ÿþ/*==================================================*

 $Id: slideshow.js,v 1.16 2003/10/14 12:39:00 pat Exp $

 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



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

// slide object

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

function slide(src,link,text,target,attr) {

  // 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;



  // Link URL

  this.link = link;



  // Text to display

  this.text = text;



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

  this.target = target;



  // Custom duration for the slide, in milliseconds.

  // This is an optional parameter.

  // this.timeout = 3000



  // 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();

  }



  // Flag to tell when load() has already been called

  this.loaded = false;



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

  this.load = function() {

    // This method loads the image for the slide



    if (!document.images) { return; }



    if (!this.loaded) {

      this.image.src = this.src;

      this.loaded = true;

    }

  }



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

  this.hotlink = function() {

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

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



    var mywindow;



    // If this slide does not have a link, do nothing

    if (!this.link) return;



    // Open the link in a separate window?

    if (this.target) {



      // If window attributes are specified,

      // use them to open the new window

      if (this.attr) {

        mywindow = 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)

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

      }



      // Pop the window to the front

      if (mywindow && mywindow.focus) mywindow.focus();



    } else {

      // Open the link 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,

  // but you might want to supply it for older browsers.

  this.textarea;



  // Milliseconds to pause between slides.

  // Individual slides can override this.

  this.timeout = 3000;



  // Hook functions to be called before and after updating the slide

  // this.pre_update_hook = function() { }

  // this.post_update_hook = function() { }



  // 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"))

  

    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 method implements the automatically running slideshow.

    // If you specify the "timeout" argument, then a new default

    // timeout will be set for the slideshow.

  

    // Make sure we're not already playing

    this.pause();

  

    // If the timeout argument was specified (optional)

    // then make it the new default

    if (timeout) {

      this.timeout = timeout;

    }

  

    // If the current slide has a custom timeout, use it;

    // otherwise use the default timeout

    if (typeof this.slides[ this.current ].timeout != 'undefined') {

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

    } else {

      timeout = this.timeout;

    }



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

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

  }



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

  this.pause = function() {

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

  

    if (this.timeoutid != 0) {



      clearTimeout(this.timeoutid);

      this.timeoutid = 0;



    }

  }



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

  this.update = function() {

    // This method updates the slideshow image on the page



    // Make sure the slideshow has been initialized correctly

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

  

    // Call the pre-update hook function if one was specified

    if (typeof this.pre_update_hook == 'function') {

      this.pre_update_hook();

    }



    // Convenience variable for the current slide

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



    // Determine if the browser supports filters

    var dofilter = false;

    if (this.image &&

        typeof this.image.filters != 'undefined' &&

        typeof this.image.filters[0] != 'undefined') {



      dofilter = true;



    }



    // 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();



    // Call the post-update hook function if one was specified

    if (typeof this.post_update_hook == 'function') {

      this.post_update_hook();

    }



    // Do we need to pre-fetch images?

    if (this.prefetch > 0) {



      var next, prev, count;



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

      next = this.current;

      prev = this.current;

      count = 0;

      do {



        // Get the next and previous slide number

        // Loop past the ends of the slideshow if necessary

        if (++next >= this.slides.length) next = 0;

        if (--prev < 0) prev = this.slides.length - 1;



        // Preload the slide image

        this.slides[next].load();

        this.slides[prev].load();



        // Keep going until we have fetched

        // the designated number of slides



      } while (++count < this.prefetch);

    }

  }



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

  this.goto_slide = function(n) {

    // This method 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.goto_random_slide = function(include_current) {

    // Picks a random slide (other than the current slide) and

    // displays it.

    // If the include_current parameter is true,

    // then 

    // See also: shuffle()



    var i;



    // Make sure there is more than one slide

    if (this.slides.length > 1) {



      // Generate a random slide number,

      // but make sure it is not the current slide

      do {

        i = Math.floor(Math.random()*this.slides.length);

      } while (i == this.current);

 

      // Display the slide

      this.goto_slide(i);

    }

  }





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

  this.next = function() {

    // This method 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 method 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.shuffle = function() {

    // This method randomly shuffles the order of the slides.



    var i, i2, slides_copy, slides_randomized;



    // Create a copy of the array containing the slides

    // in sequential order

    slides_copy = new Array();

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

      slides_copy[i] = this.slides[i];

    }



    // Create a new array to contain the slides in random order

    slides_randomized = new Array();



    // To populate the new array of slides in random order,

    // loop through the existing slides, picking a random

    // slide, removing it from the ordered list and adding it to

    // the random list.



    do {



      // Pick a random slide from those that remain

      i = Math.floor(Math.random()*slides_copy.length);



      // Add the slide to the end of the randomized array

      slides_randomized[ slides_randomized.length ] =

        slides_copy[i];



      // Remove the slide from the sequential array,

      // so it cannot be chosen again

      for (i2 = i + 1; i2 < slides_copy.length; i2++) {

        slides_copy[i2 - 1] = slides_copy[i2];

      }

      slides_copy.length--;



      // Keep going until we have removed all the slides



    } while (slides_copy.length);



    // Now set the slides to the randomized array

    this.slides = slides_randomized;

  }





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

  this.get_text = function() {

    // This method 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 && typeof this.textarea.value != 'undefined') {

      this.textarea.value = text;

    }



    // If a text id has been specified,

    // then change the contents of the HTML element

    if (this.textid) {



      r = this.getElementById(this.textid);

      if (!r) { return false; }

      if (typeof r.innerHTML == 'undefined') { return false; }



      // Update the text

      r.innerHTML = text;

    }

  }





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

  this.hotlink = function() {

    // This method 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 method 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 method is for internal use only.

    // This method 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)

    {

      return false;

    }

    else {

      return true;

    }

  }



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

  this.getElementById = function(element_id) {

    // This method returns the element corresponding to the id



    if (document.getElementById) {

      return document.getElementById(element_id);

    }

    else if (document.all) {

      return document.all[element_id];

    }

    else if (document.layers) {

      return document.layers[element_id];

    } else {

      return undefined;

    }

  }

  



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

  // 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 method 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 method 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 method is deprecated; you should use

    // the following code instead:

    // s.textid = "mytextid";

    // s.update();



    this.textid = textidstr;

    this.display_text();

  }

}