Removing white space around a saved image in matplotlib

Question

I need to take an image and save it after some process  The figure looks fine when I display it  but after saving the figure  I got some white space around the saved image  I have tried the  tight  option for savefig method  did not work either  The code    import matplotlib image as mpimg   import matplotlib pyplot as plt    fig   plt figure 1    img   mpimg imread path    plt imshow img    ax fig add subplot 1 1 1     extent   ax get window extent   transformed fig dpi scale trans inverted      plt savefig  1 png   bbox inches extent     plt axis  off      plt show    I am trying to draw a basic graph by using NetworkX on a figure and save it  I realized that without a graph it works  but when added a graph I get white space around the saved image  import matplotlib image as mpimg import matplotlib pyplot as plt import networkx as nx  G   nx Graph   G add node 1  G add node 2  G add node 3  G add edge 1 3  G add edge 1 2  pos    1  100 120   2  200 300   3  50 75    fig   plt figure 1  img   mpimg imread  quot image jpg quot   plt imshow img  ax fig add subplot 1 1 1   nx draw G  pos pos   extent   ax get window extent   transformed fig dpi scale trans inverted    plt savefig  1 png   bbox inches   extent   plt axis  off    plt show

User · Answer

So the solution depend on whether you adjust the subplot. If you specify plt.subplots_adjust (top, bottom, right, left), you don't want to use the kwargs of bbox_inches='tight' with plt.savefig, as it paradoxically creates whitespace padding. It also allows you to save the image as the same dims as the input image (600x600 input image saves as 600x600 pixel output image).

If you don't care about the output image size consistency, you can omit the plt.subplots_adjust attributes and just use the bbox_inches='tight' and pad_inches=0 kwargs with plt.savefig.

This solution works for matplotlib versions 3.0.1, 3.0.3 and 3.2.1. It also works when you have more than 1 subplot (eg. plt.subplots(2,2,...).

def save_inp_as_output(_img, c_name, dpi=100):
    h, w, _ = _img.shape
    fig, axes = plt.subplots(figsize=(h/dpi, w/dpi))
    fig.subplots_adjust(top=1.0, bottom=0, right=1.0, left=0, hspace=0, wspace=0) 
    axes.imshow(_img)
    axes.axis('off')
    plt.savefig(c_name, dpi=dpi, format='jpeg')

User · Answer

You may try this  It solved my issue  import matplotlib image as mpimg img   mpimg imread  quot src png quot   mpimg imsave  quot out png quot   img  cmap cmap

User · Answer

i followed this sequence and it worked like a charm   plt axis  off   fig plt imshow image array interpolation  nearest   fig axes get xaxis   set visible False  fig axes get yaxis   set visible False  plt savefig  destination path pdf       bbox inches  tight   pad inches 0  format  pdf   dpi 1200

User · Answer

For anyone who wants to work in pixels rather than inches this will work   Plus the usual you will also need  from matplotlib transforms import Bbox   Then you can use the following   my dpi   100   Good default - doesn t really matter    Size of output in pixels h   224 w   224  fig  ax   plt subplots 1  figsize  w my dpi  h my dpi   dpi my dpi   ax set position  0  0  1  1     Critical     Do some stuff ax imshow img  ax imshow heatmap    4-channel RGBA ax plot  50  100  150    50  100  150   color  red    ax axis  off    fig savefig  saved img png               bbox inches Bbox   0  0    w my dpi  h my dpi                 dpi my dpi

User · Answer

I cannot claim I know exactly why or how my  ldquo solution rdquo  works  but this is what I had to do when I wanted to plot the outline of a couple of aerofoil sections  mdash  without white margins  mdash  to a PDF file    Note that I used matplotlib inside an IPython notebook  with the -pylab flag    plt gca   set axis off   plt subplots adjust top   1  bottom   0  right   1  left   0               hspace   0  wspace   0  plt margins 0 0  plt gca   xaxis set major locator plt NullLocator    plt gca   yaxis set major locator plt NullLocator    plt savefig  filename pdf   bbox inches    tight       pad inches   0    I have tried to deactivate different parts of this  but this always lead to a white margin somewhere  You may even have modify this to keep fat lines near the limits of the figure from being shaved by the lack of margins

User · Answer

This worked for me plt savefig save path bbox inches  tight   pad inches 0  transparent True

User · Answer

The following function incorporates johannes-s answer above  I have tested it with plt figure and plt subplots   with multiple axes  and it works nicely   def save filepath  fig None          Save the current image with no whitespace     Example filepath   myfig png  or r C  myfig pdf               import matplotlib pyplot as plt     if not fig          fig   plt gcf        plt subplots adjust 0 0 1 1 0 0      for ax in fig axes          ax axis  off           ax margins 0 0          ax xaxis set major locator plt NullLocator            ax yaxis set major locator plt NullLocator        fig savefig filepath  pad inches   0  bbox inches  tight

User · Answer

I found the following codes work perfectly for the job   fig   plt figure figsize  6 6   ax   fig add subplot 111  ax imshow data  ax axes get xaxis   set visible False  ax axes get yaxis   set visible False  ax set frame on False  plt savefig  data png   dpi 400  bbox inches  tight  pad inches 0

User · Answer

After trying the above answers with no success  and a slew of other stack posts  what finally worked for me was just  plt gca   set axis off   plt subplots adjust top   1  bottom   0  right   1  left   0               hspace   0  wspace   0  plt margins 0 0  plt savefig  myfig pdf     Importantly this does not include the bbox or padding arguments

User · Answer

The most straightforward method is to use plt tight layout transformation which is actually more preferable as it doesn t do unnecessary cropping when using plt savefig import matplotlib as plt     plt plot  1 2 3    1 2 3   plt tight layout pad 0  plt savefig  plot png    However  this may not be preferable for complex plots that modifies the figure  Refer to Johannes S s answer that uses plt subplots adjust if that s the case

User · Answer

This works for me saving a numpy array plotted with imshow to file  import matplotlib pyplot as plt  fig   plt figure figsize  10 10   plt imshow img    your image here plt axis  off   plt subplots adjust top   1  bottom   0  right   1  left   0           hspace   0  wspace   0  plt savefig  example2 png   box inches  tight   dpi 100  plt show

User · Answer

You can remove the white space padding by setting bbox inches  tight  in savefig   plt savefig  test png  bbox inches  tight     You ll have to put the argument to bbox inches as a string  perhaps this is why it didn t work earlier for you     Possible duplicates   Matplotlib plots  removing axis  legends and white spaces  How to set the margins for a matplotlib figure   Reduce left and right margins in matplotlib plot

User · Answer

A much simpler approach I found is to use plt imsave        import matplotlib pyplot as plt     arr   plt imread path      plt imsave  test png   arr

User · Answer

I found something from Arvind Pereira  http   robotics usc edu  ampereir wordpress  p 626  and seemed to work for me   plt savefig filename  transparent   True  bbox inches    tight   pad inches   0

[python] Removing white space around a saved image in matplotlib

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