ImageAttributes.ClearColorKey Method (ColorAdjustType)
Clears the color key (transparency range) for a specified category.
Assembly: System.Drawing (in System.Drawing.dll)
An ImageAttributes object maintains color and grayscale settings for five adjustment categories: default, bitmap, brush, pen, and text. For example, you can specify one color key for the default category, a different color key for the bitmap category, and still a different color key 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.
As soon as you specify a color-adjustment or grayscale-adjustment setting for a certain category, the default adjustment settings no longer apply to that category. For example, suppose you specify a default color key that makes any color with a red component from 200 through 255 transparent, and you specify a default gamma value of 1.8. If you set the color key of the pen category by calling the SetColorKey method, the default color key and the default gamma value will not apply to pens. If you later clear the pen color key by calling the ClearColorKey method, the pen category will not revert to the default color key; rather, the pen category will have no color key. Similarly, the pen category will not revert to the default gamma value; rather, the pen category will have no gamma value.