Add GPS compass stub

openrtx/include/interfaces/graphics.h

@@ -204,6 +204,7 @@ void gfx_drawVLine(uint16_t x, uint16_t width, color_t color);
 
 /**
  * Draw a rectangle of specified width, height and color.
+ * @param start: screen position of the rectangle, in pixels
  * @param width: rectangle width, in pixels, borders included.
  * @param height: rectangle height, in pixels, borders included.
  * @param color: border and fill color, in color_t format.
@@ -211,6 +212,14 @@ void gfx_drawVLine(uint16_t x, uint16_t width, color_t color);
  */
 void gfx_drawRect(point_t start, uint16_t width, uint16_t height, color_t color, bool fill);
 
+/**
+ * Draw the outline of a circle of specified radius and color.
+ * @param start: screen position of the center of the circle, in pixels
+ * @param r: circle radius, in pixels, border included.
+ * @param color: border color, in color_t format.
+ */
+void gfx_drawCircle(point_t start, uint16_t r, color_t color);
+
 /**
  * Prints text on the screen.
  * @param start: text line start point, in pixel coordinates.
@@ -261,4 +270,13 @@ void gfx_drawSmeter(point_t start, uint16_t width, uint16_t height, float rssi,
  */
 void gfx_drawGPSgraph(point_t start, uint16_t width, uint16_t height, sat_t *sats);
 
+/**
+ * Function to draw a compass of arbitrary size.
+ * Starting coordinates are relative to the top left point.
+ * @param start: Compass start point, in pixel coordinates.
+ * @param width: Compass radius
+ * @param sats: pointer to the array of satellites data
+ */
+void gfx_drawGPScompass(point_t start, uint16_t radius, sat_t *sats);
+
 #endif /* GRAPHICS_H */

openrtx/src/graphics.c

@@ -228,6 +228,65 @@ void gfx_drawRect(point_t start, uint16_t width, uint16_t height, color_t color,
     }
 }
 
+void gfx_drawCircle(point_t start, uint16_t r, color_t color)
+{
+    int16_t f     = 1 - r;
+    int16_t ddF_x = 1;
+    int16_t ddF_y = -2 * r;
+    int16_t x     = 0;
+    int16_t y     = r;
+
+    point_t pos = start;
+    pos.y += r;
+    gfx_setPixel(pos, color);
+    pos.y -= 2 * r;
+    gfx_setPixel(pos, color);
+    pos.y += r;
+    pos.x += r;
+    gfx_setPixel(pos, color);
+    pos.x -= 2 * r;
+    gfx_setPixel(pos, color);
+
+    while (x < y)
+    {
+        if (f >= 0)
+        {
+            y--;
+            ddF_y += 2;
+            f += ddF_y;
+        }
+
+        x++;
+        ddF_x += 2;
+        f += ddF_x;
+
+        pos.x = start.x + x;
+        pos.y = start.y + y;
+        gfx_setPixel(pos, color);
+        pos.x = start.x - x;
+        pos.y = start.y + y;
+        gfx_setPixel(pos, color);
+        pos.x = start.x + x;
+        pos.y = start.y - y;
+        gfx_setPixel(pos, color);
+        pos.x = start.x - x;
+        pos.y = start.y - y;
+        gfx_setPixel(pos, color);
+        pos.x = start.x + y;
+        pos.y = start.y + x;
+        gfx_setPixel(pos, color);
+        pos.x = start.x - y;
+        pos.y = start.y + x;
+        gfx_setPixel(pos, color);
+        pos.x = start.x + y;
+        pos.y = start.y - x;
+        gfx_setPixel(pos, color);
+        pos.x = start.x - y;
+        pos.y = start.y - x;
+        gfx_setPixel(pos, color);
+    }
+}
+
 void gfx_drawHLine(uint16_t y, uint16_t height, color_t color)
 {
     point_t start = {0, y};
@@ -568,3 +627,15 @@ void gfx_drawGPSgraph(point_t start,
     gfx_drawLine(start, left_line_end, white);
     gfx_drawLine(right_line_start, right_line_end, white);
 }
+
+void gfx_drawGPScompass(point_t start,
+                        uint16_t radius,
+                        sat_t *sats)
+{
+    color_t white =  {255, 255, 255, 255};
+
+    point_t n_pos = {start.x + radius, start.y + 3};
+    gfx_print(n_pos, "N", FONT_SIZE_5PT, TEXT_ALIGN_LEFT, white);
+    point_t circle_pos = {start.x + radius + 1, start.y + radius + 3};
+    gfx_drawCircle(circle_pos, radius, white);
+}

openrtx/src/ui/ui_menu.c

@@ -294,6 +294,9 @@ void _ui_drawMenuGPS(ui_state_t* ui_state)
              last_state.gps_data.altitude);
     gfx_print(layout.bottom_pos, data_buf, layout.bottom_font, TEXT_ALIGN_CENTER,
               color_white);
+    // Draw compass
+    point_t compass_pos = {layout.horizontal_pad * 2, SCREEN_HEIGHT / 2};
+    gfx_drawGPScompass(compass_pos, SCREEN_WIDTH / 9, last_state.gps_data.satellites);
     // Draw satellites bar graph
     point_t bar_pos = {layout.line3_pos.x + SCREEN_WIDTH * 1 / 3, SCREEN_HEIGHT / 2};
     gfx_drawGPSgraph(bar_pos,