Artificial Horizon display using a gyro

Using Arduino Displays
44

@imolodkin

The redraw technique used works best on small displays but if you make the following changes to the post #27 sketch then it should fix your missing pixels. If it does not then post your sketch so I can run it and see what changes you have made.

Near the start of sketch change the line as follows:

#define HOR 400    // Horizon vector line length ### was 172

Then use this adapted drawHorizon() function:

// #########################################################################
// Draw the horizon with a new roll (angle in range -180 to +180)
// #########################################################################

void drawHorizon(int roll, int pitch)
{
  // Calculate coordinates for line start
  float sx = cos(roll * DEG2RAD);
  float sy = sin(roll * DEG2RAD);

  int16_t x0 = sx * HOR;
  int16_t y0 = sy * HOR;
  int16_t xd = 0;
  int16_t yd = 1;
  int16_t xdn  = 0;
  int16_t ydn = 0;

  if (roll > 45 && roll <  135) {
    xd = -1;
    yd =  0;
  }
  if (roll >=  135)             {
    xd =  0;
    yd = -1;
  }
  if (roll < -45 && roll > -135) {
    xd =  1;
    yd =  0;
  }
  if (roll <= -135)             {
    xd =  0;
    yd = -1;
  }

  if ((roll != last_roll) || (pitch != last_pitch))
  {
    xdn = 6 * xd;
    ydn = 6 * yd;
    tft.drawLine(XC - x0 - xdn, YC - y0 - ydn - pitch, XC + x0 - xdn, YC + y0 - ydn - pitch, SKY_BLUE);
    tft.drawLine(XC - x0 + xdn, YC - y0 + ydn - pitch, XC + x0 + xdn, YC + y0 + ydn - pitch, BROWN);
    xdn = 5 * xd;
    ydn = 5 * yd;
    tft.drawLine(XC - x0 - xdn, YC - y0 - ydn - pitch, XC + x0 - xdn, YC + y0 - ydn - pitch, SKY_BLUE);
    tft.drawLine(XC - x0 + xdn, YC - y0 + ydn - pitch, XC + x0 + xdn, YC + y0 + ydn - pitch, BROWN);
    xdn = 4 * xd;
    ydn = 4 * yd;
    tft.drawLine(XC - x0 - xdn, YC - y0 - ydn - pitch, XC + x0 - xdn, YC + y0 - ydn - pitch, SKY_BLUE);
    tft.drawLine(XC - x0 + xdn, YC - y0 + ydn - pitch, XC + x0 + xdn, YC + y0 + ydn - pitch, BROWN);
    
    xdn = 3 * xd;
    ydn = 3 * yd;
    tft.drawLine(XC - x0 - xdn, YC - y0 - ydn - pitch, XC + x0 - xdn, YC + y0 - ydn - pitch, SKY_BLUE);
    tft.drawLine(XC - x0 + xdn, YC - y0 + ydn - pitch, XC + x0 + xdn, YC + y0 + ydn - pitch, BROWN);
  }
  xdn = 2 * xd;
  ydn = 2 * yd;
  tft.drawLine(XC - x0 - xdn, YC - y0 - ydn - pitch, XC + x0 - xdn, YC + y0 - ydn - pitch, SKY_BLUE);
  tft.drawLine(XC - x0 + xdn, YC - y0 + ydn - pitch, XC + x0 + xdn, YC + y0 + ydn - pitch, BROWN);

  tft.drawLine(XC - x0 - xd, YC - y0 - yd - pitch, XC + x0 - xd, YC + y0 - yd - pitch, SKY_BLUE);
  tft.drawLine(XC - x0 + xd, YC - y0 + yd - pitch, XC + x0 + xd, YC + y0 + yd - pitch, BROWN);

  tft.drawLine(XC - x0, YC - y0 - pitch,   XC + x0, YC + y0 - pitch,   TFT_WHITE);

  last_roll = roll;
  last_pitch = pitch;

}

Since the larger display has ~ 4x the number of pixels to draw I would expect the code to run 4x slower than for a 160 x 128 display and thus the text/numbers will flicker when it is redrawn.