[bug #44933] Cairo backend: NSGraphicsContext's imageInterpolation setting is ignored

[Josh Freeman]

URL:
  <http://savannah.gnu.org/bugs/?44933>

                 Summary: Cairo backend: NSGraphicsContext's
imageInterpolation setting is ignored
                 Project: GNUstep
            Submitted by: tedge
            Submitted on: Mon 27 Apr 2015 04:32:32 AM GMT
                Category: Backend
                Severity: 3 - Normal
              Item Group: Bug
                  Status: None
                 Privacy: Public
             Assigned to: None
             Open/Closed: Open
         Discussion Lock: Any

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Details:

   Setup: VirtualBox 4.3 + Ubuntu 14.04 guest, Clang, GNUstep from current SVN
trunk

   Scaled images drawn with the Cairo backend are always interpolated
(blurred), even when interpolation is disabled in the current
NSGraphicsContext (imageInterpolation set to NSImageInterpolationNone).

   This is because the CairoGState class hard-codes all calls to
cairo_pattern_set_filter() (Cairo function for setting interpolation type)
with the interpolation value, CAIRO_FILTER_BILINEAR.

   The attached patch updates CairoGState's cairo_pattern_set_filter() calls
to use an appropriate value based on the graphicsContext's imageInterpolation
setting. Test program is also attached.




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File Attachments:


-------------------------------------------------------
Date: Mon 27 Apr 2015 04:32:32 AM GMT  Name:
CairoGState_ImageInterpolation.patch  Size: 2kB   By: tedge

<http://savannah.gnu.org/bugs/download.php?file_id=33799>
-------------------------------------------------------
Date: Mon 27 Apr 2015 04:32:32 AM GMT  Name: TestImageInterpolation.m  Size:
7kB   By: tedge

<http://savannah.gnu.org/bugs/download.php?file_id=33800>

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