This is a bug that has been around for a little while. Imagine you have a KryptonLabel inside a TableLayoutPanel and then set the TableLayoutPanel to be have transparent background. What you should see is the background from behind the table panel drawn as the background of the KryptonLabel.

Sadly this was not happening correctly. Most developers would not notice the issue because they have a solid color as the main background but if you have a gradient fill then you can clearly see the drawing problem.

This problem was not unique to the KryptonLabel but in fact present with any Krypton control that needs to draw some of its background as transparent. It is also exhibited not just when inside a TableLayoutPanel but for any control that can have a transparent background color defined, such as a regular Panel.

I won’t bore you with the tricky details of how the code solves the problem, suffice it to say it involves creating regions and adjusting them for the device content to ensure the drawing occurs in the correct location with correct clipping. Not many lines of code but a real pain to get just right in all circumstances.

To show it works here is an example. You can see below at design time a TableLayoutPanel is placed onto the gradient background. In the left cell of the table is a KryptonHeaderGroup that contains a KryptonPanel that itself contains a KryptonButton and KryptonLabel. The group and panel have been customized to have transparent backgrounds. The right cell contains a button and a couple of labels inside a traditional windows Group instance.

At runtime it works as expected with the main background showing through as required.

This entry was posted on Friday, June 1st, 2007 at 2:35 pm and is filed under Krypton Toolkit. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.