update util functions

Author: SmartToolFactory

image/src/main/java/com/smarttoolfactory/image/util/OffsetUtil.kt

@@ -0,0 +1,12 @@
+package com.smarttoolfactory.image.util
+
+import androidx.compose.ui.geometry.Offset
+
+
+/**
+ * Coerce an [Offset] x value in [horizontalRange] and y value in [verticalRange]
+ */
+fun Offset.coerceIn(
+    horizontalRange: ClosedRange<Float>,
+    verticalRange: ClosedRange<Float>
+) = Offset(this.x.coerceIn(horizontalRange), this.y.coerceIn(verticalRange))

image/src/main/java/com/smarttoolfactory/image/util/RectUtil.kt

@@ -0,0 +1,46 @@
+package com.smarttoolfactory.image.util
+
+import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.geometry.Rect
+import androidx.compose.ui.geometry.Size
+
+/**
+ * Get rectangle of current transformation of [pan], [zoom] and current bounds of the Composable's
+ * selected area as [rectSelection] in a Bitmap with [bitmapWidth] and [bitmapHeight] which
+ * is displayed in a Composable with [containerWidth] and [containerHeight].
+ *
+ * This is getting area to display or crop based on the rectangle returned
+ *
+ * @param bitmapWidth width of the physical file
+ * @param bitmapHeight height of the physical file
+ * @param containerWidth width of the Composable that displays image
+ * @param containerHeight height of the Composable that displays image
+ * @param pan current translation of image via gestures or set values
+ * @param rectSelection bounds of the selected area in Composable. This can be used for selecting
+ * area via a cropping app
+ */
+fun getCropRect(
+    bitmapWidth: Int,
+    bitmapHeight: Int,
+    containerWidth: Float,
+    containerHeight: Float,
+    pan: Offset,
+    zoom: Float,
+    rectSelection: Rect
+): Rect {
+    val widthRatio = bitmapWidth / containerWidth
+    val heightRatio = bitmapHeight / containerHeight
+
+    val width = (widthRatio * rectSelection.width / zoom).coerceIn(0f, bitmapWidth.toFloat())
+    val height = (heightRatio * rectSelection.height / zoom).coerceIn(0f, bitmapHeight.toFloat())
+
+    val offsetXInBitmap = (widthRatio * (pan.x + rectSelection.left / zoom))
+        .coerceIn(0f, bitmapWidth - width)
+    val offsetYInBitmap = heightRatio * (pan.y + rectSelection.top / zoom)
+        .coerceIn(0f, bitmapHeight - height)
+
+    return Rect(
+        offset = Offset(offsetXInBitmap, offsetYInBitmap),
+        size = Size(width, height)
+    )
+}