ImageAttributes.SetRemapTable Method (ColorMap[])

A color-remap table is an array of ColorMap structures. Each ColorMap structure has two Color objects: one that specifies an old color and one that specifies a corresponding new color. During rendering, any color that matches one of the old colors in the remap table is changed to the corresponding new color.

An ImageAttributes object maintains color and grayscale settings for five adjustment categories: default, bitmap, brush, pen, and text. For example, you can specify a color remap for the default category, a color-remap table for the bitmap category, and still a different color-remap table for the pen category.

The default color-adjustment and grayscale-adjustment settings apply to all categories that do not have adjustment settings of their own. For example, if you never specify any adjustment settings for the pen category, the default settings apply to the pen category.

The following code example is designed for use with Windows Forms, and it requires PaintEventArgs e, which is a parameter of the Paint event handler. The code performs the following actions:

1. Creates an image (a red circle), saves it as Circle2.jpg, opens that image, and draws it to the screen.

2. Creates a color map that maps the color red to the color green.

3. Draws the image created earlier to the screen again, but this time using the color map.

private void SetRemapTableExample(PaintEventArgs e)
{

    // Create a filled, red image, and save it to Circle2.jpg.
    Bitmap myBitmap = new Bitmap(50, 50);
    Graphics g = Graphics.FromImage(myBitmap);
    g.Clear(Color.White);
    g.FillEllipse(new SolidBrush(Color.Red),
        new Rectangle(0, 0, 50, 50));
    myBitmap.Save("Circle2.jpg");

    // Create an Image object from the Circle2.jpg file, and draw it to

    // the screen.
    Image myImage = Image.FromFile("Circle2.jpg");
    e.Graphics.DrawImage(myImage, 20, 20);

    // Create a color map.
    ColorMap[] myColorMap = new ColorMap[1];
    myColorMap[0] = new ColorMap();
    myColorMap[0].OldColor = Color.Red;
    myColorMap[0].NewColor = Color.Green;

    // Create an ImageAttributes object, and then pass the
   // myColorMap object to the SetRemapTable method.
    ImageAttributes imageAttr = new ImageAttributes();
    imageAttr.SetRemapTable(myColorMap);

    // Draw the image with the remap table set.
    Rectangle rect = new Rectangle(150, 20, 50, 50);
    e.Graphics.DrawImage(myImage, rect, 0, 0, 50, 50, 
        GraphicsUnit.Pixel, imageAttr);    

}

.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