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/**
* $ npm i jimp
*
* Copied from https://stackoverflow.com/a/48158807
*/
const fs = require('fs')
const util = require('util')
const Jimp = require('jimp')
const main = async () => {
if (process.argv.length != 4) {
console.log('Need two args: input filename and result filename')
console.log(`Example: ${process.argv[0]} ${process.argv[1]} HomeBackground.cpbitmap HomeBackground.png`)
return
}
const inpFileName = process.argv[2]
const outFileName = process.argv[3]
const readFile = util.promisify(fs.readFile)
const cpbmp = await readFile(inpFileName)
const width = cpbmp.readInt32LE(cpbmp.length - 4 * 5)
const height = cpbmp.readInt32LE(cpbmp.length - 4 * 4)
console.log(`Image height: ${height}, width: ${width}`)
const image = await new Jimp(width, height, 0x000000FF)
const calcOffsetInCpbmp = (x, y, width) => {
const lineSize = Math.ceil(width / 8) * 8
return x * 4 + y * lineSize * 4
}
const calcOffsetInImage = (x, y, width) => {
return x * 4 + y * width * 4
}
const swapRBColors = (c) => {
const r = c & 0xFF
const b = (c & 0xFF0000) >> 16
c &= 0xFF00FF00
c |= r << 16
c |= b
return c
}
for (let y = 0; y < height; y++) {
for (let x = 0; x < width; x++) {
const color = cpbmp.readInt32LE(calcOffsetInCpbmp(x, y, width))
image.bitmap.data.writeInt32LE(swapRBColors(color), calcOffsetInImage(x, y, width))
}
}
await image.write(outFileName)
console.log('Done')
}
main()
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