Method rgbWheel

Arduino_ST7789_Fast.cpp:650–677

------------------------------------------------ Input a value 0 to 511 (85*6) to get a color value. The colours are a transition R - Y - G - C - B - M - R.

// Input a value 0 to 511 (85*6) to get a color value.
// The colours are a transition R - Y - G - C - B - M - R.
void Arduino_ST7789::rgbWheel(int idx, uint8_t *_r, uint8_t *_g, uint8_t *_b)
{
  idx &= 0x1ff;
  if(idx < 85) { // R->Y  
    *_r = 255; *_g = idx * 3; *_b = 0;
    return;
  } else if(idx < 85*2) { // Y->G
    idx -= 85*1;
    *_r = 255 - idx * 3; *_g = 255; *_b = 0;
    return;
  } else if(idx < 85*3) { // G->C
    idx -= 85*2;
    *_r = 0; *_g = 255; *_b = idx * 3;
    return;  
  } else if(idx < 85*4) { // C->B
    idx -= 85*3;
    *_r = 0; *_g = 255 - idx * 3; *_b = 255;
    return;    
  } else if(idx < 85*5) { // B->M
    idx -= 85*4;
    *_r = idx * 3; *_g = 0; *_b = 255;
    return;    
  } else { // M->R
    idx -= 85*5;
    *_r = 255; *_g = 0; *_b = 255 - idx * 3;
   return;
  }
} 

uint16_t Arduino_ST7789::rgbWheel(int idx)
{