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Reference for unit 'Controls' (#lcl)

CheckTransparentWindow

Checks whether the handle for a windowed control (or a parent control) is transparent.

Declaration

Source position: controls.pp line 2774

procedure CheckTransparentWindow(

var Handle: THandle;

var AWinControl: TWinControl

);

Arguments

`Handle`		Handle for the control (or parent) found for the specified windowed control.
`AWinControl`		Handle for the windowed control examined in the routine.

Description

CheckTransparentWindow is procedure used to check whether the handle for a windowed control (or a parent control) is transparent. CheckTransparentWindow uses the current mouse position to locate controls or forms under the mouse rectangle. The LM_NCHITTEST message is performed for AWinControl to determine if the handle is drawn transparently. Additional Forms in the Z-Order are visited until an opaque windowed control is located. Parent controls are searched too (when needed).

CheckTransparentWindow updates the values in Handle and AWinControl to reflect the results from the search. When an overlayed control is not located, the value in Handle is set to 0, and AWinControl is set to Nil.

Version 3.2

Generated 2024-02-25

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