1567463 - [Wayland][HDPI] Wrong drag-and-drop surface offset

Status: RESOLVED INVALID

(Core :: Widget: Gtk, defect, P3)

Description

[Robert Mader [:rmader]]

User Agent: Mozilla/5.0 (X11; Fedora; Linux x86_64; rv:68.0) Gecko/20100101 Firefox/68.0

Steps to reproduce:

I'm currently working on a branch implementing proper DnD-surface offset in Mutter/GS (https://gitlab.gnome.org/GNOME/mutter/merge_requests/684). This comes down supporting the last two arguments in

wl_surface_attach(dnd_drag->drag_surface, buffer,
                  -dnd_drag->hotspot_x, -dnd_drag->hotspot_y);

This all works very well on scale=1, but in HIDPI scenarios FF (Wayland backend), in contrast to other GTK+ apps like nautilus, does not seem to take the scale into account and the DnD surface moves to far to the top left instead of matching the position where the mouse grab started.

Tested on FF 68 aswell as latest nightly.

I tried to make a screencast, but unfortunately the mouse positioning is currently broken in that scenario (mutter git master). Will post one as soon as that got fixed.

Comment 1

[Martin Stránský [:stransky] (ni? me)]

Thanks, we'll look at it when the change hits Fedora/mutter package.

Comment 2

[Robert Mader [:rmader]]

The mutter MR just landed and will be shipped in Fedora from 3.33.92 on.

Comment 3

[Robert Mader [:rmader]]

From a discussion we had today[1] it now looks like the GTK implementation is the one to be wrong and Firefox on Wayland does things right. Keeping this one open until we're sure (and Mutter behaves accordingly).

1: https://gitlab.gnome.org/GNOME/mutter/merge_requests/780#note_607671

Comment 4

[Robert Mader [:rmader]]

Ok, this I'm now sure that this is a Mutter bug, as I relied on GTK behaviour instead of actually checking the values. Should be fixed by Mutter 3.34.1.

Comment 5

[Robert Mader [:rmader]]

The MR above just landed, so confirmed to be fixed in Mutter 3.34.1