Generate or use generated graph inside pdf (prawn gem)

List of gems available for graph generation inside pdf or after generation can be 

shown inside pdf. By using cron job can frequently clean the directory to avoid memory problem.    

 prawn-graph - https://github.com/HHRy/prawn-graph/  
 gruff - https://github.com/topfunky/gruff  
 prawn_charts - https://github.com/MrPowers/prawn_charts   
 Using GChart with Prawn - http://pagodaworks.com/2013/10/16/using-gchart-with-prawn/   
 Prawn::Graph - Simple Graphing for Prawn  
 (http://ryanstenhouse.eu/projects/2010/02/12/prawn-graphs-simple-graphing-for-prawn/)

 (http://www.ruby-doc.org/gems/docs/p/prawn-graph-0.0.4/index.html)