Notes on document

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Creates a new instance of the ScreenSnippet object.

Syntax

let mySnippet = new ScreenSnippet();

...

let mySnippet = new ssf.ScreenSnippet();

Parameters

None.

Methods

capture()

Creates a new instance of the ScreenSnippet object.

Syntax

mySnippet.capture().then(function(bitmap) { ... });

Parameters

none

Returns

A Promise that resolves to an ImageBitmap object with contains the captured image and type.

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A possible idea that has been floated is to make the ScreenSnippet tool a reusable Node Module that calls to an external executable using "child_process" that could be invoked from the container.  This external executable could then use StdOut to communicate with the container to provide the result of the snippet.

class ScreenSnippet {
	capture() {
		return new Promise((resolve, reject) => {
			const childProcess = require('child_process');
			const snippetToolInterop = childProcess.fork('...', [], {
				silent: true
			});


			let response = false;
class ScreenSnippet 


			snippetToolInterop.on('exit', (code, signal) => {
				if (!response) {
					reject(...);
				}
			});


			snippetToolInterop.on('message', message => {
				if (!response) {
					response = true;
					snippetToolInterop.kill();
					if (message.error) {
						reject(...);
					} else {
						resolve(message.bitmap);
					}
				}

			});
		});
	}
}


module.exports = ScreenSnippet;

Discussion points:

• (From Gareth) I've assumed we have a preference for promises vs callbacks.  This seems inline with modern HTML5 standards which are deprecating callbacks. 

• (From Gareth) We should discuss the return object for the capture method.  I've currently followed the Minuet approach.