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