WeatherStar4000/server/scripts/modules/radar-utils.mjs

import { TILE_SIZE, TILE_FULL_SIZE } from './radar-constants.mjs';

// limit a value to within a range
const coerce = (low, value, high) => Math.max(Math.min(value, high), low);

const getXYFromLatitudeLongitudeMap = (pos) => {
	// source values for conversion
	// px		py		lon						lat
	// 589	466		-122.3615246	47.63177832
	// 5288	3638	-80.18297384	25.77018996

	// map position is calculated as a regresion from the above values (=/- a manual adjustment factor)
	// then shifted by half of the tile size (to center the map)
	// then they are limited to values between 0 and the width or height of the map
	const y = coerce(0, (-145.095 * pos.latitude + 7377.117) - 27 - (TILE_SIZE.y / 2), TILE_FULL_SIZE.y - (TILE_SIZE.y));
	const x = coerce(0, (111.407 * pos.longitude + 14220.972) + 4 - (TILE_SIZE.x / 2), TILE_FULL_SIZE.x - (TILE_SIZE.x));

	return { x, y };
};

const getXYFromLatitudeLongitudeDoppler = (pos, offsetX, offsetY) => {
	const imgHeight = 6000;
	const imgWidth = 2800;

	// map position is calculated as a regresion
	// then shifted by half of the tile size (to center the map)
	// then they are limited to values between 0 and the width or height of the map

	const y = coerce(0, (51 - pos.latitude) * 61.4481 - offsetY, imgHeight);
	const x = coerce(0, ((-129.138 - pos.longitude) * 42.1768) * -1 - offsetX, imgWidth);

	return { x: x * 2, y: y * 2 };
};

const removeDopplerRadarImageNoise = (RadarContext) => {
	const RadarImageData = RadarContext.getImageData(0, 0, RadarContext.canvas.width, RadarContext.canvas.height);

	// examine every pixel,
	// change any old rgb to the new-rgb
	for (let i = 0; i < RadarImageData.data.length; i += 4) {
		// i + 0 = red
		// i + 1 = green
		// i + 2 = blue
		// i + 3 = alpha (0 = transparent, 255 = opaque)
		let R = RadarImageData.data[i];
		let G = RadarImageData.data[i + 1];
		let B = RadarImageData.data[i + 2];
		let A = RadarImageData.data[i + 3];

		// is this pixel the old rgb?
		if ((R === 0 && G === 0 && B === 0)
			|| (R === 0 && G === 236 && B === 236)
			|| (R === 1 && G === 160 && B === 246)
			|| (R === 0 && G === 0 && B === 246)) {
			// change to your new rgb

			// Transparent
			R = 0;
			G = 0;
			B = 0;
			A = 0;
		} else if ((R === 0 && G === 255 && B === 0)) {
			// Light Green 1
			R = 49;
			G = 210;
			B = 22;
			A = 255;
		} else if ((R === 0 && G === 200 && B === 0)) {
			// Light Green 2
			R = 0;
			G = 142;
			B = 0;
			A = 255;
		} else if ((R === 0 && G === 144 && B === 0)) {
			// Dark Green 1
			R = 20;
			G = 90;
			B = 15;
			A = 255;
		} else if ((R === 255 && G === 255 && B === 0)) {
			// Dark Green 2
			R = 10;
			G = 40;
			B = 10;
			A = 255;
		} else if ((R === 231 && G === 192 && B === 0)) {
			// Yellow
			R = 196;
			G = 179;
			B = 70;
			A = 255;
		} else if ((R === 255 && G === 144 && B === 0)) {
			// Orange
			R = 190;
			G = 72;
			B = 19;
			A = 255;
		} else if ((R === 214 && G === 0 && B === 0)
			|| (R === 255 && G === 0 && B === 0)) {
			// Red
			R = 171;
			G = 14;
			B = 14;
			A = 255;
		} else if ((R === 192 && G === 0 && B === 0)
			|| (R === 255 && G === 0 && B === 255)) {
			// Brown
			R = 115;
			G = 31;
			B = 4;
			A = 255;
		}

		RadarImageData.data[i] = R;
		RadarImageData.data[i + 1] = G;
		RadarImageData.data[i + 2] = B;
		RadarImageData.data[i + 3] = A;
	}

	RadarContext.putImageData(RadarImageData, 0, 0);
};

export {
	getXYFromLatitudeLongitudeDoppler,
	getXYFromLatitudeLongitudeMap,
	removeDopplerRadarImageNoise,
};