SetLayeredWindowAttributes issue

I have created a window that is partially transparent

using a call to
SetLayeredWindowAttributes

if I pass LWA_COLORKEY into it, as in

SetLayeredWindowAttributes(Self.Handle, clWhite, ALPHA_VALUE, LWA_COLORKEY);

then everything that is white is completely transparent

if I pass the LWA_Alpha into it as in

etLayeredWindowAttributes(Self.Handle, clWhite, 128, LWA_Alpha);

then everything is 50% transparent

if I pass both parameters in as in

SetLayeredWindowAttributes(Self.Handle, clWhite, ALPHA_VALUE, LWA_Alpha or LWA_COLORKEY);

then all the white areas are transparent, and everything else is 50%

is there a way to get only the white area to be 50% transparent, and everything else to be 100% visible

It doesn't appear from the documentation that you can achieve that. I doubt that the hardware would have any trouble achieving that, but it just so happens that MS didn't allow you to choose those options.

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Mats

hmmm thats a bit of a bummer.... :-\

I wonder if there is another way to do it-you will be able to create very nice interfaces if you could- like having a mp3 player where all the controls are opaque and just where the graphic equalizers are, they on a semi- transparent surface, like they are playing over glass

Quote:

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Originally Posted by ave

hmmm thats a bit of a bummer.... :-\

I wonder if there is another way to do it-you will be able to create very nice interfaces if you could- like having a mp3 player where all the controls are opaque and just where the graphic equalizers are, they on a semi- transparent surface, like they are playing over glass

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Well, you could draw those surfaces with alphablended blits, I suppose.

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Mats

You can make very fancy shaped windows with per-pixel alpha using the layered window API. Look into UpdateLayeredWindow(). Keep in mind, this isn't exactly simple.