Why "babel ... -o svg -xP300" command is not able scale a molecule SVG image?

The "babel ... -o svg -xP300" command has a code bug that results incorrect attributes, width="px" height="px", in the top level "svg" element. in both Open 2.3 and 2.4 releases.

However, "obabel ... -o svg -xP300" command works correctly in both Open 2.3 and 2.4 releases.

Commands below shows you the incorrectly generated width="px" height="px" attributes from "babel" command in Open Babel 2.4.

fyicenter$ babel -version 
No output file or format spec!
Open Babel 2.4.1 -- May 25 2020 -- 08:24:13
Usage: babel [-i<input-type>] <name> [-o<output-type>] <name>
Try  -H option for more information.

WARNING: babel is deprecated and will be removed in a future release
         of Open Babel. You should use obabel instead. For information
         on the differences please see:
             http://openbabel.org/docs/current/Command-line_tools/babel.html
               
fyicenter$ obabel -:CCCCCCC -O carbon-chain.sdf --gen2D
1 molecule converted
            
fyicenter$ babel carbon-chain.sdf carbon-chain.svg -xP300 
1 molecule converted
20 audit log messages 

fyicenter$ grep viewBox carbon-chain.svg 
... x="0" y="0" width="px" height="px" viewBox="0 0 100 100">
<svg width="100" height="100" x="0" y="0" viewBox="0 0 253.205 140"


fyicenter$ obabel -:CCCCCCC -O carbon-chain.svg --gen2D -xP300
1 molecule converted

fyicenter$ grep viewBox carbon-chain.svg 
... x="0" y="0" width="300px" height="300px" viewBox="0 0 100 100">
<svg width="100" height="100" x="0" y="0" viewBox="0 0 253.205 140"

Commands below shows you the incorrectly generated width="px" height="px" attributes from "babel" command in Open Babel 2.3.

fyicenter$ babel -version 
No output file or format spec!
Open Babel 2.3.1 -- Oct 13 2011 -- 15:14:47
Usage: babel [-i<input-type>] <name> [-o<output-type>] <name>
Try  -H option for more information.

fyicenter$ obabel -:CCCCCCC -O carbon-chain.sdf --gen2D
1 molecule converted

fyicenter$ babel carbon-chain.sdf carbon-chain.svg -xP300 
1 molecule converted
25 audit log messages 

fyicenter$ grep viewBox carbon-chain.svg 
... x="0" y="0" width="px" height="px" viewBox="0 0 100 100">
<svg width="100" height="100" x="0" y="0" viewBox="0 0 253.205 140"


fyicenter$ obabel -:CCCCCCC -O carbon-chain.svg --gen2D -xP300
1 molecule converted

fyicenter$ grep viewBox carbon-chain.svg 
... x="0" y="0" width="300px" height="300px" viewBox="0 0 100 100">
<svg width="100" height="100" x="0" y="0" viewBox="0 0 253.205 140"

The good news is that the "babel" command is deprecated and will be removed in a future release. So we don't have to worry about it any more.

⇒ "babel ... -o svg -xd -xP300" Bug - Option -d takes a parameter

⇐ Scaling SVG Images using "viewBox" Attribute

⇑ "babel ... -o svg" - Generating SVG Pictures

⇑⇑ Open Babel Tutorials