Detect a form/control is not totaly drawn on the screen

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Benoist Demeure - 02 Feb 2005 09:06 GMT

Hi,

I'm using BitBlt to capture a screen-shot of a control.
It's works fine, but if the control is "masked" by an another windows, or
outside the screen bounds the captured bitmap is not complete. It's normal
because only the visible part of a control is drawn for optimizing paint.

So, before capturing the screen-shot, i want to verify that the control is
not masked by another windows ( wich can be a window from an external
application , for example the taskbar ) .
Is there a way to do that ?

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Joep - 02 Feb 2005 09:09 GMT

screen coordinates of control combined with screen itself (that is, its
height and width) will tell you

> Hi,
>
[quoted text clipped - 7 lines]
> application , for example the taskbar ) .
> Is there a way to do that ?

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Benoist Demeure - 02 Feb 2005 09:18 GMT

This is not enough : screen coordinates can help me to know if the control
is outside ( or partialy outside ) the screen.

But the main problem is to detect that the control is not masked by another
window

> screen coordinates of control combined with screen itself (that is, its
> height and width) will tell you
[quoted text clipped - 11 lines]
>> application , for example the taskbar ) .
>> Is there a way to do that ?

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Joep - 02 Feb 2005 09:24 GMT

you are right, i missed that part, sorry

when a window, or better any window of whatever proces, is partially hidden,
another window is hiding part of it, sounds logical, then, windows have
z-order and can be enumerated, their size/location asked, whether visible,
just some thoughts

> This is not enough : screen coordinates can help me to know if the control
> is outside ( or partialy outside ) the screen.
[quoted text clipped - 17 lines]
>>> application , for example the taskbar ) .
>>> Is there a way to do that ?

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Benoist Demeure - 02 Feb 2005 09:25 GMT

You mean that z-order of my window dynamicaly change when it is behind or
ahead ?
If true, it will be helpfull to solve my problem.

> you are right, i missed that part, sorry
>
[quoted text clipped - 24 lines]
>>>> external application , for example the taskbar ) .
>>>> Is there a way to do that ?

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Joep - 02 Feb 2005 09:31 GMT

z-order is the order in which windows are stacked on top of one another as
if the display has a third dimension (next to x and y or width and height)

so yes, your window is somewhere in that z-order as are other windows, that
means you can compare z-order programmatically giving you windows that can
overlap and then for these you check their respective location/size

> You mean that z-order of my window dynamicaly change when it is behind or
> ahead ?
[quoted text clipped - 28 lines]
>>>>> an external application , for example the taskbar ) .
>>>>> Is there a way to do that ?

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Joep - 02 Feb 2005 10:40 GMT

in addition:

by the way, this pops up, I remember something about the difference between
desktop area on the one hand and screen area on the other (the latter does
not account for taskbar if I recall well), found that in the system metrics
corner or similar one day

> z-order is the order in which windows are stacked on top of one another as
> if the display has a third dimension (next to x and y or width and height)
[quoted text clipped - 36 lines]
>>>>>> an external application , for example the taskbar ) .
>>>>>> Is there a way to do that ?

Reply to this Message

Detect a form/control is not totaly drawn on the screen

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