//Example to display simple text on I2C OLED display (128x64, SSD1306)

/******************************************************
OLED display
*******************************************************/
#include <Wire.h> //Include Arduino library for I2C communication
#include <Adafruit_SSD1306.h> //Adafruit SSD1306 library for OLED display

#define OLED_ADDRESS 0x3C //Use your OLED I2C address
#define SCREEN_WIDTH 128 //OLED display width, in pixels
#define SCREEN_HEIGHT 64 //OLED display height, in pixels

Adafruit_SSD1306 oledDisplay(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);//Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)



/******************************************************
Variable
 - variable will change
*******************************************************/
int count = 0; //value to be displayed on OLED
int sensorValue = 0;  // value read from the pot


/******************************************************
setup()
 - Mainly used for initialization (executed once)
*******************************************************/
void setup() {
  /* Serial Monitor */
  Serial.begin(9600); //initialize serial communications - for Serial Monitor


  /* OLED Display */
  // SSD1306_SWITCHCAPVCC = generate display voltage from 3.3V internally
  if(!oledDisplay.begin(SSD1306_SWITCHCAPVCC, OLED_ADDRESS)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);// Don't proceed, loop forever
  }

  delay(2000); //pause for 2 seconds
  
  oledDisplay.clearDisplay(); //clear OLED display buffer

  oledDisplay.setTextSize(1); //set text size
  oledDisplay.setTextColor(WHITE); //dark background, white text 
  //oledDisplay.setTextColor(BLACK); //bright background, black text.

  oledDisplay.setCursor(5, 10); //set cursor position (x,y) = (0,3)
  oledDisplay.println("Pot Reading:"); //display static text
  oledDisplay.display(); // update display with all of the above graphics
}



/******************************************************
loop()
 - To run the codes in an infinite manner 
*******************************************************/
void loop() {
  sensorValue = analogRead(A0);

  oledDisplay.setTextSize(3); //set text size
  oledDisplay.setCursor(10, 30); //set cursor position
  oledDisplay.print(sensorValue); //display current count value and increment count by 1
  oledDisplay.display(); // update display with all of the above graphics

  delay(50);
  
  /* Clear OLED display - count value before displaying a new value */
  clearLine(10, 30, 3); //cursorX=0, cursorY=30, TextSize=2
}


/******************************************************
User-defined function
*******************************************************/
//Clear line starting at position (cursorX, cursorY) with TextSize
void clearLine(unsigned int cursorX, unsigned int cursorY, unsigned int TextSize)
{
  //Character height is 7 pixel for text size = 1 
  
  for (int height =cursorY; height<=cursorY+(7*TextSize)-1; height++)
  {
     for (int width=cursorX; width<127; width++)
     {
        oledDisplay.drawPixel(width, height, BLACK);
      }
  }
}