Add shortcut to rotate screen

On Ctrl+r, disable auto-rotation (if enabled), set the screen rotation
and re-enable auto-rotation (if it was enabled).

Closes #11 <https://github.com/Genymobile/scrcpy/issues/11>

app/src/control_msg.c

@@ -78,6 +78,7 @@ control_msg_serialize(const struct control_msg *msg, unsigned char *buf) {
         case CONTROL_MSG_TYPE_EXPAND_NOTIFICATION_PANEL:
         case CONTROL_MSG_TYPE_COLLAPSE_NOTIFICATION_PANEL:
         case CONTROL_MSG_TYPE_GET_CLIPBOARD:
+        case CONTROL_MSG_TYPE_ROTATE_DEVICE:
             // no additional data
             return 1;
         default:

app/src/control_msg.h

@@ -28,6 +28,7 @@ enum control_msg_type {
     CONTROL_MSG_TYPE_GET_CLIPBOARD,
     CONTROL_MSG_TYPE_SET_CLIPBOARD,
     CONTROL_MSG_TYPE_SET_SCREEN_POWER_MODE,
+    CONTROL_MSG_TYPE_ROTATE_DEVICE,
 };
 
 enum screen_power_mode {

app/src/input_manager.c

@@ -211,6 +211,16 @@ clipboard_paste(struct controller *controller) {
     }
 }
 
+static void
+rotate_device(struct controller *controller) {
+    struct control_msg msg;
+    msg.type = CONTROL_MSG_TYPE_ROTATE_DEVICE;
+
+    if (!controller_push_msg(controller, &msg)) {
+        LOGW("Could not request device rotation");
+    }
+}
+
 void
 input_manager_process_text_input(struct input_manager *im,
                                  const SDL_TextInputEvent *event) {
@@ -388,6 +398,11 @@ input_manager_process_key(struct input_manager *im,
                     }
                 }
                 return;
+            case SDLK_r:
+                if (control && cmd && !shift && !repeat && down) {
+                    rotate_device(controller);
+                }
+                return;
         }
 
         return;

app/src/main.c

@@ -175,6 +175,9 @@ static void usage(const char *arg0) {
         "    " CTRL_OR_CMD "+o\n"
         "        turn device screen off (keep mirroring)\n"
         "\n"
+        "    " CTRL_OR_CMD "+r\n"
+        "        rotate device screen\n"
+        "\n"
         "    " CTRL_OR_CMD "+n\n"
         "       expand notification panel\n"
         "\n"