Smoother scrolling w/ deceleration for LC fields

[bn]

A while ago there was a discussion on the use-list to get smoother scrolling and decelerating scrolling for LC fields.
https://quality.livecode.com/show_bug.cgi?id=19759
and a an old discussion on the use-list
http://lists.runrev.com/pipermail/use-l ... 96772.html
My script is based on above proposal by John Miskimins but with added deceleration.

Here is my take on this.
Feedback welcome, especially on slower computers.

Kind regards
Bernd

[stam]

Hi Bernd,

i tested your stack on my mac (intel i7 mbp, macOS 12.3.1 Monterey, LC 10.0 DP3) but there were problems with etc 'smooth scrolling' window; it's a lot slower and laggier that the normal scroll. By slower i don't just mean scroll speed but how much of the window is scrolled for the same movement on the trackpad is much less and on a 'free scroll' it travels much less and with variable scrolling speed...

The version i have doesn't seem useable i'm afraid...

[bn]

Hi Stam,

thanks for the feedback. On my M1 MacBookPro it scrolls quite nicely. That is why I was very interested in feedback.

Could you try to change some parameters? kCutOff to 150 and kDiv to 15 and tell me if that is better?

Code: Select all

constant kCutOff = 150 -- milliseconds between rawKeyDown, below decelerating scrolling kicks in
constant kDiv = 15 -- used to adapt stepsize to scrolling speed

Kind regards
Bernd

[stam]

No sadly these changes don't improve performance, possibly it's worse.

I'll try and do a screen recording this evening or tomorrow, don't have time right now...

regards
Stam

[mrcoollion]

On Windows Laptop it works nice.
Slow scrolling is with small steps and fast scrolling is with large steps.
FYI: I do have a very fast laptop.

Regards,

Paul

[richmond62]

You can never be too careful:
-

[dunbarx]

Bernd.

iMac 27 4GHz Quad I7 on Catalina.

Took me a moment to look at the handlers to see that one should not use the scrollbar to do the scrolling, but rather the scrollwheel on the mouse.

I see a certain difference between the two fields, but not so much that I would rush to use the "smooth" one.

But why not play around with something like this?

Code: Select all

on rawKeyDown tkey
if tKey = 65308 then set the scroll of me to the scroll of me +  5 else set the scroll of me to the scroll of me - 5
end rawKeyDown

The fun thing here would be to change the "5" (an arbitrary value) to a larger one if the scroll wheel was moved more quickly.

Craig

[dunbarx]

I tried a few things, none of which seem to work. The idea is to detect the rate of scroll wheel movement, fast or slow. There does not seem to be a "scrollWheelRate" message.

Code: Select all

on rawKeyDown tkey
   get the milliseconds
   if tKey = 65308 then set the scroll of me to the scroll of me +  5 else set the scroll of me to the scroll of me - 5
   put the milliseconds - it into fld "ss"
end rawKeyDown

The number in fld "ss" (about 25) does not change much regardless of the scrollwheel speed. I was hoping that I could exploit a difference there to change the arbitrary "5", hard-coded in the handler, so that a faster wheel rate would scroll more quickly.

Still playing....

Craig

[bn]

Craig,

Apparently the code does work differently on different processors (on slower ones less well). It seems to work well for @Paul.

The whole point of the exercise was to add deceleration to mouse-wheel scrolling like native fields scroll.
The main difference would be that towards the end of a scroll the amount of scrolling goes down. You should see the effect also when using the mouse-wheel/touchpad to scroll slowly.
The field with non-smooth scrolling uses a fixed amount of pixels when scrolling, for me it is about 97 pixels up or down. There is no code interfering with what Livecode thinks it should scroll.

I guess we will have to wait until Livecode somehow hooks into the operating system and adapts scrolling accordingly.

Kind regards
Bernd

[richmond62]

Am I missing something?
-

[bn]

Am I missing something?

Not very much except for the operating system and platforms.

Kind regards
Bernd

[richmond62]

Not very much except for the operating system and platforms.

Well, obviously those matter.