I often use rdkit on jupyter notebook because notebook can render molecules very conveniently. However I couldn’t find way to edit font size of reaction some days ago.
Following code is an example. Changing atom font size of MolToImage is easy but reaction image can’t apply same manner.
from rdkit import Chem from rdkit.Chem import Draw from rdkit.Chem.Draw import rdMolDraw2D from rdkit.Chem import rdChemReactions as Reactions from rdkit.Chem.Draw import IPythonConsole from PIL import Image print(Draw.DrawingOptions.atomLabelFontSize) >12 mol = Chem.MolFromSmiles('c1ccncc1') rxn = Reactions.ReactionFromSmarts('CC(=O)C>>CC(O)C', useSmiles=True) Draw.MolToImage(mol) Draw.ReactionToImage(rxn)

OK, next tried to change font size.
Draw.DrawingOptions.atomLabelFontSize = 30 print(Draw.DrawingOptions.atomLabelFontSize) Draw.MolToImage(mol) Draw.ReactionToImage(rxn)
mol object was drawn with changed font size but reaction object wasn’t.

I found the answer to solve the issue. It was enable by using MolDraw2DCairo and change its settings. It is not efficient way because png file was required. But I could not find any other solution now.
drawer = rdMolDraw2D.MolDraw2DCairo(800, 200) drawer.DrawReaction(rxn) drawer.FinishDrawing() drawer.WriteDrawingText('test.png') im = Image.open('test.png') im drawer = rdMolDraw2D.MolDraw2DCairo(800, 200) drawer.SetFontSize(1.0) drawer.DrawReaction(rxn) drawer.FinishDrawing() drawer.WriteDrawingText('test2.png') im = Image.open('test2.png') im

As you see, atom font size was changed. ;)
Today’s code was uploaded to my gist.
Any advice will be great fully appreciated. Have a nice weekend!!!
Update
Greg showed me how to render PNG image without drawing temporal file.
Thanks so much!
I have some idea to using the method. I’ll post it after tried it.