Created
September 9, 2019 18:00
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Node.JS script to generate map tiles from a source image for leaflet.js
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// node .\tools\generate-map.js --bigfile .\src\fullmap.jpg --endpath .\public\grid\ --zoom 7 | |
const fs = require('fs'); | |
const sharp = require('sharp'); | |
const argv = require('yargs').argv; | |
const _cliProgress = require('cli-progress'); | |
const endPresentFile = argv.bigfile; | |
const gridPath = argv.endpath; | |
const bar1 = new _cliProgress.SingleBar({}, _cliProgress.Presets.shades_classic); | |
let gridDims = 256; | |
let zoomLevels = argv.zoom; | |
let generateGridPiece = function(image,x,y){ | |
return new Promise(resolve => { | |
image.extract({left:x*gridDims,top:y*gridDims,width:gridDims,height:gridDims}).toFile(path+y+'.jpg').then(function(){ | |
resolve(true); | |
}); | |
}); | |
} | |
async function go(){ | |
console.log('This will take a while...') | |
let bigFile = sharp(endPresentFile).limitInputPixels(false); | |
for (var z = zoomLevels; z >= 0; z--) { | |
if (!fs.existsSync(gridPath+z)){ | |
fs.mkdirSync(gridPath+z); | |
} | |
let tWidth = gridDims; | |
let tHeight = gridDims; | |
let pieces = 1; | |
if(z > 0){ | |
pieces = Math.pow(2,z+1)/2; | |
percent = z/zoomLevels; | |
tWidth = pieces*gridDims; | |
tHeight = pieces*gridDims; | |
} | |
console.log('Starting zoom level '+z+' at '+pieces+'x'+pieces+' ('+tWidth+'x'+tHeight+')'); | |
let resized = bigFile.clone().resize({width:tWidth,height:tHeight}); | |
bar1.start(Math.pow(pieces,2),0); | |
for (var x = 0; x < pieces; x++) { | |
path = gridPath+z+'/'+x+'/'; | |
if (!fs.existsSync(path)){ | |
fs.mkdirSync(path); | |
} | |
for (var y = 0; y < pieces; y++) { | |
var gridpiece = await generateGridPiece(resized,x,y); | |
bar1.increment(); | |
} | |
} | |
bar1.stop(); | |
} | |
} | |
go(); |
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{ | |
"dependencies": { | |
"cli-progress": "^3.1.0", | |
"sharp": "^0.23.0", | |
"yargs": "^14.0.0" | |
} | |
} |
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