Questions regarding this lib

Hello!

When I was checking out examples in this repo I came up with an idea of making software similar to LightShot but for Linux.

In this example we can see how to render current “screen dump” to other window. If I am not mistaken the first argument passed to X.getImage is supposed to be format which happens to be set to 2 in given example. I didn’t really know what it meant so I searched this repo and found this line. Unfortunately if I set format to 0 (bitmap according to previous link) in X.getImage I get this error:

{ Error: Bad param value
    at ReadFixedRequest.callback (/home/elderapo/nodejs/node-x11/lib/xcore.js:465:29)
    at ReadFixedRequest.execute (/home/elderapo/nodejs/node-x11/lib/unpackstream.js:41:10)
    at UnpackStream.resume (/home/elderapo/nodejs/node-x11/lib/unpackstream.js:165:30)
    at UnpackStream.write (/home/elderapo/nodejs/node-x11/lib/unpackstream.js:102:10)
    at Socket.<anonymous> (/home/elderapo/nodejs/node-x11/lib/xcore.js:88:21)
    at emitOne (events.js:115:13)
    at Socket.emit (events.js:210:7)
    at addChunk (_stream_readable.js:266:12)
    at readableAddChunk (_stream_readable.js:253:11)
    at Socket.Readable.push (_stream_readable.js:211:10)
  error: 2,
  seq: 7,
  message: 'Bad param value',
  badParam: 0,
  minorOpcode: 0,
  majorOpcode: 73 }

I guess this error means that 0 (bitmap) is incorrect value and that if I want to get bitmap I should convert ZPixmap to bitmap. If so any tips how I can achive that?

Also I was wondering if it’s possible to get color of the pixel at given coordinates in x window. I found some c++ snippets using XGetImage and XGetPixel to achieve that but I couldn’t find anything about GetPixel in this repo.

[sidorares]

Can’t remember what’s the status of mit-shm extension here. I did some research a while ago but as far as I can remember not finished implementation. Would be good to add it

https://www.npmjs.com/package/nodeshm https://www.x.org/releases/X11R7.7/doc/xextproto/shm.txt

[sidorares]

You can try to use MIT-SHM extension. The idea is that if server and client share same memory you can avoid copying large amount of data over network ( 1920x1080x32bit = 6 MBytes, 70 ms not that bad actually for this amount )