baCard work in progress

src/app/theme/baCard/baCardBlurHelper.service.ts

@@ -0,0 +1,51 @@
+import {Injectable} from 'angular2/core'
+
+import {BgMetrics} from './bgMetrics';
+
+@Injectable()
+export class BaCardBlurHelper {
+  private image:HTMLImageElement;
+  private imageLoadDeferred = Promise.defer(); //TODO: Promises or Observables refactor
+
+  constructor() {
+    this._genBgImage();
+    this._setImageLoadResolves()
+  }
+
+  private _genBgImage():void {
+    this.image = new Image();
+    let computedStyle = getComputedStyle(document.body, ':before');
+    this.image.src = computedStyle.backgroundImage.replace(/url\((['"])?(.*?)\1\)/gi, '$2');
+  }
+
+  private _setImageLoadResolves():void {
+    this.image.onerror = () => {
+      this.imageLoadDeferred.reject();
+    };
+    this.image.onload = () => {
+      this.imageLoadDeferred.resolve();
+    };
+  }
+
+  public bodyBgLoad():Promise {
+    return this.imageLoadDeferred.promise;
+  }
+
+  public getBodyBgImageSizes():BgMetrics {
+    let elemW = document.documentElement.clientWidth;
+    let elemH = document.documentElement.clientHeight;
+    if(elemW <= 640) return;
+    let imgRatio = (this.image.height / this.image.width);       // original img ratio
+    let containerRatio = (elemH / elemW);     // container ratio
+
+    let finalHeight, finalWidth;
+    if (containerRatio > imgRatio) {
+      finalHeight = elemH;
+      finalWidth = (elemH / imgRatio);
+    } else {
+      finalWidth = elemW;
+      finalHeight = (elemW * imgRatio);
+    }
+    return { width: finalWidth, height: finalHeight, positionX: (elemW - finalWidth)/2, positionY: (elemH - finalHeight)/2};
+  }
+}