Python save matplotlib figure with exact pixel size

Question

I want to save an matplotlib figure with an exact size in pixels. In the code below, this exact size is 500x500 pixels. Whilst the saved image is 500x500 pixels it includes padding around my shape and plot area. I want the circle to be tight to the borders. Instead there is white space around my circle. Is it possible to save the plotting area only? Please note that while the code below is reproducible, my_dpi is dependant upon your monitor DPI. 220 is my display's DPI.

import matplotlib.pyplot as plt
import matplotlib.image as mpimage
import numpy as np

H       = 500
W       = 500
radius  = H/2
my_dpi  = 220


a = np.deg2rad(0)
b = np.deg2rad(360);

t = np.linspace(a,b,100)
x = radius*np.cos(t)
y = radius*np.sin(t)
x = np.append(x,[0,x[0]])
y = np.append(y,[0,y[0]])

myFig   = plt.figure()
DPI     = my_dpi #myFig.get_dpi()
myFig.set_size_inches(float(H)/float(DPI),float(W)/float(DPI))

plt.fill(y,x,color='none',facecolor='red')
plt.axis((-W/2,W/2,-H/2,H/2))
plt.axis('off')
#plt.show()
plt.savefig('my_fig.png',dpi=DPI)

print 'Figure Size: ', myFig.get_size_inches()

Im = mpimage.imread('my_fig.png')
print 'Im Size: ', Im.shape

possible duplicate of Specifying and saving a figure with exact size in pixels — Paul H
– Paul H, Commented Feb 13, 2015 at 2:31

tmdavison · Accepted Answer · 2015-02-13 09:32:49Z

5

You can use subplots_adjust to set the padding around your plot.

myFig.subplots_adjust(bottom=0.,left=0.,right=1.,top=1.)

enter image description here

answered Feb 13, 2015 at 9:32

tmdavison

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1 Comment

Guillochon Over a year ago

This solved my problem of extra whitespace when hiding the axes on a plot with bbox_inches='tight'.

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