/*==================================================*

 $Id: slideshow.js 232 2004-05-23 03:55:34Z greengiant $

 Copyright 2000-2003 Patrick Fitzgerald

 http://slideshow.barelyfitz.com/



 This program is free software; you can redistribute it and/or modify

 it under the terms of the GNU General Public License as published by

 the Free Software Foundation; either version 2 of the License, or

 (at your option) any later version.



 This program is distributed in the hope that it will be useful,

 but WITHOUT ANY WARRANTY; without even the implied warranty of

 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 GNU General Public License for more details.



 You should have received a copy of the GNU General Public License

 along with this program; if not, write to the Free Software

 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 *==================================================*/



// There are two objects defined in this file:

// "slide" - contains all the information for a single slide

// "slideshow" - consists of multiple slide objects and runs the slideshow



/* added functionality to add height, width, and alt to the slide

 * March 5th 2004

 * Mike Willbanks

 */



//==================================================

// slide object

//==================================================

function slide(src,link,text,target,attr,height,width,alt) {

// This is the constructor function for the slide object.

// It is called automatically when you create a new slide object.

// For example:

// s = new slide();



  // Image URL

  this.src = src;

  //Image Attributes

  this.height = height;

  this.width = width;

  this.alt = alt;

  

  // Link URL

  this.link = link;



  // Text to display

  this.text = text;



  // Name of the target window ("_blank")

  this.target = target;



  // Attributes for the target window:

  // width=n,height=n,resizable=yes or no,scrollbars=yes or no,

  // toolbar=yes or no,location=yes or no,directories=yes or no,

  // status=yes or no,menubar=yes or no,copyhistory=yes or no

  // Example: "width=200,height=300"

  this.attr = attr;



  // Create an image object for the slide

  if (document.images) {

    this.image = new Image();

  }



  //--------------------------------------------------

  this.load = function() {

  // This function loads the image for the slide



    if (!document.images) { return; }



    if (this.image.src != this.src) {

      this.image.src = this.src;

    }

	 if (this.image.height != this.height) {

	   this.image.height = this.height;

	 }

	 if (this.image.width != this.width) {

	   this.image.width = this.width;

	 }

	 if (this.image.alt != this.alt) {

	   this.image.alt = this.alt;

	}

  }



  //--------------------------------------------------

  this.hotlink = function() {

  // This function jumps to the slide's link.

  // If a window was specified for the slide, then it opens a new window.



    if (this.target) {



      // If window attributes are specified, use them to open the new window

      if (this.attr) {

        window.open(this.link, this.target, this.attr);

  

      } else {

        // If window attributes are not specified, do not use them

        // (this will copy the attributes from the originating window)

        window.open(this.link, this.target);

      }



    } else {

      // Open the hotlink in the current window

      location.href = this.link;

    }

  }

}



//==================================================

// slideshow object

//==================================================

function slideshow( slideshowname ) {

// This is the constructor function for the slideshow object.

// It is called automatically when you create a new object.

// For example:

// ss = new slideshow("ss");



  // Name of this object

  // (required if you want your slideshow to auto-play)

  // For example, "SLIDES1"

  this.name = slideshowname;



  // When we reach the last slide, should we loop around to start the

  // slideshow again?

  this.repeat = true;



  // Number of images to pre-fetch.

  // -1 = preload all images.

  //  0 = load each image is it is used.

  //  n = pre-fetch n images ahead of the current image.

  // I recommend preloading all images unless you have large

  // images, or a large amount of images.

  this.prefetch = -1;



  // IMAGE element on your HTML page.

  // For example, document.images.SLIDES1IMG

  this.image;



  // ID of a DIV element on your HTML page that will contain the text.

  // For example, "slides2text"

  // Note: after you set this variable, you should call

  // the update() method to update the slideshow display.

  this.textid;



  // TEXTAREA element on your HTML page.

  // For example, document.SLIDES1FORM.SLIDES1TEXT

  // This is a depracated method for displaying the text.

  this.textarea;



   // Milliseconds to pause between slides

  this.timeout = 3000;



  // These are private variables

  this.slides = new Array();

  this.current = 0;

  this.timeoutid = 0;



  //--------------------------------------------------

  // Public methods

  //--------------------------------------------------

  this.add_slide = function(slide) {

  // Add a slide to the slideshow.

  // For example:

  // SLIDES1.add_slide(new slide("s1.jpg", "link.html"))

  

    // If this version of JavaScript does not allow us to

    // change images, then we can't do the slideshow.

    if (!document.images) { return; }

  

    var i = this.slides.length;

  

    // Prefetch the slide image if necessary

    if (this.prefetch == -1) {

      slide.load();

    }



    this.slides[i] = slide;

  }



  //--------------------------------------------------

  this.play = function(timeout) {

  // This function implements the automatically running slideshow.

  

    // Make sure we're not already playing

    this.pause();

  

    // If a new timeout was specified (optional)

    // set it here

    if (timeout) {

      this.timeout = timeout;

    }

  

    // After the timeout, call this.loop()

    this.timeoutid = setTimeout( this.name + ".loop()", this.timeout);

  }



  //--------------------------------------------------

  this.pause = function() {

  // This function stops the slideshow if it is automatically running.

  

    if (this.timeoutid != 0)

    {

      clearTimeout(this.timeoutid);

      this.timeoutid = 0;

    }

  }



  //--------------------------------------------------

  this.update = function() {

  // This function updates the slideshow image on the page



    // Convenience variables

    var slide = this.slides[ this.current ];

    var dofilter = (this.image.filters && this.image.filters[0]);



    // Make sure the slideshow has been initialized correctly

    if (! this.valid_image()) { return; }

  

    // Load the slide image if necessary

    slide.load();

  

    // Apply the filters for the image transition

    if (dofilter) {



      // If the user has specified a custom filter for this slide,

      // then set it now

      if (slide.filter &&

          this.image.style &&

          this.image.style.filter) {

        this.image.style.filter = slide.filter;

      }

      this.image.filters[0].Apply();

    }



    // Update the image.

    this.image.src = slide.image.src;



    // Play the image transition filters

    if (dofilter) {

      this.image.filters[0].Play();

    }



    // Update the text

    this.display_text();



    // Pre-fetch the next slide image(s) if necessary

    if (this.prefetch > 0) {

      for (i = this.current + 1;

           i <= (this.current + this.prefetch) && i < this.slides.length;

           i++) {

        this.slides[i].load();

      }

    }

  }



  //--------------------------------------------------

  this.goto_slide = function(n) {

  // This function jumpts to the slide number you specify.

  // If you use slide number -1, then it jumps to the last slide.

  // You can use this to make links that go to a specific slide,

  // or to go to the beginning or end of the slideshow.

  // Examples:

  // onClick="myslides.goto_slide(0)"

  // onClick="myslides.goto_slide(-1)"

  // onClick="myslides.goto_slide(5)"

  

    if (n == -1) {

      n = this.slides.length - 1;

    }

  

    if (n < this.slides.length && n >= 0) {

      this.current = n;

    }

  

    this.update();

  }



  //--------------------------------------------------

  this.next = function() {

  // This function advances to the next slide.

  

    // Increment the image number

    if (this.current < this.slides.length - 1) {

      this.current++;

    } else if (this.repeat) {

      this.current = 0;

    }

  

    this.update();

  }



  //--------------------------------------------------

  this.previous = function() {

  // This function goes to the previous slide.

  

    // Decrement the image number

    if (this.current > 0) {

      this.current--;

    } else if (this.repeat) {

      this.current = this.slides.length - 1;

    }

  

    this.update();

  }



  //--------------------------------------------------

  this.get_text = function() {

  // This function returns the text of the current slide

  

    return(this.slides[ this.current ].text);

  }



  //--------------------------------------------------

  this.get_all_text = function(before_slide, after_slide) {

  // Return the text for all of the slides.

  // For the text of each slide, add "before_slide" in front of the

  // text, and "after_slide" after the text.

  // For example:

  // document.write("<ul>");

  // document.write(s.get_all_text("<li>","\n"));

  // document.write("<\/ul>");

  

    all_text = "";

  

    // Loop through all the slides in the slideshow

    for (i=0; i < this.slides.length; i++) {

  

      slide = this.slides[i];

    

      if (slide.text) {

        all_text += before_slide + slide.text + after_slide;

      }

  

    }

  

    return(all_text);

  }



  //--------------------------------------------------

  this.display_text = function(text) {

  // Display the text for the current slide

  

    // If the "text" arg was not supplied (usually it isn't),

    // get the text from the slideshow

    if (!text) {

      text = this.slides[ this.current ].text;

    }

  

    // If a textarea has been specified,

    // then change the text displayed in it

    if (this.textarea) {

      this.textarea.value = text;

    }

  

    // If a text id has been specified,

    // then change the contents of the HTML element

    if (this.textid) {



      // Make sure we don't cause an error

      // for browsers that do not support getElementById

      if (!document.getElementById){ return false; }

      r = document.getElementById(this.textid);

      if (!r) { return false; }



      // Update the text

      r.innerHTML = text;



    }

  }



  //--------------------------------------------------

  this.hotlink = function() {

  // This function calls the hotlink() method for the current slide.

  

    this.slides[ this.current ].hotlink();

  }



  //--------------------------------------------------

  this.save_position = function(cookiename) {

  // Saves the position of the slideshow in a cookie,

  // so when you return to this page, the position in the slideshow

  // won't be lost.

  

    if (!cookiename) {

      cookiename = this.name + '_slideshow';

    }

  

    document.cookie = cookiename + '=' + this.current;

  }



  //--------------------------------------------------

  this.restore_position = function(cookiename) {

  // If you previously called slideshow_save_position(),

  // returns the slideshow to the previous state.

  

    //Get cookie code by Shelley Powers

  

    if (!cookiename) {

      cookiename = this.name + '_slideshow';

    }

  

    var search = cookiename + "=";

  

    if (document.cookie.length > 0) {

      offset = document.cookie.indexOf(search);

      // if cookie exists

      if (offset != -1) { 

        offset += search.length;

        // set index of beginning of value

        end = document.cookie.indexOf(";", offset);

        // set index of end of cookie value

        if (end == -1) end = document.cookie.length;

        this.current = parseInt(unescape(document.cookie.substring(offset, end)));

        }

     }

  }



  //--------------------------------------------------

  this.noscript = function() {

  // This function is not for use as part of your slideshow,

  // but you can call it to get a plain HTML version of the slideshow

  // images and text.

  // You should copy the HTML and put it within a NOSCRIPT element, to

  // give non-javascript browsers access to your slideshow information.

  // This also ensures that your slideshow text and images are indexed

  // by search engines.

  

    $html = "\n";

  

    // Loop through all the slides in the slideshow

    for (i=0; i < this.slides.length; i++) {

  

      slide = this.slides[i];

  

      $html += '<P>';

  

      if (slide.link) {

        $html += '<a href="' + slide.link + '">';

      }

  

      $html += '<img src="' + slide.src + '" ALT="slideshow image">';

  

      if (slide.link) {

        $html += "<\/a>";

      }

  

      if (slide.text) {

        $html += "<BR>\n" + slide.text;

      }

  

      $html += "<\/P>" + "\n\n";

    }

  

    // Make the HTML browser-safe

    $html = $html.replace(/\&/g, "&amp;" );

    $html = $html.replace(/</g, "&lt;" );

    $html = $html.replace(/>/g, "&gt;" );

  

    return('<pre>' + $html + '</pre>');

  }



  //--------------------------------------------------  

  // Private methods

  //--------------------------------------------------

  this.loop = function() {

  // This function is for internal use only.

  // This function gets called automatically by a JavaScript timeout.

  // It advances to the next slide, then sets the next timeout.

  // If the next slide image has not completed loading yet,

  // then do not advance to the next slide yet.



    // Make sure the next slide image has finished loading

    if (this.current < this.slides.length - 1) {

      next_slide = this.slides[this.current + 1];

      if (next_slide.image.complete == null || next_slide.image.complete) {

        this.next();

      }

    } else { // we're at the last slide

      this.next();

    }

    

    // Keep playing the slideshow

    this.play( );

  }



  //--------------------------------------------------

  this.valid_image = function() {

  // Returns 1 if a valid image has been set for the slideshow

  

    if (!this.image)

    {

      // Stop the slideshow

      this.pause;

  

      // Display an error message

      window.status = "Error: slideshow image not initialized for " + this.name;

          

      return 0;

    }

    else {

      return 1;

    }

  }



  //--------------------------------------------------  

  // Deprecated methods

  // I don't recommend the use of the following methods,

  // but they are included for backward compatibility.

  // You can delete them if you don't need them.

  //--------------------------------------------------



  //--------------------------------------------------

  this.set_image = function(imageobject) {

  // This function is deprecated; you should use

  // the following code instead:

  // s.image = document.images.myimagename;

  // s.update();

    if (!document.images)

      return;

    this.image = imageobject;

  }



  //--------------------------------------------------

  this.set_textarea = function(textareaobject) {

  // This function is deprecated; you should use

  // the following code instead:

  // s.textarea = document.form.textareaname;

  // s.update();

    this.textarea = textareaobject;

    this.display_text();

  }



  //--------------------------------------------------

  this.set_textid = function(textidstr) {

  // This function is deprecated; you should use

  // the following code instead:

  // s.textid = "mytextid";

  // s.update();

    this.textid = textidstr;

    this.display_text();

  }

}