Transparent Animation Control

Environment: VC6 SP3, NT4 SP4 German (demo application tested with Win98 German)

As I wanted to put some animations (animated GIFs converted to AVIs) in my application by using the standard CAnimateCtrl, I realized that Microsoft and I interprete the term "transparent" differently.
If you set the flag ACS_TRANSPARENT in CAnimateCtrl, the background of the animation is in no way transparent, instead it is changed to COLOR_WINDOW. Not what I expected...

Since my application has a bitmap background the standard control was useless for me, and after staring some time at the AVIView sample sources, I decided to make my own class that supports real transparency ;-)

The following list shows the public functions of my class CAVICtrl and the flags you can use when loading an animation:

// functions

HRESULT Load(UINT nIDResource, DWORD dwFlags = 0L,  COLORREF clrTransparent = LTGREEN); // load from resource
HRESULT Load(LPCTSTR lpszFile, DWORD dwFlags = 0L,  COLORREF clrTransparent = LTGREEN); // load from file

BOOL Play(BOOL bOnce = FALSE);
BOOL Stop(BOOL bResetToFirst = FALSE);
void Seek(UINT nTo);
BOOL IsPlaying();

// call this function if the background of the parent 
// window changesvoid ReinitBackground(); 

// flags to use with Load()

AVC_HALFSPEED 0x0000001 // plays video with half speed
AVC_DOUBLESPEED 0x0000002 // plays video with double speed

AVC_CENTERAVI 0x0000004 // centers video inside the window
AVC_STRETCHAVI 0x0000008 // stretches video to fit inside of the window
AVC_CENTERRECT 0x0000010 // resizes window, center point stays the same

AVC_AUTOPLAY 0x0000020 // starts playing automatically after Load()

// background is COLOR_WINDOW 
// instead of transparent (like CAnimateCtrl's // AVS_"TRANSPARENT")
AVC_MAPWINDOWCOLOR 0x0000040 // ignore clrTransparent parameter and uses color of first // frame's first pixel instead (works only with 8bit images)
AVC_FIRSTPIXTRANSPRNT 0x0000080 

One great flaw is that the animation function itself is driven by a timer, so it stops if you click on the parent window to move or resize it.
I'm planning to put the animation code in a different thread for better performance and appearance, but this will be my first travel into the alien world of multithreaded programming, so please be patient ;-)

Comments, suggestions, bug reports etc. are welcome! Put them here as a comment or send them directly to me.

Enjoy!

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