Fix shifting of sample waveform during zoom

[khoidauminh]

The original code was doing division in int, which causes loss of accuracy and results in the waveform randomly shifting when zooming in and out.

This should fix it by casting variables to float before dividing, as well as keeping the values in float type.

[sakertooth]

Why were the type declaration changes removed? I see @Veratil mentioned going back to auto for some of them, but I think he was referring to that part of the code alone (though, even that part of the code should specify the type in its declaration IMO, since they are used in calculations later where the types of these variables are important to get right).

[Veratil]

Why were the type declaration changes removed? I see @Veratil mentioned going back to auto for some of them, but I think he was referring to that part of the code alone (though, even that part of the code should specify the type in its declaration IMO, since they are used in calculations later where the types of these variables are important to get right).

I did mean the part mentioned only, but that's fine if we want to specify.

[khoidauminh]

Sorry for the previous weird changes, I misunderstood some of the conversations in the review. Should I change all primitive type declarations to explicit this time @sakertooth ?

[sakertooth]

Sorry for the previous weird changes, I misunderstood some of the conversations in the review. Should I change all primitive type declarations to explicit this time?

For clarity as to what the types are, I would say yes. It's important here because we do a lot of arithmetic, so we need to be careful to avoid truncation when dividing, thinking variables are in a certain type when they aren't, etc. The use of auto exclusively also might be the reason why I didn't see the bug initially when I wrote this. Though I think some people have varying opinions on the use of auto, it wouldn't hurt to specify some of the types here.

[khoidauminh]

@sakertooth I think it's still better to make all primitive declarations explicit, even though it doesn't seem necessary. It can help detect more bugs, and make future code changes easier in general, in this case the arrival of sample caching. I'll go ahead and make all primitive type declarations explicit.

For the variables created from the QRect methods at the start @Veratil, I read through the Qt docs (for both Qt5 and Qt6) and they all return int, so it's safe to also declare them as int.

[Veratil]

Sorry for causing the back and forth churn. :)

[sakertooth]

I think it's still better to make all primitive declarations explicit, even though it doesn't seem necessary. It can help detect more bugs, and make future code changes easier in general, in this case the arrival of sample caching. I'll go ahead and make all primitive type declarations explicit.

Yes, this is what I mentioned 🤣 I was in agreement in making the primitive declarations explicit for the same reasons.

[sakertooth]

After the discussion in Discord, keeping them auto is fine, but if you want to specify the type here, that's fine too (as long as there are no implicit conversions, which I believe you mentioned there weren't any).