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Thread: QImage, PNG ad Transparency

  1. #1
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    Default QImage, PNG ad Transparency

    Hi!

    I'm new to the forum and quite new to the Qt Programming.

    I've a problem with QImage.
    I need to draw an image (.png) with transparency.
    I've serched and read a lot of thread on this forum, but I did'nt found any solution.

    This is the code I used to load the image:

    Qt Code:
    1. imm=QImage(53,48,QImage::Format_ARGB32_Premultiplied);
    2. immGL=QImage(53,48,QImage::Format_ARGB32_Premultiplied);
    3.  
    4. imm.load("image.png", "PNG");
    5. immGL = QGLWidget::convertToGLFormat(imm);
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    This is the code to draw the image:


    Qt Code:
    1. glRasterPos2i(x0,y0);
    2. glDrawPixels(w, h, GL_RGBA, GL_UNSIGNED_BYTE, immGL.bits());
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    As a result, the image is drawn with all pixel that should be transparent converted to black.

    Any solutions?

    Thanks in advance,
    Rebe
    Last edited by high_flyer; 6th May 2011 at 10:09. Reason: code tags

  2. #2
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    Default Re: QImage, PNG ad Transparency

    This is not the fault of QImage but rather of the way you use it. Either your image.png doesn't contain transparency or information about it is lost in OpenGL. And first two lines of your first code snippet can be discarded as lines #4 and #5 respectively will overwrite the objects created earlier.
    Your biological and technological distinctiveness will be added to our own. Resistance is futile.

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  3. #3
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    Default Re: QImage, PNG ad Transparency

    Ok, thanks.
    I will check OpenGL options.

  4. #4
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    Default Re: QImage, PNG ad Transparency

    Hi, I've the same issue, did you solved it?
    What did you did?

    Thanks,
    GortiZ

  5. #5
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    Default Re: QImage, PNG ad Transparency

    hi i am very new to QT please help me on Immage reading(raw immage) from QT using QgraphisScreen as base calss and derived method from QGLWidget ... if provide me sample code or URL Thanks in advance ....

  6. #6
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    Default Re: QImage, PNG ad Transparency

    Qt Code:
    1. QImage img("path/to/image");
    To copy to clipboard, switch view to plain text mode 
    Your biological and technological distinctiveness will be added to our own. Resistance is futile.

    Please ask Qt related questions on the forum and not using private messages or visitor messages.


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