implementing advanced thumbnail loading scheduler

frontend/app/gallery/grid/GridPhoto.ts

@@ -2,6 +2,9 @@ import {Photo} from "../../../../common/entities/Photo";
 import {Config} from "../../config/Config";
 import {Utils} from "../../../../common/Utils";
 export class GridPhoto {
+
+    private replacementSizeCache:boolean|number = false;
+
     constructor(public photo:Photo, public renderWidth:number, public renderHeight:number) {
 
     }
@@ -19,19 +22,25 @@ export class GridPhoto {
     }
 
     getReplacementThumbnailSize() {
-        let size = this.getThumbnailSize();
-        for (let i = 0; i < this.photo.readyThumbnails.length; i++) {
-            if (this.photo.readyThumbnails[i] < size) {
-                return this.photo.readyThumbnails[i];
+
+        if (this.replacementSizeCache === false) {
+            this.replacementSizeCache = null;
+
+            let size = this.getThumbnailSize();
+            for (let i = 0; i < this.photo.readyThumbnails.length; i++) {
+                if (this.photo.readyThumbnails[i] < size) {
+                    this.replacementSizeCache = this.photo.readyThumbnails[i];
+                    break;
+                }
             }
         }
-        return null;
+        return this.replacementSizeCache;
     }
 
     isReplacementThumbnailAvailable() {
         return this.getReplacementThumbnailSize() !== null;
     }
-    
+
     isThumbnailAvailable() {
         return this.photo.readyThumbnails.indexOf(this.getThumbnailSize()) != -1;
     }
@@ -41,7 +50,7 @@ export class GridPhoto {
         return Utils.concatUrls("/api/gallery/content/", this.photo.directory.path, this.photo.directory.name, this.photo.name, "thumbnail", size.toString());
 
     }
-    
+
     getThumbnailPath() {
         let size = this.getThumbnailSize();
         return Utils.concatUrls("/api/gallery/content/", this.photo.directory.path, this.photo.directory.name, this.photo.name, "thumbnail", size.toString());

frontend/app/gallery/grid/photo/photo.grid.gallery.component.html

@@ -1,4 +1,4 @@
-<div class="photo-container" (mouseover)="hover()" (mouseout)="mouseOut()">
+<div #photoContainer class="photo-container" (mouseover)="hover()" (mouseout)="mouseOut()">
     <img #img [src]="image.src" [hidden]="!image.show">
 
     <gallery-grid-photo-loading [animate]="loading.animate" *ngIf="loading.show">

frontend/app/gallery/grid/photo/photo.grid.gallery.component.ts

@@ -1,12 +1,17 @@
 ///<reference path="../../../../browser.d.ts"/>
 
-import {Component, Input, ElementRef, ViewChild, AfterViewInit} from "@angular/core";
+import {Component, Input, ElementRef, ViewChild, OnInit, AfterViewInit, OnDestroy, HostListener} from "@angular/core";
 import {IRenderable, Dimension} from "../../../model/IRenderable";
 import {GridPhoto} from "../GridPhoto";
 import {SearchTypes} from "../../../../../common/entities/AutoCompleteItem";
 import {RouterLink} from "@angular/router-deprecated";
 import {Config} from "../../../config/Config";
-import {ThumbnailLoaderService} from "../thumnailLoader.service";
+import {
+    ThumbnailLoaderService,
+    ThumbnailTaskEntity,
+    ThumbnailLoadingListener,
+    ThumbnailLoadingPriority
+} from "../thumnailLoader.service";
 import {GalleryPhotoLoadingComponent} from "./loading/loading.photo.grid.gallery.component";
 
 @Component({
@@ -15,10 +20,11 @@ import {GalleryPhotoLoadingComponent} from "./loading/loading.photo.grid.gallery
     styleUrls: ['app/gallery/grid/photo/photo.grid.gallery.component.css'],
     directives: [RouterLink, GalleryPhotoLoadingComponent],
 })
-export class GalleryPhotoComponent implements IRenderable, AfterViewInit {
+export class GalleryPhotoComponent implements IRenderable, OnInit, AfterViewInit, OnDestroy {
     @Input() gridPhoto:GridPhoto;
     @ViewChild("img") imageRef:ElementRef;
     @ViewChild("info") infoDiv:ElementRef;
+    @ViewChild("photoContainer") container:ElementRef;
 
 
     image = {
@@ -30,7 +36,9 @@ export class GalleryPhotoComponent implements IRenderable, AfterViewInit {
         animate: false,
         show: false
     };
-    
+
+    thumbnailTask:ThumbnailTaskEntity = null;
+
     infoStyle = {
         height: 0,
         background: "rgba(0,0,0,0.0)"
@@ -44,49 +52,89 @@ export class GalleryPhotoComponent implements IRenderable, AfterViewInit {
         this.searchEnabled = Config.Client.Search.searchEnabled;
     }
 
-    ngAfterViewInit() {
-        //schedule change after Angular checks the model
-        setImmediate(() => {
-            if (this.gridPhoto.isThumbnailAvailable()) {
-                this.image.src = this.gridPhoto.getThumbnailPath();
-                this.image.show = true;
-                this.loading.show = false;
-            } else if (this.gridPhoto.isReplacementThumbnailAvailable()) {
+    ngOnInit() {
+        //set up befoar adding task to thumbnail generator
+        if (this.gridPhoto.isThumbnailAvailable()) {
+            this.image.src = this.gridPhoto.getThumbnailPath();
+            this.image.show = true;
+            this.loading.show = false;
 
+        } else {
+            if (this.gridPhoto.isReplacementThumbnailAvailable()) {
                 this.image.src = this.gridPhoto.getReplacementThumbnailPath();
                 this.image.show = true;
                 this.loading.show = false;
-                this.thumbnailService.loadImage(this.gridPhoto,
-                    ()=> { //onLoadStarted
-                    },
-                    ()=> {//onLoaded
-                        this.image.src = this.gridPhoto.getThumbnailPath();
-                    },
-                    (error)=> {//onError
-                        //TODO: handle error
-                        console.error("something bad happened");
-                        console.error(error);
-                    });
             } else {
-                this.loading.show = true; 
-                this.thumbnailService.loadImage(this.gridPhoto,
-                    ()=> { //onLoadStarted
-                        this.loading.animate = true;
-                    },
-                    ()=> {//onLoaded
-                        this.image.src = this.gridPhoto.getThumbnailPath();
-                        this.image.show = true;
-                        this.loading.show = false; 
-                    },
-                    (error)=> {//onError
-                        //TODO: handle error
-                        console.error("something bad happened");
-                        console.error(error);
-                    });
+                this.loading.show = true;
             }
-        });
+        }
     }
 
+    ngAfterViewInit() {
+        //schedule change after Angular checks the model
+        if (!this.gridPhoto.isThumbnailAvailable()) {
+            setImmediate(() => {
+
+                let listener:ThumbnailLoadingListener = {
+                    onStartedLoading: ()=> { //onLoadStarted
+                        this.loading.animate = true;
+                    },
+                    onLoad: ()=> {//onLoaded
+                        this.image.src = this.gridPhoto.getThumbnailPath();
+                        this.image.show = true;
+                        this.loading.show = false;
+                        this.thumbnailTask = null;
+                    },
+                    onError: (error)=> {//onError
+                        this.thumbnailTask = null;
+                        //TODO: handle error
+                        console.error("something bad happened");
+                        console.error(error);
+                    }
+                };
+
+                if (this.gridPhoto.isReplacementThumbnailAvailable()) {
+                    this.thumbnailTask = this.thumbnailService.loadImage(this.gridPhoto, ThumbnailLoadingPriority.medium, listener);
+                } else {
+                    this.thumbnailTask = this.thumbnailService.loadImage(this.gridPhoto, ThumbnailLoadingPriority.high, listener);
+                }
+
+
+            });
+        }
+    }
+
+    ngOnDestroy() {
+        if (this.thumbnailTask != null) {
+            this.thumbnailService.removeTask(this.thumbnailTask);
+            this.thumbnailTask = null;
+        }
+    }
+
+
+    isInView():boolean {
+        return document.body.scrollTop < this.container.nativeElement.offsetTop + this.container.nativeElement.clientHeight
+            && document.body.scrollTop + window.innerHeight > this.container.nativeElement.offsetTop;
+    }
+
+    @HostListener('window:scroll')
+    onScroll() {
+        if (this.thumbnailTask != null) {
+            if (this.isInView() == true) {
+                if (this.gridPhoto.isReplacementThumbnailAvailable()) {
+                    this.thumbnailTask.priority = ThumbnailLoadingPriority.medium;
+                } else {
+                    this.thumbnailTask.priority = ThumbnailLoadingPriority.high;
+                }
+            } else {
+                if (this.gridPhoto.isReplacementThumbnailAvailable()) {
+                    this.thumbnailTask.priority = ThumbnailLoadingPriority.low;
+                } else {
+                    this.thumbnailTask.priority = ThumbnailLoadingPriority.medium;
+                }
+            }
+        }
+    }
 
     getPositionText():string {
         if (!this.gridPhoto) {

frontend/app/gallery/grid/thumnailLoader.service.ts

@@ -4,6 +4,10 @@ import {Injectable} from "@angular/core";
 import {GridPhoto} from "./GridPhoto";
 import {Config} from "../../config/Config";
 
+export enum ThumbnailLoadingPriority{
+    high, medium, low
+}
+
 @Injectable()
 export class ThumbnailLoaderService {
 
@@ -17,7 +21,24 @@ export class ThumbnailLoaderService {
         this.que = [];
     }
 
-    loadImage(gridPhoto:GridPhoto, onStartedLoading:()=>void, onLoad:()=>void, onError:(error)=>void):void {
+    removeTask(taskEntry:ThumbnailTaskEntity) {
+
+        for (let i = 0; i < this.que.length; i++) {
+            let index = this.que[i].taskEntities.indexOf(taskEntry);
+            if (index == -1) {
+                this.que[i].taskEntities.splice(index, 1);
+                if (this.que[i].taskEntities.length == 0) {
+                    this.que.splice(i, 1);
+
+                }
+                return;
+            }
+        }
+
+    }
+
+    loadImage(gridPhoto:GridPhoto, priority:ThumbnailLoadingPriority, listener:ThumbnailLoadingListener):ThumbnailTaskEntity {
+
         let tmp:ThumbnailTask = null;
         //is image already qued?
         for (let i = 0; i < this.que.length; i++) {
@@ -26,13 +47,13 @@ export class ThumbnailLoaderService {
                 break;
             }
         }
+
+        let thumbnailTaskEntity = {priority: priority, listener: listener};
         //add to previous
         if (tmp != null) {
-            tmp.onStartedLoading.push(onStartedLoading);
-            tmp.onLoad.push(onLoad);
-            tmp.onError.push(onError);
+            tmp.taskEntities.push(thumbnailTaskEntity);
             if (tmp.inProgress == true) {
-                onStartedLoading();
+                listener.onStartedLoading();
             }
 
 
@@ -40,54 +61,105 @@ export class ThumbnailLoaderService {
             this.que.push({
                 gridPhoto: gridPhoto,
                 inProgress: false,
-                onStartedLoading: [onStartedLoading],
-                onLoad: [onLoad],
-                onError: [onError]
+                taskEntities: [thumbnailTaskEntity]
             });
         }
-        this.run();
+        setImmediate(this.run);
+        return thumbnailTaskEntity;
 
     }
 
 
-    run() {
+    private getNextTask():ThumbnailTask {
+        if (this.que.length === 0) {
+            return null;
+        }
+
+        for (let i = 0; i < this.que.length; i++) {
+            for (let j = 0; j < this.que[i].taskEntities.length; j++) {
+                if (this.que[i].taskEntities[j].priority === ThumbnailLoadingPriority.high) {
+                    return this.que[i];
+                }
+            }
+        }
+
+        for (let i = 0; i < this.que.length; i++) {
+            for (let j = 0; j < this.que[i].taskEntities.length; j++) {
+                if (this.que[i].taskEntities[j].priority === ThumbnailLoadingPriority.medium) {
+                    return this.que[i];
+                }
+            }
+        }
+
+        return this.que[0];
+    }
+
+    private taskReady(task:ThumbnailTask) {
+        let i = this.que.indexOf(task);
+        if (i == -1) {
+            if (task.taskEntities.length !== 0) {
+                console.error("ThumbnailLoader: can't find task to remove");
+            }
+            return;
+        }
+        this.que.splice(i, 1);
+    }
+
+
+    run = () => {
         if (this.que.length === 0 || this.runningRequests >= Config.Client.concurrentThumbnailGenerations) {
             return;
         }
+        let task = this.getNextTask();
+
+        if (task === null) {
+            return;
+        }
+
         this.runningRequests++;
-        let task = this.que[0];
-        task.onStartedLoading.forEach(cb=>cb());
+        task.taskEntities.forEach(te=>te.listener.onStartedLoading());
         task.inProgress = true;
-        
+
         let curImg = new Image();
         curImg.src = task.gridPhoto.getThumbnailPath();
-        
-        curImg.onload = () => {
-            
-            task.gridPhoto.thumbnailLoaded();
-            task.onLoad.forEach(cb=>cb());
 
-            this.que.shift();
+        curImg.onload = () => {
+
+            task.gridPhoto.thumbnailLoaded();
+            task.taskEntities.forEach(te=>te.listener.onLoad());
+
+            this.taskReady(task);
             this.runningRequests--;
             this.run();
         };
 
         curImg.onerror = (error) => {
-            
-            task.onLoad.forEach(cb=>cb(error));
+            task.taskEntities.forEach(te=>te.listener.onError(error));
 
-            this.que.shift();
+            this.taskReady(task);
             this.runningRequests--;
             this.run();
         };
-    }
+    };
+}
 
+
+export interface ThumbnailLoadingListener {
+    onStartedLoading:()=>void;
+    onLoad:()=>void;
+    onError:(error)=>void;
+}
+
+
+export interface ThumbnailTaskEntity {
+
+    priority:ThumbnailLoadingPriority;
+    listener:ThumbnailLoadingListener;
 }
 
 interface ThumbnailTask {
     gridPhoto:GridPhoto;
     inProgress:boolean;
-    onStartedLoading:Array<Function>;
-    onLoad:Array<Function>;
-    onError:Array<Function>;
+    taskEntities:Array<ThumbnailTaskEntity>;
+
 }