update AnimatedZoomLayout with SubcomposeLayout to match content dimensions

SubcomposeLayout is used for getting content dimensions and passing these dimensions to AnimatedZoomState for valid pan bounding based on content size

Author: SmartToolFactory

image/src/main/java/com/smarttoolfactory/image/DimensionSubcomposeLayout.kt

@@ -17,8 +17,9 @@ import androidx.compose.ui.unit.Constraints
  * some circumstances
  *
  * @param placeMainContent when set to true places main content. Set this flag to false
- * when dimensions of content is required for inside [mainContent]. Just measure it then pass
- * its dimensions to any child composable
+ * when dimensions of content is required for [mainContent]. Measure [mainContent] then pass
+ * its dimensions to any child composable but don't place it because we already place
+ * it inside [dependentContent]
  *
  * @param mainContent Composable is used for calculating size and pass it
  * to Composables that depend on it
@@ -30,7 +31,7 @@ import androidx.compose.ui.unit.Constraints
 @Composable
 fun DimensionSubcomposeLayout(
     modifier: Modifier = Modifier,
-    placeMainContent:Boolean = true,
+    placeMainContent: Boolean = true,
     mainContent: @Composable () -> Unit,
     dependentContent: @Composable (Size) -> Unit
 ) {
@@ -41,7 +42,7 @@ fun DimensionSubcomposeLayout(
         // Subcompose(compose only a section) main content and get Placeable
         val mainPlaceables: List<Placeable> = subcompose(SlotsEnum.Main, mainContent)
             .map {
-                it.measure(constraints)
+                it.measure(constraints.copy(minWidth = 0, minHeight = 0))
             }
 
         // Get max width and height of main component
@@ -63,7 +64,7 @@ fun DimensionSubcomposeLayout(
 
         layout(maxWidth, maxHeight) {
 
-            if(placeMainContent){
+            if (placeMainContent) {
                 mainPlaceables.forEach { placeable: Placeable ->
                     placeable.placeRelative(0, 0)
                 }

image/src/main/java/com/smarttoolfactory/image/zoom/AnimatedZoomLayout.kt

@@ -2,34 +2,43 @@ package com.smarttoolfactory.image.zoom
 
 import androidx.compose.foundation.border
 import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.layout.Measurable
+import androidx.compose.ui.layout.Placeable
+import androidx.compose.ui.layout.SubcomposeLayout
 import androidx.compose.ui.platform.LocalDensity
+import androidx.compose.ui.unit.Constraints
 import androidx.compose.ui.unit.DpSize
 import androidx.compose.ui.unit.dp
-import com.smarttoolfactory.image.DimensionSubcomposeLayout
+import com.smarttoolfactory.image.SlotsEnum
 
+
+/**
+ * Layout that can zoom, rotate, pan its content with fling and moving back to bounds animation.
+ */
 @Composable
 fun AnimatedZoomLayout(
     modifier: Modifier = Modifier,
     content: @Composable () -> Unit
 ) {
 
-    val density = LocalDensity.current
-
-    DimensionSubcomposeLayout(
-        placeMainContent = false,
+    AnimatedZoomSubcomposeLayout(
+        modifier = modifier,
         mainContent = { content() }
     ) {
         Box(
-            modifier
+            Modifier
+                .fillMaxSize()
                 .border(5.dp, Color.Red)
                 .animatedZoom(
                     animatedZoomState = rememberAnimatedZoomState(
                         minZoom = .5f,
-                        maxZoom = 30f
+                        maxZoom = 30f,
+                        contentSize = it
                     ),
                 ),
             contentAlignment = Alignment.Center
@@ -39,25 +48,55 @@ fun AnimatedZoomLayout(
     }
 }
 
+/**
+ * SubcomposeLayout for getting dimensions of [mainContent] while laying out with [modifier]
+ * Use of this layout is suitable when size of parent doesn't match content
+ * and size [mainContent] is required inside [dependentContent] to use [mainContent] size
+ * as reference or dimensions for child composables inside [dependentContent].
+ *
+ */
 @Composable
-fun AnimatedZoomLayout2(
+private fun AnimatedZoomSubcomposeLayout(
     modifier: Modifier = Modifier,
-    content: @Composable () -> Unit
+    mainContent: @Composable () -> Unit,
+    dependentContent: @Composable (DpSize) -> Unit
 ) {
 
-    Box(
-        modifier
-            .border(4.dp, Color.Red)
-            .animatedZoom(
-                animatedZoomState = rememberAnimatedZoomState(
-                    minZoom = .5f,
-                    maxZoom = 30f,
-                    contentSize = DpSize(200.dp, 200.dp)
-                )
-            ),
-        contentAlignment = Alignment.Center
-    ) {
-        content()
-    }
+    val density = LocalDensity.current
+
+    SubcomposeLayout(
+        modifier = modifier
+    ) { constraints: Constraints ->
+
+        // Subcompose(compose only a section) main content and get Placeable
+        val mainPlaceables: List<Placeable> = subcompose(SlotsEnum.Main, mainContent)
+            .map {
+                it.measure(constraints.copy(minWidth = 0, minHeight = 0))
+            }
+
+        // Get max width and height of main component
+        var maxWidth = 0
+        var maxHeight = 0
 
-}
+        mainPlaceables.forEach { placeable: Placeable ->
+            maxWidth += placeable.width
+            maxHeight = placeable.height
+        }
+
+        val dependentPlaceables: List<Placeable> = subcompose(SlotsEnum.Dependent) {
+            val dpSize = density.run { DpSize(maxWidth.toDp(), maxHeight.toDp()) }
+            dependentContent(dpSize)
+        }
+            .map { measurable: Measurable ->
+                measurable.measure(constraints)
+            }
+
+        layout(constraints.maxWidth, constraints.maxHeight) {
+
+
+            dependentPlaceables.forEach { placeable: Placeable ->
+                placeable.placeRelative(0, 0)
+            }
+        }
+    }
+}