src/Components/App/MenuActions.ts

@@ -2,7 +2,7 @@ import { Dispatch, SetStateAction } from 'react';
 import { IConfiguration } from '../../Interfaces/IConfiguration';
 import { ContainerModel } from '../../Interfaces/IContainerModel';
 import { fetchConfiguration } from '../API/api';
-import { IEditorState } from "../../Interfaces/IEditorState";
+import { IEditorState } from '../../Interfaces/IEditorState';
 import { LoadState } from './Load';
 
 export function NewEditor(
@@ -23,6 +23,7 @@ export function NewEditor(
           width: configuration.MainContainer.Width,
           height: configuration.MainContainer.Height,
           isRigidBody: false,
+          isAnchor: false,
           fillOpacity: 0,
           stroke: 'black'
         }

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;
+}

src/Components/Editor/Behaviors/RigidBodyBehaviors.ts

@@ -1,5 +1,13 @@
-import { IContainerModel } from '../../Interfaces/IContainerModel';
+/**
-import { ISizePointer } from '../../Interfaces/ISizePointer';
+ * @module RigidBodyBehaviors
+ * Apply the following contraints to the `container` :
+ * - The container must be kept inside its parent
+ * - The container must find an unallocated space within the parent
+ * If the contraints fails, an error message will be returned
+ */
+
+import { IContainerModel } from '../../../Interfaces/IContainerModel';
+import { ISizePointer } from '../../../Interfaces/ISizePointer';
 
 /**
  * "Transform the container into a rigid body"
@@ -82,7 +90,7 @@ function constraintBodyInsideSpace(
   if (containerX < x) {
     containerProperties.x = x;
   }
-  if (containerX + containerWidth > width) {
+  if (containerX + containerWidth > x + width) {
     containerProperties.x = x + width - containerWidth;
   }
 
@@ -90,7 +98,7 @@ function constraintBodyInsideSpace(
   if (containerY < y) {
     containerProperties.y = y;
   }
-  if (containerY + containerHeight > height) {
+  if (containerY + containerHeight > y + height) {
     containerProperties.y = y + height - containerHeight;
   }
 
@@ -104,7 +112,7 @@ function constraintBodyInsideSpace(
  * @param container
  * @returns Updated container
  */
-function constraintBodyInsideUnallocatedWidth(
+export function constraintBodyInsideUnallocatedWidth(
   container: IContainerModel
 ): IContainerModel {
   if (container.parent === null) {
@@ -114,12 +122,7 @@ function constraintBodyInsideUnallocatedWidth(
   // Get the available spaces of the parent
   const availableWidths = getAvailableWidths(container.parent, container);
   const containerX = Number(container.properties.x);
-
+  const containerWidth = Number(container.properties.width);
-  // Sort the available width to find the closest one
-  availableWidths.sort(
-    (width1, width2) =>
-      Math.abs(width1.x - containerX) - Math.abs(width2.x - containerX)
-  );
 
   // Check if there is still some space
   if (availableWidths.length === 0) {
@@ -128,6 +131,24 @@ function constraintBodyInsideUnallocatedWidth(
     );
   }
 
+  const middle = containerX + containerWidth / 2;
+  // Sort the available width to find the space with the closest position
+  availableWidths.sort(
+    (width1, width2) => {
+      let compared1X = width1.x;
+      if (width1.x < containerX) {
+        compared1X = width1.x + width1.width - containerWidth;
+      }
+
+      let compared2X = width2.x;
+      if (width2.x < containerX) {
+        compared2X = width2.x + width2.width - containerWidth;
+      }
+
+      return Math.abs(compared1X - middle) - Math.abs(compared2X - middle);
+    }
+  );
+
   // Check if the container actually fit inside
   // It will usually fit if it was alrady fitting
   const availableWidthFound = availableWidths.find((width) =>
@@ -179,17 +200,18 @@ function getAvailableWidths(
   const width = Number(container.properties.width);
   let unallocatedSpaces: ISizePointer[] = [{ x, width }];
 
-  // We will only uses containers that also have the rigid bodies
+  // We will only uses containers that also are rigid or are anchors
-  // as out-of-bound or enormouse containers should be ignored
+  const solidBodies = container.children.filter(
-  const rigidBodies = container.children.filter(
+    (child) => child.properties.isRigidBody || child.properties.isAnchor
-    (child) => child.properties.isRigidBody
   );
 
-  for (const child of rigidBodies) {
+  for (const child of solidBodies) {
     // Ignore the exception
     if (child === exception) {
       continue;
     }
+    const childX = child.properties.x;
+    const childWidth = Number(child.properties.width);
 
     // get the space of the child that is inside the parent
     let newUnallocatedSpace: ISizePointer[] = [];
@@ -202,8 +224,8 @@ function getAvailableWidths(
       const newUnallocatedWidths = getAvailableWidthsTwoLines(
         unallocatedSpace.x,
         unallocatedSpace.x + unallocatedSpace.width,
-        child.properties.x,
+        childX,
-        child.properties.x + Number(child.properties.width)
+        childX + childWidth
       );
 
       // Concat the new list of SizePointer pointing to availables spaces
@@ -218,39 +240,49 @@ function getAvailableWidths(
 
 /**
  * Returns the unallocated widths between two lines in 1D
- * @param min1 left of the first line
+ * @param unalloctedSpaceLeft left of the first line
- * @param max1 rigth of the first line
+ * @param unallocatedSpaceRight rigth of the first line
- * @param min2 left of the second line
+ * @param rectLeft left of the second line
- * @param max2 right of the second line
+ * @param rectRight right of the second line
  * @returns Available widths
  */
 function getAvailableWidthsTwoLines(
-  min1: number,
+  unalloctedSpaceLeft: number,
-  max1: number,
+  unallocatedSpaceRight: number,
-  min2: number,
+  rectLeft: number,
-  max2: number
+  rectRight: number
 ): ISizePointer[] {
-  if (min2 < min1 && max2 > max1) {
+  if (unallocatedSpaceRight < rectLeft ||
+    unalloctedSpaceLeft > rectRight
+  ) {
+    // object 1 and 2 are not overlapping
+    return [{
+      x: unalloctedSpaceLeft,
+      width: unallocatedSpaceRight - unalloctedSpaceLeft
+    }];
+  }
+
+  if (rectLeft < unalloctedSpaceLeft && rectRight > unallocatedSpaceRight) {
     // object 2 is overlapping full width
     return [];
   }
 
-  if (min1 >= min2) {
+  if (unalloctedSpaceLeft >= rectLeft) {
     // object 2 is partially overlapping on the left
     return [
       {
-        x: max2,
+        x: rectRight,
-        width: max1 - max2
+        width: unallocatedSpaceRight - rectRight
       }
     ];
   }
 
-  if (max2 >= max1) {
+  if (rectRight >= unallocatedSpaceRight) {
     // object 2 is partially overlapping on the right
     return [
       {
-        x: min2,
+        x: unalloctedSpaceLeft,
-        width: max2 - min1
+        width: rectRight - unalloctedSpaceLeft
       }
     ];
   }
@@ -258,12 +290,12 @@ function getAvailableWidthsTwoLines(
   // object 2 is overlapping in the middle
   return [
     {
-      x: min1,
+      x: unalloctedSpaceLeft,
-      width: min2 - min1
+      width: rectLeft - unalloctedSpaceLeft
     },
     {
-      x: min2,
+      x: rectRight,
-      width: max1 - max2
+      width: unallocatedSpaceRight - rectRight
     }
   ];
 }

src/Components/Editor/ContainerOperations.ts

@@ -4,6 +4,7 @@ import { IConfiguration } from '../../Interfaces/IConfiguration';
 import { ContainerModel, IContainerModel } from '../../Interfaces/IContainerModel';
 import { findContainerById } from '../../utils/itertools';
 import { getCurrentHistory } from './Editor';
+import IProperties from '../../Interfaces/IProperties';
 
 /**
  * Select a container
@@ -203,20 +204,23 @@ export function AddContainer(
     }
   }
 
-  // Create the container
+  const defaultProperties: IProperties = {
-  const newContainer = new ContainerModel(
-    parentClone,
-    {
     id: `${type}-${count}`,
     parentId: parentClone.properties.id,
     x,
     y: 0,
-      width: properties?.Width,
+    width: properties.Width,
     height: parentClone.properties.height,
     isRigidBody: false,
+    isAnchor: false,
     XPositionReference: properties.XPositionReference,
     ...properties.Style
-    },
+  };
+
+  // Create the container
+  const newContainer = new ContainerModel(
+    parentClone,
+    defaultProperties,
     [],
     {
       type

src/Components/Editor/PropertiesOperations.ts

@@ -4,7 +4,9 @@ import { IHistoryState } from '../../Interfaces/IHistoryState';
 import IProperties from '../../Interfaces/IProperties';
 import { findContainerById } from '../../utils/itertools';
 import { getCurrentHistory } from './Editor';
-import { RecalculatePhysics } from './RigidBodyBehaviors';
+import { RecalculatePhysics } from './Behaviors/RigidBodyBehaviors';
+import { INPUT_TYPES } from '../Properties/PropertiesInputTypes';
+import { ImposePosition } from './Behaviors/AnchorBehaviors';
 
 /**
   * Handled the property change event in the properties form
@@ -28,20 +30,6 @@ export function OnPropertyChange(
     throw new Error('[OnPropertyChange] Property was changed before selecting a Container');
   }
 
-  if (parent === null) {
-    const selectedContainerClone: IContainerModel = structuredClone(current.SelectedContainer);
-    (selectedContainerClone.properties as any)[key] = value;
-    setHistory(history.concat([{
-      LastAction: 'Change property of main',
-      MainContainer: selectedContainerClone,
-      SelectedContainer: selectedContainerClone,
-      SelectedContainerId: selectedContainerClone.properties.id,
-      TypeCounters: Object.assign({}, current.TypeCounters)
-    }]));
-    setHistoryCurrentStep(history.length);
-    return;
-  }
-
   const mainContainerClone: IContainerModel = structuredClone(current.MainContainer);
   const container: ContainerModel | undefined = findContainerById(mainContainerClone, current.SelectedContainer.properties.id);
 
@@ -49,7 +37,15 @@ export function OnPropertyChange(
     throw new Error('[OnPropertyChange] Container model was not found among children of the main container!');
   }
 
+  if (INPUT_TYPES[key] === 'number') {
+    (container.properties as any)[key] = Number(value);
+  } else {
     (container.properties as any)[key] = value;
+  }
+
+  if (container.properties.isAnchor) {
+    ImposePosition(container);
+  }
 
   if (container.properties.isRigidBody) {
     RecalculatePhysics(container);
@@ -88,25 +84,6 @@ export function OnPropertiesSubmit(
     throw new Error('[OnPropertyChange] Property was changed before selecting a Container');
   }
 
-  if (parent === null) {
-    const selectedContainerClone: IContainerModel = structuredClone(current.SelectedContainer);
-    for (const property in properties) {
-      const input = (event.target as HTMLFormElement).querySelector(`#${property}`);
-      if (input instanceof HTMLInputElement) {
-        (selectedContainerClone.properties as any)[property] = input.value;
-      }
-    }
-    setHistory(history.concat([{
-      LastAction: 'Change property of main',
-      MainContainer: selectedContainerClone,
-      SelectedContainer: selectedContainerClone,
-      SelectedContainerId: selectedContainerClone.properties.id,
-      TypeCounters: Object.assign({}, current.TypeCounters)
-    }]));
-    setHistoryCurrentStep(history.length);
-    return;
-  }
-
   const mainContainerClone: IContainerModel = structuredClone(current.MainContainer);
   const container: ContainerModel | undefined = findContainerById(mainContainerClone, current.SelectedContainer.properties.id);
 
@@ -118,6 +95,11 @@ export function OnPropertiesSubmit(
     const input = (event.target as HTMLFormElement).querySelector(`#${property}`);
     if (input instanceof HTMLInputElement) {
       (container.properties as any)[property] = input.value;
+      if (INPUT_TYPES[property] === 'number') {
+        (container.properties as any)[property] = Number(input.value);
+      } else {
+        (container.properties as any)[property] = input.value;
+      }
     }
   }
 

src/Components/ElementsSidebar/ElementsSidebar.test.tsx

@@ -17,7 +17,8 @@ describe.concurrent('Elements sidebar', () => {
           y: 0,
           width: 2000,
           height: 100,
-          isRigidBody: false
+          isRigidBody: false,
+          isAnchor: false
         },
         userData: {}
       }}
@@ -47,7 +48,8 @@ describe.concurrent('Elements sidebar', () => {
         y: 0,
         width: 2000,
         height: 100,
-        isRigidBody: false
+        isRigidBody: false,
+        isAnchor: false
       },
       userData: {}
     };
@@ -103,7 +105,8 @@ describe.concurrent('Elements sidebar', () => {
         y: 0,
         width: 2000,
         height: 100,
-        isRigidBody: false
+        isRigidBody: false,
+        isAnchor: false
       },
       userData: {}
     };
@@ -119,7 +122,8 @@ describe.concurrent('Elements sidebar', () => {
           y: 0,
           width: 0,
           height: 0,
-          isRigidBody: false
+          isRigidBody: false,
+          isAnchor: false
         },
         userData: {}
       }
@@ -136,7 +140,8 @@ describe.concurrent('Elements sidebar', () => {
           y: 0,
           width: 0,
           height: 0,
-          isRigidBody: false
+          isRigidBody: false,
+          isAnchor: false
         },
         userData: {}
       }
@@ -173,7 +178,8 @@ describe.concurrent('Elements sidebar', () => {
         y: 0,
         width: 2000,
         height: 100,
-        isRigidBody: false
+        isRigidBody: false,
+        isAnchor: false
       },
       userData: {}
     };
@@ -188,7 +194,8 @@ describe.concurrent('Elements sidebar', () => {
         y: 0,
         width: 0,
         height: 0,
-        isRigidBody: false
+        isRigidBody: false,
+        isAnchor: false
       },
       userData: {}
     };

src/Components/Properties/Properties.test.tsx

@@ -23,7 +23,8 @@ describe.concurrent('Properties', () => {
       parentId: 'parentId',
       x: 1,
       y: 1,
-      isRigidBody: false
+      isRigidBody: false,
+      isAnchor: false
     };
 
     const handleChange = vi.fn((key, value) => {

src/Components/Properties/PropertiesInputTypes.tsx

@@ -3,5 +3,6 @@ export const INPUT_TYPES: Record<string, string> = {
   y: 'number',
   width: 'number',
   height: 'number',
-  isRigidBody: 'checkbox'
+  isRigidBody: 'checkbox',
+  isAnchor: 'checkbox'
 };

src/Enums/AddingBehavior.ts

@@ -1,4 +0,0 @@
-export enum AddingBehavior {
-  InsertInto,
-  Replace
-}

src/Interfaces/IProperties.ts

@@ -1,11 +1,21 @@
 import * as React from 'react';
 import { XPositionReference } from '../Enums/XPositionReference';
 
+/**
+ * Properties of a container
+ * @property id id of the container
+ * @property parentId id of the parent container
+ * @property x horizontal offset of the container
+ * @property y vertical offset of the container
+ * @property isRigidBody if true apply rigid body behaviors
+ * @property isAnchor if true apply anchor behaviors
+ */
 export default interface IProperties extends React.CSSProperties {
   id: string
   parentId: string | null
   x: number
   y: number
   isRigidBody: boolean
+  isAnchor: boolean
   XPositionReference?: XPositionReference
 }

src/utils/default.ts

@@ -33,6 +33,7 @@ export const DEFAULT_MAINCONTAINER_PROPS: IProperties = {
   width: DEFAULT_CONFIG.MainContainer.Width,
   height: DEFAULT_CONFIG.MainContainer.Height,
   isRigidBody: false,
+  isAnchor: false,
   fillOpacity: 0,
   stroke: 'black'
 };