SetLayeredWindowAttributes issue

This is a discussion on SetLayeredWindowAttributes issue within the Windows Programming forums, part of the Platform Specific Boards category; I have created a window that is partially transparent using a call to SetLayeredWindowAttributes if I pass LWA_COLORKEY into it, ...

  1. #1
    ave
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    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

  2. #2
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    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
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  3. #3
    ave
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    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

  4. #4
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    Quote Originally Posted by ave View Post
    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
    Well, you could draw those surfaces with alphablended blits, I suppose.

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    Mats
    Compilers can produce warnings - make the compiler programmers happy: Use them!
    Please don't PM me for help - and no, I don't do help over instant messengers.

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    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.

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