Comment by ~jonegil on ~eliasnaur/gio
It makes sense to not use
image.RectangleforScrollBounds,But does that explain why the behaviour for Scrolls changes when I add a handler to listen for Clicks as well?
Comment by ~jonegil on ~eliasnaur/gio
Thanks Elias
A minimalist version that reproduces the effect is available here. It uses gio 0.6. The program listens for scrolls in the window and prints in the terminal. https://github.com/jonegil/gui-with-gio/blob/bug-scrolling/teleprompter/code/main.go
If the event code only listens for scroll events, it catches the Y dimension as expected, including when X in ScrollBounds is 0
// Scrolled a mouse wheel? for { ev, ok := gtx.Event( pointer.Filter{ Target: tag, Kinds: pointer.Scroll, ScrollBounds: image.Rectangle{ Min: image.Point{X: 0, Y: -1}, Max: image.Point{X: 0, Y: +1}, }, }, ) if !ok { break } fmt.Printf("SCROLL: %+v\n", ev) }Printed output, +/- 1 in Scroll.Y:
SCROLL: {Kind:Scroll Source:Mouse PointerID:0 Priority:Foremost Time:10h38m56.531s Buttons: Position:(471,276) Scroll:(0,1) Modifiers:} SCROLL: {Kind:Scroll Source:Mouse PointerID:0 Priority:Foremost Time:10h38m56.921s Buttons: Position:(471,276) Scroll:(0,-1) Modifiers:}However, if it also listens for pointer clicks, the Y dimension is ignored:
// Scrolled a mouse wheel? for { ev, ok := gtx.Event( pointer.Filter{ Target: tag, Kinds: pointer.Scroll, ScrollBounds: image.Rectangle{ Min: image.Point{X: 0, Y: -1}, Max: image.Point{X: 0, Y: +1}, }, }, ) if !ok { break } fmt.Printf("SCROLL: %+v\n", ev) } // Pressed a mouse button? for { ev, ok := gtx.Event( pointer.Filter{ Target: tag, Kinds: pointer.Press, }, ) if !ok { break } fmt.Printf("PRESS : %+v\n", ev) }Printed output, 0 Scroll.Y
SCROLL: {Kind:Scroll Source:Mouse PointerID:0 Priority:Foremost Time:10h39m12.312s Buttons: Position:(540,422) Scroll:(0,0) Modifiers:} SCROLL: {Kind:Scroll Source:Mouse PointerID:0 Priority:Foremost Time:10h39m12.671s Buttons: Position:(540,422) Scroll:(0,0) Modifiers:}However, by changing the ScrollBounds to have a +/-1 X-dimension, things start working again
ScrollBounds: image.Rectangle{ Min: image.Point{X: -1, Y: -1}, Max: image.Point{X: +1, Y: +1}, },the output again shows non-zero values in Scroll.Y even when I listen both for scrolls and for clicks.
SCROLL: {Kind:Scroll Source:Mouse PointerID:0 Priority:Foremost Time:10h50m26.484s Buttons: Position:(488,334) Scroll:(0,1) Modifiers:} SCROLL: {Kind:Scroll Source:Mouse PointerID:0 Priority:Foremost Time:10h50m26.609s Buttons: Position:(488,334) Scroll:(0,-1) Modifiers:}
on ~eliasnaur/gio
~jonegil, can I ask you to help me pinpoint the issue by minimizing your program as much as possible? As I understand it, Chris' program works as intended, so I'm trying to locate the breaking difference from his program to yours. Thank you.
Comment by ~jonegil on ~eliasnaur/gio
Thank you Chris!
Yes, your program works as intended without X coordinate. If I add an explicit X it works equally well with X:0 and X: 1 (or X:-1).
Your code gives clean events:
SCROLL: {Kind:Scroll Source:Mouse PointerID:0 Priority:Foremost Time:5h18m6.992s Buttons: Position:(64.63672,46.26953) Scroll:(0,100) Modifiers:} SCROLL: {Kind:Scroll Source:Mouse PointerID:0 Priority:Foremost Time:5h18m7.52s Buttons: Position:(64.63672,46.26953) Scroll:(0,-100) Modifiers:}Adding a print to my original progam [1 above] and removing X or setting X in Scrollbounds to 0 gives
SCROLL: {Kind:Scroll Source:Mouse PointerID:0 Priority:Foremost Time:5h19m1.32s Buttons: Position:(476.33203,382.47656) Scroll:(0,0) Modifiers:} SCROLL: {Kind:Scroll Source:Mouse PointerID:0 Priority:Foremost Time:5h19m1.62s Buttons: Position:(476.33203,382.47656) Scroll:(0,0) Modifiers:} SCROLL: {Kind:Scroll Source:Mouse PointerID:0 Priority:Foremost Time:5h19m1.688s Buttons: Position:(476.33203,382.47656) Scroll:(0,0) Modifiers:}I.e. the event registers, but the Y-value is 0.
Best regards J
Ticket created by ~jonegil on ~eliasnaur/gio
Detecting mouse scrolls is non intuitive.
In the example on https://gioui.org/doc/architecture/input,
// Declare
tagas being one of the targets. event.Op(ops, tag)is called before painting operations commence.
However, it this example [1], event.Op(&ops, tag) needs to be called at the very end of case app.FrameEvent:
If event.Op(&ops, tag) is called too early, for example around the lines of code where the tag is used and it contextually is natural to register it, behaviour is strange:
- scrolls are not detected
- however, scrolling while pressing (and not releasing) any mouse buttion works well. Strange
Finally, the scroll event in Y-direction only works if ScrollBounds has x distance as well:
ScrollBounds: image.Rectangle{ Min: image.Point{X: -1, Y: -1}, Max: image.Point{X: +1, Y: +1}, },Thanks to JK for helping identify these
Best regards JE
---------- Forwarded message --------- From: Jon Egil Strand jon.egil.strand@gmail.com Date: Tue, 19 Mar 2024 at 20:57 Subject: Re: Detecting mouse wheel To: jkvatne@online.no Cc: ~eliasnaur/gio@lists.sr.ht
Thank you for your reply.
To add mystery to the enigma:
Adding breadth to X in ScrollBounds work as you describe.
Min: image.Point{X: 0, Y: -100}, Max: image.Point{X: 1, Y: +100},
If I then press and hold Left, Right or Wheel, scrolling works as expected. No buttonpress = no scroll
Jon Egil
On Tue, 19 Mar 2024 at 09:32, Jan Kåre Vatne jkvatne@online.no wrote:
Hi Jon. Yes the scrolling is strange.
I have been able to make your app work by the following changes.
- Move the tag registration to just before the Finalize section 2a. Either change the ScrollBounds to { Min: image.Point{X: 0, Y: -100}, Max: image.Point{X: 1, Y: +100}} 2b. Or add an identical ScrollBound to the mouse button filter.
The last change is really strange. I have tried to debug the gio code, but it is very complicated. I think there must be an error in the gio code, concerning merging of filters. There is no reason the x range should be different from 0,0. And it fails only when there are two different scroll bounds.
A few more tips: The red stripe should be one line height, scaled with the font size. The maximum scroll delta (now 100) should also be one line height.
Jan Kåre Vatne
on ~eliasnaur/gio
Hi ~jonegil, nice work! I'm glad that you've got things working again with the new input system. I took your teleprompter for a spin, and I'll leave some comments about it on your repo. I'm going to close out this issue since you've got it working.
Comment by ~jonegil on ~eliasnaur/gio
Thanks this works well
I sat the limits at +/-200. In my macbook it seldom gets above 100, so 200 should be sensible.
The teleprompter is turning out a nice litte event handler. Mouse, keyboard, animation ...
- mouse for scrolling
- spacebar for animation
- B/S for bigger and smaller fonts
- W/N for wider and narrower text area
- U/D for moving the focusbar up down
- +/- for faster and slower
- Shift for larger changes
Take it for a spin at https://github.com/jonegil/gui-with-gio/tree/main/teleprompter
Comment by ~jonegil on ~eliasnaur/gio
Sure, thanks Chris!
It's from the event-handler tutorial I wrote, teleprompter, and I guess you want to look here: https://github.com/jonegil/gui-with-gio/blob/797306f67fcfeeae29cfdb5df8d5fcd44b3ddb84/teleprompter/code/main.go#L307
The smallest replication I could extract is here, same code: https://gist.github.com/jonegil/dce02fbecd444b81b72d72ab0351826b
Ticket created by ~jonegil on ~eliasnaur/gio
Listening for pointer.Scroll events works well and returns plenty of useful information, such as Position, Modifiers etc...
But I totally fail to extract any non-zero value for Scroll. At best it's -0, whatever that means.
pointer.Event{ Type:0x40, Source:0x0, PointerID:0x0, Priority:0x1, Time:21388567272986, Buttons:0x0, Position:f32.Point{X:214.54305, Y:101.27048}, Scroll:f32.Point{X:0, Y:-0}, Modifiers:0x5 }pointer.Event.Scroll.Y used to include this information which was very practical. I see there's also a gesture package, but would prefer receiving the information directly in the pointer.Scroll if possible.
The behaviour is the same on my mac laptop/touchpad and with an external mouse.
Best regards J