#include <Arduino.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

void setup() {
  Serial.begin(115200);
  Wire.begin(21, 22);   // SDA aur SCL pins

  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println("OLED init failed");
    while (true);
  }

  display.clearDisplay();
}

void loop() {

  display.clearDisplay();

  // 1️⃣ Full border
  display.drawRect(0, 0, 128, 64, WHITE);

  // 2️⃣ Horizontal line
  display.drawLine(0, 16, 127, 16, WHITE);

  // 3️⃣ Vertical line
  display.drawLine(64, 16, 64, 63, WHITE);

  // 4️⃣ Empty rectangle
  display.drawRect(10, 25, 40, 20, WHITE);

  // 5️⃣ Filled rectangle
  display.fillRect(70, 25, 40, 20, WHITE);

  // 6️⃣ Circle
  display.drawCircle(32, 50, 10, WHITE);

  display.display();

  delay(2000);
}