starting to preload in both directions

lib/ComicBook.js

@@ -455,58 +455,55 @@ function ComicBook(id, srcs, opts) {
 		this.showControl("loadingOverlay");
 
 		var i = pointer; // the current page counter for this method
-		var rendered = false;
-
-		// I am using recursion instead of a forEach loop so that the next image is
-		// only loaded when the previous one has completely finished
-		function preload(i) {
 
+		function loadImage(i) {
+console.log(i);
 			var page = new Image();
-
-			$("#cb-status").text("loading page " + (i + 1) + " of " + no_pages);
-
 			page.src = srcs[i];
 
 			page.onload = function () {
-
 				pages[i] = this;
 				loaded.push(i);
+				$("#cb-status").text("loaded page " + (i + 1) + " of " + no_pages);
 
-				// start to load from the beginning if loading started midway
+				// TODO: put back in the page render code, page request code
-				if (i === no_pages-1 && loaded.length !== no_pages) {
-					i = -1;
-				}
-
-				// there are still more pages to load, do it
-				if (loaded.length < no_pages) {
-					i++;
-					preload(i);
-				}
-
-				// double page mode needs an extra page added
-				var buffer = (options.displayMode === "double" && pointer < srcs.length-1) ? 1 : 0;
-
-				// start rendering the comic when the requested page is ready
-				if ((rendered === false && ($.inArray(pointer + buffer, loaded) !== -1)
-					||
-					(typeof page_requested === "number" && $.inArray(page_requested, loaded) !== -1))
-				) {
-					// if the user is waiting for a page to be loaded, render that one instead of the default pointer
-					if (typeof page_requested === "number") {
-						pointer = page_requested-1;
-						page_requested = false;
-					}
-
-					ComicBook.prototype.drawPage();
-					ComicBook.prototype.hideControl("loadingOverlay");
-					rendered = true;
-				}
-				if (loaded.length === no_pages) { ComicBook.prototype.hideControl("status") }
 			};
 		}
 
-		// manually trigger the first load
+		// Loads the pages at a rate of 3 forward, 1 back. This should make scrolling
-		preload(i);
+		// pages in both directions faster.
+		function preload(start, stop) {
+
+			var forward_buffer = 3;
+
+			var count = 2;
+			var forward = start+1;
+			var backward = start-1;
+
+			// always load the first requested image first
+			// TODO: remove the need for this?
+			loadImage(start);
+
+			while (forward <= stop) {
+
+				if (count > forward_buffer && backward > -1) {
+					loadImage(backward);
+					backward--;
+					count = 0;
+				} else {
+					loadImage(forward);
+				}
+				forward++;
+				count++;
+			}
+
+			while (backward > -1) {
+				loadImage(backward);
+				backward--;
+			}
+		}
+
+		preload(i, srcs.length-1);
 	};
 
 	ComicBook.prototype.pageLoaded = function (page_no) {
@@ -631,7 +628,7 @@ function ComicBook(id, srcs, opts) {
 			ComicBook.prototype.enhance[action](options);
 		});
 
-		var current_page = (options.displayMode === "double" && pointer+2 <= srcs.length) 
+		var current_page = (options.displayMode === "double" && pointer+2 <= srcs.length)
 			? (pointer+1) + "-" + (pointer+2) : pointer+1
 		$("#cb-current-page").text(current_page);