qpdfview

Bug #1339308
Comment #8

Comment 8 for bug 1339308

Revision history for this message

Adam Reichold (adamreichold) wrote on 2014-08-19: Re: [Bug 1339308] Re: View with cropped margins

Hello again,

Am 18.08.2014 um 21:37 schrieb Siep Kroonenberg:
> On Mon, Aug 18, 2014 at 05:28:38PM -0000, Adam Reichold wrote:
>> Hello again,
>>
>> Am 18.08.2014 um 11:56 schrieb Siep Kroonenberg:
>>> On Sun, Aug 17, 2014 at 03:44:52PM -0000, Adam Reichold wrote:
>>>> Hhhmmm, the caching should now work correctly, but there are at least
>>>> one critical issue: The fit-to-something scale modes can lead to
>>>> continuous adjustments because the crop box updates the apparent size of
>>>> the pages which then can change the crop box...
>>>>
>>>> Not sure how to prevent this, for one thing one could make the crop box
>>>> independent of the current transformation and calculate it only once.
>>>> But the necessary adjustments when changing the transformations together
>>>> with tiling seem quite complicated to me...
>>>
>>> One example where qpdfview got busy recalculating (page 10):
>>>
>>> http://mirror.ctan.org/info/latexcourse-rug/latexcourse-rug.pdf
>>>
>>> This document uses the LaTeX microtype package, which implements
>>> optical alignment of margins.
>>
>> Can you confirm that this happens only when tiling is enabled? I think
>> there is one more optimization that I can make here: Discarding tiles
>> only after all visible tiles have been painted (they are taken from the
>> cache otherwise).
>
> It happens with or without tiling, but, unsurprisingly, not at all
> magnifications. This is with revision 1655.

Sorry that this seem to be a bit complicated. I coupled the crop
rectangle life cycle to obsolete pixmaps and made it more explicit when
a valid crop rectangle is available. Continuous rerender because of
scale changes should not be possible anymore using branch revision 1660.
Could you please try that again?

>>> As I already mentioned in the bug report: manual cropping would be
>>> an option for me. It would take care of situations where there are
>>> meaningless page decorations or printers marks.
>>
>> I think manual cropping is much too tedious for paginated documents to
>> merit the associated development work.
>
> Ok.
>

Unrelated question. The document seems strange insofar the cropping is
minimal as the background seems to be only almost white instead of
white. Is that correct and does stem from the usage of microtype?

Beste regards, Adam.

Hello again,

Am 18.08.2014 um 21:37 schrieb Siep Kroonenberg:
> On Mon, Aug 18, 2014 at 05:28:38PM -0000, Adam Reichold wrote:
>> Hello again,
>>
>> Am 18.08.2014 um 11:56 schrieb Siep Kroonenberg:
>>> On Sun, Aug 17, 2014 at 03:44:52PM -0000, Adam Reichold wrote:
>>>> Hhhmmm, the caching should now work correctly, but there are at least
>>>> one critical issue: The fit-to-something scale modes can lead to
>>>> continuous adjustments because the crop box updates the apparent size of
>>>> the pages which then can change the crop box...
>>>>
>>>> Not sure how to prevent this, for one thing one could make the crop box
>>>> independent of the current transformation and calculate it only once.
>>>> But the necessary adjustments when changing the transformations together
>>>> with tiling seem quite complicated to me...
>>>
>>> One example where qpdfview got busy recalculating (page 10):
>>>
>>> http://mirror.ctan.org/info/latexcourse-rug/latexcourse-rug.pdf
>>>
>>> This document uses the LaTeX microtype package, which implements
>>> optical alignment of margins.
>>
>> Can you confirm that this happens only when tiling is enabled? I think
>> there is one more optimization that I can make here: Discarding tiles
>> only after all visible tiles have been painted (they are taken from the
>> cache otherwise).
> 
> It happens with or without tiling, but, unsurprisingly, not at all
> magnifications. This is with revision 1655.

Beste regards, Adam.