常由matplotlib自动添加的任何东西。下面是我所做的：def make_image(inputname,outputname):    data = mpimg.imread(inputn...

问Matplotlib图:删除轴、图例和空格
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