Mercurial > cgi-bin > hgweb.cgi > SimpleResizer
diff app/src/main/java/com/bartsent/simpleresizer/lib/LanczosKernel.kt @ 6:e8059b166de1
Lanczos works, but is painfully slow.
| author | David Barts <n5jrn@me.com> |
|---|---|
| date | Tue, 16 Feb 2021 17:29:52 -0800 |
| parents | |
| children | 6ae738b8a814 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/app/src/main/java/com/bartsent/simpleresizer/lib/LanczosKernel.kt Tue Feb 16 17:29:52 2021 -0800 @@ -0,0 +1,19 @@ +package com.bartsent.simpleresizer.lib + +import kotlin.math.PI +import kotlin.math.abs +import kotlin.math.sin + +object LanczosKernel: ScalingKernel { + override val size = 3.0 + + private fun sinc(x: Double): Double { + if (x == 0.0) + return 1.0 + val pix = PI * x + return sin(pix) / pix + } + + override fun weight(x: Double): Double = + if (abs(x) < size) sinc(x) * sinc(x/size) else 0.0 +} \ No newline at end of file