made item height for drag position dynamic

next-release-notes.md

@@ -4,6 +4,6 @@
 ### Features
 
 ### Bug Fixes and Improvements
-
+  - Fixes a bug where drag positions would be off and not work properly when you make trees have different heights for each item or each item has different heights (#338)
 ### Other Changes
 -->

packages/core/src/controlledEnvironment/layoutUtils.ts

@@ -7,6 +7,19 @@
   return firstItem?.offsetHeight ?? 5;
 };
 
+export const computeItemHeightArray = (treeId: string): number[] => {
+  const document = getDocument();
+  if (!document) {
+    console.log("Document not found");
+    return [];
+  }
+  const items = document.querySelectorAll<HTMLElement>(`[data-rct-tree="${treeId}"] [data-rct-item-container="true"]`);
+  const itemHeights = Array.from(items).map(item => item.offsetHeight);
+
+  console.log({ itemHeights });
+  return itemHeights;
+};
+
 export const isOutsideOfContainer = (e: DragEvent, treeBb: DOMRect) =>
   e.clientX < treeBb.left ||
   e.clientX > treeBb.right ||

packages/core/src/drag/DragAndDropProvider.tsx

@@ -41,6 +41,7 @@ export const DragAndDropProvider: React.FC<React.PropsWithChildren> = ({
     draggingItems,
     getDraggingPosition,
     itemHeight,
+    itemsHeightArray,
   } = useDraggingPosition();
 
   const resetProgrammaticDragIndexForCurrentTree = useCallback(
@@ -285,6 +286,7 @@ export const DragAndDropProvider: React.FC<React.PropsWithChildren> = ({
       draggingItems,
       draggingPosition,
       itemHeight: itemHeight.current,
+      itemsHeightArray: itemsHeightArray.current,
       isProgrammaticallyDragging,
       onDragOverTreeHandler,
       viableDragPositions,
@@ -296,6 +298,7 @@ export const DragAndDropProvider: React.FC<React.PropsWithChildren> = ({
       draggingPosition,
       isProgrammaticallyDragging,
       itemHeight,
+      itemsHeightArray,
       onDragOverTreeHandler,
       onStartDraggingItems,
       programmaticDragDown,

packages/core/src/drag/useDraggingPosition.ts

@@ -4,6 +4,7 @@
 import {
   computeItemHeight,
   isOutsideOfContainer,
+  computeItemHeightArray,
 } from '../controlledEnvironment/layoutUtils';
 import { useTreeEnvironment } from '../controlledEnvironment/ControlledTreeEnvironment';
 import { useStableHandler } from '../useStableHandler';
@@ -16,6 +17,7 @@
     undefined
   );
   const itemHeight = useRef(0);
+  const itemsHeightArray = useRef([0]);
   const env = useTreeEnvironment();
   const getParentOfLinearItem = useGetGetParentOfLinearItem();
 
@@ -55,19 +57,35 @@
         return undefined;
       }
 
+      itemsHeightArray.current = computeItemHeightArray(treeId);
+
       const treeBb = containerRef.current.getBoundingClientRect();
 
       if (isOutsideOfContainer(e, treeBb)) {
         return undefined;
       }
 
-      const hoveringPosition = (e.clientY - treeBb.top) / itemHeight.current;
+      const clientYRelativeToTreeTop = e.clientY - treeBb.top;
+      let cumulativeHeight = 0;
+      let linearIndex = 0;
+      let hoveringPosition = 0;
+
+      for (let i = 0; i < itemsHeightArray.current.length; i++) {
+        cumulativeHeight += itemsHeightArray.current[i];
+        if (clientYRelativeToTreeTop <= cumulativeHeight) {
+          linearIndex = i;
+          // Calculate hovering position as a fraction within the current item
+          const previousItemsHeight = cumulativeHeight - itemsHeightArray.current[i];
+          hoveringPosition = linearIndex + (clientYRelativeToTreeTop - previousItemsHeight) / itemsHeightArray.current[i];
+          break;
+        }
+      }
 
       const treeLinearItems = env.linearItems[treeId];
-      const linearIndex = Math.min(
-        Math.max(0, Math.floor(hoveringPosition)),
-        treeLinearItems.length - 1
-      );
+      // const linearIndexx = Math.min(
+      //   Math.max(0, Math.floor(hoveringPosition)),
+      //   treeLinearItems.length - 1
+      // );
 
       if (treeLinearItems.length === 0) {
         return {
@@ -149,13 +167,17 @@
       setDraggingItems(items);
       dragCode.current = 'initial';
       itemHeight.current = computeItemHeight(treeId);
+      itemsHeightArray.current = computeItemHeightArray(treeId);
+
     }
   );
 
   const resetDraggingPosition = useStableHandler(() => {
     setDraggingItems(undefined);
     dragCode.current = 'initial';
     itemHeight.current = 0;
+    itemsHeightArray.current = [0];
+
   });
 
   return {
@@ -164,5 +186,6 @@
     draggingItems,
     getDraggingPosition,
     itemHeight,
+    itemsHeightArray,
   };
 };

packages/core/src/tree/DragBetweenLine.tsx

@@ -6,7 +6,7 @@
 export const DragBetweenLine: React.FC<{
   treeId: string;
 }> = ({ treeId }) => {
-  const { draggingPosition, itemHeight } = useDragAndDrop();
+  const { draggingPosition, itemHeight, itemsHeightArray } = useDragAndDrop();
   const { renderers } = useTree();
 
   const shouldDisplay =
@@ -28,7 +28,7 @@
         position: 'absolute',
         left: '0',
         right: '0',
-        top: `${(draggingPosition?.linearIndex ?? 0) * itemHeight}px`,
+        top: `${itemsHeightArray.slice(0, draggingPosition?.linearIndex ?? 0).reduce((acc, height) => acc + height, 0)}px`,
       }}
     >
       {renderers.renderDragBetweenLine({

packages/core/src/types.ts

@@ -312,6 +312,7 @@ export interface DragAndDropContextProps<T = any> {
   onStartDraggingItems: (items: TreeItem<T>[], treeId: string) => void;
   draggingItems?: TreeItem<T>[];
   itemHeight: number;
+  itemsHeightArray: number[];
   isProgrammaticallyDragging?: boolean;
   startProgrammaticDrag: () => void;
   abortProgrammaticDrag: () => void;