1

// A source of tile images of a specific width/height, zoom level range, and some other attributes

     2

var Source = Class.create({

     3

    initialize: function (path, tile_width, tile_height, zoom_min, zoom_max) {

     4

        this.path = path;

     5

        this.tile_width = tile_width;

     6

        this.tile_height = tile_height;

     7

        this.zoom_min = zoom_min;

     8

        this.zoom_max = zoom_max;

     9

    10

        this.refresh = false;

    11

        this.opt_key = this.opt_value = null;

    12

    },

    13

    14

    // build a URL for the given tile image

    15

    build_url: function (col, row, zl, sw, sh) {

    16

        // two-bit hash (0-4) based on the (col, row)

    17

        var hash = ( (col % 2) << 1 | (row % 2) ) + 1;

    18

    19

        // the subdomain to use

    20

        var subdomain = "";

    21

    22

        if (0)

    23

            subdomain = "tile" + hash + ".";

    24

    25

        // the (x, y) co-ordinates

    26

        var x = col * this.tile_width;

    27

        var y = row * this.tile_height;

    28

    29

        var url = this.path + "?x=" + x + "&y=" + y + "&zl=" + zl; // + "&sw=" + sw + "&sh=" + sh;

    30

    31

        if (this.refresh)

    32

            url += "&ts=" + new Date().getTime();

    33

    34

        if (this.opt_key && this.opt_value)

    35

            url += "&" + this.opt_key + "=" + this.opt_value;

    36

    37

        return url;

    38

    },

    39

    40

    // build an URL for a full image

    41

    build_image_url: function (cx, cy, w, h, zl) {

    42

        return (this.path + "?cx=" + cx + "&cy=" + cy + "&w=" + w + "&h=" + h + "&zl=" + zl);

    43

    }

    44

});

    45

    46

// a viewport that contains a substrate which contains several zoom layers which contain many tiles

    47

var Viewport = Class.create({

    48

    initialize: function (source, viewport_id) {

    49

        this.source = source;

    50

    51

        this.id = viewport_id;

    52

        this.div = $(viewport_id);

    53

        this.substrate = this.div.down("div.substrate");

    54

    55

        // the stack of zoom levels

    56

        this.zoom_layers = [];

    57

    58

        // pre-populate the stack

    59

        for (var zoom_level = source.zoom_min; zoom_level <= source.zoom_max; zoom_level++) {

    60

            var zoom_layer = new ZoomLayer(source, zoom_level);

    61

    62

            this.substrate.appendChild(zoom_layer.div);

    63

            this.zoom_layers[zoom_level] = zoom_layer;

    64

        }

    65

    66

        // make the substrate draggable

    67

        this.draggable = new Draggable(this.substrate, {

    68

            onStart: this.on_scroll_start.bind(this),

    69

            onDrag: this.on_scroll_move.bind(this),

    70

            onEnd: this.on_scroll_end.bind(this),

    71

        });

    72

    73

        // event handlers

    74

        Event.observe(this.substrate, "dblclick", this.on_dblclick.bindAsEventListener(this));

    75

        Event.observe(this.substrate, "mousewheel", this.on_mousewheel.bindAsEventListener(this));

    76

        Event.observe(this.substrate, "DOMMouseScroll", this.on_mousewheel.bindAsEventListener(this));     // mozilla

    77

        Event.observe(document, "resize", this.on_resize.bindAsEventListener(this));

    78

    79

        // zoom buttons

    80

        this.btn_zoom_in = $("btn-zoom-in");

    81

        this.btn_zoom_out = $("btn-zoom-out");

    82

    83

        if (this.btn_zoom_in)

    84

            Event.observe(this.btn_zoom_in, "click", this.zoom_in.bindAsEventListener(this));

    85

    86

        if (this.btn_zoom_out)

    87

            Event.observe(this.btn_zoom_out, "click", this.zoom_out.bindAsEventListener(this));

    88

    89

        // set viewport size

    90

        this.update_size();

    91

    92

        // this comes after update_size, since it must be updated once we have the size and zoom layer...

    93

        this.image_link = $("lnk-image");

    94

    95

        // initial location?    

    96

        if (document.location.hash) {

    97

            // x:y:z tuple

    98

            var pt = document.location.hash.substr(1).split(":");

    99

   100

            // unpack

   101

            var cx = 0, cy = 0, z = 0;

   102

   103

            if (pt.length) cx = parseInt(pt.shift());

   104

            if (pt.length) cy = parseInt(pt.shift());

   105

            if (pt.length) z = parseInt(pt.shift());

   106

   107

            // initial view

   108

            this.zoom_scaled(

   109

                cx - this.center_offset_x, 

   110

                cy - this.center_offset_y, 

   111

                z

   112

            );

   113

   114

        } else {

   115

            // this sets the scroll offsets, zoom level, and loads the tiles

   116

            this.zoom_to(0, 0, 0);

   117

        }

   118

    },

   119

   120

    /* event handlers */

   121

   122

    // window resized

   123

    on_resize: function (ev) {

   124

        this.update_size();

   125

        this.update_tiles();

   126

    },

   127

   128

    // double-click handler

   129

    on_dblclick: function (ev) {

   130

        var offset = this.event_offset(ev);

   131

   132

        this.zoom_center_to(

   133

            this.scroll_x + offset.x,

   134

            this.scroll_y + offset.y,

   135

            1   // zoom in

   136

        );

   137

    },

   138

   139

    // mousewheel handler

   140

    on_mousewheel: function (ev) {

   141

        // this works in very weird ways, so it's based on code from http://adomas.org/javascript-mouse-wheel/

   142

        // (it didn't include any license, so this is written out manually)

   143

        var delta;

   144

   145

        // this is browser-dependant...

   146

        if (ev.wheelDelta) {

   147

            // IE + Opera

   148

            delta = ev.wheelDelta;

   149

   150

            if (window.opera) {  

   151

                // Opera, but apparently not newer versions?

   152

                //delta = -delta;

   153

            }

   154

   155

        } else if (ev.detail) {

   156

            // Mozilla

   157

            delta = -ev.detail;

   158

   159

        } else {

   160

            // mousewheel not supported...

   161

            return;

   162

   163

        }

   164

   165

        // don't scroll the page

   166

        if (ev.preventDefault)

   167

            ev.preventDefault();

   168

   169

        // delta > 0 : scroll up, zoom in

   170

        // delta < 0 : scroll down, zoom out

   171

        delta = delta < 0 ? -1 : 1;

   172

   173

        // Firefox's DOMMouseEvent's pageX/Y attributes are broken. layerN is for mozilla, offsetN for IE, seems to work

   174

   175

        // absolute location of the cursor

   176

        var x = parseInt(ev.target.style.left) + (ev.layerX ? ev.layerX : ev.offsetX);

   177

        var y = parseInt(ev.target.style.top) + (ev.layerY ? ev.layerY : ev.offsetY);

   178

   179

        // zoom \o/

   180

        this.zoom_center_to(x, y, delta);

   181

    },

   182

   183

    // substrate scroll was started

   184

    on_scroll_start: function (ev) {

   185

   186

    },

   187

   188

    // substrate was scrolled, update scroll_{x,y}, and then update tiles after 100ms

   189

    on_scroll_move: function (ev) {

   190

        this.update_scroll();

   191

        this.update_after_timeout();

   192

    },

   193

   194

    // substrate scroll was ended, update tiles now

   195

    on_scroll_end: function (ev) {

   196

        this.update_now();

   197

    },

   198

   199

    /* get state */

   200

   201

    // return the absolute (x, y) coords of the given event inside the viewport

   202

    event_offset: function (ev) {

   203

        var offset = this.div.cumulativeOffset();

   204

   205

        return {

   206

            x: ev.pointerX() - offset.left, 

   207

            y: ev.pointerY() - offset.top

   208

        };

   209

    },

   210

   211

    /* modify state */

   212

   213

    // scroll the view to place the given absolute (x, y) co-ordinate at the top left

   214

    scroll_to: function (x, y) {

   215

        // update it via the style

   216

        this.substrate.style.top = "-" + y + "px";

   217

        this.substrate.style.left = "-" + x + "px";

   218

   219

        // update these as well

   220

        this.scroll_x = x;

   221

        this.scroll_y = y;

   222

    },

   223

   224

    // scroll the view to place the given absolute (x, y) co-ordinate at the center

   225

    scroll_center_to: function (x, y) {

   226

        return this.scroll_to(

   227

            x - this.center_offset_x,

   228

            y - this.center_offset_y

   229

        );

   230

    },

   231

   232

    // zoom à la delta such that the given (zoomed) absolute (x, y) co-ordinates will be at the top left

   233

    zoom_scaled: function (x, y, delta) {

   234

        if (!this.update_zoom(delta))

   235

            return false;

   236

   237

        // scroll to the new position

   238

        this.scroll_to(x, y);

   239

   240

        // update view

   241

        // XXX: ...

   242

        this.update_after_timeout();

   243

   244

        return true;

   245

    },

   246

   247

    // zoom à la delta such that the given (current) absolute (x, y) co-ordinates will be at the top left

   248

    zoom_to: function (x, y, delta) {

   249

        return this.zoom_scaled(

   250

            scaleByZoomDelta(x, delta),

   251

            scaleByZoomDelta(y, delta),

   252

            delta

   253

        );

   254

    },

   255

   256

    // zoom à la delta such that the given (current) absolute (x, y) co-ordinates will be at the center

   257

    zoom_center_to: function (x, y, delta) {

   258

        return this.zoom_scaled(

   259

            scaleByZoomDelta(x, delta) - this.center_offset_x,

   260

            scaleByZoomDelta(y, delta) - this.center_offset_y,

   261

            delta

   262

        );

   263

    },

   264

   265

    // zoom à la delta, keeping the view centered

   266

    zoom_centered: function (delta) {

   267

        return this.zoom_center_to(

   268

            this.scroll_x + this.center_offset_x,

   269

            this.scroll_y + this.center_offset_y,

   270

            delta

   271

        );

   272

    },

   273

   274

    // zoom in one level, keeping the view centered

   275

    zoom_in: function () {

   276

        return this.zoom_centered(+1);

   277

    },

   278

   279

    // zoom out one leve, keeping the view centered

   280

    zoom_out: function () {

   281

        return this.zoom_centered(-1);

   282

    },

   283

   284

    /* update view/state to reflect reality */

   285

   286

    // figure out the viewport dimensions

   287

    update_size: function () {

   288

        this.view_width = this.div.getWidth();

   289

        this.view_height = this.div.getHeight();

   290

   291

        this.center_offset_x = Math.floor(this.view_width / 2);

   292

        this.center_offset_y = Math.floor(this.view_height / 2);

   293

   294

        this.update_image_link();

   295

    },

   296

   297

    // figure out the scroll offset as absolute pixel co-ordinates at the top left

   298

    update_scroll: function() {

   299

        this.scroll_x = -parseInt(this.substrate.style.left);

   300

        this.scroll_y = -parseInt(this.substrate.style.top);

   301

    },

   302

   303

    // wiggle the ZoomLevels around to match the current zoom level

   304

    update_zoom: function(delta) {

   305

        if (!this.zoom_layer) {

   306

            // first zoom operation

   307

   308

            // is the new zoom level valid?

   309

            if (!this.zoom_layers[delta])

   310

                return false;

   311

   312

            // set the zoom layyer

   313

            this.zoom_layer = this.zoom_layers[delta];

   314

   315

            // enable it

   316

            this.zoom_layer.enable(11);

   317

   318

            // no need to .update_tiles or anything like that

   319

   320

        } else {

   321

            // is the new zoom level valid?

   322

            if (!this.zoom_layers[this.zoom_layer.level + delta])

   323

                return false;

   324

   325

            var zoom_old = this.zoom_layer;

   326

            var zoom_new = this.zoom_layers[this.zoom_layer.level + delta];

   327

   328

            // XXX: ugly hack

   329

            if (this.zoom_timer) {

   330

                clearTimeout(this.zoom_timer);

   331

                this.zoom_timer = null;

   332

            }

   333

   334

            // get other zoom layers out of the way

   335

            this.zoom_layers.each(function (zl) {

   336

                zl.disable();

   337

            });

   338

   339

            // update the zoom layer

   340

            this.zoom_layer = zoom_new;

   341

   342

            // apply new z-indexes, preferr the current one over the new one

   343

            zoom_new.enable(11);

   344

            zoom_old.enable(10);

   345

   346

            // resize the tiles in the two zoom layers

   347

            zoom_new.update_tiles(zoom_new.level);

   348

            zoom_old.update_tiles(zoom_old.level);

   349

   350

            // XXX: ugly hack

   351

            this.zoom_timer = setTimeout(function () { zoom_old.disable()}, 1000);

   352

        }

   353

   354

        // update UI

   355

        this.update_zoom_ui();

   356

   357

        return true;

   358

    },

   359

   360

    // keep the zoom buttons, if any, updated

   361

    update_zoom_ui: function () {

   362

        if (this.btn_zoom_in)

   363

            (this.zoom_layer.level >= this.source.zoom_max) ? this.btn_zoom_in.disable() : this.btn_zoom_in.enable();

   364

   365

        if (this.btn_zoom_out)

   366

            (this.zoom_layer.level <= this.source.zoom_min) ? this.btn_zoom_out.disable() : this.btn_zoom_out.enable();

   367

   368

        this.update_image_link();

   369

    },

   370

   371

    // ensure that all tiles that are currently visible are loaded

   372

    update_tiles: function() {

   373

        // short names for some vars...

   374

        var x = this.scroll_x;

   375

        var y = this.scroll_y;

   376

        var sw = this.view_width;

   377

        var sh = this.view_height;

   378

        var tw = this.source.tile_width;

   379

        var th = this.source.tile_height;

   380

        var zl = this.zoom_layer.level;

   381

   382

        // figure out what set of columns are visible

   383

        var start_col = Math.max(0, Math.floor(x / tw));

   384

        var start_row = Math.max(0, Math.floor(y / th));

   385

        var end_col = Math.floor((x + sw) / tw);

   386

        var end_row = Math.floor((y + sh) / th);

   387

   388

        // loop through all those tiles

   389

        for (var col = start_col; col <= end_col; col++) {

   390

            for (var row = start_row; row <= end_row; row++) {

   391

                // the tile's id

   392

                var id = "tile_" + this.zoom_layer.level + "_" + col + "_" + row;

   393

   394

                // does the element exist already?

   395

                var t = $(id);

   396

   397

                if (!t) {

   398

                    // build a new tile

   399

                    t = Builder.node("img", {

   400

                            src:    this.source.build_url(col, row, zl, sw, sh),

   401

                            id:     id,

   402

                            title:  "(" + col + ", " + row + ")",

   403

                            // style set later

   404

                        }

   405

                    );

   406

   407

                    // set the CSS style stuff

   408

                    t.style.top = th * row;

   409

                    t.style.left = tw * col;

   410

                    t.style.display = "none";

   411

   412

                    // wait for it to load

   413

                    Event.observe(t, "load", _tile_loaded.bindAsEventListener(t));

   414

   415

                    // store the col/row

   416

                    t.__col = col;

   417

                    t.__row = row;

   418

   419

                    // add it to the zoom layer

   420

                    this.zoom_layer.add_tile(t);

   421

   422

                } else if (this.source.reload) {

   423

                    // force the tile to reload

   424

                    touch_tile(t, col, row);

   425

   426

                }

   427

            }

   428

        }

   429

   430

        this.update_scroll_ui();

   431

    }, 

   432

   433

    // update scroll-dependant UI elements

   434

    update_scroll_ui: function () {

   435

        // update link-to-image

   436

        this.update_image_link();

   437

   438

        // update the link-to-this-page thing

   439

        document.location.hash = "#" + (this.scroll_x + this.center_offset_x) + ":" + (this.scroll_y + this.center_offset_y) + ":" + this.zoom_layer.level;

   440

    },

   441

   442

    // update image link with size, zoom, pos

   443

    update_image_link: function () {

   444

        if (!this.image_link)

   445

            return;

   446

   447

        this.image_link.href = this.source.build_image_url(

   448

            this.scroll_x + this.center_offset_x,

   449

            this.scroll_y + this.center_offset_y,

   450

            this.view_width, this.view_height,

   451

            this.zoom_layer.level

   452

        );

   453

   454

        this.image_link.innerHTML = this.view_width + "x" + this.view_height + "@" + this.zoom_layer.level;

   455

    },

   456

   457

    // do update_tiles after 100ms, unless we are called again

   458

    update_after_timeout: function () {

   459

        this._update_idle = false;

   460

   461

        if (this._update_timeout)

   462

            clearTimeout(this._update_timeout);

   463

   464

        this._update_timeout = setTimeout(this._update_timeout_trigger.bind(this), 100);  

   465

    },

   466

   467

    _update_timeout_trigger: function () {

   468

        this._update_idle = true;

   469

   470

        this.update_tiles();

   471

    },

   472

   473

    // call update_tiles if it hasn't been called due to update_after_timeout

   474

    update_now: function () {

   475

        if (this._update_timeout)

   476

            clearTimeout(this._update_timeout);

   477

   478

        if (!this._update_idle)

   479

            this.update_tiles();

   480

    },

   481

   482

});

   483

   484

// used by Viewport.update_tiles to make a tile visible after it has loaded

   485

function _tile_loaded (ev) {

   486

    this.style.display = "block";

   487

}

   488

   489

// a zoom layer containing the tiles for one zoom level

   490

var ZoomLayer = Class.create({

   491

    initialize: function (source, zoom_level) {

   492

        this.source = source;

   493

        this.level = zoom_level;

   494

        this.div = Builder.node("div", { id: "zl_" + this.level, style: "position: relative; display: none;"});

   495

   496

        // our tiles

   497

        this.tiles = [];

   498

    },

   499

   500

    // add a tile to this zoom layer

   501

    add_tile: function (tile) {

   502

        this.div.appendChild(tile);

   503

        this.tiles.push(tile);

   504

    },

   505

   506

    // make this zoom layer visible with the given z-index

   507

    enable: function (z_index) {

   508

        this.div.style.zIndex = z_index;

   509

        this.div.show();

   510

    },

   511

   512

    // hide this zoom layer

   513

    disable: function (z_index) {

   514

        this.div.hide();

   515

    },

   516

   517

    // update the tiles in this zoom layer so that they are in the correct position and of the correct size when

   518

    // viewed with the given zoom level

   519

    update_tiles: function (zoom_level) {

   520

        var zd = zoom_level - this.level;

   521