dm-139

app/src/main/java/com/example/login_v3/home/Message/UI/Detail/Message_Component/ImageLightbox.kt

@@ -2,14 +2,22 @@ package com.example.login_v3.home.Message.UI.Detail.Message_Component
 
 import androidx.compose.foundation.background
 import androidx.compose.foundation.clickable
+import androidx.compose.foundation.gestures.detectTransformGestures
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.fillMaxHeight
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.geometry.Offset
 import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.graphicsLayer
+import androidx.compose.ui.input.pointer.pointerInput
 import androidx.compose.ui.layout.ContentScale
 import androidx.compose.ui.window.Dialog
 import androidx.compose.ui.window.DialogProperties
@@ -20,28 +28,57 @@ fun ImageLightbox(
     imageUrl: String,
     onDismiss: () -> Unit
 ) {
-    // 使用 Dialog 才能真正做到全螢幕蓋住 TopBar 與 BottomBar
     Dialog(
         onDismissRequest = onDismiss,
         properties = DialogProperties(
-            usePlatformDefaultWidth = false // 關閉預設寬度限制，達到真正全螢幕
+            usePlatformDefaultWidth = false
         )
     ) {
+        // 1. 宣告手勢狀態
+        var scale by remember { mutableStateOf(1f) }
+        var offset by remember { mutableStateOf(Offset.Zero) }
+
         Box(
             modifier = Modifier
                 .fillMaxSize()
-                .background(Color.Black.copy(alpha = 0.9f)) // 質感黑半透明背景
-                .clickable { onDismiss() }, // 點擊背景任何地方都能關閉
+                .background(Color.Black.copy(alpha = 0.9f))
+                // 💡 如果圖片處於放大狀態，點擊背景不觸發關閉，方便使用者操作；縮回原大小時點擊背景才關閉
+                .clickable(enabled = scale == 1f) { onDismiss() },
             contentAlignment = Alignment.Center
         ) {
             AsyncImage(
                 model = imageUrl,
                 contentDescription = "放大檢視圖片",
-                contentScale = ContentScale.Fit, // 確保整張圖片能完整塞進螢幕
+                contentScale = ContentScale.Fit,
                 modifier = Modifier
                     .fillMaxWidth()
-                    .fillMaxHeight(0.85f) // 留一點上下操作空間
-                    .clickable(enabled = false) { } // 阻止點擊圖片本身時觸發關閉
+                    .fillMaxHeight(0.85f)
+                    // 2. 透過 graphicsLayer 將手勢狀態反映到畫面上
+                    .graphicsLayer(
+                        scaleX = scale,
+                        scaleY = scale,
+                        translationX = offset.x,
+                        translationY = offset.y
+                    )
+                    // 3. 監聽雙指與單指手勢
+                    .pointerInput(Unit) {
+                        detectTransformGestures { _, pan, zoom, _ ->
+                            // 計算新的縮放值，並限制在 1倍 到 4倍 之間
+                            val newScale = (scale * zoom).coerceIn(1f, 4f)
+
+                            // 計算新的位移值（只有在放大狀態下才允許平移拖曳）
+                            val newOffset = if (newScale > 1f) {
+                                offset + pan
+                            } else {
+                                Offset.Zero // 縮回 1 倍時自動歸零
+                            }
+
+                            scale = newScale
+                            offset = newOffset
+                        }
+                    }
+                    // 阻斷點擊圖片本身會關閉 Dialog 的行為
+                    .clickable(enabled = false) { }
             )
         }
     }