screen-streamer

This module continuously takes screenshots and returns them as png or jpeg buffers. It uses FFMPEG with x11grab format support so make sure to have it installed.

Installation

npm install screen-streamer

Syntax

screenStreamer(options[, callback])

options — is an object literal with the following properties

• duration — [Integer] duration of screen capturing in seconds; default: 86400
• fps — [Integer] number of frames per second to capture; default: 1
• width — [Integer] the width of screen area to capture; required
• height — [Integer] the height of screen area to capture; required
• offsetX — [Integer] the horizontal offset of screen area to capture; default: 0
• offsetY — [Integer] the vertical offset of screen area to capture; default: 0
• maxWidth — [Integer] the maximum width of the output image; default: -1, means no scaling
• maxHeight — [Integer] the maximum height of the output image; default: -1, means no scaling
• display — [String] the display id; default: "0.0"
• format — [String] the format of the image to return, either 'png' or 'jpeg'; default: 'png'
• quality — [Integer] the jpeg image quality, from 1 (highest) to 100 (lowest); default: 1

callback — a callback function to pass the result Buffer to: function(err, buffer){ ... } if ommited then a call to screenStreamer function will return a Stream

Example

The code below takes a screenshot from main display every second during 10 seconds and saves it to "screenshot_%d.png"

var screenStreamer = require('screen-streamer');
var fs = require('fs');
var fileIndex = 0;

screenStreamer({
    width: 1024,
    height: 768,
    fps: 1,
    duration: 10,
    format: 'png'
  }, function(err, buffer){
    if (err) throw err;
  
    fs.writeFile('screenshot_' + fileIndex++ + '.png', buffer, function (err) {
      if (err) throw err;
    });
  });

This example shows how to use screenStreamer as a Stream

var screenStreamer = require('screen-streamer');
var fs = require('fs');

screenStreamer({
    width: 1024,
    height: 768,
    fps: 1,
    duration: 10,
    format: 'png'
  }).pipe(fs.createWriteStream('./screenshot.png'));