e373c63837
decimal places for the zoom level whilst still preserving accuracy sufficient to position the map within a few pixels. The relationship between zoom level, decimal places, and the accuracy with which the map can then be positioned in pixels is as follows: Zoom Decimals Accuracy (pixels) 1 0 1.42 2 0 2.84 3 1 0.57 4 1 1.14 5 1 2.28 6 2 0.46 7 2 0.91 8 2 1.82 9 3 0.36 10 3 0.73 11 3 1.46 12 4 0.29 13 4 0.58 14 4 1.17 15 5 0.23 16 5 0.47 17 5 0.93 18 6 0.19 So the worse case is at zoom 2 where accuracy is still within 3 pixels. Based on a patch by rjmunro.
91 lines
2.2 KiB
JavaScript
91 lines
2.2 KiB
JavaScript
function updatelinks(lon,lat,zoom,layers) {
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var decimals = Math.pow(10, Math.floor(zoom/3));
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var node;
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lat = Math.round(lat * decimals) / decimals;
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lon = Math.round(lon * decimals) / decimals;
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node = document.getElementById("permalinkanchor");
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if (node) {
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var args = getArgs(node.href);
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args["lat"] = lat;
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args["lon"] = lon;
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args["zoom"] = zoom;
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args["layers"] = layers;
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node.href = setArgs(node.href, args);
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}
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node = document.getElementById("viewanchor");
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if (node) {
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var args = getArgs(node.href);
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args["lat"] = lat;
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args["lon"] = lon;
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args["zoom"] = zoom;
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args["layers"] = layers;
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node.href = setArgs(node.href, args);
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}
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node = document.getElementById("editanchor");
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if (node) {
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if (zoom >= 11) {
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var args = new Object();
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args.lat = lat;
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args.lon = lon;
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args.zoom = zoom;
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node.href = setArgs("/edit.html", args);
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node.style.fontStyle = 'normal';
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} else {
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node.href = 'javascript:alert("zoom in to edit map");';
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node.style.fontStyle = 'italic';
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}
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}
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}
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function getArgs(url) {
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var args = new Object();
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var querystart = url.indexOf("?");
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if (querystart >= 0) {
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var querystring = url.substring(querystart + 1);
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var queryitems = querystring.split("&");
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for (var i = 0; i < queryitems.length; i++) {
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if (match = queryitems[i].match(/^(.*)=(.*)$/)) {
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args[unescape(match[1])] = unescape(match[2]);
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} else {
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args[unescape(queryitems[i])] = null
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}
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}
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}
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return args;
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}
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function setArgs(url, args) {
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var queryitems = new Array();
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for (arg in args)
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{
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if (args[arg] == null) {
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queryitems.push(escape(arg));
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} else {
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queryitems.push(escape(arg) + "=" + escape(args[arg]));
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}
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}
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return url.replace(/\?.*$/, "") + "?" + queryitems.join("&");
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}
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function getStyle(el, property) {
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var style;
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if (el.currentStyle) {
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style = el.currentStyle[property];
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} else if( window.getComputedStyle ) {
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style = document.defaultView.getComputedStyle(el,null).getPropertyValue(property);
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} else {
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style = el.style[property];
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}
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return style;
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}
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