source: trunk/plog-includes/js/plog-slideshow.js @ 561

/*==================================================*
 $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,exif,image_name) {
        // 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;

        //EXIF information table
        this.exif = exif;

        // image name
        this.image_name = image_name;

        // 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 = false;

        // 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;

        // ID of a DIV containing HTML for your EXIF info table
        this.exifid;

        // ID of a DIV containing HTML for your image name
        this.imagenameid;

        // TEXTAREA element on your HTML page.
        // For example, document.SLIDES1FORM.SLIDES1TEXT
        // This is a deprecated 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;

        // Redirect URL called at the end of the slideshow
        this.redirect = false;

        // 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;
                } else if (this.redirect) {
                        window.location = this.redirect;
                }

                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 ].image_name + ": " + 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();
        }
}