Draw.MolToImage(mol) does not work for Python 3, because cairo for Python 3 has not yet implemented Surface.create_for_data

[apahl]

Hi,

I'm playing around with RDKit and Python 3 to prepare my planned complete switch to Py3 (drumroll...) and stumbled upon the above mentioned error:

Steps to reproduce (latest RDKit git master compiled for Python 3):

In [1]: from rdkit.Chem import AllChem as Chem
   ...: from rdkit.Chem import Draw
   ...: from rdkit.Chem.Draw import IPythonConsole
   ...: Draw.DrawingOptions.atomLabelFontFace = "DejaVu Sans"
   ...: Draw.DrawingOptions.atomLabelFontSize = 18

In [2]: mol = Chem.MolFromSmiles("c1ccccc1O")
In [7]: Draw.MolToImage(mol)

---------------------------------------------------------------------------
NotImplementedError                       Traceback (most recent call last)
<ipython-input-7-761f43a1d43c> in <module>()
----> 1 Draw.MolToImage(mol)

/home/apl/progs/RDKit/rdkit/Chem/Draw/__init__.py in MolToImage(mol, size, kekulize, wedgeBonds, fitImage, options, canvas, **kwargs)
     92     raise ValueError('Null molecule provided')
     93   if canvas is None:
---> 94     img,canvas=_createCanvas(size)
     95   else:
     96     img=None

/home/apl/progs/RDKit/rdkit/Chem/Draw/__init__.py in _createCanvas(size)
     48       from PIL import Image
     49     img = Image.new("RGBA",size,(0,0,0,0))
---> 50     canvas = Canvas(img)
     51   else:
     52     from rdkit.Chem.Draw.spingCanvas import Canvas

/home/apl/progs/RDKit/rdkit/Chem/Draw/cairoCanvas.py in __init__(self, image, size, ctx, imageType, fileName)
     74       surface = cairo.ImageSurface.create_for_data (
     75         a, cairo.FORMAT_ARGB32,
---> 76         image.size[0], image.size[1], stride)
     77       ctx = cairo.Context(surface)
     78       size=image.size[0], image.size[1]

NotImplementedError: Surface.create_for_data: Not Implemented yet.

Also, calling the object in a IPython 3 qtconsole or notebook does not give the rendered image of the structure but just the general Python object information:

In [12]: mol
Out[12]: <rdkit.Chem.rdchem.Mol at 0x7f37bfaef730>

draw to file works as expected:

In [12]: Draw.MolToFile(mol, "test.png")

All the best,
Axel