sdl: improve window resizing on macOS

This enables smooth resizing of the window using a
fixed aspect ratio, instead of snapping into the
correct aspect ratio only when the resize operation
has finished, by using an SDL event filter that gets
events delivered during the resize operation
(whereas SDL_PollEvent blocks until done on macOS).

Change-Id: Ie6614e4b6f49a24469c5ee6a69721c9fbd440dae

firmware/drivers/button_queue.c

@@ -23,7 +23,7 @@
 #include "kernel.h"
 #include "button.h"
 #ifdef HAVE_SDL
-#include "button-sdl.h"
+#include "SDL.h"
 #include "window-sdl.h"
 #endif
 
@@ -101,7 +101,7 @@ static inline void button_queue_wait(struct queue_event *evp, int timeout)
     unsigned long curr_tick, remaining;
     while(true)
     {
-        handle_sdl_events(); /* Includes window updates after resize events */
+        SDL_PumpEvents();
         queue_wait_w_tmo(&button_queue, evp, TIMEOUT_NOBLOCK);
         if (evp->id != SYS_TIMEOUT || timeout == TIMEOUT_NOBLOCK)
             return;

firmware/target/hosted/sdl/button-sdl.c

@@ -382,11 +382,11 @@ static bool event_handler(SDL_Event *event)
 }
 
 #ifdef __APPLE__
-void handle_sdl_events(void)
+int sdl_event_filter(void *userdata, SDL_Event * event)
 {
-    SDL_Event event;
-    while(SDL_PollEvent(&event))
-        event_handler(&event);
+    (void) userdata;
+    event_handler(event);
+    return 0;
 }
 #endif
 

firmware/target/hosted/sdl/button-sdl.h

@@ -25,11 +25,12 @@
 
 #include <stdbool.h>
 #include "config.h"
+#include "SDL.h"
 
 extern int sdl_app_has_input_focus;
 
 #ifdef __APPLE__
-void handle_sdl_events(void);
+int sdl_event_filter(void *userdata, SDL_Event * event);
 #endif
 
 bool button_hold(void);

firmware/target/hosted/sdl/system-sdl.c

@@ -33,6 +33,7 @@
 #include "system-sdl.h"
 #include "sim-ui-defines.h"
 #include "window-sdl.h"
+#include "button-sdl.h"
 #include "lcd-bitmap.h"
 #ifdef HAVE_REMOTE_LCD
 #include "lcd-remote-bitmap.h"
@@ -235,6 +236,8 @@ void system_init(void)
     SDL_SemWait(s);
     /* cleanup */
     SDL_DestroySemaphore(s);
+#else
+    SDL_AddEventWatch(sdl_event_filter, NULL);
 #endif
 }
 

firmware/target/hosted/sdl/window-sdl.c

@@ -81,7 +81,9 @@ static void restore_aspect_ratio(int w, int h)
     SDL_GetWindowSize(sdlWindow, &w, &h);
     if (w != original_width || h != original_height)
     {
+        SDL_DisplayMode sdl_dm;
         h = w * aspect_ratio;
+        if (SDL_GetCurrentDisplayMode(0, &sdl_dm) || h <= sdl_dm.h)
             SDL_SetWindowSize(sdlWindow, w, h);
     }
 }