Renamed sat_t data structure to gpssat_t, changed signedness of point_t coordinates from unsigned to signed.

rename sat_t to gpssat_t to avoid future name collisions
allow signed values in point_t to allow relative values
fix crash when attempting to 'draw' negative absolute pixel values (like when zooming a map)

openrtx/include/core/gps.h

@@ -33,7 +33,7 @@ typedef struct
     uint16_t azimuth;     // Azimuth in degrees
     uint8_t  snr;         // Quality of the signal in range 0-99
 }
-sat_t;
+gpssat_t;
 
 /**
  * Data structure representing the last state received from the GPS module.
@@ -45,7 +45,7 @@ typedef struct
     uint8_t    fix_type;             // 0: no fix, 1: 2D,  2: 3D
     uint8_t    satellites_tracked;   // Number of tracked satellites
     uint8_t    satellites_in_view;   // Satellites in view
-    sat_t      satellites[12];       // Details about satellites in view
+    gpssat_t   satellites[12];       // Details about satellites in view
     uint32_t   active_sats;          // Bitmap representing which sats are part of the fix
     float      latitude;             // Latitude coordinates
     float      longitude;            // Longitude coordinates

openrtx/include/interfaces/graphics.h

@@ -73,8 +73,8 @@ extern "C" {
  */
 typedef struct point_t
 {
-    uint16_t x;
-    uint16_t y;
+    int16_t x;
+    int16_t y;
 } point_t;
 
 /**
@@ -329,7 +329,7 @@ void gfx_drawSmeterLevel(point_t start, uint16_t width, uint16_t height, float r
  * @param sats: pointer to the array of satellites data
  * @param active_sats: bitset representing which sats are part of the fix
  */
-void gfx_drawGPSgraph(point_t start, uint16_t width, uint16_t height, sat_t *sats, uint32_t active_sats);
+void gfx_drawGPSgraph(point_t start, uint16_t width, uint16_t height, gpssat_t *sats, uint32_t active_sats);
 
 /**
  * Function to draw a compass of arbitrary size.

openrtx/src/core/gps.c

@@ -138,7 +138,7 @@ void gps_taskFunc()
                 // When the first sentence arrives, clear all the old data
                 if (frame.msg_nr == 1)
                 {
-                    bzero(&gps_data.satellites[0], 12 * sizeof(sat_t));
+                    bzero(&gps_data.satellites[0], 12 * sizeof(gpssat_t));
                 }
 
                 gps_data.satellites_in_view = frame.total_sats;

openrtx/src/core/graphics.cpp

@@ -169,7 +169,8 @@ void gfx_fillScreen(color_t color)
 
 inline void gfx_setPixel(point_t pos, color_t color)
 {
-    if (pos.x >= SCREEN_WIDTH || pos.y >= SCREEN_HEIGHT)
+    if (pos.x >= SCREEN_WIDTH || pos.y >= SCREEN_HEIGHT 
+            || pos.x < 0 || pos.y < 0)
         return; // off the screen
 
 #ifdef PIX_FMT_RGB565
@@ -818,7 +819,7 @@ void gfx_drawSmeterLevel(point_t start, uint16_t width, uint16_t height, float r
 void gfx_drawGPSgraph(point_t start,
                       uint16_t width,
                       uint16_t height,
-                      sat_t *sats,
+                      gpssat_t *sats,
                       uint32_t active_sats)
 {
     color_t white =  {255, 255, 255, 255};