BitmapData Class

BitmapData Class


Specifies the attributes of a bitmap image. The BitmapData class is used by the LockBits and UnlockBits methods of the Bitmap class. Not inheritable.

Namespace:   System.Drawing.Imaging
Assembly:  System.Drawing (in System.Drawing.dll)


public sealed class BitmapData


Initializes a new instance of the BitmapData class.


Gets or sets the pixel height of the Bitmap object. Also sometimes referred to as the number of scan lines.


Gets or sets the format of the pixel information in the Bitmap object that returned this BitmapData object.


Reserved. Do not use.


Gets or sets the address of the first pixel data in the bitmap. This can also be thought of as the first scan line in the bitmap.


Gets or sets the stride width (also called scan width) of the Bitmap object.


Gets or sets the pixel width of the Bitmap object. This can also be thought of as the number of pixels in one scan line.


Determines whether the specified object is equal to the current object.(Inherited from Object.)


Serves as the default hash function. (Inherited from Object.)


Gets the Type of the current instance.(Inherited from Object.)


Returns a string that represents the current object.(Inherited from Object.)

The following code example demonstrates how to use the BitmapData class with the LockBits and UnlockBits methods. 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 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.Width, bmp.Height);
            System.Drawing.Imaging.BitmapData bmpData =
                bmp.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadWrite,

            // Get the address of the first line.
            IntPtr ptr = bmpData.Scan0;

            // Declare an array to hold the bytes of the bitmap.
            int bytes  = Math.Abs(bmpData.Stride) * bmp.Height;
���         byte[] rgbValues = new byte[bytes];

            // Copy the RGB values into the array.
            System.Runtime.InteropServices.Marshal.Copy(ptr, rgbValues, 0, bytes);

            // Set every third value to 255. A 24bpp bitmap will look red.  
            for (int counter = 2; counter < rgbValues.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.

            // Draw the modified image.
            e.Graphics.DrawImage(bmp, 0, 150);


.NET Framework
Available since 1.1

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Return to top
© 2015 Microsoft