Resizing issue

src/gridstack-dd.ts

@@ -422,6 +422,8 @@ GridStack.prototype._prepareDragDropByNode = function(node: GridStackNode): Grid
       if (node._lastTriedX === x && node._lastTriedY === y) return;
     } else if (event.type === 'resize')  {
       if (x < 0) return;
+      // Scrolling page if needed
+      Utils.updateScrollResize(event as MouseEvent, el, cellHeight);
       w = Math.round(ui.size.width / cellWidth);
       h = Math.round(ui.size.height / cellHeight);
       if (w === node.w && h === node.h) return;

src/h5/dd-resizable.ts

@@ -8,6 +8,7 @@
 import { DDResizableHandle } from './dd-resizable-handle';
 import { DDBaseImplement, HTMLElementExtendOpt } from './dd-base-impl';
 import { DDUtils } from './dd-utils';
+import { Utils } from '../utils';
 import { DDUIData, Rect, Size } from '../types';
 
 // TODO: merge with DDDragOpt
@@ -37,6 +38,12 @@ export class DDResizable extends DDBaseImplement implements HTMLElementExtendOpt
   /** @internal */
   private temporalRect: Rect;
   /** @internal */
+  private scrollY: number;
+  /** @internal */
+  private scrolled: number;
+  /** @internal */
+  private scrollEl: HTMLElement;
+  /** @internal */
   private startEvent: MouseEvent;
   /** @internal value saved in the same order as _originStyleProp[] */
   private elOriginStyleVal: string[];
@@ -152,6 +159,8 @@ export class DDResizable extends DDBaseImplement implements HTMLElementExtendOpt
   /** @internal */
   private _resizeStart(event: MouseEvent): DDResizable {
     this.originalRect = this.el.getBoundingClientRect();
+    this.scrollEl = Utils.getScrollParent(this.el);
+    this.scrollY = this.scrollEl.scrollTop;
     this.startEvent = event;
     this._setupHelper();
     this._applyChange();
@@ -166,6 +175,7 @@ export class DDResizable extends DDBaseImplement implements HTMLElementExtendOpt
 
   /** @internal */
   private _resizing(event: MouseEvent, dir: string): DDResizable {
+    this.scrolled = this.scrollEl.scrollTop - this.scrollY;
     this.temporalRect = this._getChange(event, dir);
     this._applyChange();
     const ev = DDUtils.initEvent<MouseEvent>(event, { type: 'resize', target: this.el });
@@ -188,6 +198,8 @@ export class DDResizable extends DDBaseImplement implements HTMLElementExtendOpt
     delete this.startEvent;
     delete this.originalRect;
     delete this.temporalRect;
+    delete this.scrollY;
+    delete this.scrolled;
     return this;
   }
 
@@ -218,10 +230,11 @@ export class DDResizable extends DDBaseImplement implements HTMLElementExtendOpt
     const oEvent = this.startEvent;
     const newRect = { // Note: originalRect is a complex object, not a simple Rect, so copy out.
       width: this.originalRect.width,
-      height: this.originalRect.height,
+      height: this.originalRect.height + this.scrolled,
       left: this.originalRect.left,
-      top: this.originalRect.top
+      top: this.originalRect.top - this.scrolled
     };
+
     const offsetH = event.clientX - oEvent.clientX;
     const offsetV = event.clientY - oEvent.clientY;
 
@@ -293,7 +306,13 @@ export class DDResizable extends DDBaseImplement implements HTMLElementExtendOpt
   private _ui = (): DDUIData => {
     const containmentEl = this.el.parentElement;
     const containmentRect = containmentEl.getBoundingClientRect();
-    const rect = this.temporalRect || this.originalRect;
+    const newRect = { // Note: originalRect is a complex object, not a simple Rect, so copy out.
+      width: this.originalRect.width,
+      height: this.originalRect.height + this.scrolled,
+      left: this.originalRect.left,
+      top: this.originalRect.top - this.scrolled
+    };
+    const rect = this.temporalRect || newRect;
     return {
       position: {
         left: rect.left - containmentRect.left,

src/utils.ts

@@ -280,15 +280,15 @@ export class Utils {
 
   /** @internal */
   static getScrollParent(el: HTMLElement): HTMLElement {
-    let returnEl;
-    if (el === null) {
-      returnEl = null;
-    } else if (el.scrollHeight > el.clientHeight) {
-      returnEl = el;
+    if (el === null) return document.documentElement;
+    const style = getComputedStyle(el);
+    const overflowRegex = /(auto|scroll)/;
+
+    if (overflowRegex.test(style.overflow + style.overflowY)) {
+      return el;
     } else {
-      returnEl = this.getScrollParent(el.parentElement);
+      return this.getScrollParent(el.parentElement);
     }
-    return returnEl;
   }
 
   /** @internal */
@@ -327,5 +327,31 @@ export class Utils {
       }
     }
   }
+
+  /** 
+   * @internal
+   * 
+   * Function used to scroll the page.
+   * 
+   * @param event `MouseEvent` that triggers the resize
+   * @param el `HTMLElement` that's being resized
+   * @param distance Distance to scroll
+   */
+  static updateScrollResize(event: MouseEvent, el: HTMLElement, distance: number): void {
+    const scrollEl = this.getScrollParent(el);
+    const height = scrollEl.clientHeight;
+
+    const top = event.clientY < distance;
+    const bottom = event.clientY > height - distance;
+
+    if (top) {
+      // This also can be done with a timeout to keep scrolling while the mouse is
+      // in the scrolling zone. (will have smoother behavior)
+      scrollEl.scrollBy({ behavior: 'smooth', top: event.clientY - distance});
+
+    } else if (bottom) {
+      scrollEl.scrollBy({ behavior: 'smooth', top: distance - (height - event.clientY)});
+    }
+  }
 }