feat: Arrow binding is a preference (#10839)

Co-authored-by: dwelle <5153846+dwelle@users.noreply.github.com>

packages/element/src/binding.ts

@@ -1,5 +1,4 @@
 import {
-  KEYS,
   arrayToMap,
   getFeatureFlag,
   invariant,
@@ -137,12 +136,6 @@ export const maxBindingDistance_simple = (zoom?: AppState["zoom"]): number => {
   );
 };
 
-export const shouldEnableBindingForPointerEvent = (
-  event: React.PointerEvent<HTMLElement>,
-) => {
-  return !event[KEYS.CTRL_OR_CMD];
-};
-
 export const isBindingEnabled = (appState: {
   isBindingEnabled: AppState["isBindingEnabled"];
 }): boolean => {
@@ -177,8 +170,20 @@ export const bindOrUnbindBindingElement = (
     },
   );
 
-  bindOrUnbindBindingElementEdge(arrow, start, "start", scene);
-  bindOrUnbindBindingElementEdge(arrow, end, "end", scene);
+  bindOrUnbindBindingElementEdge(
+    arrow,
+    start,
+    "start",
+    scene,
+    appState.isBindingEnabled,
+  );
+  bindOrUnbindBindingElementEdge(
+    arrow,
+    end,
+    "end",
+    scene,
+    appState.isBindingEnabled,
+  );
   if (start.focusPoint || end.focusPoint) {
     // If the strategy dictates a focus point override, then
     // update the arrow points to point to the focus point.
@@ -221,12 +226,21 @@ const bindOrUnbindBindingElementEdge = (
   { mode, element, focusPoint }: BindingStrategy,
   startOrEnd: "start" | "end",
   scene: Scene,
+  shouldSnapToOutline = true,
 ): void => {
   if (mode === null) {
     // null means break the binding
     unbindBindingElement(arrow, startOrEnd, scene);
   } else if (mode !== undefined) {
-    bindBindingElement(arrow, element, mode, startOrEnd, scene, focusPoint);
+    bindBindingElement(
+      arrow,
+      element,
+      mode,
+      startOrEnd,
+      scene,
+      focusPoint,
+      shouldSnapToOutline,
+    );
   }
 };
 
@@ -798,6 +812,7 @@ const getBindingStrategyForDraggingBindingElementEndpoints_simple = (
               startDragged ? "start" : "end",
               elementsMap,
               appState.zoom,
+              appState.isMidpointSnappingEnabled,
             ) || globalPoint,
         }
     : { mode: null };
@@ -842,6 +857,7 @@ const getBindingStrategyForDraggingBindingElementEndpoints_simple = (
               startDragged ? "end" : "start",
               elementsMap,
               appState.zoom,
+              appState.isMidpointSnappingEnabled,
             ) || otherEndpoint,
         }
       : { mode: undefined }
@@ -1005,6 +1021,7 @@ export const bindBindingElement = (
   startOrEnd: "start" | "end",
   scene: Scene,
   focusPoint?: GlobalPoint,
+  shouldSnapToOutline = true,
 ): void => {
   const elementsMap = scene.getNonDeletedElementsMap();
 
@@ -1019,6 +1036,7 @@ export const bindBindingElement = (
         hoveredElement,
         startOrEnd,
         elementsMap,
+        shouldSnapToOutline,
       ),
     };
   } else {
@@ -1352,6 +1370,7 @@ export const bindPointToSnapToElementOutline = (
   startOrEnd: "start" | "end",
   elementsMap: ElementsMap,
   customIntersector?: LineSegment<GlobalPoint>,
+  isMidpointSnappingEnabled = true,
 ): GlobalPoint => {
   const elbowed = isElbowArrow(arrowElement);
   const point = LinearElementEditor.getPointAtIndexGlobalCoordinates(
@@ -1391,13 +1410,9 @@ export const bindPointToSnapToElementOutline = (
     const isHorizontal = headingIsHorizontal(
       headingForPointFromElement(bindableElement, aabb, point),
     );
-    const snapPoint = snapToMid(
-      bindableElement,
-      elementsMap,
-      edgePoint,
-      0.05,
-      arrowElement,
-    );
+    const snapPoint = isMidpointSnappingEnabled
+      ? snapToMid(bindableElement, elementsMap, edgePoint, 0.05, arrowElement)
+      : undefined;
     const resolved = snapPoint || point;
     const otherPoint = pointFrom<GlobalPoint>(
       isHorizontal ? bindableCenter[0] : resolved[0],
@@ -1892,6 +1907,8 @@ export const calculateFixedPointForElbowArrowBinding = (
   hoveredElement: ExcalidrawBindableElement,
   startOrEnd: "start" | "end",
   elementsMap: ElementsMap,
+  shouldSnapToOutline = true,
+  isMidpointSnappingEnabled = true,
 ): { fixedPoint: FixedPoint } => {
   const bounds = [
     hoveredElement.x,
@@ -1899,12 +1916,20 @@ export const calculateFixedPointForElbowArrowBinding = (
     hoveredElement.x + hoveredElement.width,
     hoveredElement.y + hoveredElement.height,
   ] as Bounds;
-  const snappedPoint = bindPointToSnapToElementOutline(
-    linearElement,
-    hoveredElement,
-    startOrEnd,
-    elementsMap,
-  );
+  const snappedPoint = shouldSnapToOutline
+    ? bindPointToSnapToElementOutline(
+        linearElement,
+        hoveredElement,
+        startOrEnd,
+        elementsMap,
+        undefined,
+        isMidpointSnappingEnabled,
+      )
+    : LinearElementEditor.getPointAtIndexGlobalCoordinates(
+        linearElement,
+        startOrEnd === "start" ? 0 : -1,
+        elementsMap,
+      );
   const globalMidPoint = pointFrom(
     bounds[0] + (bounds[2] - bounds[0]) / 2,
     bounds[1] + (bounds[3] - bounds[1]) / 2,