public partial class Form1 : Form
{
private Bitmap bitmapOriginal;
private Bitmap bitmapModified;
public Form1()
{
InitializeComponent();
this.Paint += new System.Windows.Forms.PaintEventHandler(this.MyPaint);
try
{
//load original bitmap from a file
bitmapOriginal = (Bitmap)Bitmap.FromFile(
@"..\..\katie_plaintext.jpg");
//center to screen
this.CenterToScreen();
}
catch (Exception ex)
{
MessageBox.Show(
"Error loading image. " +
ex.Message);
}
}
private void MyPaint(
object sender,
System.Windows.Forms.PaintEventArgs e)
{
try
{
//get Graphics object for painting original
Graphics gPanelOriginal =
Graphics.FromHwnd(
panelOriginalImage.Handle);
//draw original bitmap into panel
gPanelOriginal.DrawImage(
bitmapOriginal, new Point(0, 0));
//return if there is no modified image yet
if (bitmapModified == null)
return;
//get Graphics object for painting modified
Graphics gPanelModified =
Graphics.FromHwnd(
panelModifiedImage.Handle);
//draw modified bitmap into panel
gPanelModified.DrawImage(
bitmapModified, new Point(0, 0));
}
catch (Exception ex)
{
MessageBox.Show(
"Error drawing image." +
ex.Message);
this.Close();
}
}
private void button1_Click(object sender, EventArgs e)//写入
{
try
{
//show wait cursor
this.Cursor = Cursors.WaitCursor;
//start off with copy of original image
bitmapModified = new Bitmap(
bitmapOriginal,
bitmapOriginal.Width,
bitmapOriginal.Height);
//get original message to be hidden
int numberbytes =
(byte)textBoxOriginalMessage.Text.Length;
byte[] bytesOriginal = new byte[numberbytes + 1];
bytesOriginal[0] = (byte)numberbytes;
Encoding.UTF8.GetBytes(
textBoxOriginalMessage.Text,
0,
textBoxOriginalMessage.Text.Length,
bytesOriginal,
1);
//set bits 1, 2, 3 of byte into LSB red
//set bits 4, 5, 6 of byte into LSB green
//set bits 7 and 8 of byte into LSB blue
int byteCount = 0;
for (int i = 0; i < bitmapOriginal.Width; i++)
{
for (int j = 0; j < bitmapOriginal.Height; j++)
{
if (bytesOriginal.Length == byteCount)
return;
Color clrPixelOriginal =
bitmapOriginal.GetPixel(i, j);
byte r =
(byte)((clrPixelOriginal.R & ~0x7) |
(bytesOriginal[byteCount] >> 0) & 0x7);
byte g =
(byte)((clrPixelOriginal.G & ~0x7) |
(bytesOriginal[byteCount] >> 3) & 0x7);
byte b =
(byte)((clrPixelOriginal.B & ~0x3) |
(bytesOriginal[byteCount] >> 6) & 0x3);
byteCount++;
//set pixel to modified color
bitmapModified.SetPixel(
i, j, Color.FromArgb(r, g, b));
}
}
}
catch (Exception ex)
{
MessageBox.Show(
"Error hiding message." +
ex.Message);
}
finally
{
//show normal cursor
this.Cursor = Cursors.Arrow;
//repaint
Invalidate();
}
}
private void button2_Click(object sender, EventArgs e)//读取
{
//get bytes of message from modified image
byte[] bytesExtracted = new byte[256 + 1];
try
{
//show wait cursor, can be time-consuming
this.Cursor = Cursors.WaitCursor;
//get bits 1, 2, 3 of byte from LSB red
//get bits 4, 5, 6 of byte from LSB green
//get bits 7 and 8 of byte from LSB blue
int byteCount = 0;
for (int i = 0; i < bitmapModified.Width; i++)
{
for (int j = 0; j < bitmapModified.Height; j++)
{
if (bytesExtracted.Length == byteCount)
return;
Color clrPixelModified =
bitmapModified.GetPixel(i, j);
byte bits123 =
(byte)((clrPixelModified.R & 0x7) << 0);
byte bits456 = (
byte)((clrPixelModified.G & 0x7) << 3);
byte bits78 = (
byte)((clrPixelModified.B & 0x3) << 6);
bytesExtracted[byteCount] =
(byte)(bits78 | bits456 | bits123);
byteCount++;
}
}
}
catch (Exception ex)
{
MessageBox.Show(
"Error extracting message." +
ex.Message);
}
finally
{
//show normal cursor
this.Cursor = Cursors.Arrow;
//get number of bytes from start of array
int numberbytes = bytesExtracted[0];
//get remaining bytes in array into string
textBoxExtractedlMessage.Text =
Encoding.UTF8.GetString(
bytesExtracted,
1,
numberbytes);
}
}
}
demo：http://files.cnblogs.com/hdjjun/windowsapplication1.rar