[poppler] About pdf to image

[杨辉强]

Hi, suzuki toshiya:
    I want to save the whole image binary into database(cassandra) with 
the form of key-value pair and support the rpc service for the frontend 
to retrieve the image. Heh, heh, I am not so familiar with the poppler's 
code. Does it has some documents for new developer. I really appreciate 
your help for several times.

Best regards.

On 12/19/2011 04:52 PM, suzuki toshiya wrote:
> About your original request; writing image to memory buffer,
> do you need the image file header, or, the array of the pixel
> data is sufficient?
>
> If former, maybe modifying ImgWriter::init() in Goo library
> to accept the pointer to pre-allocated buffer as the destination
> (currently, it accepts only the file handle), then, modifying
> SplashBitmap::writeImageFile() to accept the pointer to pre-allocated
> buffer would be the easiest way.
>
> If latter, SplashBitmap class is already what you want. It
> has the methods to access each pixel or the pointer to whole
> buffer.
>
> Regards,
> mpsuzuki
>
> suzuki toshiya wrote:
>> Hi,
>>
>> Good to hear that your target platform is Ubuntu, yes, what I mean
>> is the utilization of ramdisk-like filesystem. Please check the output
>> of the command "cat /proc/mounts". I guess there might be some entries
>> including the word "tmpfs" (maybe "/dev/shm" would be there). It is
>> the files system like ramdisk, so writing/removing files in there would
>> be faster than those in the harddisks. Please check if tmpfs will serve
>> for your purpose.
>>
>> Regards,
>> mpsuzuki
>>
>> 杨辉强 wrote:
>>> Hi, mpsuzuki:
>>>    Thank you very much. My system is ubuntu. I don't know much about 
>>> memory-based file system.
>>> Does it mean utility such as ramdisk.
>>>
>>> On 12/19/2011 12:01 PM, suzuki toshiya wrote:
>>>> Hi,
>>>>
>>>> I guess poppler should have something you want, at least
>>>> internally, because the bindings for other frameworks (Qt,
>>>> GLib, cpp etc) may deal with the images without creating/
>>>> cleaning temporary image files.
>>>>
>>>> BTW, before searching such, I want to ask an off-topic question;
>>>> your target operating system does not support memory-based
>>>> file system?
>>>>
>>>> Regards,
>>>> mpsuzuki
>>>>
>>>> 杨辉强 wrote:
>>>>> Hi, all:
>>>>>   Thank Brad. I don't want to save images into files and then read 
>>>>> files into memory.
>>>>> The disk IO expense is high. So what's the utility from another 
>>>>> application can do this job? Wish your advice.
>>>>>
>>>>> Thank you!
>>>>>
>>>>> On Sun, 18 Dec 2011 11:34:17 AM Brad Hards wrote:
>>>>>
>>>>> This should have gone to a mailing list.
>>>>>
>>>>> How are you possibly going to use the utility from another 
>>>>> application and
>>>>> copy to memory without making any code changes?
>>>>>
>>>>> Brad
>>>>>
>>>>>
>>>>>
>>>>> On 12/18/2011 08:47 AM, 杨辉强 wrote:
>>>>>> Hi, all:
>>>>>>    In web search engine, I want to support the pdf snapshot. So I 
>>>>>> want to convert pdf files to images and save the images in a 
>>>>>> database. I don't want to change the poppler code.
>>>>>> Because that's notconvenient for upgrade the poppler's code.
>>>>>>
>>>>>> Thank you for your precious advices.
>>>>>>
>>>>>> On 12/17/2011 03:16 PM, Brad Hards wrote:
>>>>>>> On Sat, 17 Dec 2011 02:09:21 PM 杨辉强 wrote:
>>>>>>>>      I am a newbie to poppler. I use utils/pdftoppm.cc to 
>>>>>>>> convert a pdf
>>>>>>>> file into jpeg images.The generated images are save to disk 
>>>>>>>> files. Now I
>>>>>>>> wish to know whether it can save the images in memory such as a
>>>>>>>> vector<std::string>.  Wishing you can give me some advices.
>>>>>>> I'm sure that is possible, but you'd need to make some code 
>>>>>>> changes (and
>>>>>>> consider whether an arbitrary binary blob, containing nulls, is 
>>>>>>> really a good
>>>>>>> idea in a std::string). The code changes should basically be 
>>>>>>> taking the
>>>>>>> existing output writer and copying in to a memory location 
>>>>>>> instead. I don't
>>>>>>> see you'd need to make any real popper changes. How you 
>>>>>>> integrate that depends
>>>>>>> on the application you're trying to create.
>>>>>>>
>>>>>>> What is the end-use for this?
>>>>>>>
>>>>>>> Brad
>>>>>>> _______________________________________________
>>>>>>> poppler mailing list
>>>>>>> poppler at lists.freedesktop.org
>>>>>>> http://lists.freedesktop.org/mailman/listinfo/poppler
>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> poppler mailing list
>>>>>> poppler at lists.freedesktop.org
>>>>>> http://lists.freedesktop.org/mailman/listinfo/poppler
>>>>>
>>>>>
>>>>>
>>>>> ------------------------------------------------------------------------ 
>>>>>
>>>>>
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>>>>
>>>
>>
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