[poppler] Image optimization

Leonard Rosenthol leonardr at pdfsages.com
Thu May 19 19:24:16 PDT 2005

At 01:54 PM 5/19/2005, Kristian Høgsberg wrote:
>I've been looking into optimizing the slow image handling in poppler.


>As Jeff identifier earlier on, the color space conversion (surprisingly)
>is taking a lot of time.  Here's a patch that adds a getRGBLine()
>function to the color space object so we avoid a virtual function call
>per pixel, plus it converts to bytes instead of doubles in the 0-1

         All good things - but you might also want to look at color 
conversion value caching - as that's a big part of the issue as 
well.  Simple lookup table works nicely for this and should improve 
performance for certain types of conversions.

         Also, if you want a REALLY GOOD image performance test - esp. one 
that uses a variety of different colorspaces, try the Altona Visual test at 


Leonard Rosenthol                            <mailto:leonardr at pdfsages.com>
Chief Technical Officer                      <http://www.pdfsages.com>
PDF Sages, Inc.                              215-938-7080 (voice)
                                              215-938-0880 (fax)

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