move remember functions for zoom states to separate file

Author: SmartToolFactory

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

@@ -1,16 +1,8 @@
 package com.smarttoolfactory.image.zoom
 
-import androidx.compose.animation.core.exponentialDecay
-import androidx.compose.runtime.*
-import androidx.compose.ui.Modifier
-import androidx.compose.ui.geometry.Offset
-import androidx.compose.ui.geometry.Rect
-import androidx.compose.ui.geometry.Size
-import androidx.compose.ui.input.pointer.PointerInputChange
-import androidx.compose.ui.input.pointer.util.VelocityTracker
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.remember
 import androidx.compose.ui.unit.IntSize
-import kotlinx.coroutines.coroutineScope
-
 
 /**
  * * Create and [remember] the [ZoomState] based on the currently appropriate transform
@@ -32,7 +24,8 @@ import kotlinx.coroutines.coroutineScope
  */
 @Composable
 fun rememberEnhancedZoomState(
-    size: IntSize,
+    imageSize: IntSize,
+    containerSize: IntSize,
     initialZoom: Float = 1f,
     initialRotation: Float = 0f,
     minZoom: Float = 1f,
@@ -45,9 +38,9 @@ fun rememberEnhancedZoomState(
 ): EnhancedZoomState {
     return remember(key1) {
         EnhancedZoomState(
-            size = size,
+            imageSize = imageSize,
+            containerSize = containerSize,
             initialZoom = initialZoom,
-            initialRotation = initialRotation,
             minZoom = minZoom,
             maxZoom = maxZoom,
             zoomEnabled = zoomEnabled,
@@ -67,7 +60,6 @@ fun rememberEnhancedZoomState(
  * values
  *
  * @param initialZoom zoom set initially
- * @param initialRotation rotation set initially
  * @param minZoom minimum zoom value this Composable can possess
  * @param maxZoom maximum zoom value this Composable can possess
  * @param limitPan limits pan to bounds of parent Composable. Using this flag prevents creating
@@ -78,9 +70,9 @@ fun rememberEnhancedZoomState(
  */
 @Composable
 fun rememberEnhancedZoomState(
-    size: IntSize,
+    imageSize: IntSize,
+    containerSize: IntSize,
     initialZoom: Float = 1f,
-    initialRotation: Float = 0f,
     minZoom: Float = 1f,
     maxZoom: Float = 5f,
     zoomEnabled: Boolean = true,
@@ -92,9 +84,9 @@ fun rememberEnhancedZoomState(
 ): EnhancedZoomState {
     return remember(key1, key2) {
         EnhancedZoomState(
-            size = size,
+            imageSize = imageSize,
+            containerSize = containerSize,
             initialZoom = initialZoom,
-            initialRotation = initialRotation,
             minZoom = minZoom,
             maxZoom = maxZoom,
             zoomEnabled = zoomEnabled,
@@ -110,7 +102,6 @@ fun rememberEnhancedZoomState(
  * configuration to allow changing pan, zoom, and rotation.
  *
  * @param initialZoom zoom set initially
- * @param initialRotation rotation set initially
  * @param minZoom minimum zoom value this Composable can possess
  * @param maxZoom maximum zoom value this Composable can possess
  * @param limitPan limits pan to bounds of parent Composable. Using this flag prevents creating
@@ -124,9 +115,9 @@ fun rememberEnhancedZoomState(
  */
 @Composable
 fun rememberEnhancedZoomState(
-    size: IntSize,
+    imageSize: IntSize,
+    containerSize: IntSize,
     initialZoom: Float = 1f,
-    initialRotation: Float = 0f,
     minZoom: Float = 1f,
     maxZoom: Float = 5f,
     zoomEnabled: Boolean = true,
@@ -137,9 +128,9 @@ fun rememberEnhancedZoomState(
 ): EnhancedZoomState {
     return remember(keys) {
         EnhancedZoomState(
-            size = size,
+            imageSize = imageSize,
+            containerSize = containerSize,
             initialZoom = initialZoom,
-            initialRotation = initialRotation,
             minZoom = minZoom,
             maxZoom = maxZoom,
             zoomEnabled = zoomEnabled,
@@ -148,227 +139,4 @@ fun rememberEnhancedZoomState(
             limitPan = limitPan
         )
     }
-}
-
-/**
- *  * State of the zoom. Allows the developer to change zoom, pan,  translate,
- *  or get current state by
- * calling methods on this object. To be hosted and passed to [Modifier.zoom]
- * @param limitPan limits pan to bounds of parent Composable. Using this flag prevents creating
- * empty space on sides or edges of parent.
-
- * @param zoomEnabled when set to true zoom is enabled
- * @param panEnabled when set to true pan is enabled
- * @param rotationEnabled when set to true rotation is enabled
- */
-open class EnhancedZoomState constructor(
-    var size: IntSize,
-    initialZoom: Float = 1f,
-    initialRotation: Float = 0f,
-    minZoom: Float = .5f,
-    maxZoom: Float = 5f,
-    override var zoomEnabled: Boolean = true,
-    override var panEnabled: Boolean = true,
-    override var rotationEnabled: Boolean = true,
-    override var limitPan: Boolean = false
-) : ZoomState(
-    initialZoom, initialRotation, minZoom, maxZoom, zoomEnabled
-) {
-
-    val isZooming = animatableZoom.isRunning
-    val isPanning = animatablePan.isRunning
-    val isRotating = animatableRotation.isRunning
-
-    val isAnimationRunning = isZooming || isPanning || isRotating
-
-    var rectDraw =
-        Rect(offset = Offset.Zero, size = Size(size.width.toFloat(), size.height.toFloat()))
-    var rectCrop by mutableStateOf(rectDraw.copy())
-
-    private val velocityTracker = VelocityTracker()
-
-    val enhancedZoomData: EnhancedZoomData
-        get() = EnhancedZoomData(
-            zoom = animatableZoom.targetValue,
-            pan = animatablePan.targetValue,
-            rotation = animatableRotation.targetValue,
-            drawRect = rectDraw,
-            cropRect = rectCrop
-        )
-
-    private fun getBounds(): Offset {
-        return getBounds(size)
-    }
-
-    // Touch gestures
-    open suspend fun onDown(change: PointerInputChange) {}
-
-    open suspend fun onMove(change: PointerInputChange) {}
-
-    open suspend fun onUp(change: PointerInputChange) {}
-
-    // Transform Gestures
-    internal open suspend fun onGestureStart(change: PointerInputChange) {}
-
-    internal open suspend fun onGesture(
-        centroid: Offset,
-        pan: Offset,
-        zoom: Float,
-        rotation: Float,
-        mainPointer: PointerInputChange,
-        changes: List<PointerInputChange>
-    ) = coroutineScope {
-
-        updateZoomState(
-            size = size,
-            gestureZoom = zoom,
-            gesturePan = pan,
-            gestureRotate = rotation
-        )
-
-        // Fling Gesture
-        if (changes.size == 1) {
-            addPosition(
-                mainPointer.uptimeMillis,
-                mainPointer.position
-            )
-        }
-    }
-
-    internal suspend fun onGestureEnd(onAnimationEnd: () -> Unit) {
-        if (zoom > 1) {
-            fling()
-        }
-        resetToValidBounds()
-        onAnimationEnd()
-    }
-
-    // Double Tap
-    internal suspend fun onDoubleTap(onAnimationEnd: () -> Unit) {
-        resetTracking()
-        resetWithAnimation()
-        onAnimationEnd()
-    }
-
-    /**
-     * Resets to bounds with animation and resets tracking for fling animation
-     */
-    private suspend fun resetToValidBounds() {
-        val zoom = zoom.coerceAtLeast(1f)
-        val bounds = getBounds()
-
-        val pan = Offset(
-            pan.x.coerceIn(-bounds.x, bounds.x),
-            pan.y.coerceIn(-bounds.y, bounds.y)
-        )
-
-        resetWithAnimation(pan = pan, zoom = zoom)
-        resetTracking()
-    }
-
-
-    // Fling gesture
-    private fun addPosition(timeMillis: Long, position: Offset) {
-        velocityTracker.addPosition(
-            timeMillis = timeMillis,
-            position = position
-        )
-    }
-
-    private suspend fun fling() {
-        val velocityTracker = velocityTracker.calculateVelocity()
-        val velocity = Offset(velocityTracker.x, velocityTracker.y)
-
-        animatablePan.animateDecay(
-            velocity,
-            exponentialDecay(
-                absVelocityThreshold = 20f
-            )
-        )
-    }
-
-    private fun resetTracking() {
-        velocityTracker.resetTracking()
-    }
-
-    override suspend fun updateZoomState(
-        size: IntSize,
-        gesturePan: Offset,
-        gestureZoom: Float,
-        gestureRotate: Float,
-    ) {
-        val zoom = (zoom * gestureZoom).coerceIn(zoomMin, zoomMax)
-        val rotation = if (rotationEnabled) {
-            rotation + gestureRotate
-        } else {
-            0f
-        }
-
-        if (panEnabled) {
-            val newOffset = pan + gesturePan.times(zoom)
-            snapPanTo(newOffset)
-        }
-
-        if (zoomEnabled) {
-            snapZoomTo(zoom)
-        }
-
-        if (rotationEnabled) {
-            snapRotationTo(rotation)
-        }
-
-        val width = size.width
-        val height = size.height
-        val offsetX = (width * (zoom - 1) / 2f).coerceAtLeast(0f) - pan.x
-        val offsetY = (height * (zoom - 1) / 2f).coerceAtLeast(0f) - pan.y
-
-        rectCrop = getCropRect(
-            bitmapWidth = 1024,
-            bitmapHeight = 768,
-            imageWidth = width.toFloat(),
-            imageHeight = height.toFloat(),
-            pan = Offset(
-                x = offsetX / zoom,
-                y = offsetY / zoom,
-            ),
-            zoom = zoom,
-            rectBounds = rectDraw
-        )
-        println(
-            "🔥 EnhancedZoomState updateZoomState()\n" +
-                    "offsetX: $offsetX, offsetY: $offsetY" +
-                    "size: $size, pan: $pan, zoom: $zoom\n" +
-                    "rectCrop: $rectCrop"
-        )
-    }
-}
-
-/**
- * Get rectangle of current transformation of [pan], [zoom] and current bounds of the Composable's
- * selected area as [rectBounds]
- */
-fun getCropRect(
-    bitmapWidth: Int,
-    bitmapHeight: Int,
-    imageWidth: Float,
-    imageHeight: Float,
-    pan: Offset,
-    zoom: Float,
-    rectBounds: Rect
-): Rect {
-    val widthRatio = bitmapWidth / imageWidth
-    val heightRatio = bitmapHeight / imageHeight
-
-    val width = (widthRatio * rectBounds.width / zoom).coerceIn(0f, bitmapWidth.toFloat())
-    val height = (heightRatio * rectBounds.height / zoom).coerceIn(0f, bitmapHeight.toFloat())
-
-    val offsetXInBitmap = (widthRatio * (pan.x + rectBounds.left / zoom))
-        .coerceIn(0f, bitmapWidth - width)
-    val offsetYInBitmap = heightRatio * (pan.y + rectBounds.top / zoom)
-        .coerceIn(0f, bitmapHeight - height)
-
-    return Rect(
-        offset = Offset(offsetXInBitmap, offsetYInBitmap),
-        size = Size(width, height)
-    )
 }