TWidgetSet.DrawFocusRect function

Member of TWidgetSetpublicIn unit InterfaceBase

Shows or hides a focus rectangle.

Declaration

pascal

function DrawFocusRect(DC: HDC; const Rect: TRect): Boolean; virtual

Description

This function is intended to temporarily outline part of a canvas, e.g. a rectangular selection following mouse moves (rubber banding box, DockRect).

A second call of the function, with the same parameters, removes the rectangle (XOR painting). Due to this behavior the frame should be removed before it might be overwritten by any other painting operation.

Not all platforms allow for painting outside WM_PAINT events.

Child windows may be excluded (clipped), i.e. the rectangle is not necessarily fully shown.

An experiment, built from Lazarus main 2dfa93c66e of 10-22-2026. Not the official Lazarus documentation.