if (img_prefix == undefined) var img_prefix = 'http://pano.tetaneutral.net/data/tsf2/vpongnian/tiles/ttn_mediatheque/mediatheque_70';

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

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

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

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

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

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

if (ref_points == undefined) var ref_points = new Array();

if (image_loop == undefined) var image_loop = true;

var debug_mode = false;

var canvas;

var cntext;

var point_list = new Array();

var zoom = 0;

var zooms = new Array();

var prev_zm;

var zm;

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

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

var border_width = 2;

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 is_located = false;

var point_colors = {'pano_point' : '255,128,128',

                    'ref_point'  : '128,128,255',

                    'loc_point'  : '128,255,128',

                    'temporary'  : '255,255,128',

                    'unlocated'  : '255,255,255'};

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) {

    var ref_vals  = {x:last.x, y:last.y, zoom:zoom};

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

    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;

        while (cpx < ox+canvas.width) {

            var cur_width = zm.tile.width;

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

            if (cpx >= ox-cur_width) {

                var nx = i%Nx;

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

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

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

                } else {

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

                    imageObj[idx] = new Image();

                    imageObj[idx].src = fname;

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

                    cntext.fillRect(cpx-ox, dy, ts.width, ts.height);

                    imageObj[idx].addEventListener('load', (function(ref, idx, dx, dy, ox, oy, ts) {

                        return function() {        // closure nécéssaire pour gestion assynchronisme !!!

                            draw_tile_del(ref, idx, dx, dy, ox, oy, ts.width, ts.height);

                        };

                    })(ref_vals, idx, cpx-ox, dy, ox, oy, ts), false);

                }

//                load_image(zoom, nx, ny, shx, shy, cpx-ox, dy, ox, oy);

            }

            cpx += cur_width;

            i++;

        }

    }

    drawDecorations(ox, oy);

}

function draw_tile_del(ref, idx, tx, ty, ox, oy, twidth, theight) {

    if (ref.zoom == zoom && ref.x == last.x && ref.y == last.y) {

        draw_tile(idx, tx, ty);

        drawDecorations(ox, oy, tx, ty, twidth, theight);

    }

}

function draw_tile(idx, ox, oy) {

    var img = imageObj[idx];

    cntext.drawImage(img, ox, oy);

}

function drawDecorations(ox, oy, tx, ty, twidth, theight) {

    if (twidth) {

        cntext.save();

        cntext.beginPath();

        cntext.rect(tx, ty, twidth, theight);

        cntext.clip();

    } 

    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;

    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++) {

        if (zm.pt_list[i]['type'] != 'unlocated') {

            cntext.fillStyle = 'rgba('+point_colors[zm.pt_list[i]['type']]+',0.5)';

            var cx = nmodulo(zm.pt_list[i]['xc'] - ox, zm.im.width);

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

            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);

    //}

    if (twidth) {

        cntext.restore();

    }

}

function insert_drawn_point(lat,lon,alt) {

        var rt = 6371;  // Rayon de la terre

    var alt1 = document.getElementById('pos_alt').childNodes[0].nodeValue;

    var lat1 = document.getElementById('pos_lat').childNodes[0].nodeValue*Math.PI/180;

    var lon1 = document.getElementById('pos_lon').childNodes[0].nodeValue*Math.PI/180;

    var alt2 = alt;

    var lat2 = lat*Math.PI/180;

    var lon2 = lon*Math.PI/180;

    var dLat = lat2-lat1;

    var dLon = lon2-lon1; 

    var a = Math.sin(dLat/2)*Math.sin(dLat/2) + Math.sin(dLon/2)*Math.sin(dLon/2)*Math.cos(lat1)*Math.cos(lat2);  // 

    var angle = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));

    var d = angle*rt;                    // distance du point en Kms

    var y = Math.sin(dLon) * Math.cos(lat2);

    var x = Math.cos(lat1)*Math.sin(lat2) - Math.sin(lat1)*Math.cos(lat2)*Math.cos(dLon);

    var cap = Math.atan2(y,x);                 // cap pour atteindre le point en radians

    var e = Math.atan2((alt2 - alt1)/1000 - d*d/(2*rt),d);  // angle de l'élévation en radians

    return {d:d, cap:cap*180/Math.PI, ele:e*180/Math.PI};   // les résultats sont en degrés

}

localate_point = function () {

    var lat = document.getElementById("loca_latitude").value;

    var lon = document.getElementById("loca_longitude").value;

    var alt = document.getElementById("loca_altitude").value;

    if (lat == '' || isNaN(lat) || lat <= -90 || lat > 90) {

        alert("La latitude "+lat+"n'est pas correcte");

        return;

    }

    if (lat == '' || isNaN(lon) || lon <= -180 || lon > 180) {

        alert("La longitude "+lon+"n'est pas correcte");

        return;

    }

    if (lat == '' || isNaN(alt) || alt < -400) {

        alert("l'altitude "+alt+"n'est pas correcte");

        return;

    }

            var opt_ced = new Array();

            opt_dce = insert_drawn_point(lat,lon,alt);

            // -----Première solution : afficher dynamiquement le point !

            var d = opt_dce.d;

            var cap = opt_dce.cap;

            var ele = opt_dce.ele;

            display_temp(d, cap, ele);

}

function display_temp(d,cap,ele) {

    point_list[point_list.length] = new Array("point temporaire", d,cap,ele, "temporary");

    reset_zooms();

    putImage(last.x, last.y);

}

function arrayUnset(array, value){

    array.splice(array.indexOf(value), 1);

}

erase_point = function() {

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

                if(point_list[i][0] == "point temporaire"){

                        arrayUnset(point_list,point_list[i]);

                        loop = erase_point();

                }        

        }        

        reset_zooms();

    putImage(last.x, last.y);   

}

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) {

    hide_links();

    evt = key || event;

    //evt.preventDefault();

    //evt.stopPropagation();

    if (!key) {

        key = window.event;

        key.which = key.keyCode;

    }

//    alert(key);

//    if (!evt.shiftKey) return;

    switch (key.which) {

    /*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 36: // home

        putImage(0, zm.im.height/2);

        return;

    case 35: // end

        putImage(last.x+zm.im.width/2, last.y);

        return;

    case 39: // left

        putImage(last.x+40, last.y);

        return;

    case 40: // up

        putImage(last.x, last.y+20);

        return;

    case 37: // right

        putImage(last.x-40, last.y);

        return;

    case 38: // down

        putImage(last.x, last.y-20);

        return;

    case 33: // pageup

        zoom_control.value--;

        change_zoom()

        return;

    case 34: // pagedown

        zoom_control.value++;

        change_zoom()

        return;

    default:

//        alert(key.which)

        return;

    }

}

function onImageClick(e) {

    hide_contextmenu();

    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);

    //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;

    }

    last.x = x;

    last.y = y;

    draw_image(x, 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);

    } else {

        show_links();

    }

}

function tri_ref_points(v1, v2) {

    return v1['x'] - v2['x'];

}

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.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;

        this.im.width = this.im.visible_width;

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

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

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

        if (this.last_tile.height > this.tile.height) this.max_tile.height = this.im.last_tile.height;

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

        var ord_pts = new Array();

        i=0;

        for(var label in ref_points) {

            ord_pts[i++] = ref_points[label]

        }

        ord_pts = ord_pts.sort(tri_ref_points);

        is_located = i > 1 || image_loop && i > 0;

        var alpha_domain = {start:0, end:360}; 

        this.pixel_y_ratio = this.im.width/360;

        if (is_located) {

            this.ref_pixels = new Array;

            this.ref_pixels[0] = new Array();    // Attention il faut compter un intervalle de plus !

            for (var i=0; i < ord_pts.length; i++) { // premier parcours pour les paramètres cap/x

                this.ref_pixels[i+1] = new Array();

                this.ref_pixels[i+1].x = Math.floor(ord_pts[i].x*this.im.width);

                this.ref_pixels[i+1].cap = fmodulo(ord_pts[i].cap, 360);

                if (i != ord_pts.length-1) {

                    this.ref_pixels[i+1].ratio_x = (ord_pts[i+1].x - ord_pts[i].x)/fmodulo(ord_pts[i+1].cap - ord_pts[i].cap, 360)*this.im.width;

                }

            }

            if (image_loop == true) {

                var dpix = this.im.width;

                var dangle = 360;

                if (ord_pts.length > 1) {

                    dpix = this.im.width - this.ref_pixels[this.ref_pixels.length-1].x + this.ref_pixels[1].x;

                    dangle = fmodulo(this.ref_pixels[1].cap - this.ref_pixels[this.ref_pixels.length-1].cap, 360);

                }

                this.ref_pixels[0].ratio_x = dpix/dangle;

                this.ref_pixels[ord_pts.length].ratio_x = this.ref_pixels[0].ratio_x;

                dpix = this.im.width - this.ref_pixels[ord_pts.length].x;

                this.ref_pixels[0].cap = fmodulo(this.ref_pixels[ord_pts.length].cap + dpix / this.ref_pixels[0].ratio_x, 360);

            } else {

                this.ref_pixels[0].ratio_x = this.ref_pixels[1].ratio_x;

                this.ref_pixels[ord_pts.length].ratio_x = this.ref_pixels[ord_pts.length-1].ratio_x;

                this.ref_pixels[0].cap = fmodulo(this.ref_pixels[1].cap - this.ref_pixels[1].x / this.ref_pixels[1].ratio_x, 360);

                alpha_domain.start = this.ref_pixels[0].cap;

                alpha_domain.end = fmodulo(this.ref_pixels[ord_pts.length].cap+(this.im.width-this.ref_pixels[ord_pts.length].x)/this.ref_pixels[ord_pts.length].ratio_x, 360);

                this.pixel_y_ratio = this.im.width/fmodulo(alpha_domain.end-alpha_domain.start, 360);

            }

            this.ref_pixels[0].x = 0;

            for (var i=0; i < ord_pts.length; i++) { // second parcours pour les paramètres elevation/y

                this.ref_pixels[i+1].shift_y = Math.floor(this.pixel_y_ratio*ord_pts[i].ele - ord_pts[i].y*this.im.height);

                if (i != ord_pts.length-1) {

                    var next_shift = Math.floor(this.pixel_y_ratio*ord_pts[i+1].ele - ord_pts[i+1].y*this.im.height);

                    this.ref_pixels[i+1].dshft_y = (next_shift - this.ref_pixels[i+1].shift_y)/(this.ref_pixels[i+2].x - this.ref_pixels[i+1].x);

                }

            }

            if (image_loop == true) {

                var dpix  = this.im.width;

                var delt = 0;

                if (ord_pts.length > 1) {

                    dpix  = this.im.width - this.ref_pixels[this.ref_pixels.length-1].x + this.ref_pixels[1].x;

                    delt = this.ref_pixels[this.ref_pixels.length-1].shift_y - this.ref_pixels[1].shift_y;

                }

                this.ref_pixels[0].dshft_y = delt/dpix;

                this.ref_pixels[ord_pts.length].dshft_y = this.ref_pixels[0].dshft_y;

                dpix = this.im.width - this.ref_pixels[ord_pts.length].x;

                this.ref_pixels[0].shift_y = this.ref_pixels[ord_pts.length].shift_y - dpix*this.ref_pixels[0].dshft_y;

            } else {

                this.ref_pixels[0].shift_y = this.ref_pixels[1].shift_y;

                this.ref_pixels[ord_pts.length].shift_y = this.ref_pixels[ord_pts.length-1].shift_y;

                this.ref_pixels[0].dshft_y = 0;

                this.ref_pixels[ord_pts.length].dshft_y = 0;

            }

            if (debug_mode) {

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

                res.innerHTML = 'liste des '+this.ref_pixels.length+' valeurs de correction (image = '+this.im.width+'x'+this.im.height+') zoom = '+this.value+':<br/>';

                for (var i=0; i < this.ref_pixels.length; i++) { // pour le debug

                    res.innerHTML += '<p>point '+i+' :</p><ul>';

                    for (var key in this.ref_pixels[i]) { // pour le debug

                        res.innerHTML += '<li>'+key + '['+i+'] = '+this.ref_pixels[i][key]+'</li>';

                    }

                    if (i != this.ref_pixels.length-1) {

                        var tx0 = this.ref_pixels[i+1].x-1;

                        //var ty0 = this.ref_pixels[i+1].shift_y;

                        var ty0 = 0;

                    } else {

                        var tx0 = this.im.width-1;

                        var ty0 = 0;

                    }

                    res.innerHTML += '</ul><p>test sur : '+tx0+','+ty0+'</p>';

                    var tst = this.get_cap_ele(tx0, ty0);

                    res.innerHTML += '<p>cap:'+tst.cap+', shift:'+tst.ele+'</p>';

                    var tst2 = this.get_pos_xy(tst.cap, tst.ele);

                    res.innerHTML += '</ul><p>x:'+tst2.x+', y:'+tst2.y+'</p>';

                }

            }

        }

        this.pt_list = new Array();

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

            var lbl = point_list[i][0];

            var dst = point_list[i][1];

            var cap = point_list[i][2];

            var ele = point_list[i][3];

            var lnk = point_list[i][4];

            var typ = 'unlocated';

            var rxy = this.get_pos_xy(cap, ele);

            var is_visible = fmodulo(cap - alpha_domain.start, 360) <= fmodulo(alpha_domain.end - alpha_domain.start -0.0001, 360)+0.0001 && is_located;

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

            if (ref_points[lbl] != undefined) {

                typ = 'ref_point';

                if (!is_located) rxy = {x:ref_points[lbl].x*this.im.width, y:ref_points[lbl].y*this.im.height}

            } else if(lnk == '' && is_visible && lbl != 'point temporaire') {

                typ = 'loc_point';

            }else if(is_visible && lbl =='point temporaire') {

            typ = 'temporary';

            } else if(is_visible) {

                typ = 'pano_point';

                lnk += '&to_zoom='+this.value;

            } 

            this.pt_list[i]['type'] = typ;

            this.pt_list[i]['cap'] = cap;

            this.pt_list[i]['ele'] = ele;

            this.pt_list[i]['dist'] = dst;

            this.pt_list[i]['label'] = lbl;

            this.pt_list[i]['lnk'] = lnk;

            this.pt_list[i]['xc'] = rxy.x;

            this.pt_list[i]['yc'] = Math.floor(this.im.height/2 - rxy.y);

        }

    }

    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;

    }

    this.get_cap_ele = function(px, py) {               // recherche d'un cap et d'une élévation à partir d'un pixel X,Y.

        if (is_located) {

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

                if (i == this.ref_pixels.length - 1 || px < this.ref_pixels[i+1].x) {

                    var dpix = px-this.ref_pixels[i].x;

                    var cp = fmodulo(this.ref_pixels[i].cap + dpix/this.ref_pixels[i].ratio_x, 360);

                    var el = (py+this.ref_pixels[i].shift_y+this.ref_pixels[i].dshft_y*dpix)/this.pixel_y_ratio;

                    return {cap:cp, ele:el};

                }

            }

        } else {

            var cp = 360*px/this.im.width;

            var el = 360*py/this.im.height;

            return {cap:cp, ele:el};

        }

    }

    this.get_pos_xy = function(cap, ele) {                  // recherche des coordonnées pixel à partir d'un cap et d'une élévation.

        if (is_located) {

            var dcap = fmodulo(cap-this.ref_pixels[0].cap, 360);

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

                if (i == this.ref_pixels.length - 1 || dcap < fmodulo(this.ref_pixels[i+1].cap-this.ref_pixels[0].cap, 360)) {

                    var px = this.ref_pixels[i].x + this.ref_pixels[i].ratio_x*fmodulo(cap - this.ref_pixels[i].cap, 360);

                    var dpix = px-this.ref_pixels[i].x;

                    var py = this.pixel_y_ratio*ele - this.ref_pixels[i].shift_y - this.ref_pixels[i].dshft_y*dpix;

                    return {x:px, y:py};

                }

            }

        } else {

            var px = fmodulo(cap, 360)/360*this.im.width;

            var py = ele/360*this.im.height;

            return {x:px, y:py};

        }

    }

}

function reset_zooms () {

    for(i=0; i<zooms.length; i++) zooms[i].is_updated = false;

    zm.refresh();

}

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 resxy = zm.get_pos_xy(angle_control.value, elvtn_control.value);

    var pos_x = resxy.x;

    var pos_y = Math.floor(zm.im.height/2 - resxy.y);

    putImage(pos_x, pos_y);

}

function check_prox(x, y, r) {   //verification si un point de coordonnées x, y est bien dans un cercle de rayon r centré en X,Y. 

    return Math.sqrt(x*x + y*y) < r;

}

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 (is_located && zm.pt_list[i]['type'] == 'pano_point') {

            if (check_prox(zm.pt_list[i]['xc']-pos_x, zm.pt_list[i]['yc']-pos_y, 20)) {

                if (zm.pt_list[i]['lnk'] != '') 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 res = zm.get_cap_ele(pos_x, zm.im.height/2 - pos_y);

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

    info.innerHTML = 'élévation : '+res.ele.toFixed(2)+'<br/>cap : '+res.cap.toFixed(2);

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

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

    info.style.backgroundColor = '#FFC';

    info.style.display = 'block';

    canvas.style.cursor='crosshair';

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

        if (is_located || zm.pt_list[i]['type'] == 'ref_point') {

            if (check_prox(zm.pt_list[i]['xc']-pos_x, zm.pt_list[i]['yc']-pos_y, 20)) {

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

                if (zm.pt_list[i]['dist'] < 10) var dst = Math.round(zm.pt_list[i]['dist']*1000)+' m';

                else var dst = zm.pt_list[i]['dist'].toFixed(1)+' kms';

                info.innerHTML += '<br/> à ' + dst;

                info.style.backgroundColor = 'rgb('+point_colors[zm.pt_list[i]['type']]+')';

                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 hide_contextmenu() {

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

}

function manage_ref_points(e) {

    //event.preventDefault();

    //event.stopPropagation();

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

    document.getElementById('do-cancel').onclick = hide_contextmenu;

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

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

    insrt.style.display = 'block';

    var sel_pt = document.getElementById('sel_point');

    var do_insert = document.getElementById('do-insert');

    var do_delete = document.getElementById('do-delete');

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

    var pos_y = last.y + e.pageY - canvas_pos.y - canvas.height/2;

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

        if (zm.pt_list[i]['type'] == 'ref_point') {

            if (check_prox(zm.pt_list[i]['xc']-pos_x, zm.pt_list[i]['yc']-pos_y, 20)) {

                sel_pt.value = zm.pt_list[i]['label'];

            }

        }

    }

    do_delete.onclick = function() {delete_ref_point(insrt)};

    do_insert.onclick = function() {insert_ref_point(insrt, e.pageX-canvas_pos.x, e.pageY-canvas_pos.y)};

    return false;

}

function insert_ref_point(el, x, y) {

    var label;

    el.style.display = 'none';

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

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

        if(label == document.getElementById('sel_point').value) {

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

            var posy = 0.5 - (last.y + y - canvas.height/2)/zm.im.height;

            var pval = {x:posx, y:posy, cap:zm.pt_list[i]['cap'], ele:zm.pt_list[i]['ele'], label:label};

            ref_points[label] = pval;

            document.getElementById('res').innerHTML = '<h4>Dernier point entré</h4>';

            document.getElementById('res').innerHTML += '<p>reference["'+label+'"] = '+posx.toFixed(5)+','+posy.toFixed(5)+'</p>';

            reset_zooms();

             putImage(last.x, last.y);

            break;

        }

    }

    show_result();

}

function show_result(clear_before) {

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

    var strg = '';

    for (var lbl in ref_points) {

        strg += '<li>reference["'+lbl+'"] = '+ref_points[lbl].x.toFixed(5)+','+ref_points[lbl].y.toFixed(5)+'</li>';

    }

    if (strg) strg = '<h3>Liste de tous les points de référence</h3>\n<ul>' + strg + '</ul>';

    if (clear_before) res.innerHTML = strg;

    else res.innerHTML += strg;

}

function delete_ref_point(el) {

    el.style.display = 'none';

    delete ref_points[document.getElementById('sel_point').value];

    reset_zooms();

    putImage(last.x, last.y);

    show_result(true);

}

function clean_canvas_events(e) {

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

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

    speed.x = 0;

    speed.y = 0;

}

canvas_set_size = function() {

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

    canvas.width = window.innerWidth-2*border_width;

    canvas.height = window.innerHeight-2*border_width;

    canvas_pos.x = canvas.offsetLeft+border_width;

    canvas_pos.y = canvas.offsetTop+border_width;

}

canvas_resize = function() {

    canvas_set_size();

    putImage(last.x, last.y);

}

function paramIn(e) {

         e = e || window.event; 

         var relatedTarget = e.relatedTarget || e.fromElement; 

         while (relatedTarget != adding && relatedTarget.nodeName != 'BODY' && relatedTarget != document && relatedTarget != localisation) {

                relatedTarget = relatedTarget.parentNode;

         }

         if (relatedTarget != adding && relatedTarget != localisation) {

                 document.removeEventListener('keydown', keys, false);

         }

}

function paramOut(e) {

    e = e || window.event; 

    var relatedTarget = e.relatedTarget || e.toElement; 

    while (relatedTarget != adding && relatedTarget.nodeName != 'BODY' && relatedTarget != document && relatedTarget != localisation) {

        relatedTarget = relatedTarget.parentNode;

    }

    if (relatedTarget != adding && relatedTarget != localisation) {

            document.addEventListener('keydown', keys, false);

    }

}

window.onload = function() {

        localisation = document.getElementById("locadraw");

        adding = document.getElementById("adding");

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

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

    canvas_set_size();

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

    //canvas.addEventListener("oncontextmenu", manage_ref_points, false);

    canvas.oncontextmenu = manage_ref_points;

    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 > 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;

    elvtn_control = document.getElementById("elvtn_ctrl");

    elvtn_control.value = to_ele;

    elvtn_control.onchange = change_angle;

    elvtn_control.onclick = change_angle;

    change_angle();

    loca_temp = document.getElementById("loca_button");

    loca_temp.onclick = localate_point;

    loca_erase = document.getElementById("loca_erase");

    loca_erase.onclick = erase_point;

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

    document.addEventListener('keydown', keys, false);

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

    window.onresize = canvas_resize;

    adding.addEventListener('mouseover',paramIn,false);

    adding.addEventListener('mouseout',paramOut,false);

    localisation.addEventListener('mouseover',paramIn,false);

    localisation.addEventListener('mouseout',paramOut,false);

};