terom@30: // A source of tile images of a specific width/height, zoom level range, and some other attributes
terom@30: var Source = Class.create({
terom@30:     initialize: function (path, tile_width, tile_height, zoom_min, zoom_max) {
terom@30:         this.path = path;
terom@30:         this.tile_width = tile_width;
terom@30:         this.tile_height = tile_height;
terom@30:         this.zoom_min = zoom_min;
terom@30:         this.zoom_max = zoom_max;
terom@30: 
terom@30:         this.refresh = false;
terom@30:         this.opt_key = this.opt_value = null;
terom@30:     },
terom@30:     
terom@30:     // build a URL for the given tile image
terom@30:     build_url: function (col, row, zl, sw, sh) {
terom@30:         // two-bit hash (0-4) based on the (col, row)
terom@30:         var hash = ( (col % 2) << 1 | (row % 2) ) + 1;
terom@30:         
terom@30:         // the subdomain to use
terom@30:         var subdomain = "";
terom@30:         
terom@30:         if (0)
terom@30:             subdomain = "tile" + hash + ".";
terom@30: 
terom@30:         // the (x, y) co-ordinates
terom@30:         var x = col * this.tile_width;
terom@30:         var y = row * this.tile_height;
terom@30: 
terom@40:         var url = this.path + "?x=" + x + "&y=" + y + "&zl=" + zl; // + "&sw=" + sw + "&sh=" + sh;
terom@30: 
terom@30:         if (this.refresh)
terom@30:             url += "&ts=" + new Date().getTime();
terom@30: 
terom@30:         if (this.opt_key && this.opt_value)
terom@30:             url += "&" + this.opt_key + "=" + this.opt_value;
terom@30: 
terom@30:         return url;
terom@30:     },
terom@40: 
terom@40:     // build an URL for a full image
terom@40:     build_image_url: function (cx, cy, w, h, zl) {
terom@40:         return (this.path + "?cx=" + cx + "&cy=" + cy + "&w=" + w + "&h=" + h + "&zl=" + zl);
terom@40:     }
terom@30: });
terom@30: 
terom@30: // a viewport that contains a substrate which contains several zoom layers which contain many tiles
terom@30: var Viewport = Class.create({
terom@30:     initialize: function (source, viewport_id) {
terom@30:         this.source = source;
terom@30: 
terom@30:         this.id = viewport_id;
terom@30:         this.div = $(viewport_id);
terom@30:         this.substrate = this.div.down("div.substrate");
terom@30:     
terom@30:         // the stack of zoom levels
terom@30:         this.zoom_layers = [];
terom@30:         
terom@30:         // pre-populate the stack
terom@30:         for (var zoom_level = source.zoom_min; zoom_level <= source.zoom_max; zoom_level++) {
terom@30:             var zoom_layer = new ZoomLayer(source, zoom_level);
terom@30: 
terom@30:             this.substrate.appendChild(zoom_layer.div);
terom@30:             this.zoom_layers[zoom_level] = zoom_layer;
terom@30:         }
terom@30: 
terom@30:         // make the substrate draggable
terom@30:         this.draggable = new Draggable(this.substrate, {
terom@30:             onStart: this.on_scroll_start.bind(this),
terom@30:             onDrag: this.on_scroll_move.bind(this),
terom@30:             onEnd: this.on_scroll_end.bind(this),
terom@30:         });
terom@30: 
terom@30:         // event handlers
terom@30:         Event.observe(this.substrate, "dblclick", this.on_dblclick.bindAsEventListener(this));
terom@30:         Event.observe(this.substrate, "mousewheel", this.on_mousewheel.bindAsEventListener(this));
terom@30:         Event.observe(this.substrate, "DOMMouseScroll", this.on_mousewheel.bindAsEventListener(this));     // mozilla
terom@30:         Event.observe(document, "resize", this.on_resize.bindAsEventListener(this));
terom@39:         
terom@39:         // zoom buttons
terom@39:         this.btn_zoom_in = $("btn-zoom-in");
terom@39:         this.btn_zoom_out = $("btn-zoom-out");
terom@39: 
terom@39:         if (this.btn_zoom_in)
terom@39:             Event.observe(this.btn_zoom_in, "click", this.zoom_in.bindAsEventListener(this));
terom@39:         
terom@39:         if (this.btn_zoom_out)
terom@39:             Event.observe(this.btn_zoom_out, "click", this.zoom_out.bindAsEventListener(this));
terom@32:     
terom@32:         // set viewport size
terom@30:         this.update_size();
terom@32:         
terom@40:         // this comes after update_size, since it must be updated once we have the size and zoom layer...
terom@40:         this.image_link = $("lnk-image");
terom@40:         
terom@32:         // initial location?    
terom@32:         if (document.location.hash) {
terom@32:             // x:y:z tuple
terom@32:             var pt = document.location.hash.substr(1).split(":");
terom@32:             
terom@32:             // unpack
terom@32:             var cx = 0, cy = 0, z = 0;
terom@32:             
terom@32:             if (pt.length) cx = parseInt(pt.shift());
terom@32:             if (pt.length) cy = parseInt(pt.shift());
terom@32:             if (pt.length) z = parseInt(pt.shift());
terom@30: 
terom@32:             // initial view
terom@38:             this.zoom_scaled(
terom@38:                 cx - this.center_offset_x, 
terom@38:                 cy - this.center_offset_y, 
terom@38:                 z
terom@38:             );
terom@32: 
terom@32:         } else {
terom@32:             // this sets the scroll offsets, zoom level, and loads the tiles
terom@32:             this.zoom_to(0, 0, 0);
terom@32:         }
terom@30:     },
terom@30:     
terom@30:     /* event handlers */
terom@30: 
terom@30:     // window resized
terom@30:     on_resize: function (ev) {
terom@30:         this.update_size();
terom@30:         this.update_tiles();
terom@30:     },
terom@30:     
terom@30:     // double-click handler
terom@30:     on_dblclick: function (ev) {
terom@30:         var offset = this.event_offset(ev);
terom@30:         
terom@30:         this.zoom_center_to(
terom@30:             this.scroll_x + offset.x,
terom@30:             this.scroll_y + offset.y,
terom@30:             1   // zoom in
terom@30:         );
terom@30:     },
terom@30: 
terom@30:     // mousewheel handler
terom@30:     on_mousewheel: function (ev) {
terom@30:         // this works in very weird ways, so it's based on code from http://adomas.org/javascript-mouse-wheel/
terom@30:         // (it didn't include any license, so this is written out manually)
terom@30:         var delta;
terom@30:         
terom@30:         // this is browser-dependant...
terom@30:         if (ev.wheelDelta) {
terom@30:             // IE + Opera
terom@30:             delta = ev.wheelDelta;
terom@30: 
terom@30:             if (window.opera) {  
terom@30:                 // Opera, but apparently not newer versions?
terom@30:                 //delta = -delta;
terom@30:             }
terom@30: 
terom@30:         } else if (ev.detail) {
terom@30:             // Mozilla
terom@30:             delta = -ev.detail;
terom@30: 
terom@30:         } else {
terom@30:             // mousewheel not supported...
terom@30:             return;
terom@30: 
terom@30:         }
terom@30:         
terom@30:         // don't scroll the page
terom@30:         if (ev.preventDefault)
terom@30:             ev.preventDefault();
terom@30:         
terom@30:         // delta > 0 : scroll up, zoom in
terom@30:         // delta < 0 : scroll down, zoom out
terom@30:         delta = delta < 0 ? -1 : 1;
terom@30: 
terom@30:         // Firefox's DOMMouseEvent's pageX/Y attributes are broken. layerN is for mozilla, offsetN for IE, seems to work
terom@30: 
terom@30:         // absolute location of the cursor
terom@30:         var x = parseInt(ev.target.style.left) + (ev.layerX ? ev.layerX : ev.offsetX);
terom@30:         var y = parseInt(ev.target.style.top) + (ev.layerY ? ev.layerY : ev.offsetY);
terom@30:         
terom@30:         // zoom \o/
terom@30:         this.zoom_center_to(x, y, delta);
terom@30:     },
terom@30:     
terom@30:     // substrate scroll was started
terom@30:     on_scroll_start: function (ev) {
terom@30: 
terom@30:     },
terom@30:     
terom@30:     // substrate was scrolled, update scroll_{x,y}, and then update tiles after 100ms
terom@30:     on_scroll_move: function (ev) {
terom@30:         this.update_scroll();
terom@30:         this.update_after_timeout();
terom@30:     },
terom@30:     
terom@30:     // substrate scroll was ended, update tiles now
terom@30:     on_scroll_end: function (ev) {
terom@30:         this.update_now();
terom@30:     },
terom@30: 
terom@30:     /* get state */
terom@30: 
terom@30:     // return the absolute (x, y) coords of the given event inside the viewport
terom@30:     event_offset: function (ev) {
terom@30:         var offset = this.div.cumulativeOffset();
terom@30: 
terom@30:         return {
terom@30:             x: ev.pointerX() - offset.left, 
terom@30:             y: ev.pointerY() - offset.top
terom@30:         };
terom@30:     },
terom@30: 
terom@30:     /* modify state */
terom@30: 
terom@30:     // scroll the view to place the given absolute (x, y) co-ordinate at the top left
terom@30:     scroll_to: function (x, y) {
terom@30:         // update it via the style
terom@30:         this.substrate.style.top = "-" + y + "px";
terom@30:         this.substrate.style.left = "-" + x + "px";
terom@30:         
terom@30:         // update these as well
terom@30:         this.scroll_x = x;
terom@30:         this.scroll_y = y;
terom@30:     },
terom@30: 
terom@30:     // scroll the view to place the given absolute (x, y) co-ordinate at the center
terom@30:     scroll_center_to: function (x, y) {
terom@30:         return this.scroll_to(
terom@30:             x - this.center_offset_x,
terom@30:             y - this.center_offset_y
terom@30:         );
terom@30:     },
terom@30:  
terom@30:     // zoom à la delta such that the given (zoomed) absolute (x, y) co-ordinates will be at the top left
terom@30:     zoom_scaled: function (x, y, delta) {
terom@30:         if (!this.update_zoom(delta))
terom@30:             return false;
terom@30: 
terom@30:         // scroll to the new position
terom@30:         this.scroll_to(x, y);
terom@30:         
terom@30:         // update view
terom@30:         // XXX: ...
terom@30:         this.update_after_timeout();
terom@30:         
terom@30:         return true;
terom@30:     },
terom@30:    
terom@30:     // zoom à la delta such that the given (current) absolute (x, y) co-ordinates will be at the top left
terom@30:     zoom_to: function (x, y, delta) {
terom@30:         return this.zoom_scaled(
terom@30:             scaleByZoomDelta(x, delta),
terom@30:             scaleByZoomDelta(y, delta),
terom@30:             delta
terom@30:         );
terom@30:     },
terom@30:     
terom@30:     // zoom à la delta such that the given (current) absolute (x, y) co-ordinates will be at the center
terom@30:     zoom_center_to: function (x, y, delta) {
terom@30:         return this.zoom_scaled(
terom@30:             scaleByZoomDelta(x, delta) - this.center_offset_x,
terom@30:             scaleByZoomDelta(y, delta) - this.center_offset_y,
terom@30:             delta
terom@30:         );
terom@30:     },
terom@30: 
terom@39:     // zoom à la delta, keeping the view centered
terom@39:     zoom_centered: function (delta) {
terom@39:         return this.zoom_center_to(
terom@39:             this.scroll_x + this.center_offset_x,
terom@39:             this.scroll_y + this.center_offset_y,
terom@39:             delta
terom@39:         );
terom@39:     },
terom@39: 
terom@39:     // zoom in one level, keeping the view centered
terom@39:     zoom_in: function () {
terom@39:         return this.zoom_centered(+1);
terom@39:     },
terom@39:     
terom@39:     // zoom out one leve, keeping the view centered
terom@39:     zoom_out: function () {
terom@39:         return this.zoom_centered(-1);
terom@39:     },
terom@30: 
terom@30:     /* update view/state to reflect reality */
terom@30: 
terom@30:     // figure out the viewport dimensions
terom@30:     update_size: function () {
terom@30:         this.view_width = this.div.getWidth();
terom@30:         this.view_height = this.div.getHeight();
terom@30: 
terom@30:         this.center_offset_x = Math.floor(this.view_width / 2);
terom@30:         this.center_offset_y = Math.floor(this.view_height / 2);
terom@40: 
terom@40:         this.update_image_link();
terom@30:     },
terom@30:     
terom@30:     // figure out the scroll offset as absolute pixel co-ordinates at the top left
terom@30:     update_scroll: function() {
terom@30:         this.scroll_x = -parseInt(this.substrate.style.left);
terom@30:         this.scroll_y = -parseInt(this.substrate.style.top);
terom@30:     },
terom@30: 
terom@30:     // wiggle the ZoomLevels around to match the current zoom level
terom@30:     update_zoom: function(delta) {
terom@30:         if (!this.zoom_layer) {
terom@30:             // first zoom operation
terom@30: 
terom@30:             // is the new zoom level valid?
terom@30:             if (!this.zoom_layers[delta])
terom@30:                 return false;
terom@30:             
terom@30:             // set the zoom layyer
terom@30:             this.zoom_layer = this.zoom_layers[delta];
terom@30:             
terom@30:             // enable it
terom@30:             this.zoom_layer.enable(11);
terom@30:             
terom@30:             // no need to .update_tiles or anything like that
terom@30:             
terom@30:         } else {
terom@30:             // is the new zoom level valid?
terom@30:             if (!this.zoom_layers[this.zoom_layer.level + delta])
terom@30:                 return false;
terom@30: 
terom@30:             var zoom_old = this.zoom_layer;
terom@30:             var zoom_new = this.zoom_layers[this.zoom_layer.level + delta];
terom@30:             
terom@30:             // XXX: ugly hack
terom@30:             if (this.zoom_timer) {
terom@30:                 clearTimeout(this.zoom_timer);
terom@30:                 this.zoom_timer = null;
terom@30:             }
terom@30:             
terom@30:             // get other zoom layers out of the way
terom@30:             this.zoom_layers.each(function (zl) {
terom@30:                 zl.disable();
terom@30:             });
terom@30:             
terom@30:             // update the zoom layer
terom@30:             this.zoom_layer = zoom_new;
terom@30:             
terom@30:             // apply new z-indexes, preferr the current one over the new one
terom@30:             zoom_new.enable(11);
terom@30:             zoom_old.enable(10);
terom@30:             
terom@30:             // resize the tiles in the two zoom layers
terom@30:             zoom_new.update_tiles(zoom_new.level);
terom@30:             zoom_old.update_tiles(zoom_old.level);
terom@30:             
terom@30:             // XXX: ugly hack
terom@30:             this.zoom_timer = setTimeout(function () { zoom_old.disable()}, 1000);
terom@30:         }
terom@30: 
terom@39:         // update UI
terom@39:         this.update_zoom_ui();
terom@39: 
terom@30:         return true;
terom@30:     },
terom@39: 
terom@39:     // keep the zoom buttons, if any, updated
terom@39:     update_zoom_ui: function () {
terom@39:         if (this.btn_zoom_in)
terom@39:             (this.zoom_layer.level >= this.source.zoom_max) ? this.btn_zoom_in.disable() : this.btn_zoom_in.enable();
terom@39:         
terom@39:         if (this.btn_zoom_out)
terom@39:             (this.zoom_layer.level <= this.source.zoom_min) ? this.btn_zoom_out.disable() : this.btn_zoom_out.enable();
terom@40:         
terom@40:         this.update_image_link();
terom@39:     },
terom@30:     
terom@30:     // ensure that all tiles that are currently visible are loaded
terom@30:     update_tiles: function() {
terom@30:         // short names for some vars...
terom@30:         var x = this.scroll_x;
terom@30:         var y = this.scroll_y;
terom@30:         var sw = this.view_width;
terom@30:         var sh = this.view_height;
terom@30:         var tw = this.source.tile_width;
terom@30:         var th = this.source.tile_height;
terom@30:         var zl = this.zoom_layer.level;
terom@30:         
terom@30:         // figure out what set of columns are visible
terom@30:         var start_col = Math.max(0, Math.floor(x / tw));
terom@30:         var start_row = Math.max(0, Math.floor(y / th));
terom@30:         var end_col = Math.floor((x + sw) / tw);
terom@30:         var end_row = Math.floor((y + sh) / th);
terom@30: 
terom@30:         // loop through all those tiles
terom@30:         for (var col = start_col; col <= end_col; col++) {
terom@30:             for (var row = start_row; row <= end_row; row++) {
terom@30:                 // the tile's id
terom@30:                 var id = "tile_" + this.zoom_layer.level + "_" + col + "_" + row;
terom@30:                 
terom@30:                 // does the element exist already?
terom@30:                 var t = $(id);
terom@30: 
terom@30:                 if (!t) {
terom@30:                     // build a new tile
terom@30:                     t = Builder.node("img", {
terom@30:                             src:    this.source.build_url(col, row, zl, sw, sh),
terom@30:                             id:     id,
terom@30:                             title:  "(" + col + ", " + row + ")",
terom@30:                             // style set later
terom@30:                         }
terom@30:                     );
terom@30:                     
terom@30:                     // set the CSS style stuff
terom@30:                     t.style.top = th * row;
terom@30:                     t.style.left = tw * col;
terom@30:                     t.style.display = "none";
terom@30:                     
terom@30:                     // wait for it to load
terom@30:                     Event.observe(t, "load", _tile_loaded.bindAsEventListener(t));
terom@30: 
terom@30:                     // store the col/row
terom@30:                     t.__col = col;
terom@30:                     t.__row = row;
terom@30:                     
terom@30:                     // add it to the zoom layer
terom@30:                     this.zoom_layer.add_tile(t);
terom@30: 
terom@30:                 } else if (this.source.reload) {
terom@30:                     // force the tile to reload
terom@30:                     touch_tile(t, col, row);
terom@30: 
terom@30:                 }
terom@30:             }
terom@30:         }
terom@40:         
terom@40:         this.update_scroll_ui();
terom@40:     }, 
terom@40:     
terom@40:     // update scroll-dependant UI elements
terom@40:     update_scroll_ui: function () {
terom@40:         // update link-to-image
terom@40:         this.update_image_link();
terom@30: 
terom@30:         // update the link-to-this-page thing
terom@32:         document.location.hash = "#" + (this.scroll_x + this.center_offset_x) + ":" + (this.scroll_y + this.center_offset_y) + ":" + this.zoom_layer.level;
terom@40:     },
terom@40:     
terom@40:     // update image link with size, zoom, pos
terom@40:     update_image_link: function () {
terom@40:         if (!this.image_link)
terom@40:             return;
terom@40: 
terom@40:         this.image_link.href = this.source.build_image_url(
terom@40:             this.scroll_x + this.center_offset_x,
terom@40:             this.scroll_y + this.center_offset_y,
terom@40:             this.view_width, this.view_height,
terom@40:             this.zoom_layer.level
terom@40:         );
terom@40: 
terom@40:         this.image_link.innerHTML = this.view_width + "x" + this.view_height + "@" + this.zoom_layer.level;
terom@40:     },
terom@30: 
terom@30:     // do update_tiles after 100ms, unless we are called again
terom@30:     update_after_timeout: function () {
terom@30:         this._update_idle = false;
terom@30: 
terom@30:         if (this._update_timeout)
terom@30:             clearTimeout(this._update_timeout);
terom@30: 
terom@30:         this._update_timeout = setTimeout(this._update_timeout_trigger.bind(this), 100);  
terom@30:     },
terom@30:     
terom@30:     _update_timeout_trigger: function () {
terom@30:         this._update_idle = true;
terom@30: 
terom@30:         this.update_tiles();
terom@30:     },
terom@30: 
terom@30:     // call update_tiles if it hasn't been called due to update_after_timeout
terom@30:     update_now: function () {
terom@30:         if (this._update_timeout)
terom@30:             clearTimeout(this._update_timeout);
terom@30:         
terom@30:         if (!this._update_idle)
terom@30:             this.update_tiles();
terom@30:     },
terom@30: 
terom@30: });
terom@30: 
terom@30: // used by Viewport.update_tiles to make a tile visible after it has loaded
terom@30: function _tile_loaded (ev) {
terom@30:     this.style.display = "block";
terom@30: }
terom@30: 
terom@30: // a zoom layer containing the tiles for one zoom level
terom@30: var ZoomLayer = Class.create({
terom@30:     initialize: function (source, zoom_level) {
terom@30:         this.source = source;
terom@30:         this.level = zoom_level;
terom@30:         this.div = Builder.node("div", { id: "zl_" + this.level, style: "position: relative; display: none;"});
terom@30: 
terom@30:         // our tiles
terom@30:         this.tiles = [];
terom@30:     },
terom@30:     
terom@30:     // add a tile to this zoom layer
terom@30:     add_tile: function (tile) {
terom@30:         this.div.appendChild(tile);
terom@30:         this.tiles.push(tile);
terom@30:     },
terom@30:     
terom@30:     // make this zoom layer visible with the given z-index
terom@30:     enable: function (z_index) {
terom@30:         this.div.style.zIndex = z_index;
terom@30:         this.div.show();
terom@30:     },
terom@30:    
terom@30:     // hide this zoom layer
terom@30:     disable: function (z_index) {
terom@30:         this.div.hide();
terom@30:     },
terom@30:     
terom@30:     // update the tiles in this zoom layer so that they are in the correct position and of the correct size when
terom@30:     // viewed with the given zoom level
terom@30:     update_tiles: function (zoom_level) {
terom@30:         var zd = zoom_level - this.level;
terom@30: 
terom@30:         var tw = scaleByZoomDelta(this.source.tile_width, zd);
terom@30:         var th = scaleByZoomDelta(this.source.tile_height, zd);
terom@30: 
terom@30:         var tiles = this.tiles;
terom@30:         var tiles_len = tiles.length;
terom@30:         var t, ts;
terom@30:         
terom@30:         for (var i = 0; i < tiles_len; i++) {
terom@30:             t = tiles[i];
terom@30:             ts = t.style;
terom@30: 
terom@30:             ts.width = tw;
terom@30:             ts.height = th;
terom@30:             ts.top = th*t.__row;
terom@30:             ts.left = tw*t.__col;
terom@30:         }
terom@30:     },
terom@30: 
terom@30: 
terom@30: 
terom@30: });
terom@30: 
terom@30: // scale the given co-ordinate by a zoom delta. If we zoom in (dz > 0), n will become larger, and if we zoom 
terom@30: // out (dz < 0), n will become smaller.
terom@30: function scaleByZoomDelta (n, dz) {
terom@30:     if (dz > 0)
terom@30:         return n << dz;
terom@30:     else
terom@30:         return n >> -dz;
terom@30: }
terom@30: