public void drawHorizontalLine(byte[] screen, int width, int x1, int x2, int y){
		int X1ByteIndex = 0;
		int X2ByteIndex = 0;
	
		int bytesPerLine = width/8;		
		int startIndexY = y*bytesPerLine;
	
		X1ByteIndex = startIndexY + x1/8;
		X2ByteIndex = startIndexY + x2/8;
		
		int x1OffsetInByte = x1%8;
		int x2OffsetInByte = x2%8;
		
		//change anything in the X1Byte from x1OffsetInByte to end of Byte to 1;
		//same to X2Byte;
		//screen[X1ByteIndex] = convertBitsToValue(screen[X1ByteIndex], x1OffsetInByte,7,true);
		screen[X2ByteIndex] = convertBitsToValue(screen[X2ByteIndex], 0, x2OffsetInByte,true);
		
		//change every bits in every bytes between X1Byte and X2Byte to 1;
		for(int i = X1ByteIndex+1;i < X2ByteIndex; i++){
			screen[i] = convertBitsToValue(screen[i], 0,7,true);
		}
		
		this.printScreen(screen,16);
	}