[Feature request] RIS

[zvezdochiot]

Hi @vigri and @lightsilverberryfox .

Interested in using RIS (Reverse Interpolate Scale) instead of normal scaling.

I0 = image{w0,h0}
// RIS begin
I1 = Interpolation(I0,{w0,h0}->{w1,h1})
I2 = Interpolation(I1,{w1,h1}->{w0,h0})
k = sqrt(2.0f) * 0.5f // == 0.70710678f
I0 = I0 + (I0 - I2) * k // this RIS prefilter!
// RIS end
I1 = Interpolation(I0,{w0,h0}->{w1,h1})

See also:

• https://github.com/ImageProcessing-ElectronicPublications/gimp-plugin-ris
• https://github.com/ImageProcessing-ElectronicPublications/gimp-plugin-resize-ris
• https://github.com/ImageProcessing-ElectronicPublications/stb-image-resize and https://github.com/ImageProcessing-ElectronicPublications/stb-image-resize-demo
• https://github.com/ImageProcessing-ElectronicPublications/imthreshold
• https://github.com/ImageProcessing-ElectronicPublications/gimp-plugin-scaler-biakima-demo
• https://github.com/ImageProcessing-ElectronicPublications/photoquick and https://github.com/ImageProcessing-ElectronicPublications/photoquick-examples