if (img_prefix == undefined) var img_prefix = './tiles/ttn_mediatheque/mediatheque_70';

if (to_cap == undefined) var to_cap = 0;

if (to_ele == undefined) var to_ele = 0;

if (cap == undefined) var cap = 0;

if (elevation == undefined) var elevation = 0;

if (cap_min == undefined) var cap_min = cap;

if (cap_max == undefined) var cap_max = cap_min+360;

var inserted_points = new Array();

var canvas;

var cntext;

var point_list = new Array();

var zoom;

var to_zoom;

var zooms = new Array();

var prev_zm;

var zm;

var tile = {width:256, height:256};

var ntiles = {x:228, y:9};

var border_width = 5;

var imageObj = new Array();

var last  = {x:0,y:0};

var shift = {x:0,y:0};

var mouse = {x:0,y:0};

var speed = {x:0,y:0};

var canvas_pos = {x:0,y:0};

var tmt;

var test = {x:0, y:0, i:100};

function nmodulo(val, div) {                // pour obtenir un modulo dans l'espace des nombres naturels N.

    return Math.floor((val%div+div)%div);   // il y a peut être plus simple, mais en attendant .... 

}

function fmodulo(val, div) {                // pour obtenir un modulo dans l'espace des nombres réels positifs.

    return (val%div+div)%div;               // il y a peut être plus simple, mais en attendant .... 

}

function distort_canvas(p, x, y) {

    if (p == 0) distort = 0;

    else {

        cntext.save();

        distort++;

        cntext.clearRect(0, 0, canvas.width, 2*canvas.height);

        var ratio = (canvas.width-2*distort)/canvas.width;

        var shift = canvas.height/2*(1-ratio);

        cntext.scale(1, ratio);

        if (p == 1) cntext.translate(0, 0);

        else if (p == -1) cntext.translate(0, 0);

        draw_image(x, y);

        cntext.restore();

        document.getElementById('res').innerHTML = 'distort : ' + distort + ' shift ' + shift + ' ratio : ' + ratio + '<br/>';

    }

}

function draw_image(ox, oy) {

    ox = nmodulo(ox-canvas.width/2, zm.im.width);        // pour placer l'origine au centre du canvas 

    var ocx = nmodulo(ox - zm.phase_pix, zm.im.width);

    //document.getElementById('res').innerHTML = zm.phase_pix + ' -- ' + zm.im.width + ' shift(x,y) ' + shift.x;

    oy = Math.floor(oy-canvas.height/2);                             // pas de rebouclage vertical

    cntext.clearRect(0, 0, canvas.width, canvas.height);

    cntext.fillStyle = "rgba(128,128,128,0.8)";

    if (canvas.height > zm.im.height) {

        var fy = Math.floor((oy+canvas.height/2-zm.im.height/2)/(tile.height*zm.ntiles.y))*zm.ntiles.y;

        if (fy < 0) fy = 0; 

        var ly = fy + zm.ntiles.y;

    } else {

        var fy = Math.floor(oy/tile.height);

        var ly = Math.floor((oy+canvas.height+tile.height-1)/tile.height+1);

        if (fy < 0) fy = 0; 

        if (ly > zm.ntiles.y) ly = zm.ntiles.y; 

    }

    for (var j=fy; j<ly; j++) {

        var delta_y = (Math.floor(j/zm.ntiles.y) - Math.floor(fy/zm.ntiles.y)) * (tile.height - zm.last_tile.height);

        var dy = j*tile.height - oy - delta_y;

        var ny = j%ntiles.y;

        var wy = zm.tile.width;

        if (ny == zm.ntiles.y - 1) wy = zm.last_tile.height;

        var cpx = 0;

        var i = 0;

        var Nx = zm.ntiles.x;

        if (zm.im.unused_width != 0) Nx++;

        while (cpx < ocx+canvas.width) {

            var cur_width = zm.tile.width;

            if (i%Nx == zm.ntiles.x-1) cur_width = zm.last_tile.width;

            else if (i%Nx == Nx-1) cur_width = zm.im.unused_width;

            if (cpx >= ocx-cur_width) {

                if (i%Nx == Nx-1 && zm.im.unused_width != 0) {

                    cntext.fillRect(cpx-ocx, dy, zm.im.unused_width, wy);

                } else {

                    var nx = i%Nx;

                    load_image(nx, ny, cpx-ocx, dy, ox, oy);

                }

            }

            cpx += cur_width;

            i++;

        }

    }

    drawDecorations(ox, oy);

}

function load_image(nx, ny, ox, oy, x, y) {

    var idx = nx+'-'+ny+'-'+zoom;

    if (imageObj[idx] && imageObj[idx].complete) {

        draw_tile(idx, ox, oy); // l'image est déja en mémoire, on force le dessin sans attendre.

    } else {

        var fname = get_file_name(nx, ny, zoom);

        imageObj[idx] = new Image();

        imageObj[idx].src = fname;

        var ts = zm.get_tile_size(nx, ny);

        cntext.fillRect(ox, oy, ts.width, ts.height);

        var dx = shift.x;

        var dy = shift.y;

        imageObj[idx].addEventListener('load', function() {draw_tile_del(zoom, dx, dy, idx, ox, oy, x, y)}, false);

    }

}

function draw_tile_del(ezoom, dx, dy, idx, ox, oy, x, y) {

    if (ezoom == zoom && dx == shift.x && dy == shift.y) {

        draw_tile(idx, ox, oy);

        drawDecorations(x, y);

    }

}

function draw_tile(idx, ox, oy) {

    var img = imageObj[idx];

    cntext.drawImage(img, ox, oy);

}

function drawDecorations(ox, oy) {

    var wgrd = zm.im.width/360;

    var od = ((ox+canvas.width/2)/wgrd)%360;

    var el = (zm.im.height/2 - (oy+canvas.height/2))/wgrd;

//    document.getElementById('angle_ctrl').value = od.toFixed(2);

//    document.getElementById('elvtn_ctrl').value = el.toFixed(2);

    cntext.fillStyle = "rgba(0,128,128,0.9)";

    cntext.strokeStyle = "rgb(255,255,255)";

    cntext.lineWidth = 1;

    cntext.fillRect(canvas.width/2-5, canvas.height/2-5, 10, 10);

    cntext.strokeRect(canvas.width/2-5, canvas.height/2-5, 10, 10);

    for(var i = 0; i < zm.pt_list.length; i++) {

        var cx = zm.pt_list[i]['xc'] - ox;

        var cy = zm.pt_list[i]['yc'] - oy;

        if (zm.pt_list[i]['lnk'] != undefined) cntext.fillStyle = "rgba(255,128,128,0.5)";

        else cntext.fillStyle = "rgba(128,255,128,0.5)";

        cntext.beginPath();

        cntext.arc(cx, cy, 20, 0, 2*Math.PI, true);

        cntext.fill();

    }

    //cntext.font = "20pt Arial";

    //cntext.fillRect(0, 0, 200, 20);

    //cntext.fillStyle = "rgb(255,0,0)";

    //cntext.fillText(od.toFixed(2), 5, 20);

    //for (i=0; i<canvas.width/wgrd; i++) {

        //cntext.strokeRect(i*wgrd, 0, wgrd, 20);

    //}

}

function get_file_name(x, y, z) { // recherche du fichier correspondant au zoom et à la position

    var prm = [z, x, y];

    var fname = img_prefix;

    for (var i = 0; i < prm.length; i++) {

        fname += '_';

        if (prm[i] < 10) fname += '00';

        else if (prm[i] < 100) fname += '0';

        fname += prm[i];

    }

    fname += '.jpg';

    return fname;

}

function keys(key) {

    event.preventDefault();

    event.stopPropagation();

    if (!key) {

        key = event;

        key.which = key.keyCode;

    }

    evt = key || event;

//    alert(key);

//    if (!evt.shiftKey) return;

    switch (key.which) {

    case 36: // home

        test.x=0;

        test.y=0;

        putImage(test.x, test.y);

        return;

    case 66: // b

        alert(key.pageX);

        test.x=tile.width*(ntiles.x-3);

        test.y=0;

        putImage(test.x, test.y);

        return;

    case 67: // c

        test.x=0;

        test.y=tile.height*(ntiles.y-3);

        putImage(test.x, test.y);

        return;

    case 35: // end

        test.x=tile.width*(ntiles.x-3);

        test.y=tile.height*(ntiles.y-3);

        putImage(test.x, test.y);

        return;

    case 39: // left

        test.x+=test.i;

        putImage(test.x, test.y);

        return;

    case 40: // up

        test.y+=test.i;

        putImage(test.x, test.y);

        return;

    case 37: // right

        test.x-=test.i;

        putImage(test.x, test.y);

        return;

    case 38: // down

        test.y-=test.i;

        putImage(test.x, test.y);

        return;

    case 33: // pageup

        test.y=0;

        putImage(test.x, test.y);

        return;

    case 34: // pagedown

        test.y=tile.height*(ntiles.y-3);

        putImage(test.x, test.y);

        return;

    default:

        //alert(key.which)

        return;

    }

}

function onImageClick(e) {

    shift.x = last.x;

    shift.y = last.y;

    speed.x = 0;

    speed.y = 0;

    mouse.x = e.pageX;

    mouse.y = e.pageY;

    clearTimeout(tmt);  //arrêt de l'éffet eventuel d'amorti en cours.

    canvas.addEventListener('mousemove', stickImage, false);

    canvas.addEventListener('mouseup', launchImage, false);

    //canvas.addEventListener('mouseout', launchImage, false);

    canvas.style.cursor='move';

    //document.onmousemove = stickImage;

    document.onmouseup = launchImage;

    hide_links();

}

function stickImage(e) {

    var xs = mouse.x - e.pageX + shift.x;

    var ys = mouse.y - e.pageY + shift.y;

    speed.x = xs - last.x;  //mémorisation des vitesses horizontales

    speed.y = ys - last.y;  //et verticales lors de ce déplacement

    putImage(xs, ys);

}

function launchImage(e) {

    distort_canvas(0);

    canvas.removeEventListener('mousemove', stickImage, false);

    show_links();

    //document.onmousemove = null;

    shift.x = e.pageX - mouse.x + shift.x;

    shift.y = e.pageY - mouse.y + shift.y;

    tmt = setTimeout(inertialImage, 100);

}

function putImage(x, y) { // est destiné à permettre l'effet d'amortissement par la mémorisation de la position courante.

    if (!zm.is_updated) return; 

    if (x >= zm.im.width) {   // rebouclage horizontal

        shift.x -= zm.im.width;

        x -= zm.im.width;

    } else if (x < 0) {

        shift.x += zm.im.width;

        x += zm.im.width;

    }

    if (y >= zm.im.height) {   // pas de rebouclage vertical mais blocage

        //distort_canvas(1, x, y);

        shift.y = zm.im.height-1;

        y = zm.im.height-1;

    } else if (y < 0) {

        //distort_canvas(-1, x, y);

        shift.y = 0;

        y = 0;

    }

    draw_image(x, y);

    last.x = x;

    last.y = y;

}

function inertialImage() {

    speed.x *= 0.9;

    speed.y *= 0.9;

    if (Math.abs(speed.x) > 2 || Math.abs(speed.y) > 2) {

        putImage(last.x+speed.x, last.y+speed.y);

        tmt = setTimeout(inertialImage, 100);

    }

}

function tzoom(zv) {

    this.value = zv;

    this.ntiles = {x:0,y:0};

    this.tile = {width:0,height:0};

    this.last_tile = {width:0,height:0};

    this.max_tile = {width:0,height:0};

    this.im = {width:0,height:0};

    this.im.unused_width = 0;

    this.pt_list = new Array();

    this.is_updated = false;

    this.refresh = function() {

        this.im.visible_width = this.tile.width*(this.ntiles.x-1)+this.last_tile.width;

        this.is_updated = true;

        var cap_int = (Math.abs(cap_max - cap_min + 0.005)) % 360.0;

        if (cap_int < 0.01) this.im.unused_width = 0;

        else this.im.unused_width = Math.floor(fmodulo(cap_min - cap_max, 360)*this.im.visible_width/fmodulo(cap_max - cap_min, 360));

//        document.getElementById('res').innerHTML += 'unuse_cap ' + fmodulo(cap_min - cap_max) + ' used_cap ' + fmodulo(cap_max - cap_min);

        this.im.width = this.im.visible_width+this.im.unused_width;

        this.im.height = this.tile.height*(this.ntiles.y-1)+this.last_tile.height;

        if (this.im.unused_width > this.tile.width) this.max_tile.width = this.im.unused_width;

        else this.max_tile.width = this.tile.width;

        this.max_tile.height = this.tile.height;

        this.max_tile.width = 

        this.phase_pix = Math.floor(this.im.width*cap_min/360);

        for (var i=0; i<point_list.length; i++) {

            var tmp = fmodulo(point_list[i][2], 360);

            this.pt_list[i] = new Array();

            this.pt_list[i]['label'] = point_list[i][0];

            this.pt_list[i]['xc'] = Math.floor(tmp * this.im.width/360);

            this.pt_list[i]['yc'] = Math.floor(this.im.height/2 - (point_list[i][3] + elevation) * this.im.width/360);

            this.pt_list[i]['angle'] = point_list[i][2];

            if (point_list[i][4] != '') this.pt_list[i]['lnk'] = point_list[i][4]+'&to_zoom='+zv;

        }

    }

    this.get_tile_size = function(nx, ny) {

        var res = {width:0, height:0};

        if (nx == this.ntiles.x-1) res.width = this.last_tile.width;

        else res.width = this.tile.width;

        if (ny == this.ntiles.y-1) res.height = this.last_tile.height;

        else res.height = this.tile.height;

        return res;

    }

}

function wheel_zoom (event) {

    var zshift = {x:0, y:0};

    if (event.pageX != undefined && event.pageX != undefined) {

        zshift.x = event.pageX-canvas.width/2-canvas_pos.x;

        zshift.y = event.pageY-canvas.height/2-canvas_pos.y;

    }

    event.preventDefault();

    if (event.wheelDelta < 0 && zoom_control.value < zoom_control.max) {

        zoom_control.value++;

        change_zoom(zshift.x, zshift.y);

    } else if (event.wheelDelta > 0 && zoom_control.value > zoom_control.min) {

        zoom_control.value--; 

        change_zoom(zshift.x, zshift.y);

    }

}

function change_zoom(shx, shy) {

    var zoom_control = document.getElementById("zoom_ctrl");

    var v = zoom_control.value;

    prev_zm = zm;

    if (zooms[v]) {

        if (!zooms[v].is_updated) zooms[v].refresh();

    } else {

        zooms[v] = new tzoom(v);

    }

    if (zooms[v].is_updated) {

        if (shx == undefined || shy == undefined) {

            shx=0;

            shy=0;

        }

        zm = zooms[v];

        var px = (last.x+shx)*zm.im.width/prev_zm.im.width - shx;

        var py = (last.y+shy)*zm.im.height/prev_zm.im.height - shy;

        if (py < zm.im.height && py >= 0) {

            zoom = zm.value;

            tile = zm.tile;

            ntiles = zm.ntiles;

            putImage(px, py);

        } else {

            zm = prev_zm;

            zoom_control.value = zm.value;

        }

    }

}

function change_angle() {

    var elvtn_control = document.getElementById('elvtn_ctrl');

    var angle_control = document.getElementById('angle_ctrl');

    var pos_x = zm.im.width*angle_control.value/360;

    var pos_y = Math.floor(zm.im.height/2 - zm.im.width*elvtn_control.value/360);

    putImage(pos_x, pos_y);

}

function check_links(e) {

    var mouse_x = e.pageX-canvas_pos.x;

    var mouse_y = e.pageY-canvas_pos.y;

    var pos_x = nmodulo(last.x + mouse_x - canvas.width/2, zm.im.width);

    var pos_y = last.y + mouse_y - canvas.height/2;

    for(var i = 0; i < zm.pt_list.length; i++) {

        if (Math.sqrt((zm.pt_list[i]['xc'] - pos_x) * (zm.pt_list[i]['xc'] - pos_x) + (zm.pt_list[i]['yc'] - pos_y) * (zm.pt_list[i]['yc'] - pos_y)) < 20) {

            if (zm.pt_list[i]['lnk'] != undefined) window.location = zm.pt_list[i]['lnk'];

            break;

        }

    }

}

function display_links(e) {

    var info = document.getElementById('info');

    var mouse_x = e.pageX-canvas_pos.x;

    var mouse_y = e.pageY-canvas_pos.y;

    var pos_x = nmodulo(last.x + mouse_x - canvas.width/2, zm.im.width);

    var pos_y = last.y + mouse_y - canvas.height/2;

    var cap = ((pos_x/zm.im.width)*360).toFixed(2);

    var elev = (((zm.im.height/2 - pos_y)/zm.im.width)*360 - elevation).toFixed(2);

    info.innerHTML = 'élévation :'+elev+'<br/>cap :'+cap;

    info.style.top = e.pageY+'px';

    info.style.left = e.pageX+'px';

    info.style.backgroundColor = '#FFC';

    canvas.style.cursor='crosshair';

    for(var i = 0; i < zm.pt_list.length; i++) {

        if (Math.sqrt((zm.pt_list[i]['xc'] - pos_x) * (zm.pt_list[i]['xc'] - pos_x) + (zm.pt_list[i]['yc'] - pos_y) * (zm.pt_list[i]['yc'] - pos_y)) < 20) {

            info.innerHTML = zm.pt_list[i]['label'];

            info.style.backgroundColor = '#FC8';

            canvas.style.cursor='auto';

            break;

        }

    }

}

function hide_links() {

    canvas.removeEventListener( "mousemove", display_links, false);

    var info = document.getElementById('info');

    info.style.display = 'none';

}

function show_links() {

    canvas.addEventListener( "mousemove", display_links, false);

    var info = document.getElementById('info');

    info.style.display = 'block';

}

function show_insert_point(e) {

    event.preventDefault();

    event.stopPropagation();

    var insrt = document.getElementById('insert');

    document.getElementById('do-insert').onclick = function() {insert_point(insert, e.pageX-canvas_pos.x, e.pageY-canvas_pos.y)};

    document.getElementById('do-cancel').onclick = function() {insert.style.display = 'none'};

    insrt.style.left = e.pageX+'px';

    insrt.style.top = e.pageY+'px';

    insrt.style.display = 'block';

}

function insert_point(el, x, y) {

    el.style.display = 'none';

    for(var i = 0; i < zm.pt_list.length; i++) {

        if(zm.pt_list[i]['label'] == document.getElementById('sel_point').value) {

            var posx = nmodulo(last.x + x - canvas.width/2 - zm.phase_pix, zm.im.width)/zm.im.width;

            var pval = {ratio:posx, angle:zm.pt_list[i]['angle']};

            inserted_points.push(pval);

            document.getElementById('res').innerHTML += zm.pt_list[i]['label'] + '. ' + posx + '=' + zm.pt_list[i]['angle'] + '<br/>';

            if (inserted_points.length > 1) {

                var pval0 = inserted_points[inserted_points.length-2];

                var origin = fmodulo(pval0.angle - ((pval.angle - pval0.angle)/(pval.ratio - pval0.ratio))*pval0.ratio, 360);

                var end = fmodulo(pval.angle + ((pval.angle - pval0.angle)/(pval.ratio - pval0.ratio))*(1-pval.ratio), 360);

                document.getElementById('res').innerHTML += 'cap_min = ' + origin + '<br/>';

                document.getElementById('res').innerHTML += 'cap_max = ' + end + '<br/>';

            }

            break;

        }

    }

}

function clean_canvas_events(e) {

    canvas.removeEventListener('mousemove', stickImage, false);

    document.getElementById('info').style.display = 'none';

    speed.x = 0;

    speed.y = 0;

}

window.onload = function() {

    canvas = document.getElementById("mon-canvas");

    canvas.style.border = border_width+"px solid red";

    cntext = canvas.getContext("2d");

    canvas.width = window.innerWidth-200;

    canvas.height = window.innerHeight-20;

    canvas.addEventListener("click", check_links, false);

    canvas_pos.x = canvas.offsetLeft+border_width;

    canvas_pos.y = canvas.offsetTop+border_width;

    canvas.addEventListener("contextmenu", show_insert_point, false);

    canvas.addEventListener("mouseout", clean_canvas_events, false);

    show_links();

    var max_zoom = zooms.length - 1;

    zoom_control = document.getElementById("zoom_ctrl");

    zoom_control.onchange = change_zoom;

    zoom_control.max = max_zoom;

    if (to_zoom == undefined || to_zoom > max_zoom) to_zoom = Math.floor(max_zoom/2);

    zm = zooms[to_zoom];

    zoom_control.value = to_zoom;

    zm.refresh();

    zoom = zm.value;

    tile = zm.tile;

    ntiles = zm.ntiles;

    angle_control = document.getElementById("angle_ctrl");

    angle_control.value = to_cap;

    angle_control.onchange = change_angle;

    angle_control.onclick = change_angle;

    angle_control.onkeyup = change_angle;

    elvtn_control = document.getElementById("elvtn_ctrl");

    elvtn_control.value = to_ele+elevation;

    elvtn_control.onchange = change_angle;

    elvtn_control.onclick = change_angle;

    elvtn_control.onkeyup = change_angle;

    change_angle();

    canvas.addEventListener('mousedown', onImageClick, false);

    addEventListener('keyup', keys, false);

    canvas.addEventListener('mousewheel', wheel_zoom, false);

};