🚀 go-pugleaf

"Asger Joergensen" <junk@Asger-P.dk> wrote in message 
news:MPG.21d0abd3ce2daf26989982@newsgroups.borland.com...
> Hi there
>
> I have a situation where I have a HBITMAP handle
> and I would like to paint this Bitmap to a Canvas,
> but BitBlt takes a HDC.
>
> So how do I get a HDC from a HBITMAP ?
>

You need to create a memory dc and select the HBITMAP into it first.

-- 
Bruce

"Asger Joergensen" <junk@Asger-P.dk> wrote in message 
news:MPG.21d0abd3ce2daf26989982@newsgroups.borland.com...

> So how do I get a HDC from a HBITMAP ?

CreateCompatibleDC(), SelectObject(), and SelectPalette(), and 
RealizePalette().

> I know I can assign the HBITMAP to a TBitmap->Handle
> but I'm not interested in an extra copy of the bitmap.

Assigning an HBITMAP to a TBitmap does not make a copy.  The TBitmap takes 
ownership of the HBITMAP instead.


Gambit 

Thanks Remy
 
 Remy Lebeau (TeamB) says:
> 
> "Asger Joergensen" <junk@Asger-P.dk> wrote in message 
> news:MPG.21d0abd3ce2daf26989982@newsgroups.borland.com...
> 
> > So how do I get a HDC from a HBITMAP ?
> 
> CreateCompatibleDC(), SelectObject(), and SelectPalette(), and 
> RealizePalette().

Do I  need the palette in 24bit ?
> 
> > I know I can assign the HBITMAP to a TBitmap->Handle
> > but I'm not interested in an extra copy of the bitmap.
> 
> Assigning an HBITMAP to a TBitmap does not make a copy.  The TBitmap takes 
> ownership of the HBITMAP instead.

I tried using the TBitmap Handle and it works, but I'm not sure 
if it will work corectly.

The thing is that I an using a TImageList to hold some bitmaps, 
but I don't like the ImageList:Draw function, it makes some 
realy bad looking blended images + it is extremly slow.

So I have written my own Draw function, but I need to get the 
bitmaps, since I use the scanlines in my draw function.

Imagelist::GetBitmap uses Draw to return the image, so that would 
eat the speed I gained.

I was thinking that I could use GetImageBitmap() but I would like 
it to work with the System Imagelist as well as with a user filled 
Imagelist.

Do You know if the HBITMAP returned from GetImageBitmap() is valid 
when images are aded to the System Imagelist after a call to 
SHGetFileInfo() ?
By valid I mean containing all images in the list.

When You mentioned that TBitmap takes ownership I got my doubts.

I have tried adding an OnChange event to the ImageList but
that isn't called when the system adds images.

Do You have some suggestions ?

Thanks in advance
Asger 

"Asger Joergensen" <junk@Asger-P.dk> wrote in message
news:MPG.21d14e86b29b3fb5989988@newsgroups.borland.com...

> Do I  need the palette in 24bit ?

No.

> Do You know if the HBITMAP returned from GetImageBitmap()
> is valid when images are aded to the System Imagelist after a call
> to SHGetFileInfo() ?

I doubt it.

> I have tried adding an OnChange event to the ImageList but
> that isn't called when the system adds images.

Of course not.  It is only triggered when you resize or change the
TImageList itself, assign its Handle property, or add/remove images.  There
are no system-generated notifications for ImageList modifications that occur
outside of the TImageList.

> Do You have some suggestions ?

What exactly are you having a problem with?


Gambit