hw/xwin: Restore non-latching modifier key state when an X window gains focus

In multiwindow mode, the state of the modifier keys was lost when a window is
created (or raised) and focus moved to that window.

For example: In window A Ctrl + some key opens a window B, then in window B Ctrl
+ some other key triggers the next action. However after the opening of window B
the Ctrl key has to be released and pressed again. If the user keeps the Ctrl
key held down when the window B is opened, the next key press X will be
interpreted as X and not as Ctrl+X.

Extended the function winRestoreModeKeyStates in winkeybd.c to consider not only
the latching modifier keys but also the modifiers Ctrl, Shift, Alt/AltGr by
using the Windows function GetAsyncKeyState.

A combined Ctrl+AltGr modifier state cannot be restored correctly, as Windows
always fakes a Ctrl-L when AltGr is pressed.

Signed-off-by: Oliver Schmidt <oschmidt-mailinglists@gmx.de>
Reviewed-by: Jon TURNEY <jon.turney@dronecode.org.uk>
Reviewed-by: Colin Harrison <colin.harrison@virgin.net>

1 files changed, 22 insertions, 0 deletions

diff --git a/hw/xwin/winkeybd.c b/hw/xwin/winkeybd.c
index 104ca589a..a70cdcd16 100644
--- a/hw/xwin/winkeybd.c
+++ b/hw/xwin/winkeybd.c
@@ -262,6 +262,28 @@ winRestoreModeKeyStates(void)
         XkbStateFieldFromRec(&inputInfo.keyboard->key->xkbInfo->state);
     winDebug("winRestoreModeKeyStates: state %d\n", internalKeyStates);
 
+    /* Check if modifier keys are pressed, and if so, fake a press */
+    {
+        BOOL ctrl = (GetAsyncKeyState(VK_CONTROL) < 0);
+        BOOL shift = (GetAsyncKeyState(VK_SHIFT) < 0);
+        BOOL alt = (GetAsyncKeyState(VK_LMENU) < 0);
+        BOOL altgr = (GetAsyncKeyState(VK_RMENU) < 0);
+
+        if (ctrl && altgr)
+            ctrl = FALSE;
+
+        if (LOGICAL_XOR(internalKeyStates & ControlMask, ctrl))
+            winSendKeyEvent(KEY_LCtrl, ctrl);
+
+        if (LOGICAL_XOR(internalKeyStates & ShiftMask, shift))
+            winSendKeyEvent(KEY_ShiftL, shift);
+
+        if (LOGICAL_XOR(internalKeyStates & Mod1Mask, alt))
+            winSendKeyEvent(KEY_Alt, alt);
+
+        if (LOGICAL_XOR(internalKeyStates & Mod5Mask, altgr))
+            winSendKeyEvent(KEY_AltLang, altgr);
+    }
 
     /*
        Check if latching modifier key states have changed, and if so,