🔧 Refactor all resize functions into resize handler classes.

Author: SaadArdati

packages/box_transform/lib/src/resize_handlers/freeform_resizing.dart

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+part of 'resize_handler.dart';
+
+/// Handles resizing for [ResizeMode.freeform].
+final class FreeformResizeHandler extends ResizeHandler {
+  /// A default constructor for [FreeformResizeHandler].
+  const FreeformResizeHandler();
+
+  @override
+  (Box rect, Box largest, bool hasValidFlip) resize({
+    required Box initialRect,
+    required Box explodedRect,
+    required Box clampingRect,
+    required HandlePosition handle,
+    required Constraints constraints,
+    required Flip flip,
+  }) {
+    final flippedHandle = handle.flip(flip);
+    Box effectiveInitialRect = flipBox(initialRect, flip, handle);
+
+    Box newRect = Box.fromLTRB(
+      max(explodedRect.left, clampingRect.left),
+      max(explodedRect.top, clampingRect.top),
+      min(explodedRect.right, clampingRect.right),
+      min(explodedRect.bottom, clampingRect.bottom),
+    );
+
+    bool isValid = true;
+    if (!constraints.isUnconstrained) {
+      final constrainedWidth =
+      newRect.width.clamp(constraints.minWidth, constraints.maxWidth);
+      final constrainedHeight =
+      newRect.height.clamp(constraints.minHeight, constraints.maxHeight);
+
+      newRect = Box.fromHandle(
+        flippedHandle.anchor(effectiveInitialRect),
+        flippedHandle,
+        constrainedWidth,
+        constrainedHeight,
+      );
+
+      isValid = isValidBox(newRect, constraints, clampingRect);
+      if (!isValid) {
+        newRect = Box.fromHandle(
+          handle.anchor(initialRect),
+          handle,
+          !handle.isSide || handle.isHorizontal
+              ? constraints.minWidth
+              : constrainedWidth,
+          !handle.isSide || handle.isVertical
+              ? constraints.minHeight
+              : constrainedHeight,
+        );
+      }
+    }
+
+    // Not used but calculating it for returning correct largest box.
+    final Box area = getAvailableAreaForHandle(
+      rect: isValid ? effectiveInitialRect : initialRect,
+      handle: isValid ? flippedHandle : handle,
+      clampingRect: clampingRect,
+    );
+
+    return (newRect, area, isValid);
+  }
+}

packages/box_transform/lib/src/resize_handlers/resize_handler.dart

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+library resize_handlers;
+
+import 'dart:math';
+
+import '../../box_transform.dart';
+
+part 'freeform_resizing.dart';
+part 'symmetric_resizing.dart';
+part 'symmetric_scale_resizing.dart';
+part 'scale_resizing.dart';
+
+/// An abstract class the provides a common interface for all resize modes.
+sealed class ResizeHandler {
+  /// A default constructor for [ResizeHandler].
+  const ResizeHandler();
+
+  /// Resizes the given [explodedRect] to fit within the [clampingRect].
+  ///
+  /// Specifying the [handle] will determine how the [explodedRect] will be
+  /// resized.
+  ///
+  /// The [initialRect] helps determine the initial state of the rectangle.
+  ///
+  /// The [clampingRect] is the box that the [explodedRect] is not allowed
+  /// to go outside of when dragging or resizing.
+  ///
+  /// The [constraints] is the constraints that the [explodedRect] is not
+  /// allowed to shrink or grow beyond.
+  (Box, Box, bool) resize({
+    required Box initialRect,
+    required Box explodedRect,
+    required Box clampingRect,
+    required HandlePosition handle,
+    required Constraints constraints,
+    required Flip flip,
+  });
+}