#!/usr/bin/env python
# coding: utf-8

# In[34]:


import matplotlib.pyplot as plt
plt.ion()

fig = plt.gcf()
plt.plot([1,3,2])


# In[52]:


class MyFigure:
    width = None
    height = None
    obj = None
    def _repr_png_(self):
        metadata = {}
        if self.width:
            metadata['width'] = self.width
        if self.height:
            metadata['height'] = self.height
        pngdata = self.render_png()
        return pngdata, metadata
    
    def render_png(self):
        if isinstance(self.obj, int):
            pass #...
        else:
            data, metadata = get_ipython().display_formatter.format(self.obj)
            if 'image/png' in data:
                return data['image/png']


# In[53]:


img = MyFigure()
img


# In[55]:


img.obj = fig
img.width = 20


# In[58]:


img.width = 100
img