Baidu map map coordinates converted to page pixels __ Baidu Map

Recently used Baidu map to do the data display, but the use of their own definition of pictures and notes must be positioned on the page to achieve the effect, which must be used to pixel coordinates, online Baidu for a long time, found a set of feasible methods, the following code test available, if necessary partners can refer to

/********************** Basic parameters start **********************/Mcband = [12890594.86, 8362377.87, 5591021, 3481989.83, 1678043.12, 0] Llband = [0] mc2ll = [[1.410526172116255e-8, 0.00000898305509648872,-1.9939833816331, 200.9824383106796,-187.2403703815547, 91.6087516669843,-23.38765649603339, 2.57121317296198,-0.03801003308653, 17337981.2], [ -7.435856389565537e-9, 0.000008983055097726239,-0.78625201886289, 96.32687599759846,- 1.85204757529826,-59.36935905485877, 47.40033549296737,-16.50741931063887, 2.28786674699375, 10260144.86], [- 3.030883460898826e-8, 0.00000898305509983578, 0.30071316287616, 59.74293618442277, 7.357984074871,- 25.38371002664745, 13.45380521110908, -3.29883767235584, 0.32710905363475, 6856817.37], [ -1.981981304930552e-8, 0.000008983055099779535, 0.03278182852591, 40.31678527705744, 0.65659298677277,-4.44255534477492, 0.85341911805263 , 0.12923347998204, -0.04625736007561, 4482777.06], [3.09191371068437e-9, 0.000008983055096812155, 0.00006995724062, 23.10934304144901,-0.00023663490511,-0.6321817810242,-0.00663494467273, 0.03430082397953,- 0.00466043876332, 2555164.4], [2.890871144776878e-9, 0.000008983055095805407, -3.068298e-8, 7.47137025468032,- 0.00000353937994, -0.02145144861037, -0.00001234426596, 0.00010322952773, -0.00000323890364, 826088.5]] LL2MC = [[- 0.0015702102444, 111320.7020616939, 1704480524535203,-10338987376042340, 26112667856603880,-35149669176653700, 26595700718403920,-10725012454188240, 1800819912950474, 82.5], [0.0008277824516172526, 111320.7020463578, 647795574.6671607,-4082003173.641316, 10774905663.51142,-15171875531.51559, 12053065338.62167,-5124939663.577472 , 913311935.9512032, 67.5], [0.00337398766765, 111320.7020202162, 4481351.045890365,-23393751.19931662, 79682215.471 86455,-115964993.2797253, 97236711.15602145,-43661946.33752821, 8477230.501135234, 52.5], [0.00220636496208, 111320 .7020209128, 51751.86112841131, 3796837.749470245, 992013.7397791013,-1221952.21711287, 1340652.697009075,-620943.6990984312, 144416.9293806241, 37.5], [-0.0003441963504368392, 111320.7020576856, 278.2353980772752, 2485758.690035394, 6070.750963243378, 54821.18345352118, 9540.606633304236,- 2710.55326746645, 1405.483844121726, 22.5], [-0.0003218135878613132, 111320.7020701615, 0.00369383431289,
823725.6402795718, 0.46104986909093, 2351.343141331292, 1.58060784298199, 8.77738589078284, 0.37238884252424, 7.45]] /********************** Basic parameter End **********************//*********** convert pixels to map coordinates ***********///point: current pixel var point = new
Bmap.point (x, y);
Zoom: Current map zoom level var zoom = Map.getzoom ();
Center: Current map visual range Central Point coordinates var center = map.getcenter ();
Bounds: Map visible region var bound = map.getsize ();
    var pixeltopoint = function (point, Zoom, center, bounds) {if (!point) {return;
    var zoomunit = getzoomunits (zoom);
    var mercatorlng = center.lng + zoomunit * (POINT.X-BOUNDS.WIDTH/2); var Mercatorlat = Center.lat-zoomunit * (Point.y-bounDS.HEIGHT/2);
    var Mercatorlnglat = {lng:mercatorlng, lat:mercatorlat}; Return Mercatortolnglat (Mercatorlnglat)}/*********** convert map coordinates to imaging element ***********///point: current pixel var point = new Bmap.point (x,
y);
Zoom: Current map zoom level var zoom = Map.getzoom ();
Center: Current map visual range Central Point coordinates var center = map.getcenter ();
Bounds: Map visible region var bound = map.getsize (); var pointtopixel = function (point, Zoom, center, bounds) {//coordinate to pixel if (!point) {return} point
    = Formatpoint (point);
    Center = formatpoint (center);
    var units = getzoomunits (zoom);
    var x = Math.Round ((POINT.LNG-CENTER.LNG)/units + BOUNDS.WIDTH/2);
    var y = Math.Round ((Center.lat-point.lat)/units + BOUNDS.HEIGHT/2); return {x:x, y:y}}//Convert zoom level var getzoomunits = function (zoom) {return Math.pow (2, (18-zoom));} var Formatpoi
    NT = function (point) {var lng_lat, MC;
    POINT.LNG = Getloop (POINT.LNG,-180, 180);
    Point.lat = GetRange (Point.lat,-74, 74);
Lng_lat = {        LNG:POINT.LNG, Lat:point.lat};
            for (var i = 0; i < llband.length i++) {if (Lng_lat.lat >= llband[i)) {MC = ll2mc[i]; Break}} if (!MC) {for (var i = llband.length-1 i >= 0; i--) {if (lng_l
                At.lat <=-llband[i]) {MC = ll2mc[i];
    Break}} The var CE = convertor (point, MC);
    var Lng_lat = {lng:cE.lng.toFixed (2), lat:cE.lat.toFixed (2)}; Return Lng_lat} var getloop = function (LNG, a, b) {while (LNG > B) {LNG-= b-a} while (LNG & Lt A) {LNG + = B-a} return LNG} var getrange = function (lat, a, b) {if (a!= null) {lat =  Math.max (Lat, a)} if (b!= null) {lat = math.min (lat, b)} return lat} var convertor = function (Point, MC) {if (!point | |!mc) {return} var LNG = mc[0] + mc[1] * Math.Abs (POINT.LNG);
    var c = math.abs (Point.lat)/mc[9]; var lat = mc[2] + mc[3] * C + mc[4] * c * C + mc[5] * c * c * C + mc[6] * c * c * c * C + mc[7] * c * c * c * c * C + mc[8
    ] * c * c * c * c * c * * C;
    LNG *= (POINT.LNG < 0 -1:1);
    Lat *= (Point.lat < 0 -1:1); return {LNG:LNG, Lat:lat}}

However, you can also use the Map.pointtooverlaypixel method to convert geographic coordinates to the required pixel coordinates (not quite accurate) for the overlay