AP_OSD: New per screen PARAMs for OSD overlay resolution and font

This adds
 OSDn_TXT_RES to select SD/HD overlay resoloution
 OSDn_FONT_INDEX for font index selection

Right now support is limited to MSP Displayport OSD devices

libraries/AP_MSP/AP_MSP_Telem_Backend.cpp

@@ -1217,6 +1217,12 @@ void AP_MSP_Telem_Backend::msp_displayport_write_string(uint8_t col, uint8_t row
 
     msp_send_packet(MSP_DISPLAYPORT, MSP::MSP_V1, &packet, 4 + len, false);
 }
+
+void AP_MSP_Telem_Backend::msp_displayport_set_options(const uint8_t font_index, const uint8_t screen_resolution)
+{
+    const uint8_t subcmd[] = { msp_displayport_subcmd_e::MSP_DISPLAYPORT_SET_OPTIONS, font_index, screen_resolution };
+    msp_send_packet(MSP_DISPLAYPORT, MSP::MSP_V1, subcmd, sizeof(subcmd), false);
+}
 #endif //HAL_WITH_MSP_DISPLAYPORT
 bool AP_MSP_Telem_Backend::displaying_stats_screen() const
 {

libraries/AP_MSP/AP_MSP_Telem_Backend.h

@@ -88,6 +88,7 @@ public:
     virtual void msp_displayport_clear_screen();
     virtual void msp_displayport_draw_screen();
     virtual void msp_displayport_write_string(uint8_t col, uint8_t row, bool blink, const char *string);
+    virtual void msp_displayport_set_options(const uint8_t font_index, const uint8_t screen_resolution);
 #endif
 protected:
     enum msp_packet_type : uint8_t {

libraries/AP_MSP/msp.h

@@ -104,6 +104,7 @@ typedef enum : uint8_t {
     MSP_DISPLAYPORT_CLEAR_SCREEN = 2,
     MSP_DISPLAYPORT_WRITE_STRING = 3,
     MSP_DISPLAYPORT_DRAW_SCREEN = 4,
+    MSP_DISPLAYPORT_SET_OPTIONS = 5,
 } msp_displayport_subcmd_e;
 
 typedef struct PACKED {

libraries/AP_OSD/AP_OSD.h

@@ -94,7 +94,14 @@ public:
 
 protected:
     bool check_option(uint32_t option);
-
+#ifdef HAL_WITH_MSP_DISPLAYPORT
+    virtual uint8_t get_txt_resolution() const {
+        return 0;
+    }
+    virtual uint8_t get_font_index() const {
+        return 0;
+    }
+#endif
     enum unit_type {
         ALTITUDE=0,
         SPEED=1,
@@ -134,6 +141,14 @@ public:
     static const struct AP_Param::GroupInfo var_info[];
     static const struct AP_Param::GroupInfo var_info2[];
 
+#ifdef HAL_WITH_MSP_DISPLAYPORT
+    uint8_t get_txt_resolution() const override {
+        return txt_resolution;
+    }
+    uint8_t get_font_index() const override {
+        return font_index;
+    }
+#endif
 private:
     friend class AP_MSP;
     friend class AP_MSP_Telem_Backend;
@@ -214,6 +229,12 @@ private:
     AP_OSD_Setting batt_bar{true, 1, 1};
     AP_OSD_Setting arming{true, 1, 1};
 
+#ifdef HAL_WITH_MSP_DISPLAYPORT
+    // Per screen HD resolution options (currently supported only by DisplayPort)
+    AP_Int8 txt_resolution;
+    AP_Int8 font_index;
+#endif
+
     void draw_altitude(uint8_t x, uint8_t y);
     void draw_bat_volt(uint8_t x, uint8_t y);
     void draw_avgcellvolt(uint8_t x, uint8_t y);
@@ -281,7 +302,6 @@ private:
 #endif
     void draw_rngf(uint8_t x, uint8_t y);
 
-
     struct {
         bool load_attempted;
         const char *str;

libraries/AP_OSD/AP_OSD_MSP_DisplayPort.cpp

@@ -60,6 +60,14 @@ void AP_OSD_MSP_DisplayPort::osd_thread_run_once()
 
 void AP_OSD_MSP_DisplayPort::clear(void)
 {
+    // check if we need to enable some options
+    // but only for actual OSD screens
+    if (_osd.get_current_screen() < AP_OSD_NUM_DISPLAY_SCREENS) {
+        const uint8_t txt_resolution = _osd.screen[_osd.get_current_screen()].get_txt_resolution();
+        const uint8_t font_index = _osd.screen[_osd.get_current_screen()].get_font_index();
+        _displayport->msp_displayport_set_options(font_index, txt_resolution);
+    }
+
     // clear remote MSP screen
     _displayport->msp_displayport_clear_screen();
 

libraries/AP_OSD/AP_OSD_Screen.cpp

@@ -1022,6 +1022,21 @@ const AP_Param::GroupInfo AP_OSD_Screen::var_info2[] = {
     // @Range: 0 15
     AP_SUBGROUPINFO(link_quality, "LINK_Q", 1, AP_OSD_Screen, AP_OSD_Setting),
 
+#if HAL_WITH_MSP_DISPLAYPORT
+    // @Param: TXT_RES
+    // @DisplayName: Sets the overlay text resolution (MSP DisplayPort only)
+    // @Description: Sets the overlay text resolution for this screen to either LD 30x16 or HD 50x18 (MSP DisplayPort only)
+    // @Values: 0:30x16,1:50x18
+    // @User: Standard
+    AP_GROUPINFO("TXT_RES", 3, AP_OSD_Screen, txt_resolution, 0),
+
+    // @Param: FONT
+    // @DisplayName: Sets the font index for this screen (MSP DisplayPort only)
+    // @Description: Sets the font index for this screen (MSP DisplayPort only)
+    // @Range: 0 15
+    // @User: Standard
+    AP_GROUPINFO("FONT", 4, AP_OSD_Screen, font_index, 0),
+#endif
     AP_GROUPEND
 };