stb-image-frpf2 demo

The image is scaled using "Find Replicant Pixel Fast".

Origin

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Upsampling x2

stbimfrpf2 butterfly.png butterfly.x2frpf2.png 

Load: butterfly.png
image: 256x256:3
process: downsample
process: gradient
process: FRPF2
 region: all
 threshold: 0
Save png: butterfly.x2frpf2.png

Upsampling x4

stbimfrpf2 butterfly.x2frpf2.png butterfly.x4frpf2.png 

Load: butterfly.x2frpf2.png
image: 256x256:3
process: downsample
process: gradient
process: FRPF2
 region: all
 threshold: 0
Save png: butterfly.x4frpf2.png

Compare

Bicubic

stbresize -r 4 butterfly.png butterfly.x4cubic.png

Load: butterfly.png
image: 256x256:3
resize: 1024x1024:3
method: bicubic
Save png: butterfly.x4cubic.png

FRP2 (long!!!)

stbimfrp2 butterfly.png butterfly.x2frp2.png 

Load: butterfly.png
image: 256x256:3
process: downsample
process: gradient
process: FRP2
Save png: butterfly.x2frp2.png

stbimfrp2 butterfly.x2frp2.png butterfly.x4frp2.png 

Load: butterfly.x2frp2.png
image: 256x256:3
process: downsample
process: gradient
process: FRP2
Save png: butterfly.x4frp2.png

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Option radius find

Balance of execution time and quality of the result.

stbimfrpf2 -r 32 butterfly.png butterfly.x2frpf2.r32.png 

Load: butterfly.png
image: 256x256:3
process: downsample
process: gradient
process: FRPF2
 region: 65x65
 threshold: 0
Save png: butterfly.x2frpf2.r32.png

stbimfrpf2 -r 32 butterfly.x2frpf2.r32.png butterfly.x4frpf2.r32.png 

Load: butterfly.x2frpf2.r32.png
image: 512x512:3
process: downsample
process: gradient
process: FRPF2
 region: 65x65
 threshold: 0
Save png: butterfly.x4frpf2.r32.png

stbimfrpf2 -r 64 butterfly.x4frpf2.r32.png butterfly.x8frpf2.r32.png 

Load: butterfly.x4frpf2.r32.png
image: 1024x1024:3
process: downsample
process: gradient
process: FRPF2
 region: 65x65
 threshold: 0
Save png: butterfly.x8frpf2.r32.png

stbimfrpf2 -r 64 butterfly.png butterfly.x2frpf2.r64.png 

Load: butterfly.png
image: 256x256:3
process: downsample
process: gradient
process: FRPF2
 region: 129x129
 threshold: 0
Save png: butterfly.x2frpf2.r64.png

stbimfrpf2 -r 64 butterfly.x2frpf2.r64.png butterfly.x4frpf2.r64.png 

Load: butterfly.x2frpf2.r64.png
image: 512x512:3
process: downsample
process: gradient
process: FRPF2
 region: 129x129
 threshold: 0
Save png: butterfly.x4frpf2.r64.png

stbimfrpf2 -r 64 butterfly.x4frpf2.r64.png butterfly.x8frpf2.r64.png 

Load: butterfly.x4frpf2.r64.png
image: 1024x1024:3
process: downsample
process: gradient
process: FRPF2
 region: 129x129
 threshold: 0
Save png: butterfly.x8frpf2.r64.png

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Option threshold find

Balance of execution time and search accuracy.

stbimfrpf2 -t 16 butterfly.png butterfly.x2frpf2.t16.png 

Load: butterfly.png
image: 256x256:3
process: downsample
process: gradient
process: FRPF2
 region: all
 threshold: 16
Save png: butterfly.x2frpf2.t16.png

stbimfrpf2 -t 16 butterfly.x2frpf2.t16.png butterfly.x4frpf2.t16.png 

Load: butterfly.x2frpf2.t16.png
image: 512x512:3
process: downsample
process: gradient
process: FRPF2
 region: all
 threshold: 16
Save png: butterfly.x4frpf2.t16.png

stbimfrpf2 -t 16 butterfly.x4frpf2.t16.png butterfly.x8frpf2.t16.png 

Load: butterfly.x4frpf2.t16.png
image: 1024x1024:3
process: downsample
process: gradient
process: FRPF2
 region: all
 threshold: 16
Save png: butterfly.x8frpf2.t16.png

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