Menu applet/Shell Toolkit: Add a polygon widget class and implement it in the menu applet

[mtwebster]

This is to prevent inadvertant category changes when moving the mouse
over to the applications box.

See issue #1775

The polygon is drawn and acts like a mask, preventing selection changing while
your mouse movement is towards the app box.

It is normally invisible but can be made visible to help debugging.

https://dl.dropbox.com/u/8201170/cinnamon-20130311-1.webm

[mtwebster]

I'm fairly satisfied with this now. I've turned off debugging mode (easily turned back on if you want) - seeing the mask actually influences how you move the mouse it turns out - it works quite well when you're not thinking about it though.

Sluggish on my virtual machine here, but that's normal... I'll try again later on my laptop and see how it works. Performance was fine in earlier iterations of it.

[mtwebster]

New video, improved behavior:

https://dl.dropbox.com/u/8201170/cinnamon-20130312-1.webm

[dalcde]

Looks cool :)

[Topperfalkon]

That's a massive improvement in my opinion. I look forward to trying that out next time I jump on Linux Mint.

[Lusito]

Been tinkering with this as well, ever since 1775, but I don't really see the point in the polygon ui element. Can you explain why you need this instead of a triangle ?

[gauravjuvekar]

@Lusito A triangle is a polygon.
Would make using other shapes possible rather than a triangle eg for a larger area perhaps enabled through some accessibility setting.

[mtwebster]

I'm not using a triangle because I want to encompass the height of the selected category in my mask, not just a point leading from the mouse position.

Technically it's a quadrilateral - a rectangle with uneven sides/angles.

[Lusito]

or a triangle with a cut off tip. But I don't see the point of adding the height of the selected category, since when you are still on the category, there will be no changes anyhow.
(I' assuming the left part of the polygon is aligned with the button top/bottom position, at least that's how it looks in the video.)

[mtwebster]

Couple reasons - it gives a larger masking envelope, for the user, and it means less redraws of the polygon from simple up/down movement.

It's really an inexact thing - I'll definitely look into having an area smaller than the button height, since it improves category navigation, but I don't think having it come to a point would work out that well.

[mtwebster]

@Lusito it did seem to improve responsiveness making it more 'pointy' - didn't appear to affect performance much, I think it's just about perfect now

[VolMi]

I love you. ;-)

Really, it's great to see you solving this so elegantly. Thank you very much!