piano metronome fix

[Commanderk3]

metro.mp4

@pikurasa I found that while using the metronome, it records the last rest note also. So when you switch it ON again next time, it adds the previous rest duration. In this PR, a rest note is not added when you start playing the piano after switching the metronome ON. Please watch the video.
But imagine a case where a user wants to add rest before starting. The user can turn ON the metronome, he will wait for the right time, and then start playing the piano. Currently, there is no implementation for this. Do you think this would make sense?

[Commanderk3]

Now I am working on the countdown.

[pikurasa]

I think this is an improvement.

However, I'm still experiencing a mysterious issue where rests are inserted between notes. Do you experience that, too, @Commanderk3 ?

You can see the issue in this test:
test3.webm

[Commanderk3]

@pikurasa Yes, I have tested it.
I will fix it.

[Commanderk3]

But apart from that one thing, I want to ask, why can't notes overlap? Each note value corresponds to only one note. Look at this image :

Notice how E6 and D6 have the same starting time but has different end time. We can't do this in music keyboard. Is it because we can't perform such actions in blocks?
Also you cant record playing chords, I will fix that too, maybe in a different PR.

[walterbender]

You can do the E6/D6 thing if you put the D6 note inside the E6 note.

[Commanderk3]

You can do the E6/D6 thing if you put the D6 note inside the E6 note.

Yup, it's working. Thank you.

[Commanderk3]

The latest commits resolve the issue. The following features were added :->

1. Added count-down box before music keyboard starts recording.

2. When the metronome is ON it will highlight its background giving feedback that it is ON.

3. Enhanced the existing implementation of recording rest duration. Added a threshold value "EPSILON" which can be changed according to need. Now it won't record any unnecessary rest notes.

Have a look at the demo video :->

metrofix.mp4

@walterbender @pikurasa Please review this PR. Any kind of feedback is welcome!

[walterbender]

@pikurasa