Use DrawHeaderChevron to draw the chevron of the header of the category panel according to properties of the parent category panel group. The ACanvas parameter requires a TCanvas instance created with the window's device context assigned to the canvas's Handle property. This canvas instance should be freed after the DrawHeaderChevron is called.  

If the category panel group's HeaderStyle property is set to hsThemed, the HeaderState and the Collapsed property of this category panel instance are passed to the Windows DrawThemeBackground procedure.  

If the category panel group contains an image list in it's Images property and the Collapsed, ExpandedImageIndex and CollapsedImageIndex properties are set as to require the use of an image in the chevron, the category panel group's Images Draw routine is used to display the chevron.  

If themes are not enabled and images are not used, the default is to display the chevron with the GraphUtil DrawChevron routine.  

DrawHeaderChevron is a protected method and so can only be called in the implementation of an extended class of TCustomCategoryPanel. 

Handle 

HeaderStyle 

HeaderState 

Collapsed 

Images 

Draw 

DrawChevron 

TCustomCategoryPanelGroup