Bitmap-type print to printer and preview produces low resolution output

[Oldřich Jedlička]

The printing dialog provides two possible formats: Vector and Bitmap. When I select Bitmap and enter 600 DPI, the DPI is not used neither in "Print to file", nor when I select my printer "hp_3650" (and of course when I select "600 dpi, Photo, Photo + Color Cartr., Photo Paper" on Advanced tab). The generated PDF (in "Print to file") is very low resolution (75 DPI?); also when the output goes directly to the printer, it is very low resolution.

It looks like the print surface has wrong resolution (some default?). I saw cairo_surface_set_fallback_resolution() function used somewhere on the internet, but it is not used in Inkscape.

SW versions (packages from Gentoo Linux):

Inkscape: 0.46-r3
gtk+: 2.12.11
gtkmm: 2.12.7
cairo: 1.6.4
cairomm: 1.6.0
hplip (printer drivers): 2.8.6b

[Oldřich Jedlička (oldium)]

After some investigation I discovered the intermediate PNG file has wrong resolution. It is problem in src/ui/dialogs/print.cpp in draw_page() method:

  sp_export_png_file(junk->_doc, tmp_png.c_str(), 0.0, 0.0, width, height, (unsigned long)(width * PT_PER_IN / PX_PER_IN), (unsigned long)(height * PT_PER_IN / PX_PER_IN), dpi, dpi, bgcolor, NULL, NULL, true, NULL);

The generated PNG file is in PT_PER_IN resolution: 72 DPI! But when I change PT_PER_IN to "dpi", the generated temporary PNG looks good (at least for me), but the PDF contains zoomed-in picture - looks like it doesn't use the PNG's DPI (600), but forces it to use 72 DPI again (I don't know how to check the size of the picture in the PDF to verify this), so the resulting PNG's size in PDF is 8 times (600/72) bigger than the page.

Some hints?

[Niko Kiirala (kiirala)]

Fix for this is committed as SVN revision 19909. With this, I successfully printed a bunch of images containing blur, gradients and such, at 300 dpi.

[Olivier Samyn (olivier-oleastre)]

Porting this fix to the future intrepid release is trivial and will save some paper ;-)

[Olivier Samyn (olivier-oleastre)]

Shouldn't the patch for ubuntu be:

http://inkscape.svn.sourceforge.net/viewvc/inkscape/inkscape/trunk/src/ui/dialog/print.cpp?view=patch&r1=19909&r2=19908&pathrev=19909

[Bryce Harrington (bryce)]

Ah, thanks good catch

[Launchpad Janitor (janitor)]

This bug was fixed in the package inkscape - 0.46-5ubuntu3

---------------
inkscape (0.46-5ubuntu3) jaunty; urgency=low

  * Add 102_sp_pattern_painter_free.dpatch: Fix SIGSEGV in
    sp_pattern_painter_free that occurs when drawing gears and creating 3d
    boxes.
    (LP: #198608)
  * Add 103_bitmap_type_print.dpatch: Bitmap-type print to printer and
    preview produces low resolution output.
    (LP: #258916)

 -- Bryce Harrington <email address hidden> Wed, 08 Apr 2009 00:35:13 -0700