matplotlib：保存的 imshow pdf 看起来与绘图窗口不同

Question

The following figure was plotted using imshow in matplotlib with option interpolation='none' : However, after I saved it as a pdf file, the saved pdf file looks quite different: The problem is: the blue patterns become very blurry.

My question is: How can I save a pdf figure that looks exactly like the plot window?

Answer 1

I solved this problem by specifying the dpi in the savefig for filetype pdf. Even though i read online that dpi is not supposed to make a difference in the vector based pdf format in theory, it did solve the problem for me in practice.

plt.imshow(np.random.random((10,10)))
plt.savefig("test.pdf", dpi=300)

Answer 2

PDF format is a vector image format. This means it is upto the program you open it in to interpret how it should be drawn. This can have some benefits when you want to be able to arbitrarily zoom in and out of an image while keeping high quality. However some programs can modify the image through anti-aliasing.

Your best bet for consistency is to use a pixel based image format. I would suggest try saving it as a .png.