Fretboard OnClick, clickable area slighty off from note position

[Aduffy]

If you click on the bottom part of a note on String 6, it returns that note from string 1
View console for output.
https://codepen.io/aduffy/pen/dypvjKa?editors=0001

[moonwave99]

The hover div does not resize accordingly, that's the problem ^^

Will look into that, thanks for reporting!

[Aduffy]

Hey Diago I know your a busy guy right now, but any chance you might have a chance to look at this bug?

[moonwave99]

I have it a look under xmas and looks trickier than expected (due to svg scaling / padding).

Atm I have definitely 0% time unfortunately. Hope to find some in the next weeks!

[PhilJollans]

I have created a pull request (#67) which I think will fix this problem.

The strings group is offset vertically from hoverDiv by topPadding, so this should be subtracted from the Y coordinate.

At the same time, the Y coordinate is compared to 1 * stringDistance for the first string, up to 6 * stringDistance for the sixth string. This is not really correct. We ought to compare the Y coordinate to 0.5 * stringDistance up 6.5 * stringDistance.

This previously worked more or less correctly if topPadding was approximately half the string separation, in which case the two effect cancelled each other out. If you change the height option, making the strings closer or further apart, it is easy to generate an error.

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Sorry, I might have been a bit too quick with my pull request. There still appears to be a problem, in particular if you set the height to a low value, like 75 or even 50.

[PhilJollans]

I have closed my first pull request, but now made a second pull request (#68) with a new fix to the problem.

The size of the hoverDiv was unreliable, in particular if you started resizing the window. This could change the size of the SVG diagram, but it did not modify the bottom margin. I have simply dumped the bottom margin, setting it to zero.

This however means the hoverDiv is typically too big and can generate events away from the fretboard (in the fret numbers). To counter that I have changed the return type of getPositionFromMouseCoords to return undefined if the mouse position is more than half the string separation outside the fretboard.

Determining the position was actually more complicated than necessary. In particular, it now only fetches the strings group, and calculates the position relative to its top left corner.