From 7a020f25a2890a277edcbd048359ac894372cf7a Mon Sep 17 00:00:00 2001
From: wonseok <dnjstjr245@gmail.com>
Date: Sat, 30 Dec 2023 23:34:40 +0900
Subject: [PATCH] Optimized memory caching for image picking in Android using
 LruCache (#35)

---
 .../picker/ImagePickerLauncher.android.kt     | 18 +++++----
 .../image/picker/PeekabooBitmapCache.kt       | 39 +++++++++++++++++++
 2 files changed, 50 insertions(+), 7 deletions(-)
 create mode 100644 peekaboo-image-picker/src/androidMain/kotlin/com/preat/peekaboo/image/picker/PeekabooBitmapCache.kt

diff --git a/peekaboo-image-picker/src/androidMain/kotlin/com/preat/peekaboo/image/picker/ImagePickerLauncher.android.kt b/peekaboo-image-picker/src/androidMain/kotlin/com/preat/peekaboo/image/picker/ImagePickerLauncher.android.kt
index c8117f1..2d0ed0a 100644
--- a/peekaboo-image-picker/src/androidMain/kotlin/com/preat/peekaboo/image/picker/ImagePickerLauncher.android.kt
+++ b/peekaboo-image-picker/src/androidMain/kotlin/com/preat/peekaboo/image/picker/ImagePickerLauncher.android.kt
@@ -25,6 +25,7 @@ import androidx.activity.result.contract.ActivityResultContracts
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.remember
 import androidx.compose.ui.platform.LocalContext
+import com.preat.peekaboo.image.picker.PeekabooBitmapCache.bitmapToByteArray
 import com.preat.peekaboo.image.picker.SelectionMode.Companion.INFINITY
 import kotlinx.coroutines.CoroutineScope
 import java.io.ByteArrayOutputStream
@@ -166,11 +167,13 @@ private fun resizeImage(
     width: Int,
     height: Int,
 ): ByteArray? {
+    val cacheKey = "${uri}_w${width}_h$height"
+    PeekabooBitmapCache.instance.get(cacheKey)?.let { cachedBitmap ->
+        return bitmapToByteArray(cachedBitmap)
+    }
+
     context.contentResolver.openInputStream(uri)?.use { inputStream ->
-        val options =
-            BitmapFactory.Options().apply {
-                inJustDecodeBounds = true
-            }
+        val options = BitmapFactory.Options().apply { inJustDecodeBounds = true }
         BitmapFactory.decodeStream(inputStream, null, options)
 
         var inSampleSize = 1
@@ -182,11 +185,12 @@ private fun resizeImage(
         options.inSampleSize = inSampleSize
 
         context.contentResolver.openInputStream(uri)?.use { scaledInputStream ->
-            val scaledBitmap = BitmapFactory.decodeStream(scaledInputStream, null, options)
-            if (scaledBitmap != null) {
+            BitmapFactory.decodeStream(scaledInputStream, null, options)?.let { scaledBitmap ->
                 ByteArrayOutputStream().use { byteArrayOutputStream ->
                     scaledBitmap.compress(Bitmap.CompressFormat.JPEG, 100, byteArrayOutputStream)
-                    return byteArrayOutputStream.toByteArray()
+                    val byteArray = byteArrayOutputStream.toByteArray()
+                    PeekabooBitmapCache.instance.put(cacheKey, scaledBitmap)
+                    return byteArray
                 }
             }
         }
diff --git a/peekaboo-image-picker/src/androidMain/kotlin/com/preat/peekaboo/image/picker/PeekabooBitmapCache.kt b/peekaboo-image-picker/src/androidMain/kotlin/com/preat/peekaboo/image/picker/PeekabooBitmapCache.kt
new file mode 100644
index 0000000..9d4a708
--- /dev/null
+++ b/peekaboo-image-picker/src/androidMain/kotlin/com/preat/peekaboo/image/picker/PeekabooBitmapCache.kt
@@ -0,0 +1,39 @@
+/*
+ * Copyright 2023 onseok
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.preat.peekaboo.image.picker
+
+import android.graphics.Bitmap
+import android.util.LruCache
+import java.io.ByteArrayOutputStream
+
+internal object PeekabooBitmapCache {
+    internal val instance: LruCache<String, Bitmap> by lazy {
+        LruCache<String, Bitmap>(calculateMemoryCacheSize())
+    }
+
+    private fun calculateMemoryCacheSize(): Int {
+        val maxMemory = Runtime.getRuntime().maxMemory() / 1024
+        val cacheSize = (maxMemory * 0.25).toInt()
+        return cacheSize.coerceAtLeast(1024 * 1024)
+    }
+
+    internal fun bitmapToByteArray(bitmap: Bitmap): ByteArray {
+        ByteArrayOutputStream().use { stream ->
+            bitmap.compress(Bitmap.CompressFormat.JPEG, 100, stream)
+            return stream.toByteArray()
+        }
+    }
+}