From 3dbbe161c24a9edbbad82d605b463f723f14931a Mon Sep 17 00:00:00 2001
From: Fonger <5862369+Fonger@users.noreply.github.com>
Date: Tue, 16 May 2023 13:12:40 +0800
Subject: [PATCH 1/2] Improve decode speed by avoiding re-calculating same
 cosine value

---
 Kotlin/lib/src/main/java/com/wolt/blurhashkt/BlurHashDecoder.kt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Kotlin/lib/src/main/java/com/wolt/blurhashkt/BlurHashDecoder.kt b/Kotlin/lib/src/main/java/com/wolt/blurhashkt/BlurHashDecoder.kt
index 3278868b..eb45483a 100644
--- a/Kotlin/lib/src/main/java/com/wolt/blurhashkt/BlurHashDecoder.kt
+++ b/Kotlin/lib/src/main/java/com/wolt/blurhashkt/BlurHashDecoder.kt
@@ -114,9 +114,9 @@ object BlurHashDecoder {
                 var g = 0f
                 var b = 0f
                 for (j in 0 until numCompY) {
+                    val cosY = cosinesY.getCos(calculateCosY, j, numCompY, y, height)
                     for (i in 0 until numCompX) {
                         val cosX = cosinesX.getCos(calculateCosX, i, numCompX, x, width)
-                        val cosY = cosinesY.getCos(calculateCosY, j, numCompY, y, height)
                         val basis = (cosX * cosY).toFloat()
                         val color = colors[j * numCompX + i]
                         r += color[0] * basis

From fbfe95fe173526c268df07c5b323c5f5f7dfaa19 Mon Sep 17 00:00:00 2001
From: Fonger <5862369+Fonger@users.noreply.github.com>
Date: Tue, 16 May 2023 13:14:56 +0800
Subject: [PATCH 2/2] Improve decode speed by avoiding re-calculating same
 cosine value

---
 Swift/BlurHashDecode.swift | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Swift/BlurHashDecode.swift b/Swift/BlurHashDecode.swift
index 7fe3b398..70e8c3e8 100644
--- a/Swift/BlurHashDecode.swift
+++ b/Swift/BlurHashDecode.swift
@@ -37,8 +37,9 @@ extension UIImage {
                 var b: Float = 0
 
                 for j in 0 ..< numY {
+                    let basisY = cos(Float.pi * Float(y) * Float(j) / Float(height)
                     for i in 0 ..< numX {
-                        let basis = cos(Float.pi * Float(x) * Float(i) / Float(width)) * cos(Float.pi * Float(y) * Float(j) / Float(height))
+                        let basis = cos(Float.pi * Float(x) * Float(i) / Float(width)) * basisY)
                         let colour = colours[i + j * numX]
                         r += colour.0 * basis
                         g += colour.1 * basis