Commit 79cd8cab08615a656e51b021e0e8397fd869d1a3
2021-01-27T20:41:36
Add default handler for Alt+Tab while keyboard grab is enabled By default, we will minimize the window when we receive Alt+Tab with a full-screen keyboard grabbed window to allow the user to escape the full-screen application. Some applications like remote desktop clients may want to handle Alt+Tab themselves, so provide an opt-out via SDL_HINT_ALLOW_ALT_TAB_WHILE_GRABBED=0.
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diff --git a/include/SDL_hints.h b/include/SDL_hints.h
index bacfe17..5c320dc 100644
--- a/include/SDL_hints.h
+++ b/include/SDL_hints.h
@@ -1587,6 +1587,19 @@ extern "C" {
*/
#define SDL_HINT_AUDIO_DEVICE_STREAM_NAME "SDL_AUDIO_DEVICE_STREAM_NAME"
+/**
+ * \brief Specify the behavior of Alt+Tab while the keyboard is grabbed.
+ *
+ * By default, SDL emulates Alt+Tab functionality while the keyboard is grabbed
+ * and your window is full-screen. This prevents the user from getting stuck in
+ * your application if you've enabled keyboard grab.
+ *
+ * The variable can be set to the following values:
+ * "0" - SDL will not handle Alt+Tab. Your application is responsible
+ for handling Alt+Tab while the keyboard is grabbed.
+ * "1" - SDL will minimize your window when Alt+Tab is pressed (default)
+*/
+#define SDL_HINT_ALLOW_ALT_TAB_WHILE_GRABBED "SDL_ALLOW_ALT_TAB_WHILE_GRABBED"
/**
* \brief Override for SDL_GetPreferredLocales()
diff --git a/src/events/SDL_keyboard.c b/src/events/SDL_keyboard.c
index 356f6f5..c0a541d 100644
--- a/src/events/SDL_keyboard.c
+++ b/src/events/SDL_keyboard.c
@@ -22,6 +22,7 @@
/* General keyboard handling code for SDL */
+#include "SDL_hints.h"
#include "SDL_timer.h"
#include "SDL_events.h"
#include "SDL_events_c.h"
@@ -799,6 +800,22 @@ SDL_SendKeyboardKeyInternal(Uint8 source, Uint8 state, SDL_Scancode scancode)
event.key.windowID = keyboard->focus ? keyboard->focus->id : 0;
posted = (SDL_PushEvent(&event) > 0);
}
+
+ /* If the keyboard is grabbed and the grabbed window is in full-screen,
+ minimize the window when we receive Alt+Tab, unless the application
+ has explicitly opted out of this behavior. */
+ if (keycode == SDLK_TAB &&
+ state == SDL_PRESSED &&
+ (keyboard->modstate & KMOD_ALT) &&
+ keyboard->focus &&
+ (keyboard->focus->flags & SDL_WINDOW_KEYBOARD_GRABBED) &&
+ (keyboard->focus->flags & SDL_WINDOW_FULLSCREEN) &&
+ SDL_GetHintBoolean(SDL_HINT_ALLOW_ALT_TAB_WHILE_GRABBED, SDL_TRUE)) {
+ /* We will temporarily forfeit our grab by minimizing our window,
+ allowing the user to escape the application */
+ SDL_MinimizeWindow(keyboard->focus);
+ }
+
return (posted);
}