AttachmentViewer: Make it zoomable using a library

app/build.gradle

@@ -83,7 +83,14 @@ dependencies {
     // Jetpack Compose Integration
     implementation "androidx.navigation:navigation-compose:$nav_version"
 
-    implementation 'androidx.activity:activity-compose:1.4.3'
+    // Jetpack Compose
+    def compose_version = "1.4.3"
+    implementation "androidx.compose.ui:ui:$compose_version"
+    implementation "androidx.compose.material:material:$compose_version"
+    implementation "androidx.compose.foundation:foundation:$compose_version"
+
+
+    implementation "androidx.activity:activity-compose:$compose_version"
 
     // Lifecycle
     def lifecycle_version = "2.6.1"
@@ -91,9 +98,6 @@ dependencies {
     implementation "androidx.lifecycle:lifecycle-runtime-ktx:$lifecycle_version"
     implementation "androidx.lifecycle:lifecycle-viewmodel-compose:$lifecycle_version"
 
-    implementation "androidx.compose.ui:ui:1.4.3"
-    implementation 'androidx.compose.material:material:1.4.3'
-    implementation "androidx.compose.foundation:foundation:1.4.3"
 
     // Hilt (dependency injection)
     implementation "com.google.dagger:hilt-android:${hilt_version}"
@@ -107,7 +111,10 @@ dependencies {
     // Disk LRU Cache
     implementation "com.jakewharton:disklrucache:2.0.2"
 
-    debugImplementation 'androidx.compose.ui:ui-tooling:1.4.3'
+    // Zooming in images
+    implementation "net.engawapg.lib:zoomable:$compose_version"
+
+    debugImplementation "androidx.compose.ui:ui-tooling:$compose_version"
 }
 
 // Allow references to generated code

app/src/main/java/net/buzzert/kordophonedroid/ui/attachments/AttachmentViewer.kt

@@ -1,9 +1,17 @@
 package net.buzzert.kordophonedroid.ui.attachments
 
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
 import androidx.compose.material.Scaffold
 import androidx.compose.material.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalContext
 import androidx.hilt.navigation.compose.hiltViewModel
@@ -11,28 +19,44 @@ import coil.compose.AsyncImage
 import coil.request.ImageRequest
 import net.buzzert.kordophonedroid.ui.LocalNavController
 import net.buzzert.kordophonedroid.ui.theme.KordophoneTopAppBar
+import net.engawapg.lib.zoomable.rememberZoomState
+import net.engawapg.lib.zoomable.zoomable
 
 @Composable
 fun AttachmentViewer(
     attachmentGuid: String,
     attachmentViewModel: AttachmentViewModel = hiltViewModel()
 ) {
+    var topBarVisible = remember { mutableStateOf(true) }
     val navController = LocalNavController.current
     Scaffold(topBar = {
         KordophoneTopAppBar(
             title = "Attachment",
-            backAction = { navController.popBackStack() }
+            backAction = { navController.popBackStack() },
+            visible = topBarVisible.value
         )
     }) { padding ->
+        val zoomState = rememberZoomState()
         val data = AttachmentFetchData(attachmentGuid, preview = false)
-        AsyncImage(
-            model = ImageRequest.Builder(LocalContext.current)
-                .data(data)
-                .crossfade(true)
-                .build(),
-            contentDescription = "",
-            modifier = Modifier
-                .padding(padding)
-        )
+        Column(modifier = Modifier.padding(padding)) {
+            Spacer(modifier = Modifier.weight(1f))
+
+            AsyncImage(
+                model = ImageRequest.Builder(LocalContext.current)
+                    .data(data)
+                    .crossfade(true)
+                    .build(),
+                contentDescription = "",
+                modifier = Modifier
+                    .zoomable(zoomState)
+                    .fillMaxWidth()
+                    .align(Alignment.CenterHorizontally)
+                    .clickable {
+                        topBarVisible.value = !topBarVisible.value
+                    }
+            )
+
+            Spacer(modifier = Modifier.weight(1f))
+        }
     }
 }

app/src/main/java/net/buzzert/kordophonedroid/ui/theme/Theme.kt

@@ -1,5 +1,8 @@
 package net.buzzert.kordophonedroid.ui.theme
 
+import androidx.compose.animation.AnimatedVisibility
+import androidx.compose.animation.slideInVertically
+import androidx.compose.animation.slideOutVertically
 import androidx.compose.foundation.isSystemInDarkTheme
 import androidx.compose.material.Icon
 import androidx.compose.material.IconButton
@@ -55,20 +58,26 @@ fun KordophoneTheme(
 
 
 @Composable
-fun KordophoneTopAppBar(title: String, backAction: () -> Unit) {
-    TopAppBar(
-        title = {
-            Text(
-                text = title,
-                maxLines = 1,
-                overflow = TextOverflow.Ellipsis,
-            )
-        },
-        navigationIcon = {
-            IconButton(onClick = backAction) {
-                Icon(Icons.Filled.ArrowBack, null)
-            }
-        },
-        actions = {}
-    )
+fun KordophoneTopAppBar(title: String, backAction: () -> Unit, visible: Boolean = true) {
+    AnimatedVisibility(
+        visible = visible,
+        enter = slideInVertically { -it },
+        exit = slideOutVertically { -it },
+    ) {
+        TopAppBar(
+            title = {
+                Text(
+                    text = title,
+                    maxLines = 1,
+                    overflow = TextOverflow.Ellipsis,
+                )
+            },
+            navigationIcon = {
+                IconButton(onClick = backAction) {
+                    Icon(Icons.Filled.ArrowBack, null)
+                }
+            },
+            actions = {}
+        )
+    }
 }