GPS NMEA -> Ability to see speed in Km/h

Use right button to switch between modes

applications/external/gps_nmea_uart/README.md

@@ -12,6 +12,7 @@ repository.
 ## Modifications made by @xMasterX
 - Ability to change baudrate using Up button, hold button to switch between baudrates (9600, 57600, 115200) (i set 57600 as default)
 - Ok button will set backlight to always on mode, to disable press ok button again (it will restore default settings after app exit too)
+- Long press Right button to change speed from knots to kilometers per hour
 - Exit from app using long press on back button instead of short press, may be useful in case you want to turn backlight on and accidentally click back
 
 ## Hardware Setup

applications/external/gps_nmea_uart/gps.c

@@ -37,7 +37,11 @@ static void render_callback(Canvas* const canvas, void* context) {
         canvas_draw_str_aligned(canvas, 96, 18, AlignCenter, AlignBottom, buffer);
         snprintf(buffer, 64, "%.1f", (double)gps_uart->status.course);
         canvas_draw_str_aligned(canvas, 21, 40, AlignCenter, AlignBottom, buffer);
-        snprintf(buffer, 64, "%.2f kn", (double)gps_uart->status.speed);
+        if(!gps_uart->speed_in_kms) {
+            snprintf(buffer, 64, "%.2f kn", (double)gps_uart->status.speed);
+        } else {
+            snprintf(buffer, 64, "%.2f km", (double)(gps_uart->status.speed * 1.852));
+        }
         canvas_draw_str_aligned(canvas, 64, 40, AlignCenter, AlignBottom, buffer);
         snprintf(
             buffer,
@@ -154,6 +158,13 @@ int32_t gps_app(void* p) {
                         view_port_update(view_port);
                         furi_mutex_release(gps_uart->mutex);
                         break;
+                    case InputKeyRight:
+                        if(gps_uart->speed_in_kms) {
+                            gps_uart->speed_in_kms = false;
+                        } else {
+                            gps_uart->speed_in_kms = true;
+                        }
+                        break;
                     case InputKeyBack:
                         processing = false;
                         break;

applications/external/gps_nmea_uart/gps_uart.h

@@ -33,6 +33,7 @@ typedef struct {
     uint32_t baudrate;
     bool changing_baudrate;
     bool backlight_on;
+    bool speed_in_kms;
 
     GpsStatus status;
 } GpsUart;