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comparison app/src/main/java/com/bartsent/simpleresizer/lib/LanczosKernel.kt @ 6:e8059b166de1

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Lanczos works, but is painfully slow.
author David Barts <n5jrn@me.com>
date Tue, 16 Feb 2021 17:29:52 -0800
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children 6ae738b8a814
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5:247e03baf77c 6:e8059b166de1
1 package com.bartsent.simpleresizer.lib
2
3 import kotlin.math.PI
4 import kotlin.math.abs
5 import kotlin.math.sin
6
7 object LanczosKernel: ScalingKernel {
8 override val size = 3.0
9
10 private fun sinc(x: Double): Double {
11 if (x == 0.0)
12 return 1.0
13 val pix = PI * x
14 return sin(pix) / pix
15 }
16
17 override fun weight(x: Double): Double =
18 if (abs(x) < size) sinc(x) * sinc(x/size) else 0.0
19 }