Bitmap.UnlockBits Method
.NET Framework 3.0
Unlocks this Bitmap from system memory.
Namespace: System.Drawing
Assembly: System.Drawing (in system.drawing.dll)
Assembly: System.Drawing (in system.drawing.dll)
'Declaration Public Sub UnlockBits ( _ bitmapdata As BitmapData _ ) 'Usage Dim instance As Bitmap Dim bitmapdata As BitmapData instance.UnlockBits(bitmapdata)
public void UnlockBits ( BitmapData bitmapdata )
public function UnlockBits ( bitmapdata : BitmapData )
Not applicable.
Parameters
- bitmapdata
A BitmapData specifying information about the lock operation.
The following code example demonstrates how to use the PixelFormat, Height, Width, and Scan0 properties; the LockBits and UnlockBits methods; and the ImageLockMode enumeration. This example is designed to be used with Windows Forms. To run this example, paste it into a form and handle the form's Paint event by calling the LockUnlockBitsExample method, passing e as PaintEventArgs.
Private Sub LockUnlockBitsExample(ByVal e As PaintEventArgs) ' Create a new bitmap. Dim bmp As New Bitmap("c:\fakePhoto.jpg") ' Lock the bitmap's bits. Dim rect As New Rectangle(0, 0, bmp.Width, bmp.Height) Dim bmpData As System.Drawing.Imaging.BitmapData = bmp.LockBits(rect, _ Drawing.Imaging.ImageLockMode.ReadWrite, bmp.PixelFormat) ' Get the address of the first line. Dim ptr As IntPtr = bmpData.Scan0 ' Declare an array to hold the bytes of the bitmap. ' This code is specific to a bitmap with 24 bits per pixels. Dim bytes As Integer = bmp.Width * bmp.Height * 3 Dim rgbValues(bytes - 1) As Byte ' Copy the RGB values into the array. System.Runtime.InteropServices.Marshal.Copy(ptr, rgbValues, 0, bytes) ' Set every red value to 255. For counter As Integer = 2 To rgbValues.Length - 1 Step 3 rgbValues(counter) = 255 Next ' Copy the RGB values back to the bitmap System.Runtime.InteropServices.Marshal.Copy(rgbValues, 0, ptr, bytes) ' Unlock the bits. bmp.UnlockBits(bmpData) ' Draw the modified image. e.Graphics.DrawImage(bmp, 0, 150) End Sub
private void LockUnlockBitsExample(PaintEventArgs e)
{
// Create a new bitmap.
Bitmap bmp = new Bitmap("c:\\fakePhoto.jpg");
// Lock the bitmap's bits.
Rectangle rect = new Rectangle(0, 0, bmp.get_Width(), bmp.get_Height());
System.Drawing.Imaging.BitmapData bmpData = bmp.LockBits(rect,
System.Drawing.Imaging.ImageLockMode.ReadWrite,
bmp.get_PixelFormat());
// Get the address of the first line.
IntPtr ptr = bmpData.get_Scan0();
// Declare an array to hold the bytes of the bitmap.
// This code is specific to a bitmap with 24 bits per pixels.
int bytes = bmp.get_Width() * bmp.get_Height() * 3;
ubyte rgbValues[] = new ubyte[bytes];
// Copy the RGB values into the array.
System.Runtime.InteropServices.Marshal.Copy(ptr, rgbValues, 0, bytes);
// Set every red value to 255.
for (int counter = 2; counter < rgbValues.get_Length(); counter+=3) {
rgbValues[counter] = 255;
}
// Copy the RGB values back to the bitmap
System.Runtime.InteropServices.Marshal.Copy(rgbValues, 0, ptr, bytes);
// Unlock the bits.
bmp.UnlockBits(bmpData);
// Draw the modified image.
e.get_Graphics().DrawImage(bmp, 0, 150);
} //LockUnlockBitsExample
Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.Community Additions
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