nanogui: Thread: Totally cool alpha blending is here with Microwindows

Yes, it is possible to keep up with Windows 2000 and
MAC OS X's coolest new features - translucent windows.
And now Microwindows has them.  For a preview, check
out this screenshot:

ftp://microwindows.censoft.com/pub/microwindows/ScreenShots/Microwindows-alphabl
end.gif

This version requires programming on the part of the application
window.  Soon, you can just set a window style bit.  All of the
alpha blending (implemented as a blit opcode) can be compiled
out if desired.

Regards,

Greg

Greg,

That looks really cool.  So out of curiosity, what happens when drawing
occurs in a window that is "obscured" by a transparent window?

- Ben.

-------------------------------------------------------------------
Ben Williamson       ####@####.####     http://www.pobox.com/~benw/


On Sat, 5 Feb 2000, Greg Haerr wrote:

> Yes, it is possible to keep up with Windows 2000 and
> MAC OS X's coolest new features - translucent windows.
> And now Microwindows has them.  For a preview, check
> out this screenshot:
> 
> ftp://microwindows.censoft.com/pub/microwindows/ScreenShots/Microwindows-alphabl
> end.gif
> 
> This version requires programming on the part of the application
> window.  Soon, you can just set a window style bit.  All of the
> alpha blending (implemented as a blit opcode) can be compiled
> out if desired.
> 
> Regards,
> 
> Greg
> 
> 
> 
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: ####@####.####
> For additional commands, e-mail: ####@####.####
> 
> 

hehehe this is cool :-)
So we might need the "alpha" part in the colormap of the framebuffer
after all ?

but is there a update problem with the bottom window ?
And how do you update generaly , you will always have to redraw the
place
where the window was (all windows in the place) and where it goes, bit
different
than the normal window clipping.

- Erwin


Greg Haerr wrote:
> 
> Yes, it is possible to keep up with Windows 2000 and
> MAC OS X's coolest new features - translucent windows.
> And now Microwindows has them.  For a preview, check
> out this screenshot:
> 
> ftp://microwindows.censoft.com/pub/microwindows/ScreenShots/Microwindows-alphabl
> end.gif
> 
> This version requires programming on the part of the application
> window.  Soon, you can just set a window style bit.  All of the
> alpha blending (implemented as a blit opcode) can be compiled
> out if desired.
> 
> Regards,
> 
> Greg
> 
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: ####@####.####
> For additional commands, e-mail: ####@####.####

: That looks really cool.  So out of curiosity, what happens when drawing
: occurs in a window that is "obscured" by a transparent window?

The window side of the translucent drawing algorithm is rather
complicated.  Basically, for every translucent window to be
drawn, all the windows underneath it need to be drawn, and the
results alpha-blended into it's drawing.  Then, afterwards, all
translucent windows (but not regular windows ABOVE each
translucent window need to be redrawn.  This needs to happen
for every translucent window affected by the original change.

So, to answer your question, the obscuring translucent window
needs to be redrawn after the lower translucent window finishes
drawing... ;-)  Now, the trick is, how to accomplish this in a single
offscreen graphics context with maximal clipping for no flicker... 
I'm working on it.

Regards,

Greg

: hehehe this is cool :-)
: So we might need the "alpha" part in the colormap of the framebuffer
: after all ?
: 
Possibly for non-constant alpha blending.  My demo shows constant
(per image or window) blending.



: but is there a update problem with the bottom window ?
: And how do you update generaly , you will always have to redraw the
: place
: where the window was (all windows in the place) and where it goes, bit
: different
: than the normal window clipping.

Actually the clipping can remain exactly the same, but, as explained
in my last email, drawing must occur multiple times for each overlapped
translucency...

Regards,

Greg