[reportlab-users] Visual Diff Tool

[Robin Becker]

Dirk Holtwick wrote:

> Hi,

> 

> while working on xhtml2pdf <http://www.xhtml2pdf.com/> I have the 

> general problem that writing test cases is quite difficult. The normal 

> way is to create some test PDF and then have a look at them if they are 

> looking fine. But that is a source of human errors. Therefore I am 

> looking for a automatic solution.

> 

> My idea is to automatically do a visual compare of a reference PDF that 

> was already rendered fine once and the recent PDF. Technically I am 

> found out that it would work fine if I use ImageMagic to first create 

> images from PDF and if they differ I can show them in TortoiseIDiff.

> 

> I started writing such a visual diff tool, but maybe there already 

> exists something similar and I can use this instead of wasting my time 

> on writing the reinvention of the wheel ;)

> 

> So my question: has anyone seen a tool like this around? If so, please 

> let me know where to find it. Otherwise I would write the visual diff 

> tool and maybe Reportlab also likes to use visual test cases for their 

> toolkit?

> 

......
We have been using ghostscript in one of our server based tools. I tried the 
pdftoppm route, but couldn't get a working version from source on freebsd.

Ghostscript works pretty well, we use commands like

gs -q -dSAFER -dNOPAUSE -dBATCH \
     -sOutputFile=rl_hello-page%04d.jpg \
     -sDEVICE=jpeg -r144x144 -f rl_hello.pdf


-- 
Robin Becker