Do not init SDL video subsystem if no display

The SDL video subsystem is not necessary if we don't display the video.

Move the sdl_init_and_configure() function from screen.c to scrcpy.c,
because it is not only related to the screen display.

app/src/scrcpy.c

@@ -42,6 +42,40 @@ static struct input_manager input_manager = {
     .control = true,
 };
 
+// init SDL and set appropriate hints
+static bool
+sdl_init_and_configure(bool display) {
+    uint32_t flags = display ? SDL_INIT_VIDEO : SDL_INIT_EVENTS;
+    if (SDL_Init(flags)) {
+        LOGC("Could not initialize SDL: %s", SDL_GetError());
+        return false;
+    }
+
+    atexit(SDL_Quit);
+
+    if (!display) {
+        return true;
+    }
+
+    // Use the best available scale quality
+    if (!SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "2")) {
+        LOGW("Could not enable bilinear filtering");
+    }
+
+#ifdef SCRCPY_SDL_HAS_HINT_MOUSE_FOCUS_CLICKTHROUGH
+    // Handle a click to gain focus as any other click
+    if (!SDL_SetHint(SDL_HINT_MOUSE_FOCUS_CLICKTHROUGH, "1")) {
+        LOGW("Could not enable mouse focus clickthrough");
+    }
+#endif
+
+    // Do not disable the screensaver when scrcpy is running
+    SDL_EnableScreenSaver();
+
+    return true;
+}
+
+
 #if defined(__APPLE__) || defined(__WINDOWS__)
 # define CONTINUOUS_RESIZING_WORKAROUND
 #endif
@@ -240,7 +274,10 @@ scrcpy(const struct scrcpy_options *options) {
 
     bool ret = true;
 
-    if (!sdl_init_and_configure()) {
+    bool display = !options->no_display;
+    bool control = !options->no_control;
+
+    if (!sdl_init_and_configure(display)) {
         ret = false;
         goto finally_destroy_server;
     }
@@ -264,9 +301,6 @@ scrcpy(const struct scrcpy_options *options) {
         goto finally_destroy_server;
     }
 
-    bool display = !options->no_display;
-    bool control = !options->no_control;
-
     input_manager.control = control;
 
     struct decoder *dec = NULL;

app/src/screen.c

@@ -13,33 +13,6 @@
 
 #define DISPLAY_MARGINS 96
 
-bool
-sdl_init_and_configure(void) {
-    if (SDL_Init(SDL_INIT_VIDEO)) {
-        LOGC("Could not initialize SDL: %s", SDL_GetError());
-        return false;
-    }
-
-    atexit(SDL_Quit);
-
-    // Use the best available scale quality
-    if (!SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "2")) {
-        LOGW("Could not enable bilinear filtering");
-    }
-
-#ifdef SCRCPY_SDL_HAS_HINT_MOUSE_FOCUS_CLICKTHROUGH
-    // Handle a click to gain focus as any other click
-    if (!SDL_SetHint(SDL_HINT_MOUSE_FOCUS_CLICKTHROUGH, "1")) {
-        LOGW("Could not enable mouse focus clickthrough");
-    }
-#endif
-
-    // Do not disable the screensaver when scrcpy is running
-    SDL_EnableScreenSaver();
-
-    return true;
-}
-
 // get the window size in a struct size
 static struct size
 get_native_window_size(SDL_Window *window) {

app/src/screen.h

@@ -38,10 +38,6 @@ struct screen {
     .no_window = false,   \
 }
 
-// init SDL and set appropriate hints
-bool
-sdl_init_and_configure(void);
-
 // initialize default values
 void
 screen_init(struct screen *screen);