[poppler] Getting a raster image like pdf2ppm

[Angus March]

Albert Astals Cid wrote:
> A Dimecres, 20 de maig de 2009, Angus March va escriure:
>   
>> Albert Astals Cid wrote:
>>     
>>> A Dimarts, 19 de maig de 2009, Angus March va escriure:
>>>       
>>>> Adrian Johnson wrote:
>>>>         
>>>>> Angus March wrote:
>>>>>           
>>>>>> I tried using Poppler to get a Cairo surface and then saving the
>>>>>> surface to a PNG. Unfortunately, the resulting image was of
>>>>>> disastrously low quality.
>>>>>>             
>>>>> Without seeing your code or the output you are getting I can only
>>>>> guess at what the problem might be. Did you alter the cairo scale to
>>>>> get the desired image dpi?
>>>>>           
>>>>     It was definitely an improvement, but I think the only thing that
>>>> did improve was the resolution. The old problems that caused me to
>>>> abandon Cairo persisted, which are: gradients have ugly stripes on them,
>>>> a background that should be white and opaque is black and transparent,
>>>> and some text that has a shadow in the PDF doesn't in the image. I don't
>>>> suppose you know of a way to deal w/those problems.
>>>>
>>>>     But this is my code for the Splash solution I was using, derived
>>>> from the pdftoppm code I found. Again, my problems there are
>>>> segmentation faults, which valgrind reported on. I won't repeat those
>>>> reports, unless someone asks me to. Don't be fooled by the word
>>>> "thread".
>>>>         
>>> Poppler works perfectly inside threads.
>>>       
>>     If so, then this is out-of-date:
>> http://lists.freedesktop.org/archives/poppler/2007-November/003083.html
>>     
>
> Yeah, i wonder why Jeff said that, poppler has always been ok running in a 
> thread afair.
>
>   
>>> ?
>>>
>>> I don't see anything obviously wrong.
>>>
>>> Basically it is:
>>>  * Create PDFDoc
>>>  * Create SplashOutputDev
>>>  * Call SplashOutputDev::startDoc
>>>  * Call PDFDoc::displayPageSlice
>>>       
>>     Well there definitely is something wrong, because it works with
>> pdftoppm. I thought of things like the __attribute__((constructor))
>> attribute, or static objects, but I don't see any evidence of the
>> attribute and I wouldn't know how to find a static object in all that
>> code. Maybe multiple processes causes problems for Splash. 
>>     
>
> How can multiple process create problems if processes are totally separated? 
> Besides i run various pdftoppm in parallel usually and there's no problem.
>   

    At this point I'm keeping a pretty open mind. Anyway, the problem
wouldn't be one process interfering with another, but perhaps based on
the process which calls Splash being a different one from the one that
started the app.

>> It's hard to know where to go.
>>     
>
> The crashes you pasted are from poppler compiled with -O2? If so remove the -
> O2 and substitute -g by -g3. Optimized poppler backtraces are really 
> misleading.
>   

    I thought I was using the debug poppler, but I guess not, since the
poppler functions mentioned in the backtrace don't mention the source
file names, and are also pointed to the distro poppler.
    But now I'm having problems rolling my own poppler. I'm using
0.10.1, btw, because that's what my distro has. I'm trying to configure
with "CPPFLAGS="-g3 -O0" ./configure --prefix=/usr/local" but then when
I go to make I see both "-g3 -O0" and "-g -O2" on the compile lines. How
do I get rid of the of the optimization options? Also, the Splash
headers don't get installed when I call make install. How do I do that?