Reproduce detection of fluorescent lights from legacy capture interface into new capture interface (this then offers to calibrate, with an alert along the top!)

[Georjane]

@jywarren and @Tlazypanda
I think I will be picking up this issue next from publiclab/spectral-workbench.js#265

thank you

[jywarren]

So we found that is_cfl maybe is not even used??? Because the line of code actually run is observe_contrast() which checks the average amount of "steepness" or contrast in the data every half second. I bet this run faster and more reliably than actually checking if the data matched a fluorescent light pattern, which is interesting:

https://github.com/publiclab/spectral-workbench.js/blob/4e3c9f65d51d3dacd4a831ab2aebf39181620db8/examples/capture/api.js#L41-L64

So, that should be something we can integrate here!

[jywarren]

Here's where it's used in the legacy code:

spectral-workbench/app/views/capture/_capture.html.erb

Lines 55 to 65 in 98dbde7

	jQuery(document).ready(function() {
	$W.observe_contrast(
	false,
	function() {
	$('#cfl-detect i').css('color','red');
	},
	function() {
	$('#cfl-detect i').css('color','white');
	}
	)
	})

[jywarren]

And here it is in the new capture code. Is it actually running?

spectral-workbench/app/views/capture/index2.html.erb

Lines 188 to 195 in 98014b8

	$W.observe_contrast(
	false,
	function() {
	$('#cfl-detect i').css('color','red');
	},
	function() {
	$('#cfl-detect i').css('color','white');
	})