> On Aug. 6, 2017, 3:17 p.m., Albert Astals Cid wrote: > > Rasterizing usually makes stuff look quite bad (because the wrong > > resolution is chosen) , have you tried printing text or things with sharp > > lines? > > Oliver Sander wrote: > Yes I tried that, and it looks very good. It looks so good I wasn't even > able to tell that it was rasterized before printing. The resolution chosen > by the code adapts to the printer > > QImage img = pp->renderToImage( printer.physicalDpiX(), > printer.physicalDpiY() ); > > and I guess it must be pretty large when printing to an actual printer. > > Albert Astals Cid wrote: > So we will kill cheap printers/computers by using lots of memory? Can you > try to see how much memory is used printing an A4 page? Also make sure that > printing N pages doesn't need N times the memory (i guess using heaptrack or > similar) > > Oliver Sander wrote: > Quick first results: printer.physicalDpiX() returns a value of 1200, both > for printing to my office printer and for printing to a file. An A4 printout > results in a 9921 x 14032 bitmap; the corresponding file size is 804 KB > (greyscale). Testing the actual memory consumption will take me a bit more > time. > > I don't actually care about the exact resolution. If you say "bah, just > hard-code 72dpi there" that's fine with me. > > Albert Astals Cid wrote: > > 9921 x 14032 bitmap > > Does that mean that you need 9921x14032x32 bits in memory? That's around > 530 MB, right? I guess it's not horrible in todays big scheme of things if it > doesn't get multiplied by the number of pages. > > Oliver Sander wrote: > I now tried to measure the heap consumptions using valgrind/massif. I > printed to files exclusively, to save some trees. > > If I read the massif output correctly, the new code needs about 1GB of > heap space to print A4 pages, and that is independent of the number of pages. > > On the other hand, printing an A0-size poster fails with the friendly > message "Bogus memory allocation size". Not really surprising: that would > need an enormous amount of memory. > > Albert Astals Cid wrote: > > On the other hand, printing an A0-size poster fails with the friendly > message "Bogus memory allocation size". Not really surprising: that would > need an enormous amount of memory. > > I'm not sure i'm ok with that. > > Why are we discussing this instead of printing pdf directly?
> I'm not sure i'm ok with that. Okay. I changed the patch to always use 300dpi when the platform is not Windows. That is the resolution that was used previously (see poppler/PSOutputDev.cc:1260). Therefore, this patch does not bring functional changes anymore: with and without the patch, the rasterization resolution is printer.physicalDpiX() for Windows, and 300 for all others. > Why are we discussing this instead of printing pdf directly? - Printing the pdf does not rasterize it, but this patch is about rasterized printing - The new code does not involve the detour via postscript - It does not rely on CUPS tools like 'lpr' - It is platform-independent (exception: the rasterization resolution) - It is short and elegant - It fixes at least one bug: greyscale printing Follow-up patches are in the pipeline. - Oliver ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://git.reviewboard.kde.org/r/130218/#review103569 ----------------------------------------------------------- On Aug. 9, 2017, 8:58 p.m., Oliver Sander wrote: > > ----------------------------------------------------------- > This is an automatically generated e-mail. To reply, visit: > https://git.reviewboard.kde.org/r/130218/ > ----------------------------------------------------------- > > (Updated Aug. 9, 2017, 8:58 p.m.) > > > Review request for Okular. > > > Repository: okular > > > Description > ------- > > When the users chooses to print with rasterization and annotations, it is > easy to print directly to a QPrinter, rather than converting to PostScript > and then using CUPS tools. The code for it was already there, but it was > hidden behind an #ifdef Q_OS_WIN. This patch enables it for all plattforms. > If nothing else, it will make an interesting debugging tool, because it > allows to bypass the postscript & cups toolchain from the GUI. This may allow > to track down some of the numerous my-printer-settings-are-getting-ignored > bugs. > > Incidentally, this patch does fix at least one bug for me: Without it, my > printer will happily ignore the 'print in grayscale' button. With the patch, > that button is suddenly honoured. > > This patch is a part of https://git.reviewboard.kde.org/r/130055/ . I post > it here separately because I am not sure anymore whether the other stuff in > that larger patch is a good idea. > > > Diffs > ----- > > generators/poppler/generator_pdf.cpp 42ccb3a26 > > Diff: https://git.reviewboard.kde.org/r/130218/diff/ > > > Testing > ------- > > Printed a few test sheets, to a printer and a file. > > > Thanks, > > Oliver Sander > >
