From cde13120ae276a182300fa36f6efc5d747b0a92f Mon Sep 17 00:00:00 2001
From: Michel Pastor <shellixyz@users.noreply.github.com>
Date: Wed, 12 Aug 2020 17:08:02 +0200
Subject: [PATCH] Take into account video aspect ratio when drawing AHI (#5962)

---
 src/main/io/osd.c      |  8 ++++++--
 src/main/io/osd.h      |  1 +
 src/main/io/osd_grid.c | 17 ++++++++++++-----
 3 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/src/main/io/osd.c b/src/main/io/osd.c
index 29bdaedd9..0e4586075 100755
--- a/src/main/io/osd.c
+++ b/src/main/io/osd.c
@@ -110,7 +110,6 @@ FILE_COMPILE_FOR_SPEED
 #endif
 
 #define VIDEO_BUFFER_CHARS_PAL    480
-#define IS_DISPLAY_PAL (displayScreenSize(osdDisplayPort) == VIDEO_BUFFER_CHARS_PAL)
 
 #define GFORCE_FILTER_TC 0.2
 
@@ -201,6 +200,11 @@ static int digitCount(int32_t value)
     return digits;
 }
 
+bool osdDisplayIsPAL(void)
+{
+    return displayScreenSize(osdDisplayPort) == VIDEO_BUFFER_CHARS_PAL;
+}
+
 /**
  * Formats a number given in cents, to support non integer values
  * without using floating point math. Value is always right aligned
@@ -2874,7 +2878,7 @@ static void osdShowStats(void)
 
     displayBeginTransaction(osdDisplayPort, DISPLAY_TRANSACTION_OPT_RESET_DRAWING);
     displayClearScreen(osdDisplayPort);
-    if (IS_DISPLAY_PAL)
+    if (osdDisplayIsPAL())
         displayWrite(osdDisplayPort, statNameX, top++, "  --- STATS ---");
 
     if (STATE(GPS_FIX)) {
diff --git a/src/main/io/osd.h b/src/main/io/osd.h
index 6415b7530..f1510ac41 100755
--- a/src/main/io/osd.h
+++ b/src/main/io/osd.h
@@ -280,6 +280,7 @@ typedef struct displayPort_s displayPort_t;
 typedef struct displayCanvas_s displayCanvas_t;
 
 void osdInit(displayPort_t *osdDisplayPort);
+bool osdDisplayIsPAL(void);
 void osdUpdate(timeUs_t currentTimeUs);
 void osdStartFullRedraw(void);
 // Sets a fixed OSD layout ignoring the RC input. Set it
diff --git a/src/main/io/osd_grid.c b/src/main/io/osd_grid.c
index 26a1c6433..fe8124b97 100644
--- a/src/main/io/osd_grid.c
+++ b/src/main/io/osd_grid.c
@@ -34,6 +34,7 @@
 #include "common/utils.h"
 
 #include "drivers/display.h"
+#include "drivers/osd.h"
 #include "drivers/osd_symbols.h"
 #include "drivers/time.h"
 
@@ -103,6 +104,11 @@ void osdGridDrawDirArrow(displayPort_t *display, unsigned gx, unsigned gy, float
     displayWriteChar(display, gx, gy, SYM_ARROW_UP + arrowOffset);
 }
 
+static float osdGetAspectRatioCorrection(void)
+{
+    return osdDisplayIsPAL() ? 12.0f/15.0f : 12.0f/18.46f;
+}
+
 void osdGridDrawArtificialHorizon(displayPort_t *display, unsigned gx, unsigned gy, float pitchAngle, float rollAngle)
 {
     UNUSED(gx);
@@ -117,10 +123,11 @@ void osdGridDrawArtificialHorizon(displayPort_t *display, unsigned gx, unsigned
     static int8_t previous_written[OSD_AHI_PREV_SIZE];
     static int8_t previous_orient = -1;
 
-    float pitch_rad_to_char = (float)(OSD_AHI_HEIGHT / 2 + 0.5) / DEGREES_TO_RADIANS(osdConfig()->ahi_max_pitch);
+    const float pitch_rad_to_char = (float)(OSD_AHI_HEIGHT / 2 + 0.5) / DEGREES_TO_RADIANS(osdConfig()->ahi_max_pitch);
 
-    float ky = sin_approx(rollAngle);
-    float kx = cos_approx(rollAngle);
+    const float ky = sin_approx(rollAngle);
+    const float kx = cos_approx(rollAngle);
+    const float ratio = osdGetAspectRatioCorrection();
 
     if (previous_orient != -1) {
         for (int i = 0; i < OSD_AHI_PREV_SIZE; ++i) {
@@ -138,7 +145,7 @@ void osdGridDrawArtificialHorizon(displayPort_t *display, unsigned gx, unsigned
         previous_orient = 0;
 
         for (int8_t dx = -OSD_AHI_WIDTH / 2; dx <= OSD_AHI_WIDTH / 2; dx++) {
-            float fy = dx * (ky / kx) + pitchAngle * pitch_rad_to_char + 0.49f;
+            float fy = (ratio * dx) * (ky / kx) + pitchAngle * pitch_rad_to_char + 0.49f;
             int8_t dy = floorf(fy);
             const uint8_t chX = elemPosX + dx, chY = elemPosY - dy;
             uint16_t c;
@@ -155,7 +162,7 @@ void osdGridDrawArtificialHorizon(displayPort_t *display, unsigned gx, unsigned
         previous_orient = 1;
 
         for (int8_t dy = -OSD_AHI_HEIGHT / 2; dy <= OSD_AHI_HEIGHT / 2; dy++) {
-            const float fx = (dy - pitchAngle * pitch_rad_to_char) * (kx / ky) + 0.5f;
+            const float fx = ((dy / ratio) - pitchAngle * pitch_rad_to_char) * (kx / ky) + 0.5f;
             const int8_t dx = floorf(fx);
             const uint8_t chX = elemPosX + dx, chY = elemPosY - dy;
             uint16_t c;
-- 
2.11.4.GIT