hidden transparent full desktop window?

hidden transparent full desktop window?

Post by Postin » Sat, 19 Dec 1998 04:00:00



I have an application that needs to be able to scribble anywhere
on the desktop, but the application's window should be completely
transparent and hidden until needed.  It should become visible
with the overlay drawing, then disappear after a short delay.
I don't want title bars, menus, frames, or anything else to
show in the overlay window except the graphic elements.  I have
a hotkey functioning to bring control to my application at any
time, but I am having a hard time understanding the blizzard of
available window styles, extended styles, and show commands to
get the window to do what I need.  Does anyone have any tips or
pointers they might be able to share on this problem?

The target is NT 4.0, but I don't think this depends on the
platform.

Thanks alot!

Lester

--

 
 
 

hidden transparent full desktop window?

Post by William DePalo [MVP » Sun, 20 Dec 1998 04:00:00



>I have an application that needs to be able to scribble anywhere
>on the desktop, but the application's window should be completely
>transparent and hidden until needed.

Create a parentless, popup window (WS_POPUP style), possibly borderless and
don't show it. When you like, place it anywhere on the desktop and draw it
however you like. If you want the desktop to show thru your window you _may_
be able to use a transparent window (WS_EX_TRANSPARENT). I say may because
if what underlies your so-called transparent window changes, those changes
will not be reflected in your window. And if something else overlays yours
and then moves away, you'll have to figure out how to display it.

Regards,
Will

 
 
 

hidden transparent full desktop window?

Post by Dmitry Streblechenk » Sun, 20 Dec 1998 04:00:00


Why don't you create an irregular shaped window using a region
that includes every area you will draw on and excluding any area
that has to be transparent?
No messing with styles, that would work no matter what is
underneath your window.

Dmitry


>I have an application that needs to be able to scribble anywhere
>on the desktop, but the application's window should be completely
>transparent and hidden until needed.  It should become visible
>with the overlay drawing, then disappear after a short delay.
>I don't want title bars, menus, frames, or anything else to
>show in the overlay window except the graphic elements.  I have
>a hotkey functioning to bring control to my application at any
>time, but I am having a hard time understanding the blizzard of
>available window styles, extended styles, and show commands to
>get the window to do what I need.  Does anyone have any tips or
>pointers they might be able to share on this problem?

>The target is NT 4.0, but I don't think this depends on the
>platform.

>Thanks alot!

>Lester

>--


 
 
 

hidden transparent full desktop window?

Post by William DePalo [MVP » Sun, 20 Dec 1998 04:00:00



>WS_EX_TRANSPARENT only acts transparently with respect to sibling
>windows on the same thread, and even then, transparently only
>with respect to hit-testing, not with respect to painting.

Oops. Thanks for the clarification.

Regards,
Will

 
 
 

hidden transparent full desktop window?

Post by Raymond Ch » Mon, 21 Dec 1998 04:00:00


On Sat, 19 Dec 1998 02:11:11 -0500, "William DePalo [MVP]"


>If you want the desktop to show thru your window you _may_
>be able to use a transparent window (WS_EX_TRANSPARENT).

WS_EX_TRANSPARENT only acts transparently with respect to sibling
windows on the same thread, and even then, transparently only
with respect to hit-testing, not with respect to painting.

Use a regional window for this.
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