From a3a090162cf50221004026886d437b1626c49e2f Mon Sep 17 00:00:00 2001
From: Valentin Mihai <valentin@devplant.ro>
Date: Thu, 17 Feb 2022 09:05:11 +0200
Subject: [PATCH] fix to display helpers only when the elements are visible

---
 src/assets/styles/common-help-mode.scss       |  3 -
 src/lib/help-mode/help-mode.directive.ts      |  3 +-
 src/lib/help-mode/help-mode.service.ts        | 71 ++++++++++++++++---
 .../scroll-button.component.html              |  4 +-
 .../table-content.component.html              |  1 +
 5 files changed, 66 insertions(+), 16 deletions(-)

diff --git a/src/assets/styles/common-help-mode.scss b/src/assets/styles/common-help-mode.scss
index bd92653..9f7a7b8 100644
--- a/src/assets/styles/common-help-mode.scss
+++ b/src/assets/styles/common-help-mode.scss
@@ -10,6 +10,3 @@
     box-shadow: 0 0 0 2px var(--iqser-helpmode-primary) inset;
     cursor: help;
 }
-
-
-
diff --git a/src/lib/help-mode/help-mode.directive.ts b/src/lib/help-mode/help-mode.directive.ts
index a446861..dac74b5 100644
--- a/src/lib/help-mode/help-mode.directive.ts
+++ b/src/lib/help-mode/help-mode.directive.ts
@@ -8,6 +8,7 @@ import { Router } from '@angular/router';
 })
 export class HelpModeDirective implements OnInit {
     @Input('iqserHelpMode') elementName!: string;
+    @Input() isVirtualScrollElement: boolean = false;
     private _path: string;
 
     constructor(
@@ -34,7 +35,7 @@ export class HelpModeDirective implements OnInit {
         this._renderer.setAttribute(helperElement, 'href', this._helpModeService.getDocsLink(this.elementName));
         this._renderer.setAttribute(helperElement, 'target', '_blank');
         this._renderer.addClass(helperElement, 'help-mode');
-        this._helpModeService.addElement(helperElementName, element, helperElement);
+        this._helpModeService.addElement(helperElementName, element, helperElement, this.isVirtualScrollElement);
     }
 
     private _generateId(): string {
diff --git a/src/lib/help-mode/help-mode.service.ts b/src/lib/help-mode/help-mode.service.ts
index 140186e..de00234 100644
--- a/src/lib/help-mode/help-mode.service.ts
+++ b/src/lib/help-mode/help-mode.service.ts
@@ -8,8 +8,12 @@ import { HELP_DOCS, MANUAL_BASE_URL } from './tokens';
 interface Helper {
     readonly element: HTMLElement;
     readonly helperElement: HTMLElement;
+    readonly isVirtualScrollElement: boolean;
 }
 
+const VIRTUAL_SCROLL_ID = 'virtual-scroll';
+const SCROLL_BUTTONS_IDS = ['scroll-up', 'scroll-down'];
+
 @Injectable({
     providedIn: 'root',
 })
@@ -77,7 +81,7 @@ export class HelpModeService {
     }
 
     highlightHelperElements(): void {
-        Object.values(this._helperElements).forEach(({ helperElement }) => {
+        Object.values(this._helperElements).forEach(({ element, helperElement }) => {
             this._renderer.addClass(helperElement, 'help-highlight');
             setTimeout(() => {
                 this._renderer.removeClass(helperElement, 'help-highlight');
@@ -85,30 +89,77 @@ export class HelpModeService {
         });
     }
 
-    addElement(helperElementName: string, element: HTMLElement, helperElement: HTMLElement): void {
-        this._helperElements[helperElementName] = { element, helperElement };
+    addElement(helperElementName: string, element: HTMLElement, helperElement: HTMLElement, isVirtualScrollElement: boolean): void {
+        this._helperElements[helperElementName] = { element, helperElement, isVirtualScrollElement };
     }
 
     updateHelperElements() {
-        Object.values(this._helperElements).forEach(({element, helperElement }) => {
-            this._updateHelperElement(element, helperElement);
+        Object.values(this._helperElements).forEach(({element, helperElement, isVirtualScrollElement }) => {
+            this._updateHelperElement(element, helperElement, isVirtualScrollElement);
         });
     }
 
-    private _updateHelperElement(element: HTMLElement, helperElement: HTMLElement) {
-        const dimensions = this._getElementDimensions(element);
-        helperElement.style.cssText = `
+    private _isElementVisible(element: HTMLElement, isVirtualScrollElement: boolean): boolean {
+
+        const elementRect = element.getBoundingClientRect();
+        if (elementRect.top === 0 && elementRect.left === 0 && elementRect.bottom === 0 && elementRect.bottom === 0) {
+            return false;
+        }
+
+        if (isVirtualScrollElement) {
+            const virtualScroll: any = document.getElementById(VIRTUAL_SCROLL_ID);
+
+            if (!virtualScroll) {
+                return false;
+            }
+
+            const virtualScrollRect = virtualScroll.getBoundingClientRect();
+
+            if (!(elementRect.top > virtualScrollRect.top
+                && elementRect.left > virtualScrollRect.left
+                && elementRect.bottom < virtualScrollRect.bottom
+                && elementRect.right < virtualScrollRect.right)) {
+                return false;
+            }
+
+            for (const id of SCROLL_BUTTONS_IDS) {
+                const scroll: any = document.getElementById(id);
+
+                const elementRect = element.getBoundingClientRect();
+                const scrollRect = scroll.getBoundingClientRect();
+
+                if(elementRect.top + elementRect.height > scrollRect.top
+                    && elementRect.left + elementRect.width > scrollRect.left
+                    && elementRect.bottom - elementRect.height < scrollRect.bottom
+                    && elementRect.right - elementRect.width < scrollRect.right) {
+                    return false
+                }
+            }
+        }
+
+        return true;
+    }
+
+    private _updateHelperElement(element: HTMLElement, helperElement: HTMLElement, isVirtualScrollElement: boolean) {
+        if (this._isElementVisible(element, isVirtualScrollElement)) {
+            const dimensions = this._getElementDimensions(element);
+            helperElement.style.cssText = `
                 top:${dimensions.y}px;
                 left:${dimensions.x}px;
                 width:${dimensions.width}px;
                 height:${dimensions.height}px;
             `;
+            helperElement.classList.add('help-mode')
+        } else {
+            helperElement.classList.remove('help-mode')
+        }
+
     }
 
     private _enableHelperElements() {
-        Object.values(this._helperElements).forEach(({ element, helperElement }) => {
+        Object.values(this._helperElements).forEach(({ element, helperElement, isVirtualScrollElement }) => {
             document.body.appendChild(helperElement)
-            this._updateHelperElement(element, helperElement);
+            this._updateHelperElement(element, helperElement, isVirtualScrollElement);
         });
     }
 
diff --git a/src/lib/listing/scroll-button/scroll-button.component.html b/src/lib/listing/scroll-button/scroll-button.component.html
index e30974d..a0954c3 100644
--- a/src/lib/listing/scroll-button/scroll-button.component.html
+++ b/src/lib/listing/scroll-button/scroll-button.component.html
@@ -1,7 +1,7 @@
-<button (click)="scroll(buttonType.top)" [hidden]="(showScrollUp$ | async) === false" class="scroll-button top pointer" iqserHelpMode="scroll_up_and_down">
+<button (click)="scroll(buttonType.top)" [hidden]="(showScrollUp$ | async) === false" class="scroll-button top pointer" iqserHelpMode="scroll_up_and_down" id="scroll-up">
     <mat-icon svgIcon="iqser:arrow-down-o"></mat-icon>
 </button>
 
-<button (click)="scroll(buttonType.bottom)" [hidden]="(showScrollDown$ | async) === false" class="scroll-button bottom pointer" iqserHelpMode="scroll_up_and_down">
+<button (click)="scroll(buttonType.bottom)" [hidden]="(showScrollDown$ | async) === false" class="scroll-button bottom pointer" iqserHelpMode="scroll_up_and_down" id="scroll-down">
     <mat-icon svgIcon="iqser:arrow-down-o"></mat-icon>
 </button>
diff --git a/src/lib/listing/table-content/table-content.component.html b/src/lib/listing/table-content/table-content.component.html
index 7e6ce90..12f79ee 100644
--- a/src/lib/listing/table-content/table-content.component.html
+++ b/src/lib/listing/table-content/table-content.component.html
@@ -5,6 +5,7 @@
         [maxBufferPx]="1500"
         [minBufferPx]="300"
         iqserHasScrollbar
+        id="virtual-scroll"
     >
         <ng-container *cdkVirtualFor="let entity of listingComponent.sortedDisplayedEntities$; trackBy: trackBy; templateCacheSize: 60">
             <!-- mouseenter and mouseleave triggers change detection event if itemMouse functions are undefined -->