From fca0f491195f1ca804bf7a19687d7e1edba2ceb5 Mon Sep 17 00:00:00 2001
From: "konstantina.galouni" <kgalouni@di.uoa.gr>
Date: Fri, 28 Jan 2022 11:01:22 +0200
Subject: [PATCH] [new-theme | Library]: section-scroll.component: Scroll
 component used by connect home page updated - opacity changes according to
 intersectionRatio of IntersectionObserver | css for medium screens added.

---
 .../section-scroll.component.css              |  79 ++++++++-----
 .../section-scroll.component.ts               | 107 ++++++++++++++----
 2 files changed, 134 insertions(+), 52 deletions(-)

diff --git a/utils/section-scroll/section-scroll.component.css b/utils/section-scroll/section-scroll.component.css
index 2dd17209..083e5faa 100644
--- a/utils/section-scroll/section-scroll.component.css
+++ b/utils/section-scroll/section-scroll.component.css
@@ -1,44 +1,65 @@
-.section {
-    position: relative;
-    height: auto;
+/*.section {*/
+    /*position: relative;*/
+    /*height: auto;*/
     /*display: flex;*/
-}
+/*}*/
 
-.section [top] {
-    /*height: 80vh;*/
-    /*border: 1px solid rebeccapurple;*/
-}
+/*.section [top] {*/
+/*    !*height: 80vh;*!*/
+/*    !*border: 1px solid rebeccapurple;*!*/
+/*}*/
 
-.section [top] {
-    position: sticky;
-    top: 0;
-    z-index: 2;
-    height: auto;
-    /*max-height: 80vh;*/
-    /*border: 1px solid deeppink;*/
-}
-
-/*.content {*/
-/*    position: relative;*/
+/*.section [top] {*/
+/*    top: 0;*/
 /*    height: auto;*/
-/*    z-index: 1;*/
-/*    border: 1px solid cyan;*/
+/*    !*border: 1px solid deeppink;*!*/
 /*}*/
 
 [left] {
+    position: -webkit-sticky; /* Safari */
     position: sticky;
     top: 0;
     height: 100vh;
     /*border: 1px solid red;*/
 }
 
-[left] img {
-    /*position: absolute;*/
-    /*top: 50%;*/
-    /*left: 50%;*/
-    /*transform: translate(-50%, -50%);*/
-    position: sticky;
-    top: 50%;
-    left: 10%;
+[left] .imgContainer {
+    position: absolute;
+    top: 20%;
+    left: 0;
+    width: 100%;
+    height: 70%;
     /*border: 1px solid greenyellow;*/
 }
+
+@media (max-width: 960px) {
+    [left] .imgContainer {
+        top: 5%;
+        height: 40%;
+    }
+
+    [left] > * {
+        align-items: flex-start;
+    }
+
+    [scroll] > * {
+        align-items: flex-end;
+    }
+}
+
+[left] img {
+    width: auto;
+    height: auto;
+    max-width: 100%;
+    max-height: 100%;
+}
+
+[scroll] {
+    margin-top: 15vh;
+    margin-bottom: 25vh;
+}
+
+[scroll] > * {
+    height: 60vh;
+    /*    border: 1px solid darkorange;*/
+}
\ No newline at end of file
diff --git a/utils/section-scroll/section-scroll.component.ts b/utils/section-scroll/section-scroll.component.ts
index fb8ae08d..ddfcbc26 100644
--- a/utils/section-scroll/section-scroll.component.ts
+++ b/utils/section-scroll/section-scroll.component.ts
@@ -2,30 +2,26 @@ import {Component, HostListener, Input, OnInit, ViewEncapsulation} from "@angula
 
 
 /**
- * <section-scroll [customClass]="'optional classes for grid e.g. uk-flex-bottom'">
- *   <div fixed>...</div>
- *   <div scroll>...</div> # use uk-flex-first to change order
+ * <section-scroll [customClass]="'optional classes for section e.g. uk-section-primary'"
+ *                 [childrenCustomClass]="'optional classes for content e.g. uk-container'">
+ *   <div top>...</div>
+ *   <div left>...</div>
+ *   <div scroll>...</div>
  * </section-scroll>
  *
  * */
 @Component({
   selector: 'section-scroll',
   template: `
-
-<!--&lt;!&ndash;alternative&ndash;&gt;-->
-<!--<div class="section" [ngClass]="customClass">-->
-<!--  <ng-content select="[top]"></ng-content>-->
-<!--  <div class="uk-grid content"  [ngClass]="childrenCustomClass">-->
-<!--    <ng-content select="[left]"></ng-content>-->
-<!--    <ng-content select="[scroll]"></ng-content>-->
-<!--  </div>-->
-<!--</div>-->
-
-<div class="section uk-grid" [ngClass]="customClass">
-  <ng-content select="[top]"></ng-content>
-    <ng-content select="[left]"></ng-content>
-    <ng-content select="[scroll]"></ng-content>
-</div>
+    <div class="section" [ngClass]="customClass">
+      <ng-content select="[top]"></ng-content>
+      <div class="content"  [ngClass]="childrenCustomClass">
+        <div class="uk-grid">
+          <ng-content select="[left]"></ng-content>
+          <ng-content select="[scroll]"></ng-content>
+        </div>
+      </div>
+    </div>
   `,
   styleUrls: ['section-scroll.component.css'],
   encapsulation: ViewEncapsulation.None
@@ -38,16 +34,22 @@ export class SectionScrollComponent implements OnInit {
   public childrenCustomClass = null;
   private absolute: HTMLCollectionOf<Element>;
   private scroll: HTMLElement;
-  
-  constructor() {
-  }
-  
+
+  private observer: IntersectionObserver = null;
+
+  constructor() {}
+
   @HostListener('window:resize', ['$event'])
   onResize(event) {
     //this.setHeight();
   }
   
-  
+  ngOnDestroy() {
+    if(this.observer) {
+      this.observer.disconnect();
+    }
+  }
+
   ngOnInit() {
     //this.setHeight();
   }
@@ -66,4 +68,63 @@ export class SectionScrollComponent implements OnInit {
     let htmlElement = this.absolute&&this.absolute.length>0?this.absolute[0]:null;
     return htmlElement?htmlElement['offsetHeight']:0;
   }
+
+  ngAfterViewInit() {
+    if(typeof document !== "undefined") {
+      this.createObserver();
+    }
+  }
+
+  createObserver() {
+    let observer;
+
+    let options = {
+      root: null,
+      rootMargin: "-20%",
+      threshold: this.buildThresholdList()
+    };
+
+    let imgElement1: HTMLElement = document.getElementById("imgId1");
+    let imgElement2: HTMLElement = document.getElementById("imgId2");
+    let imgElement3: HTMLElement = document.getElementById("imgId3");
+    let imgElement4: HTMLElement = document.getElementById("imgId4");
+    let imgElement5: HTMLElement = document.getElementById("imgId5");
+
+    observer = new IntersectionObserver(entries => {
+      entries.forEach((entry) => {
+        entry.target['style'].opacity = entry.intersectionRatio;
+
+        if (entry.target.id == "1st") {
+          imgElement1.parentElement.style.opacity = String(entry.intersectionRatio);
+        } else if (entry.target.id == "2nd") {
+          imgElement2.parentElement.style.opacity = String(entry.intersectionRatio);
+        } else if (entry.target.id == "3rd") {
+          imgElement3.parentElement.style.opacity = String(entry.intersectionRatio);
+        } else if (entry.target.id == "4th") {
+          imgElement4.parentElement.style.opacity = String(entry.intersectionRatio);
+        } else if (entry.target.id == "5th") {
+          imgElement5.parentElement.style.opacity = String(entry.intersectionRatio);
+        }
+      });
+    }, options);
+
+    let targets: NodeListOf<HTMLElement> = document.getElementsByName('txt');
+    targets.forEach(target =>
+    {
+      observer.observe(target)
+    });
+  }
+
+  buildThresholdList() {
+    let thresholds = [];
+    let numSteps = 20;
+
+    for (let i=1.0; i<=numSteps; i++) {
+      let ratio = i/numSteps;
+      thresholds.push(ratio);
+    }
+
+    thresholds.push(0);
+    return thresholds;
+  }
 }