preview and birdseye

[Torsten Rahn]

Am Mittwoch, 4. Januar 2006 18:50 schrieb Bart Coppens:
> On Wednesday 04 January 2006 18:37, Casper Boemann wrote:
> > if(scale down)
> > {
> >     for each pixel in destination
> >     {
> >         srcpixel = nearest match in source
> > 	apply filter to that pixel
> > 	write to destination pixel
> >      }
> >     convert destination to monitor profile (QImage)
> > }
>
> This is all well when the filter can be applied to individual pixels, but
> don't forget the ones like roundcorners, or raindrops: these apply to an
> entire 'area' of a paint device at once, not a single pixel...

Well in that case one would have to figure out what neighbours are 
significanly affected by applying the effect to one pixel and how this would 
be propagated even further by applying the effect to the neighbours. 

By doing so it should be possible to find a _fraction_ of the 
source-image-makropixel (which represents the area that is covered by the 
respective pixel on the preview image) which will -- after applying the 
effect -- show almost the same results to the pixel as with filtering the 
full image. Depending on the size of the image this could give a huge boost 
to the filter preview indeed. While this also might not work for all filters 
this will probably work for most of them.

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-- 
Mit freundlichen Grüßen / Kind regards,

        Torsten Rahn

--
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