[Gimp-developer] Scaling in Gimp 2.6 is much slower than in Gimp 2.4

[David Gowers]

Hi Liam,

On Fri, Oct 31, 2008 at 11:55 AM, Liam R E Quin <liam at holoweb.net> wrote:
> On Fri, 2008-10-31 at 01:44 +0100, Joern P. Meier wrote:
> [...]
>> By the way, what kind of downscaling is used for the view zooming?
>
> GEGL is doing that.
GEGL is not doing that. GEGL certainly has display-pyramid code, but
GIMP does not currently use GEGL's implementation, it has it's own
(app/base/tile-pyramid.c)

As far as I understand it, each step of the image-pyramid is produced
by averaging every 2x2 pixel square from the step above it. If the
zoom matches exactly one of the stored pyramid levels, it is used
directly in the display.. Otherwise, it interpolates between the next
smaller step and the next bigger step to produce the display.

HTH,
David