fix: Restore arrow start point when self binding

packages/element/src/binding.ts

@@ -665,41 +665,46 @@ const getBindingStrategyForDraggingBindingElementEndpoints_simple = (
         otherBinding.elementId,
       ) as NonDeleted<ExcalidrawBindableElement>)
     : undefined;
-  const otherFocusPoint =
-    otherBinding &&
-    otherBindableElement &&
-    getGlobalFixedPointForBindableElement(
-      otherBinding.fixedPoint,
-      otherBindableElement,
-      elementsMap,
-    );
-  const otherPoint = LinearElementEditor.getPointAtIndexGlobalCoordinates(
-    arrow,
-    startDragged ? -1 : 0,
-    elementsMap,
-  );
-  const otherFocusPointIsInElement =
-    otherBindableElement &&
-    otherFocusPoint &&
-    isPointInElement(otherFocusPoint, otherBindableElement, elementsMap);
+  // const otherFocusPoint =
+  //   otherBinding &&
+  //   otherBindableElement &&
+  //   getGlobalFixedPointForBindableElement(
+  //     otherBinding.fixedPoint,
+  //     otherBindableElement,
+  //     elementsMap,
+  //   );
+  // const otherPoint = LinearElementEditor.getPointAtIndexGlobalCoordinates(
+  //   arrow,
+  //   startDragged ? -1 : 0,
+  //   elementsMap,
+  // );
+  // const otherFocusPointIsInElement =
+  //   otherBindableElement &&
+  //   otherFocusPoint &&
+  //   isPointInElement(otherFocusPoint, otherBindableElement, elementsMap);
 
-  // Handle outside-outside binding with the same element
-  if (
-    otherBinding &&
-    otherBinding.elementId === hit?.id &&
-    !pointInElement &&
-    !otherFocusPointIsInElement
-  ) {
+  // Handle outside-outside binding to the same element
+  if (otherBinding && otherBinding.elementId === hit?.id) {
     const [startFixedPoint, endFixedPoint] = getGlobalFixedPoints(
       arrow,
       elementsMap,
     );
 
+    invariant(
+      !opts?.newArrow || appState.selectedLinearElement?.initialState.origin,
+      "appState.selectedLinearElement.initialState.origin must be defined for new arrows",
+    );
+
     return {
       start: {
         mode: "inside",
         element: hit,
-        focusPoint: startDragged ? globalPoint : startFixedPoint,
+        focusPoint: startDragged
+          ? globalPoint
+          : // NOTE: Can only affect the start point because new arrows always drag the end point
+          opts?.newArrow
+          ? appState.selectedLinearElement!.initialState.origin!
+          : startFixedPoint,
       },
       end: {
         mode: "inside",
@@ -709,8 +714,31 @@ const getBindingStrategyForDraggingBindingElementEndpoints_simple = (
     };
   }
 
+  // Handle special alt key case to inside bind no matter what
+  if (opts?.altKey) {
+    return {
+      start:
+        startDragged && hit
+          ? {
+              mode: "inside",
+              element: hit,
+              focusPoint: globalPoint,
+            }
+          : start,
+      end:
+        endDragged && hit
+          ? {
+              mode: "inside",
+              element: hit,
+              focusPoint: globalPoint,
+            }
+          : end,
+    };
+  }
+
+  // Handle normal cases
   const current: BindingStrategy = hit
-    ? pointInElement || opts?.altKey
+    ? pointInElement
       ? {
           mode: "inside",
           element: hit,
@@ -731,26 +759,12 @@ const getBindingStrategyForDraggingBindingElementEndpoints_simple = (
     : { mode: null };
 
   const other: BindingStrategy =
-    !opts?.altKey && opts?.newArrow && otherBindableElement
-      ? otherBindableElement.id === hit?.id
+    otherBindableElement &&
+    appState.selectedLinearElement?.initialState.altFocusPoint
       ? {
-            mode: "inside",
-            element: otherBindableElement,
-            focusPoint: otherPoint,
-          }
-        : {
           mode: "orbit",
           element: otherBindableElement,
-            focusPoint:
-              otherFocusPointIsInElement && !opts?.initialBinding
-                ? otherFocusPoint
-                : projectFixedPointOntoDiagonal(
-                    arrow,
-                    otherPoint,
-                    otherBindableElement,
-                    startDragged ? "end" : "start",
-                    elementsMap,
-                  ) || otherPoint,
+          focusPoint: appState.selectedLinearElement.initialState.altFocusPoint,
         }
       : { mode: undefined };
 
@@ -2128,7 +2142,7 @@ export class BindableElement {
 }
 
 export const getGlobalFixedPointForBindableElement = (
-  fixedPointRatio: [number, number],
+  fixedPointRatio: FixedPoint,
   element: ExcalidrawBindableElement,
   elementsMap: ElementsMap,
 ): GlobalPoint => {

packages/element/src/linearElementEditor.ts

@@ -29,6 +29,7 @@ import {
   getHoveredElementForBinding,
   isPathALoop,
   moveArrowAboveBindable,
+  projectFixedPointOntoDiagonal,
   type Store,
 } from "@excalidraw/element";
 
@@ -139,6 +140,7 @@ export class LinearElementEditor {
       added: boolean;
     };
     arrowStartIsInside: boolean;
+    altFocusPoint: Readonly<GlobalPoint> | null;
   }>;
 
   /** whether you're dragging a point */
@@ -189,6 +191,7 @@ export class LinearElementEditor {
         added: false,
       },
       arrowStartIsInside: false,
+      altFocusPoint: null,
     };
     this.hoverPointIndex = -1;
     this.segmentMidPointHoveredCoords = null;
@@ -395,9 +398,28 @@ export class LinearElementEditor {
       return null;
     }
 
+    const startBindingElement =
+      isBindingElement(element) &&
+      element.startBinding &&
+      (elementsMap.get(
+        element.startBinding.elementId,
+      ) as ExcalidrawBindableElement | null);
     const newLinearElementEditor = {
       ...linearElementEditor,
       customLineAngle,
+      initialState: {
+        ...linearElementEditor.initialState,
+        altFocusPoint:
+          !linearElementEditor.initialState.altFocusPoint && startBindingElement
+            ? projectFixedPointOntoDiagonal(
+                element,
+                pointFrom<GlobalPoint>(element.x, element.y),
+                startBindingElement,
+                "start",
+                elementsMap,
+              )
+            : linearElementEditor.initialState.altFocusPoint,
+      },
     };
 
     return {
@@ -582,6 +604,12 @@ export class LinearElementEditor {
         : null;
 
     const newHoverPointIndex = newLastClickedPoint;
+    const startBindingElement =
+      isBindingElement(element) &&
+      element.startBinding &&
+      (elementsMap.get(
+        element.startBinding.elementId,
+      ) as ExcalidrawBindableElement | null);
 
     const newLinearElementEditor = {
       ...linearElementEditor,
@@ -589,6 +617,16 @@ export class LinearElementEditor {
       initialState: {
         ...linearElementEditor.initialState,
         lastClickedPoint: newLastClickedPoint,
+        altFocusPoint:
+          !linearElementEditor.initialState.altFocusPoint && startBindingElement
+            ? projectFixedPointOntoDiagonal(
+                element,
+                pointFrom<GlobalPoint>(element.x, element.y),
+                startBindingElement,
+                "start",
+                elementsMap,
+              )
+            : linearElementEditor.initialState.altFocusPoint,
       },
       segmentMidPointHoveredCoords: newSelectedMidPointHoveredCoords,
       hoverPointIndex: newHoverPointIndex,
@@ -959,6 +997,7 @@ export class LinearElementEditor {
       appState,
       elementsMap,
     );
+    const point = pointFrom<GlobalPoint>(scenePointer.x, scenePointer.y);
     let segmentMidpointIndex = null;
 
     if (segmentMidpoint) {
@@ -990,7 +1029,7 @@ export class LinearElementEditor {
         initialState: {
           prevSelectedPointsIndices: linearElementEditor.selectedPointsIndices,
           lastClickedPoint: -1,
-          origin: pointFrom<GlobalPoint>(scenePointer.x, scenePointer.y),
+          origin: point,
           segmentMidpoint: {
             value: segmentMidpoint,
             index: segmentMidpointIndex,
@@ -999,6 +1038,7 @@ export class LinearElementEditor {
           arrowStartIsInside:
             !!app.state.newElement &&
             (app.state.bindMode === "inside" || app.state.bindMode === "skip"),
+          altFocusPoint: null,
         },
         selectedPointsIndices: [element.points.length - 1],
         lastUncommittedPoint: null,
@@ -1051,7 +1091,7 @@ export class LinearElementEditor {
       initialState: {
         prevSelectedPointsIndices: linearElementEditor.selectedPointsIndices,
         lastClickedPoint: clickedPointIndex,
-        origin: pointFrom<GlobalPoint>(scenePointer.x, scenePointer.y),
+        origin: point,
         segmentMidpoint: {
           value: segmentMidpoint,
           index: segmentMidpointIndex,
@@ -1060,6 +1100,7 @@ export class LinearElementEditor {
         arrowStartIsInside:
           !!app.state.newElement &&
           (app.state.bindMode === "inside" || app.state.bindMode === "skip"),
+        altFocusPoint: null,
       },
       selectedPointsIndices: nextSelectedPointsIndices,
       pointerOffset: targetPoint
@@ -2280,7 +2321,8 @@ const pointDraggingUpdates = (
       )! as ExcalidrawBindableElement)
     : null;
 
-  const startLocalPoint = endIsDraggingOverStartElement
+  const startLocalPoint =
+    endIsDraggingOverStartElement && getFeatureFlag("COMPLEX_BINDINGS")
       ? nextArrow.points[0]
       : startIsDraggingOverEndElement &&
         app.state.bindMode !== "inside" &&
@@ -2337,49 +2379,6 @@ const pointDraggingUpdates = (
   };
 };
 
-// const shouldAllowDraggingPoint = (
-//   element: ExcalidrawLinearElement,
-//   scenePointerX: number,
-//   scenePointerY: number,
-//   selectedPointsIndices: readonly number[],
-//   elementsMap: Readonly<NonDeletedSceneElementsMap>,
-//   app: AppClassProperties,
-// ) => {
-//   if (!isSimpleArrow(element)) {
-//     return true;
-//   }
-
-//   const scenePointer = pointFrom<GlobalPoint>(scenePointerX, scenePointerY);
-
-//   // Do not allow dragging the bound arrow closer to the shape than
-//   // the dragging threshold
-//   let allowDrag = true;
-
-//   if (selectedPointsIndices.includes(0) && element.startBinding) {
-//     const boundElement = elementsMap.get(
-//       element.startBinding.elementId,
-//     )! as ExcalidrawBindableElement;
-//     const dist = distanceToElement(boundElement, elementsMap, scenePointer);
-//     const inside = isPointInElement(scenePointer, boundElement, elementsMap);
-//     allowDrag =
-//       allowDrag && (dist > getFixedBindingDistance(boundElement) || inside);
-//   }
-//   if (
-//     selectedPointsIndices.includes(element.points.length - 1) &&
-//     element.endBinding
-//   ) {
-//     const boundElement = elementsMap.get(
-//       element.endBinding.elementId,
-//     )! as ExcalidrawBindableElement;
-//     const dist = distanceToElement(boundElement, elementsMap, scenePointer);
-//     const inside = isPointInElement(scenePointer, boundElement, elementsMap);
-//     allowDrag =
-//       allowDrag && (dist > getFixedBindingDistance(boundElement) || inside);
-//   }
-
-//   return allowDrag;
-// };
-
 const determineCustomLinearAngle = (
   pivotPoint: LocalPoint,
   draggedPoint: LocalPoint,

packages/element/src/utils.ts

@@ -31,6 +31,7 @@ import { elementCenterPoint, getDiamondPoints } from "./bounds";
 
 import { generateLinearCollisionShape } from "./shape";
 
+import { isPointInElement } from "./collision";
 import { LinearElementEditor } from "./linearElementEditor";
 import { isRectangularElement } from "./typeChecks";
 
@@ -557,14 +558,17 @@ export const projectFixedPointOntoDiagonal = (
   element: ExcalidrawElement,
   startOrEnd: "start" | "end",
   elementsMap: ElementsMap,
-) => {
+): GlobalPoint | null => {
+  invariant(arrow.points.length >= 2, "Arrow must have at least two points");
+  if (arrow.width < 1 && arrow.height < 1) {
+    return null;
+  }
+
   const [diagonalOne, diagonalTwo] = getDiagonalsForBindableElement(
     element,
     elementsMap,
   );
 
-  invariant(arrow.points.length >= 2, "Arrow must have at least two points");
-
   const a = LinearElementEditor.getPointAtIndexGlobalCoordinates(
     arrow,
     startOrEnd === "start" ? 1 : arrow.points.length - 2,
@@ -587,9 +591,12 @@ export const projectFixedPointOntoDiagonal = (
   const d1 = p1 && pointDistance(a, p1);
   const d2 = p2 && pointDistance(a, p2);
 
+  let p = null;
   if (d1 != null && d2 != null) {
-    return d1 < d2 ? p1 : p2;
+    p = d1 < d2 ? p1 : p2;
+  } else {
+    p = p1 || p2 || null;
   }
 
-  return p1 || p2 || null;
+  return p && isPointInElement(p, element, elementsMap) ? p : null;
 };