/*
   RollableImage Object, 
   API for image rollovers
   gcpeters Wed., 10/03/01

   Copyright (c) 2001 Grant Peters.
   This code is free for use, and modify 
   with the precept that this copyright information
   remains with all implementations of this source code.
   
   Thank you, and enjoy.

*/

function RollableImage(theDocument, rootDir, name) {
    this.theDocument  = theDocument;
    this.rootDir      = rootDir;// the directory in which the images are found, if it is the same directory that the web page is, use '.'
    if(this.rootDir.charAt(this.rootDir.length - 1) != '/')
        this.rootDir += '/';
    this.name         = name;// the name and/or id value for the <img> tag
    // the following are optional fields
    this.prefix           = (arguments.length >= 4) ? arguments[3] : '';// the pre fix if any such as btn-<image name> this field may be an empty string
    this.ovrId            = (arguments.length >= 5) ? arguments[4] : '-ovr';// this whatever you wnat to use for an ID for the over image, it must be in the for of <image name><over-id> if you leave it blank it will be <image name>-ovr
    this.sufix             = (arguments.length == 6) ? arguments[5] : '.gif';// self explanitory
    
    this.offImage       = new Image();
    this.offImage.src  = this.rootDir + this.prefix + this.name + this.sufix;
    this.ovrImage      = new Image();
    this.ovrImage.src = this.rootDir + this.prefix + this.name + this.ovrId + this.sufix;
    this.isOff = true;
}
// just for debugging
RollableImage.prototype.showImages = function() {
                                        var s = '';
                                        for(var i=0;i<this.theDocument.images.length;i++)
                                            s += this.theDocument.images[i].name + '\n';
                                        alert(s);
                                    }

RollableImage.prototype.getOffStateSrc = function(){return this.offImage.src;}
RollableImage.prototype.getOvrStateSrc = function(){return this.ovrImage.src;}

RollableImage.prototype.setOffStateSrc = function(src){this.offImage.src = src;}
RollableImage.prototype.setOvrStateSrc = function(src){this.ovrImage.src = src;}

RollableImage.prototype.matchName      = function(name) {return this.name == name;}
// this is a "smart function" that knows the current state and rolls accordingly
RollableImage.prototype.roll           = function () {
                                             this.theDocument.images[this.name].src = (this.isOff) ? 
                                                                                         this.getOvrStateSrc() : 
                                                                                         this.getOffStateSrc();
                                             this.isOff = !this.isOff;
                                         }