kopia lustrzana https://github.com/rastapasta/mapscii
104 wiersze
2.2 KiB
JavaScript
104 wiersze
2.2 KiB
JavaScript
/*
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termap - Terminal Map Viewer
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by Michael Strassburger <codepoet@cpan.org>
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methods used all around
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*/
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'use strict';
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const config = require('./config');
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const constants = {
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RADIUS: 6378137,
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};
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const utils = {
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clamp: (num, min, max) => {
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if (num <= min) {
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return min;
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} else if (num >= max) {
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return max;
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} else {
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return num;
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}
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},
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baseZoom: (zoom) => {
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return Math.min(config.tileRange, Math.max(0, Math.floor(zoom)));
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},
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tilesizeAtZoom: (zoom) => {
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return config.projectSize * Math.pow(2, zoom-utils.baseZoom(zoom));
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},
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deg2rad: (angle) => {
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// (angle / 180) * Math.PI
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return angle * 0.017453292519943295;
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},
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ll2tile: (lon, lat, zoom) => {
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return {
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x: (lon+180)/360*Math.pow(2, zoom),
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y: (1-Math.log(Math.tan(lat*Math.PI/180)+1/Math.cos(lat*Math.PI/180))/Math.PI)/2*Math.pow(2, zoom),
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z: zoom,
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};
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},
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tile2ll: (x, y, zoom) => {
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const n = Math.PI - 2*Math.PI*y/Math.pow(2, zoom);
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return {
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lon: x/Math.pow(2, zoom)*360-180,
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lat: 180/Math.PI*Math.atan(0.5*(Math.exp(n)-Math.exp(-n))),
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};
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},
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metersPerPixel: (zoom, lat = 0) => {
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return (Math.cos(lat * Math.PI/180) * 2 * Math.PI * constants.RADIUS) / (256 * Math.pow(2, zoom));
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},
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hex2rgb: (color) => {
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if (typeof color !== 'string') return [255, 0, 0];
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if (!/^#[a-fA-F0-9]{3,6}$/.test(color)) {
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throw new Error(`${color} isn't a supported hex color`);
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}
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color = color.substr(1);
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const decimal = parseInt(color, 16);
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if (color.length === 3) {
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const rgb = [decimal>>8, (decimal>>4)&15, decimal&15];
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return rgb.map((c) => {
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return c + (c<<4);
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});
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} else {
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return [(decimal>>16)&255, (decimal>>8)&255, decimal&255];
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}
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},
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digits: (number, digits) => {
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return Math.floor(number*Math.pow(10, digits))/Math.pow(10, digits);
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},
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normalize: (ll) => {
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if (ll.lon < -180) ll.lon += 360;
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if (ll.lon > 180) ll.lon -= 360;
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if (ll.lat > 85.0511) ll.lat = 85.0511;
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if (ll.lat < -85.0511) ll.lat = -85.0511;
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return ll;
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},
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population: (val) => {
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let bits = 0;
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while (val > 0) {
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bits += val & 1;
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val >>= 1;
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}
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return bits;
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},
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};
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module.exports = utils;
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