OSD 2D map enhancements: configurable margins and reference line

docs/Settings.md

@@ -4762,6 +4762,36 @@ Number of decimals for the battery voltages displayed in the OSD [1-2].
 
 ---
 
+### osd_map2d_hmargin
+
+OSD 2D Map horizontal margin (on left and right, columns the map won't use for drawing)
+
+| Default | Min | Max |
+| --- | --- | --- |
+| 5 | 0 | 15 |
+
+---
+
+### osd_map2d_ref_line_heading
+
+OSD 2D Map reference line heading (0 is north, 90 east, 180 south and so on, -1 disabled). Requires using "up is north" map setting. The dashed line will be aligned to the heading set by this parameter. So should be set to the same heading as an easily recognizable and static feature nearby the place you are flying, for example a runway, a street, a fence, etc. Then you are able to compare the craft's position on the OSD map with this reference, making it easier to orientate yourself, align directional antennas and so on.
+
+| Default | Min | Max |
+| --- | --- | --- |
+| -1 | -1 | 359 |
+
+---
+
+### osd_map2d_vmargin
+
+OSD 2D Map vertical margin (on top and bottom, lines the map won't use for drawing)
+
+| Default | Min | Max |
+| --- | --- | --- |
+| 3 | 0 | 10 |
+
+---
+
 ### osd_msp_displayport_fullframe_interval
 
 Full Frame redraw interval for MSP DisplayPort [deciseconds]. This is how often a full frame update is sent to the DisplayPort, to cut down on OSD artifacting. The default value should be fine for most pilots. Though long range pilots may benefit from increasing the refresh time, especially near the edge of range. -1 = disabled (legacy mode) | 0 = every frame (not recommended) | default = 10 (1 second)

src/main/fc/settings.yaml

@@ -3742,7 +3742,27 @@ groups:
         description: Show question marks where there is no symbol in the DJI font to represent the INAV OSD element's symbol. When off, blank spaces will be used. Only relevent for DJICOMPAT modes.
         field: highlight_djis_missing_characters
         default_value: ON
-        type: bool
+        type: bool      
+      - name: osd_map2d_vmargin
+        description: OSD 2D Map vertical margin (on top and bottom, lines the map won't use for drawing)
+        field: map2d_vmargin
+        default_value: 3
+        min: 0
+        max: 10      
+      - name: osd_map2d_hmargin
+        description: OSD 2D Map horizontal margin (on left and right, columns the map won't use for drawing)
+        field: map2d_hmargin
+        default_value: 5
+        min: 0
+        max: 15
+
+      - name: osd_map2d_ref_line_heading
+        description: OSD 2D Map reference line heading (0 is north, 90 east, 180 south and so on, -1 disabled). Requires using "up is north" map setting. The dashed line will be aligned to the heading set by this parameter. So should be set to the same heading as an easily recognizable and static feature nearby the place you are flying, for example a runway, a street, a fence, etc. Then you are able to compare the craft's position on the OSD map with this reference, making it easier to orientate yourself, align directional antennas and so on.
+        field: map2d_ref_line_heading
+        default_value: -1
+        min: -1
+        max: 359
+
   - name: PG_OSD_COMMON_CONFIG
     type: osdCommonConfig_t
     headers: ["io/osd_common.h"]

src/main/io/osd.c

@@ -1253,6 +1253,41 @@ int osdGetHeadingAngle(int angle)
 
 #if defined(USE_GPS)
 
+/* Draws a reference line in the center of screen, based on configurable heading (assuming north is up).
+ * Code borrowed and simplified from osdGridDrawArtificialHorizon(), since it's essentially the same thing
+ * as the artificial horizon line, but fixed on the same position and with roll only, no pitch.
+ */
+static void osdDrawMapReferenceLine(uint8_t midX, uint8_t midY)
+{   
+    float heading = osdConfig()->map2d_ref_line_heading;
+    float rollAngle = DEGREES_TO_RADIANS(90.f - (heading > 180.f ? heading - 180.f: heading));
+    const float ky = sin_approx(rollAngle);
+    const float kx = cos_approx(rollAngle);
+    const float ratio = osdDisplayIsPAL() ? 12.0f/15.0f : 12.0f/18.46f;
+
+    // Reduce the size so as not to be confused with the AHI, if both are used at the same time
+    static const uint8_t ref_line_width = OSD_AHI_WIDTH - 6U;
+    static const uint8_t ref_line_height = OSD_AHI_HEIGHT - 4U;
+
+    if (fabsf(ky) < fabsf(kx)) {             
+        for (int8_t dx = -ref_line_width / 2; dx <= ref_line_width / 2; dx++) {            
+            float fy = (ratio * dx) * (ky / kx) + 0.49f;
+            int8_t dy = floorf(fy);
+            const uint8_t chX = midX + dx, chY = midY - dy;
+            uint16_t c = SYM_AH_H_START + ((OSD_AHI_H_SYM_COUNT - 1) - (uint8_t)((fy - dy) * OSD_AHI_H_SYM_COUNT));
+            displayWriteChar(osdDisplayPort, chX, chY, c);                
+        }
+    } else {       
+        for (int8_t dy = -ref_line_height / 2; dy <= ref_line_height / 2; dy++) {
+            const float fx = (dy / ratio) * (kx / ky) + 0.5f;
+            const int8_t dx = floorf(fx);
+            const uint8_t chX = midX + dx, chY = midY - dy;
+            uint16_t c = SYM_AH_V_START + (fx - dx) * OSD_AHI_V_SYM_COUNT;
+            displayWriteChar(osdDisplayPort, chX, chY, c);                            
+        }
+    }
+}
+
 /* Draws a map with the given symbol in the center and given point of interest
  * defined by its distance in meters and direction in degrees.
  * referenceHeading indicates the up direction in the map, in degrees, while
@@ -1265,10 +1300,9 @@ static void osdDrawMap(int referenceHeading, uint16_t referenceSym, uint16_t cen
                        uint32_t poiDistance, int16_t poiDirection, uint16_t poiSymbol,
                        uint16_t *drawn, uint32_t *usedScale)
 {
-    // TODO: These need to be tested with several setups. We might
-    // need to make them configurable.
-    const int hMargin = 5;
-    const int vMargin = 3;
+    // Configurable horizontal and vertical margins
+    const int hMargin = osdConfig()->map2d_hmargin;
+    const int vMargin = osdConfig()->map2d_vmargin;
 
     // TODO: Get this from the display driver?
     const int charWidth = 12;
@@ -1281,7 +1315,14 @@ static void osdDrawMap(int referenceHeading, uint16_t referenceSym, uint16_t cen
     uint8_t midX = osdDisplayPort->cols / 2;
     uint8_t midY = osdDisplayPort->rows / 2;
 
-    // Fixed marks
+    // Fixed marks  
+    if(osdConfig()->map2d_ref_line_heading >= 0 && referenceSym == 'N') {
+        // Reference line is only drawn if enabled (ref heading == -1 disables it)
+        // and using North as the map reference
+        osdDrawMapReferenceLine(midX, midY);
+    }
+
+    // Draw the center symbol after the reference line so it overwrites the line center character
     displayWriteChar(osdDisplayPort, midX, midY, centerSym);
 
     // First, erase the previous drawing.
@@ -3952,7 +3993,11 @@ PG_RESET_TEMPLATE(osdConfig_t, osdConfig,
 
     .stats_energy_unit = SETTING_OSD_STATS_ENERGY_UNIT_DEFAULT,
     .stats_page_auto_swap_time = SETTING_OSD_STATS_PAGE_AUTO_SWAP_TIME_DEFAULT,
-    .stats_show_metric_efficiency = SETTING_OSD_STATS_SHOW_METRIC_EFFICIENCY_DEFAULT
+    .stats_show_metric_efficiency = SETTING_OSD_STATS_SHOW_METRIC_EFFICIENCY_DEFAULT,    
+
+    .map2d_vmargin = SETTING_OSD_MAP2D_VMARGIN_DEFAULT,
+    .map2d_hmargin = SETTING_OSD_MAP2D_HMARGIN_DEFAULT,
+    .map2d_ref_line_heading = SETTING_OSD_MAP2D_REF_LINE_HEADING_DEFAULT
 );
 
 void pgResetFn_osdLayoutsConfig(osdLayoutsConfig_t *osdLayoutsConfig)

src/main/io/osd.h

@@ -460,11 +460,16 @@ typedef struct osdConfig_s {
 #ifndef DISABLE_MSP_DJI_COMPAT
     bool            highlight_djis_missing_characters;  // If enabled, show question marks where there is no character in DJI's font to represent an OSD element symbol
 #endif
+
 #ifdef USE_ADSB
     uint16_t adsb_distance_warning;                     // in metres
     uint16_t adsb_distance_alert;                       // in metres
     uint16_t adsb_ignore_plane_above_me_limit;          // in metres
 #endif
+
+    uint8_t         map2d_vmargin; // Vertical lines margin for 2D map (lines where nothing will be drawn)
+    uint8_t         map2d_hmargin; // Horizontal lines margin for 2D map
+    int16_t         map2d_ref_line_heading; // Reference line heading (0 to 360, -1 to disable)
 } osdConfig_t;
 
 PG_DECLARE(osdConfig_t, osdConfig);