打印到图像对象

Question

我可以用imshow()保存一个绘图，因为它返回一个图像对象，如下所示：

image = plt.imshow(list, interpolation=None)

稍后，我想创建许多这些图像的动画，保存在列表中，并将其渲染为视频。（如果这种方法很愚蠢，请让我知道，我担心我做错了什么。）

anim = animation.ArtistAnimation(fig, images, interval=15, blit=True)

但是我不知道我怎么能用两个子地块的图形做同样的事情。难道不应该有一个函数返回图像对象吗

list = [[1,2,3,4,5,6,7,8],
        [1,2,3,4,5,6,7,8]]
list2 = [[1,2,3,4,5,6,7,8],
        [1,2,3,4,5,6,7,8]]

fig = plt.figure()

ax = fig.add_subplot(2, 1, 1)
ax.imshow(list, interpolation=None)

ax2 = fig.add_subplot(2, 1, 2)
ax2.imshow(list, interpolation=None)

plt.show()

我不想显示绘图，而是想将其保存为图像对象。 我的目标是创建一个动画（许多情节）并将其渲染为视频。也许我的方法是错误的。有更好的解决办法吗

Answer 1

plt.savefig('someimgname.jpg')

这样就行了。但请记住，在完成此操作后，使用Image.Open()打开此操作，此操作将起作用

im  = Image.open('someimgname.jpg')
im.show() # or do whatever you want to do with this image object

示例代码：

from matplotlib import pyplot as plt
from PIL import Image

list = [[1,2,3,4,5,6,7,8],
        [1,2,3,4,5,6,7,8]]
list2 = [[1,2,3,4,5,6,7,8],
        [1,2,3,4,5,6,7,8]]

fig = plt.figure()

ax = fig.add_subplot(2, 1, 1)
ax.imshow(list, interpolation=None)

ax2 = fig.add_subplot(2, 1, 2)
ax2.imshow(list, interpolation=None)
plt.savefig('someimgname.jpg')
im = Image.open("someimgname.jpg")  # desired image object
im.show()
plt.show()

参考资料：

1. Pillow Reference
2. Matplotlib Reference

好的，回答的第二部分，当我检查文档中的matplotlib.pyplot.savefig(*args, **kwargs)时，它说

第一个参数fname是A path, or a Python file-like object, or possibly some backend-dependent object such as

在python中，类文件对象是StringIO对象

buf = io.BytesIO()
plt.savefig(buf, format='jpg')
buf.seek(0)
im = Image.open(buf)

从python文档来看，它更有意义：-

In-memory streams: It is also possible to use a str or bytes-like object as a file for both reading and writing. For strings StringIO can be used like a file opened in text mode. BytesIO can be used like a file opened in binary mode. Both provide full read-write capabilities with random access.

示例代码：（内存中的）

from matplotlib import pyplot as plt
from PIL import Image
import io

list = [[1,2,3,4,5,6,7,8],
        [1,2,3,4,5,6,7,8]]
list2 = [[1,2,3,4,5,6,7,8],
        [1,2,3,4,5,6,7,8]]

fig = plt.figure()

ax = fig.add_subplot(2, 1, 1)
ax.imshow(list, interpolation=None)

ax2 = fig.add_subplot(2, 1, 2)
ax2.imshow(list, interpolation=None)
plt.show()
buf = io.BytesIO()
plt.savefig(buf, format='jpg')
buf.seek(0)
im = Image.open(buf)
im.show()

参考： 3. Python docs

Answer 2

您可以使用：

plt.savefig('name.png')

Answer 3

您可以将其保存到“内存中”缓冲区，如下所示：

# Save PNG to memory buffer as BytesIO
from io import BytesIO
buffer = BytesIO()

plt.savefig(buffer,format='png')
PNG = buffer.getvalue()

如果您的意思是希望从中获得PIL/枕头图像：

reloadedPILImage = Image.open(buffer)