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author | Matthias Clasen <mclasen@redhat.com> | 2020-04-02 17:40:44 -0400 |
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committer | Matthias Clasen <mclasen@redhat.com> | 2020-04-02 17:43:14 -0400 |
commit | cffa45d5ff97b3b6107bb9d563a84a529014342a (patch) | |
tree | 46374e83cf20937de4247fb607b4706de3172bb3 | |
parent | 14166b09b5d62ed7a8b78179d6fe655250b4083a (diff) | |
download | gtk+-cffa45d5ff97b3b6107bb9d563a84a529014342a.tar.gz |
wayland: Add a comment about keyboard state handling
Clarify a point that took me a few hours to fully track
down, so lets preserve what I found for the next poor
sould coming this way.
-rw-r--r-- | gdk/wayland/gdkdevice-wayland.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/gdk/wayland/gdkdevice-wayland.c b/gdk/wayland/gdkdevice-wayland.c index 0e1ac1d283..dcb38c2953 100644 --- a/gdk/wayland/gdkdevice-wayland.c +++ b/gdk/wayland/gdkdevice-wayland.c @@ -2160,6 +2160,21 @@ keyboard_handle_modifiers (void *data, direction = gdk_keymap_get_direction (keymap); xkb_state = _gdk_wayland_keymap_get_xkb_state (keymap); + /* Note: the docs for xkb_state_update mask state that all parameters + * must be passed, or we may end up with an 'incoherent' state. But the + * Wayland modifiers event only includes a single group field, so we + * can't pass depressed/latched/locked groups. + * + * We assume that the compositor is sending us the 'effective' group + * (the protocol is not clear on that point), and pass it as the depressed + * group - we are basically pretending that the user holds down a key for + * this group at all times. + * + * This means that our xkb_state would answer a few questions differently + * from the compositors xkb_state - e.g. if you asked it about the latched + * group. But nobody is asking it those questions, so it does not really + * matter. We hope. + */ xkb_state_update_mask (xkb_state, mods_depressed, mods_latched, mods_locked, group, 0, 0); seat->key_modifiers = gdk_keymap_get_modifier_state (keymap); |