Darktable is unusable with a trackpad.

[schwerdf]

Describe the bug
When using a trackpad to scroll in the latest Git master revision, the scrolling moves so fast that it is impossible to use (just a twitch of the finger can change the light table zoom from 1 to 25 or scroll halfway through a large collection of images).
As I recall, this same problem was encountered a few years ago and was resolved by disabling the use of smooth scrolling altogether, treating trackpads the same as regular scroll wheels.

Platform (please complete the following information):

• Darktable Version: master revision 7c22327
• OS: Fedora 32

[Nilvus]

I confirm this behavior, scrolling is really not possible with trackpad. @AlicVB: should this be related to your recent lighttable rework?

[AlicVB]

@Nilvus : yes, certainly. Sadly I've no idea what is doing a trackpad different from a mouse... Do you have one ? if yes, we can eventually can do another interactive debugging session if you have time...

[parafin]

darktable/src/gui/gtk.c

Line 499 in 7ffecde

gboolean dt_gui_get_scroll_deltas(const GdkEventScroll *event, gdouble *delta_x, gdouble *delta_y)

- these functions might be of interest (look for GDK_SCROLL_SMOOTH).

[AlicVB]

yes, I've seen them already... but thanks anyway !

[Nilvus]

@Nilvus : yes, certainly. Sadly I've no idea what is doing a trackpad different from a mouse... Do you have one ? if yes, we can eventually can do another interactive debugging session if you have time...

Yes I have. A debugging session is possible tomorrow evening or thursday one.

[Nilvus]

@AlicVB: just a thing I just test. filter collections is really smooth with trackpad. Maybe something to check on that side to compare.

[MStraeten]

then i'm glad to be on a macbook - there the trackpad works fine ;) But in fact scrolling in lighttable is very sensitive but also with my mouse or graphic tablet or by dragging the slider

[Nilvus]

then i'm glad to be on a macbook - there the trackpad works fine ;) But in fact scrolling in lighttable is very sensitive but also with my mouse or graphic tablet or by dragging the slider

Hmm, I'm on a Macbook pro (on Linux) and scroll is smooth with my wheel mouse but not with trackpad on lighttable filemanager (or zoomable one) but smooth with wheel mouse AND trackpad on filter collections.