Bitmap Class

A bitmap consists of the pixel data for a graphics image and its attributes. There are many standard formats for saving a bitmap to a file. GDI+ supports the following file formats: BMP, GIF, EXIF, JPG, PNG and TIFF. For more information about supported formats, see Types of Bitmaps.

You can create images from files, streams, and other sources by using one of the Bitmap constructors and save them to a stream or to the file system with the Save method. Images are drawn to the screen or to memory by using the DrawImage method of the Graphics object. For a list of topics about working with image files, see Working with Images, Bitmaps, Icons, and Metafiles.

Note

The Bitmap class is not accessible across application domains. For example, if you create a dynamic AppDomain and create several brushes, pens, and bitmaps in that domain, then pass these objects back to the main application domain, you can successfully use the pens and brushes. However, if you call the DrawImage method to draw the marshaled Bitmap, you receive the following exception. Remoting cannot find field "native image" on type "System.Drawing.Image".

The following code example demonstrates how to construct a new Bitmap from a file, using the GetPixel and SetPixel methods to recolor the image. It also uses the PixelFormat, Width, and Height properties.

This example is designed to be used with a Windows Forms that contains a Label, PictureBox, and Button named Label1, PictureBox1, and Button1, respectively. Paste the code into the form and associate the Button1_Click method with the button's Click event.

Bitmap image1;

private void Button1_Click(System.Object sender, System.EventArgs e)
{

    try
    {
        // Retrieve the image.
        image1 = new Bitmap(@"C:\Documents and Settings\All Users\" 
            + @"Documents\My Music\music.bmp", true);

        int x, y;

        // Loop through the images pixels to reset color.
        for(x=0; x<image1.Width; x++)
        {
            for(y=0; y<image1.Height; y++)
            {
                Color pixelColor = image1.GetPixel(x, y);
                Color newColor = Color.FromArgb(pixelColor.R, 0, 0);
                image1.SetPixel(x, y, newColor);
            }
        }

        // Set the PictureBox to display the image.
        PictureBox1.Image = image1;

        // Display the pixel format in Label1.
        Label1.Text = "Pixel format: "+image1.PixelFormat.ToString();

    }
    catch(ArgumentException)
    {
        MessageBox.Show("There was an error." +
            "Check the path to the image file.");
    }
}

.NET Framework

.NET Framework Client Profile

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference

Other Resources