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 Post subject: GDK_INTERP_HYPER versus Cubic
PostPosted: Tue Oct 08, 2013 11:23 pm 
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Familiar Face

Joined: Tue Oct 08, 2013 6:04 pm
Posts: 13
If GDK_INTERP_HYPER is better than Cubic why doesn't GIMP have it as an option?


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 Post subject: Re: GDK_INTERP_HYPER versus Cubic
PostPosted: Wed Oct 09, 2013 5:39 am 
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Never Seen the Sunlight

Joined: Mon Apr 28, 2008 5:52 am
Posts: 709
Location: UK
Hello,

This is the choice of the developers! It maybe because it is too slow for processing large amounts of image data.

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 Post subject: Re: GDK_INTERP_HYPER versus Cubic
PostPosted: Wed Oct 09, 2013 2:13 pm 
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Familiar Face

Joined: Tue Oct 08, 2013 6:04 pm
Posts: 13
errol wrote:
Hello,

This is the choice of the developers! It maybe because it is too slow for processing large amounts of image data.

I'm sure it is their choice, but the GKT+ documentation asserts that GDK_INTERP_HYPER is "just as fast and results in higher quality". Gimp has scaling options of Linear, Cubic and Sinc (Lanczos3) all of which I have heard about. I have not heard of hyperbolic interpolation and I'm not about to spring for $90 to buy Wolberg's out of print book (which I probably wouldn't understand anyway). There is scant reference to this method on the web which makes me really curious. The GDK+ developers will know.

Quote:
Note
Cubic filtering is missing from the list; hyperbolic interpolation is just as fast and results in higher quality.
GDK_INTERP_NEAREST
Nearest neighbor sampling; this is the fastest and lowest quality mode. Quality is normally unacceptable when scaling down, but may be OK when scaling up.
GDK_INTERP_TILES
This is an accurate simulation of the PostScript image operator without any interpolation enabled. Each pixel is rendered as a tiny parallelogram of solid color, the edges of which are implemented with antialiasing. It resembles nearest neighbor for enlargement, and bilinear for reduction.
GDK_INTERP_BILINEAR
Best quality/speed balance; use this mode by default. Bilinear interpolation. For enlargement, it is equivalent to point-sampling the ideal bilinear-interpolated image. For reduction, it is equivalent to laying down small tiles and integrating over the coverage area.
GDK_INTERP_HYPER
This is the slowest and highest quality reconstruction function. It is derived from the hyperbolic filters in Wolberg's "Digital Image Warping", and is formally defined as the hyperbolic-filter sampling the ideal hyperbolic-filter interpolated image (the filter is designed to be idempotent for 1:1 pixel mapping).


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