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Use SparseArrayCompat for better performance #108

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Use SparseArrayCompat for better performance #108

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35b22bb
use SparseArrayCompat for better performance
isfaaghyth Feb 18, 2021
eabdd81
fix typo
isfaaghyth Feb 20, 2021
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13 changes: 7 additions & 6 deletions Kotlin/lib/src/main/java/com/wolt/blurhashkt/BlurHashDecoder.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@ package com.wolt.blurhashkt

import android.graphics.Bitmap
import android.graphics.Color
import androidx.collection.SparseArrayCompat
import kotlin.math.cos
import kotlin.math.pow
import kotlin.math.withSign
Expand All @@ -11,8 +12,8 @@ object BlurHashDecoder {
// cache Math.cos() calculations to improve performance.
// The number of calculations can be huge for many bitmaps: width * height * numCompX * numCompY * 2 * nBitmaps
// the cache is enabled by default, it is recommended to disable it only when just a few images are displayed
private val cacheCosinesX = HashMap<Int, DoubleArray>()
private val cacheCosinesY = HashMap<Int, DoubleArray>()
private val cacheCosinesX = SparseArrayCompat<DoubleArray>()
private val cacheCosinesY = SparseArrayCompat<DoubleArray>()

/**
* Clear calculations stored in memory cache.
Expand Down Expand Up @@ -133,21 +134,21 @@ object BlurHashDecoder {
private fun getArrayForCosinesY(calculate: Boolean, height: Int, numCompY: Int) = when {
calculate -> {
DoubleArray(height * numCompY).also {
cacheCosinesY[height * numCompY] = it
cacheCosinesY.put(height * numCompY, it)
}
}
else -> {
cacheCosinesY[height * numCompY]!!
cacheCosinesY.get(height * numCompY)!!
}
}

private fun getArrayForCosinesX(calculate: Boolean, width: Int, numCompX: Int) = when {
calculate -> {
DoubleArray(width * numCompX).also {
cacheCosinesX[width * numCompX] = it
cacheCosinesX.put(width * numCompX, it)
}
}
else -> cacheCosinesX[width * numCompX]!!
else -> cacheCosinesX.get(width * numCompX)!!
}

private fun DoubleArray.getCos(
Expand Down