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Re: How to clear transparent Canvas?

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Jamie於 2011年12月27日星期二UTC+8上午10時27分52秒寫道：
> aaaa wrote:
> > I know that and I wonder how to do this most efficiently.
> > 
> > When I do:
> > MyComponent.Visible := False;
> > MyComponent.Visible := True;
> > everything that is behind my component gets repainted and then my 
> > component's Paint() method gets called and everything looks great.
> > And my component is transparent because I can see the labels and other 
> > controls placed behind it.
> > 
> > The thing is- what exactly is this "Visible" doing...?
> > 
> > The idea of saving the snapshop as TBitmap is nice- I think it should 
> > make "clearing" faster. After all nothing will change behind my 
> > component as long as it is Focused and when it looses Focus I can resave 
> > the snapshop.
> > 
> > How to get the snapshop in the best way? Should I iterate all controls 
> > of my component's parent and invoke their WM_PAINT somehow onto my 
> > snapshot's TBitmap? Or is there any easier way?
> > 
> > Best regards,
> > A
>   You could wedge into the Paint Method of each control but wouldn't
> be easier to simply create a control of your own that will do this for you?
>    You simply start with an existing control and build on that.
> 
>   Its not clear exactly what you're trying to do yet..
> 
>   P.S.
> 
>     If you have not made a control yet, maybe this is a good time to
> learn.
> 
>   Jamie

In Delphie the object in the display image  of a Window is different 
from the image.scanline[j] as far as I know. 

The container and the content are separate objects  to be programmed 
by the programmer. 

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How to clear transparent Canvas? "aaaa" <aaaa@aaaaaaaaaaaaaaaaaaa.com> - 2011-12-26 17:44 +0100
  Re: How to clear transparent Canvas? Jamie <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> - 2011-12-26 13:47 -0500
    Re: How to clear transparent Canvas? "aaaa" <aaaa@aaaaaaaaaaaaaaaaaaa.com> - 2011-12-26 23:31 +0100
      Re: How to clear transparent Canvas? Jamie <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> - 2011-12-26 21:27 -0500
        Re: How to clear transparent Canvas? 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-27 12:20 -0800
  Re: How to clear transparent Canvas? battles <battles@mailinator.com> - 2011-12-27 16:59 -0800

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