[Bf-blender-cvs] [7e5cb947483] blender-v3.4-release: Fix T103119: Allow Win32 Diacritical Composition

[Harley Acheson]

Commit: 7e5cb9474837ea25cbdb8ae36c67faacb74ed317
Author: Harley Acheson
Date:   Tue Dec 13 18:30:20 2022 -0800
Branches: blender-v3.4-release
https://developer.blender.org/rB7e5cb9474837ea25cbdb8ae36c67faacb74ed317

Fix T103119: Allow Win32 Diacritical Composition

Allow keyboard layouts which include "dead keys" to enter diacritics
by calling MapVirtualKeyW even when not key_down.

See D16770 for more details.

Differential Revision: https://developer.blender.org/D16770

Reviewed by Campbell Barton

===================================================================

M	intern/ghost/intern/GHOST_SystemWin32.cpp

===================================================================

diff --git a/intern/ghost/intern/GHOST_SystemWin32.cpp b/intern/ghost/intern/GHOST_SystemWin32.cpp
index 4d016373fc6..dc350bb58a1 100644
--- a/intern/ghost/intern/GHOST_SystemWin32.cpp
+++ b/intern/ghost/intern/GHOST_SystemWin32.cpp
@@ -1195,16 +1195,16 @@ GHOST_EventKey *GHOST_SystemWin32::processKeyEvent(GHOST_WindowWin32 *window, RA
     const bool ctrl_pressed = has_state && state[VK_CONTROL] & 0x80;
     const bool alt_pressed = has_state && state[VK_MENU] & 0x80;
 
-    if (!key_down) {
-      /* Pass. */
-    }
+    /* We can be here with !key_down if processing dead keys (diacritics). See T103119. */
+
     /* No text with control key pressed (Alt can be used to insert special characters though!). */
-    else if (ctrl_pressed && !alt_pressed) {
+    if (ctrl_pressed && !alt_pressed) {
       /* Pass. */
     }
     /* Don't call #ToUnicodeEx on dead keys as it clears the buffer and so won't allow diacritical
-     * composition. */
-    else if (MapVirtualKeyW(vk, 2) != 0) {
+     * composition. XXX: we are not checking return of MapVirtualKeyW for high bit set, which is
+     * what is supposed to indicate dead keys. But this is working now so approach cautiously. */
+    else if (MapVirtualKeyW(vk, MAPVK_VK_TO_CHAR) != 0) {
       wchar_t utf16[3] = {0};
       int r;
       /* TODO: #ToUnicodeEx can respond with up to 4 utf16 chars (only 2 here).
@@ -1219,6 +1219,10 @@ GHOST_EventKey *GHOST_SystemWin32::processKeyEvent(GHOST_WindowWin32 *window, RA
           utf8_char[0] = '\0';
         }
       }
+      if (!key_down) {
+        /* Clear or wm_event_add_ghostevent will warn of unexpected data on key up. */
+        utf8_char[0] = '\0';
+      }
     }
 
 #ifdef WITH_INPUT_IME