From 3aa2f5da8403e721d7b19ee8b905707805d6a77a Mon Sep 17 00:00:00 2001
From: Bala Clark <balaclark@gmail.com>
Date: Sun, 26 Dec 2010 19:15:43 +0100
Subject: [PATCH] added support for double page spreads

---
 lib/ComicBook.js | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/lib/ComicBook.js b/lib/ComicBook.js
index 6724b0c..e5a7a70 100644
--- a/lib/ComicBook.js
+++ b/lib/ComicBook.js
@@ -62,6 +62,7 @@ function ComicBook(id, srcs, opts) {
 	var buffer = 1;		// image preload buffer level
 	var loaded = [];	// the images that have been loaded so far
 	var scale = 1;		// page zoom scale, 1 = 100%
+	var is_double_page_spread = false;
 	
 	// the current page, can pass a default as a url hash
 	var pointer = (parseInt(location.hash.substring(1),10) - 1) || 0;
@@ -218,7 +219,11 @@ function ComicBook(id, srcs, opts) {
 		// reset the canvas to stop duplicate pages showing
 		canvas.width = 0;
 		canvas.height = 0;
-		
+
+		// show double page spreads on a single page
+		is_double_page_spread = ((page.width > page.height || page2.width > page2.height) && options.displayMode === "double");
+		if (is_double_page_spread) { options.displayMode = "single"; }
+
 		if (options.displayMode === "double") {
 
 			// for double page spreads, factor in the width of both pages
@@ -238,7 +243,7 @@ function ComicBook(id, srcs, opts) {
 				
 			case "fitWidth":
 				document.body.style.overflowX = "hidden";
-				zoom_scale =  (window.innerWidth > width) ? ((window.innerWidth - width) / window.innerWidth) + 1 // scale up if the window is wider than the page
+				zoom_scale = (window.innerWidth > width) ? ((window.innerWidth - width) / window.innerWidth) + 1 // scale up if the window is wider than the page
 					  : window.innerWidth / width; // scale down if the window is narrower than the page
 				break;
 				
@@ -290,6 +295,9 @@ function ComicBook(id, srcs, opts) {
 		$.each(options.enhance, function(action, options) {
 			ComicBook.prototype.enhance[action](options);
 		});
+
+		// revert page mode back to double if it was auto switched for a double page spread
+		if (is_double_page_spread) { options.displayMode = "double"; }
 	};
 	
 	/**
@@ -299,7 +307,7 @@ function ComicBook(id, srcs, opts) {
 	 */
 	ComicBook.prototype.drawNextPage = function () {
 		if (pointer + 1 < pages.length) {
-			pointer += (options.displayMode === "single") ? 1 : 2;
+			pointer += (options.displayMode === "single" || is_double_page_spread) ? 1 : 2;
 			this.drawPage();
 		}
 	};
@@ -310,8 +318,11 @@ function ComicBook(id, srcs, opts) {
 	 * @see #drawPage
 	 */
 	ComicBook.prototype.drawPrevPage = function () {
+
+		is_double_page_spread = (pages[pointer-1].width > pages[pointer-1].height); // need to run double page check again here as we are going backwards
+
 		if (pointer > 0) {
-			pointer -= (options.displayMode === "single") ? 1 : 2;
+			pointer -= (options.displayMode === "single" || is_double_page_spread) ? 1 : 2;
 			this.drawPage();
 		}
 	};