Re: Blit operation failed on MSWindows

[Marc Brünink]

> > From: Marc Brünink <mbruen@smartsoft.de>
> > Date: Do Jun 23, 2005  10:36:28 Europe/Berlin
> > To: Richard Frith-Macdonald <richard@brainstorm.co.uk>
> > Subject: Re: Blit operation failed on MSWindows
> >
> >
> > On Donnerstag, Jun 23, 2005, at 06:50 Europe/Berlin, Richard  
> > Frith-Macdonald wrote:
> >
> > > On 2005-06-23 01:59:10 +0100 Fred Kiefer <fredkiefer@gmx.de> wrote:
> > >
> > > > Marc Brünink wrote:
> > > > > On Dienstag, Jun 21, 2005, at 21:29 Europe/Berlin, Marc Brünink  
> > > > > wrote:
> > > > > > on my Windows 2000 machine I'm getting
> > > > > > "Blit operation failed 87"
> > > > > > while an application is started up.
> > > > > >
> > > > > > 87 = ERROR_INVALID_PARAMETER
> > > > > > so I logged some of the parameters:
> > > > > > x:8, y:8 rectFrom.right:48 rectFrom.left:0 rectFrom.top:0 h:48
> > > > > >
> > > > > > I guess these parameters are okay. But the AlphaBlend(..) Funktion
> > > > > > return FALSE. So what's going wrong?
> > > > > >
> > > > > > Actually this occurs while loading the tab images.
> > > > >
> > > > >
> > > > > It all comes down to
> > > > > #define USE_ALPHABLEND
> > > > > Simply comment this line out (in WIN32GState.m) and the tab images  
> > > > > are
> > > > > shown.
> > > > >
> > > > > Actually this line was commented out in version 1.18 of  
> > > > > WIN32GState.m,
> > > > > but changed in version 1.19
> > > > > Was it intent?
> > > >
> > > > This change surely was intentional, as Richard only did switch alpha
> > > > blending on, when he got it working.
> > >
> > > Yes ... but not necessarily correct everywhere ... just in the code  
> > > I tested ... mostly I was running Gorm as a test application.
> > >
> > > Also, I was testing on Windows-XP ...
> > >
> > > When I was trawling the net for info on windows transparency, I came  
> > > across stuff saying that older (but quite recent) versions of  
> > > windows didn't support it, so I suppose that it's possible that  
> > > Windows 2000 doesn't ... in which case I guess we need to work out  
> > > autoconf stuff to determine the windows version and enable/disable  
> > > it accordingly.
> >
> > If I trust
> > http://msdn.microsoft.com/library/default.asp?url=/library/en-us/gdi/ 
> > bitmaps_6ig4.asp
> > AlphaBlend should work since Windows 98. Further I've a Windows 2000  
> > SP4 machine on which AlphaBlend seems to work. At least the tab  
> > images are shown. But I also have a Windows 2000 SP4 machine on which  
> > the AlphaBlend function returns the error described above. Perhaps  
> > it's a hardware issue???
> >
> > Marc

Until this issue is clarified I suggest a fallback to BitBlt:

success = AlphaBlend(hDC,
                             x, y, (rectFrom.right - rectFrom.left), h,
                             sourceDC,
                             rectFrom.left, rectFrom.top,
                             (rectFrom.right - rectFrom.left), h,  
blendFunc);
if(success)
        break;


regards
Marc