const byte width=10, height=10;
byte bitmapArray[width][height];
byte xCnt=0, yCnt=0; 
byte startX, startY, endX, endY;

void setup()
{
  Serial.begin(115200);
  clearBitmap();
}

void loop()
{
  for(startY=0; startY<height; startY++)
  {
    for(startX=0; startX<width; startX++)
    {
      for(endY=0; endY<height; endY++)
      {
        for(endX=0; endX<width; endX++)
        {
           Line((float)startX,(float)startY,(float)endX,(float)endY);
           dumpBitmap();
           //delay(100);
           clearBitmap();
        } 
      }    
    } 
  }
}

void clearBitmap()
{
   for(yCnt=0; yCnt<height; yCnt++)
  {
    for(xCnt=0; xCnt<width; xCnt++)
    {
      bitmapArray[yCnt][xCnt] = 0;
    }   
  }
 
}
void dumpBitmap()
{
  Serial.print("-----------------------------\r\n");
  for(yCnt=0; yCnt<height; yCnt++)
  {
    for(xCnt=0; xCnt<width; xCnt++)
    {
      if(bitmapArray[yCnt][xCnt]==0)
      {
        Serial.print( "   ");
      }
      else
      {
        Serial.print( "#  " );
      }
    }   
    Serial.print("\r\n");
  } 
}

void Line( float x1, float y1, float x2, float y2)
{
  const bool steep = (fabs(y2 - y1) > fabs(x2 - x1));
  float tempVal=0;
  
  if(steep)
  {
    tempVal = x1;
    x1 = y1;
    y1 = tempVal;
    tempVal = x2;
    x2 = y2;
    x2 = tempVal;
  }
 
  if(x1 > x2)
  {
    tempVal = x1;
    x1 = x2;
    x2 = tempVal;
    tempVal = y1;
    y1 = y2;
    y2 = tempVal;
  }
 
  const float dx = x2 - x1;
  const float dy = fabs(y2 - y1);
 
  float error = dx / 2.0f;
  const int ystep = (y1 < y2) ? 1 : -1;
  int y = (int)y1;
 
  const int maxX = (int)x2;
 
  for(int x=(int)x1; x<maxX; x++)
  {
    if(steep)
    {
        SetPixel(y,x, 1);
    }
    else
    {
        SetPixel(x,y, 1);
    }
 
    error -= dy;
    if(error < 0)
    {
        y += ystep;
        error += dx;
    }
  }
}

void SetPixel(int x, int y, byte value)
{
  if(x>=0 && x<width && y>=0 && y<height)
  {
     bitmapArray[y][x] = value;
  } 
}