Custom Draw Basics

• Apr 02, 2024

The NavBar control supports a custom draw feature. It provides a number of events occurring when painting of specific NavBar elements is required. Writing these event handlers gives a user full control of the NavBar control appearance.

Custom drawing can be implemented for the following elements of the NavBar control:

• Control background;

• Group background;

• Group foreground;

• Group caption;

• Group hint;

• Item link;

• Item link hint;

• Navigation Pane’s header section;

• Navigation Pane’s splitter;

• Navigation Pane’s overflow panel;

• Hints displayed for icons within the overflow panel.

Custom draw events accept a number of parameters. These parameters identify:

• Sender – a NavBar control element to be painted;

• ACanvas – drawing surface of a specific element (specified via a TCanvas instance);

• AViewInfo – information on the element layout (specified via a ViewInfo class instance, whose type corresponds to the painted element);

• AHandled – a parameter, determining whether the default painting is not required. Set it to True if the custom drawing is implemented by an event handler.