ImageAttributes::SetRemapTable Method (array<ColorMap^>^)

 

Sets the color-remap table for the default category.

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

public:
void SetRemapTable(
	array<ColorMap^>^ map
)

Parameters

map
Type: array<System.Drawing.Imaging::ColorMap^>^

An array of color pairs of type ColorMap. Each color pair contains an existing color (the first value) and the color that it will be mapped to (the second value).

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 PaintEventArgse, 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 = gcnew Bitmap( 50,50 );
      Graphics^ g = Graphics::FromImage( myBitmap );
      g->Clear( Color::White );
      g->FillEllipse( gcnew SolidBrush( Color::Red ), 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.
      array<ColorMap^>^myColorMap = gcnew array<ColorMap^>(1);
      myColorMap[ 0 ] = gcnew 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 = gcnew ImageAttributes;
      imageAttr->SetRemapTable( myColorMap );

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

.NET Framework
Available since 1.1
Return to top
Show: