Observation of a zoom-engine of PS

[LukasT.dev@gmail.com]

On Sunday 01 November 2009 15:25:58 Dmitry Kazakov wrote:
> Hi!
> 
> Just an observation i got today while using PS7.  =)
> It has quite good and fast zooming engine. And the most interesting fact
> about that - it uses different zoom-algorithms for different zoom-levels.
> More exactly:
> 
> For zoom-levels 100,50,25,12.5 - it uses smooth-scale algorithm
> For other levels - nearest-neighbor. More than that, it uses nearest
> prescaled(?) image for NN-sampling.
> 

In Krita's OpenGL canvas we use linear interpolation (you called that smooth-
scale) for zoom level below 200 % and nearest neighbour for the levels above.
Check kis_opengl_canvas2.cpp (line 223).