Implement anchor and fix bugs with rigid body (#27)

Co-authored-by: Eric NGUYEN <enguyen@techform.fr>
Reviewed-on: https://git.siklos-chaneru.duckdns.org/Siklos/svg-layout-designer-react/pulls/27

src/Components/Editor/Behaviors/AnchorBehaviors.ts

@@ -0,0 +1,70 @@
+/**
+ * @module AnchorBehavior
+ *
+ * An anchor is a container that takes physical priority in the representation :
+ * - It cannot be moved by other rigid siblings container
+ * - It cannot be resized by any other siblings container
+ * - It cannot overlap any other siblings rigid container :
+ *  - overlapping container are shifted to the nearest available space/width
+ *  - or resized when there is no available space left other than theirs
+ *  - or lose their rigid body properties when there is no available space left)
+ * Meaning that:
+ * - Moving an anchor container will resize the width of an overlapping container
+ *   or make them lose their property as a rigid body
+ */
+
+import { IContainerModel } from '../../../Interfaces/IContainerModel';
+import { constraintBodyInsideUnallocatedWidth } from './RigidBodyBehaviors';
+
+/**
+ * Impose the container position to its siblings
+ * Apply the following modification to the overlapping rigid body container :
+ * @param container Container to impose its position
+ */
+export function ImposePosition(container: IContainerModel): IContainerModel {
+  if (container.parent === undefined ||
+    container.parent === null) {
+    return container;
+  }
+
+  const rigidBodies = container.parent.children.filter(
+    child => child.properties.isRigidBody && !child.properties.isAnchor
+  );
+
+  const overlappingContainers = getOverlappingContainers(container, rigidBodies);
+  for (const overlappingContainer of overlappingContainers) {
+    constraintBodyInsideUnallocatedWidth(overlappingContainer);
+  }
+  return container;
+}
+
+/**
+ * Returns the overlapping containers with container
+ * @param container A container
+ * @param containers A list of containers
+ * @returns A list of overlapping containers
+ */
+function getOverlappingContainers(
+  container: IContainerModel,
+  containers: IContainerModel[]
+): IContainerModel[] {
+  const min1 = container.properties.x;
+  const max1 = container.properties.x + Number(container.properties.width);
+  const overlappingContainers: IContainerModel[] = [];
+  for (const other of containers) {
+    if (other === container) {
+      continue;
+    }
+
+    const min2 = other.properties.x;
+    const max2 = other.properties.x + Number(other.properties.width);
+    const isOverlapping = Math.min(max1, max2) - Math.max(min1, min2) > 0;
+
+    if (!isOverlapping) {
+      continue;
+    }
+
+    overlappingContainers.push(other);
+  }
+  return overlappingContainers;
+}