Adding the generic image preloading javascript to the htmllib.

1 files changed, 62 insertions, 2 deletions

diff --git a/lib/htmllib.lua b/lib/htmllib.lua
index 9603b4f..ab10530 100644
--- a/lib/htmllib.lua
+++ b/lib/htmllib.lua
@@ -19,7 +19,7 @@
  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
-/* $Id: htmllib.lua,v 1.1 2008-01-15 18:20:23 pixel Exp $ */
+/* $Id: htmllib.lua,v 1.2 2008-01-16 14:23:49 pixel Exp $ */
 
 ]]--
 
@@ -64,7 +64,6 @@ function removeAllOptions(selectbox)
     }
 }
 
-
 function addOption(selectbox, value, text )
 {
     selectbox = getObjById(selectbox);
@@ -75,6 +74,67 @@ function addOption(selectbox, value, text )
     selectbox.options.add(optn);
 }
 
+//=============================================================================
+// Image Preloader
+function ImagePreloader(images, callback) {
+    // store the callback
+    this.callback = callback;
+
+    // initialize internal state.
+    this.nLoaded = 0;
+    this.nProcessed = 0;
+    this.aImages = new Array;
+
+    // record the number of images.
+    this.nImages = images.length;
+    
+    // for each image, call preload()
+    for (var i = 0; i < images.length; i++)
+        this.preload(images[i]);
+}
+
+ImagePreloader.prototype.preload = function(image) {
+    // create new Image object and add to array
+    var oImage = new Image;
+    this.aImages.push(oImage);
+
+    // set up event handlers for the Image object
+    oImage.onload = ImagePreloader.prototype.onload;
+    oImage.onerror = ImagePreloader.prototype.onerror;
+    oImage.onabort = ImagePreloader.prototype.onabort;
+
+    // assign pointer back to this.
+    oImage.oImagePreloader = this;
+    oImage.bLoaded = false;
+    oImage.source = image;
+
+    // assign the .src property of the Image object
+    oImage.src = image;
+}
+
+ImagePreloader.prototype.onComplete = function() {
+    this.nProcessed++;
+    if (this.nProcessed == this.nImages)
+        this.callback(this.aImages);
+}
+
+ImagePreloader.prototype.onload = function() {
+    this.bLoaded = true;
+    this.oImagePreloader.nLoaded++;
+    this.oImagePreloader.onComplete();
+}
+
+ImagePreloader.prototype.onerror = function() {
+    this.bError = true;
+    this.oImagePreloader.onComplete();
+}
+
+ImagePreloader.prototype.onabort = function() {
+    this.bAbort = true;
+    this.oImagePreloader.onComplete();
+}
+//=============================================================================
+
 /////////////////////////////////////////////////////////////////////
 /*-------------------------------------------------------------------
   AKX GetVariables