[poppler] Image optimization

Leonard Rosenthol leonardr at pdfsages.com
Sun May 22 07:12:53 PDT 2005

At 09:52 AM 5/22/2005, Jeff Muizelaar wrote:
>They don't need to support everything exactly. The current code is not
>being ripped out. It is just being moved. If a backend doesn't support a
>certain type of the shading properly they just call the helper methods
>which decompose it into simpler primitives.

         So you invert the process - rather than Xpdf calling on the 
backend (OutputDev), the backend calls on Xpdf?

         It's an interesting concept, but I think it's going to introduce 
the type of "special case" inconsistencies that making testing/QA much 

>I haven't actually tested it with those things because I couldn't find
>any pdfs that used them (esp. the vertical writing mode).

         I'll dig some up for you...

>  However, there shouldn't be any problems. It is basically the difference 
> between

         It isn't that simple..

         Look at Gfx::doShowText, which is where the magic happens.

         In the case of a drawChar() model, it does all the relevant 
calculations between characters (and words) to place the glyphs as the 
correct location.  In the case of drawString(), it expects that the 
OutputDev is going to do all that.  I don't know if Cairo has been properly 
setup to address all the necessary transforms and spacing values.


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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