TiComponent.Transparent
TiComponent See Also
Specifies whether the background behind the control shows through.
property Transparent : Boolean;
Description
Use the Transparent property to specify whether the background behind the
control shows through.
This feature utilizes a cached bitmap of the background behind the control
when enabled to minimize the performance penalty. For controls that already use a
cache background when transparency is disable, there is no performance penalty
when enabling transparency because the control uses the transparency cache
instead of the background cache.
Due to limitations in the Microsoft API for transparent controls, the
following issues must be taken into account when implementing...
Background controls that change dynamically at runtime will cause flicker
(Recommend that you only place static or semi-static controls behind transparent
controls)
Controls can appear to disappear if the background control underneath it is
moved. This is due to a bug in the Microsoft API, the API fails to send a repaint
message to the foreground transparent control making it look like it has
disappeared (Resizing the background control will make the transparent foreground
controls reappear).
At design-time, it is recommend but not required that you leave the
Transparent property set to FALSE. At run-time, set the Transparent property to TRUE when
the Form/Dialog initializes. During design-time, the controls can appear to
disappear if the background control underneath it is moved. Also, depending on
the development environment, the background of the transparent controls can
become solid white or black.
During run-time, if the background is changed, the transparent foreground
control can disappear or its cached snapshot of the background can get out of sync
with the actual background. Call the RepaintAll method of the control each time the background is changed to keep in sync.
Example
Delphi
iComponent.Transparent := True;
C++ Builder
iComponent->Transparent = True;
Note: Not all descendants implement this property.
Contents | Index | Previous | Next