Qtwidget: use the new features of qt4.5 to implement a cool and transparent form

Qt4.2 introduces the qwidget: setwindowopacity function. You can set the transparency for the form. The smaller the value, the more transparent the value is. The set form can display transparent effects as a whole. However, this setting is rough and can only have one overall effect. It can be used only for example when you drag the image. Most of the time it is not practical. The new form transparency feature is introduced in qt4.5, which is the attribute of a widget, called QT: wa_translucentbackground. This attribute can be set separately for each qwidget, and the transparency level can be controlled by the drawn color or the alpha channel value of the image.

I wrote an example to demonstrate its amazing effect. First look at one:

This is the result of my example. The background is www.cuteqt.com. The following describes how to implement the Code.

Translucentbackground controls transparent form attributes
In this example, a qwidget is used on the main interface, and four controls are placed on it. The two sub-classes are custom qwidgets. A transparent background image is drawn in paintevent, and the words "cuteqt" are written in the book; the following two are standard qlabel controls, but two different effects are displayed.

The translucentbackground attribute of transparent controls is true (inherits the parent attribute), while non-transparent controls forcibly set translucentbackground to false in code, which creates interesting results. The code snippet is as follows:
Label = new qlabel ("www.cuteqt.com ");
Label-> setattribute (QT: wa_translucentbackground, false );
Label-> setautofillbackground (true );

Alpha Channel controls transparency
In this example, modify the Alpha value of the background color to show different transparency. The method is to set the palette attribute of the form and set the Alpha value for the colorrole color of background. The code snippet is as follows:
Qpalette pal = palette ();
Pal. setcolor (qpalette: Background, qcolor (255, 0, 0,200 ));
Setpalette (PAL );

The different display effects of alpha values 100 and 200 are shown.

How is this example interesting? Download the complete code to learn more ~ Do you have any questions about blog or BBS messages ~

Translucent.tar.gz

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Posted on Ben's snail reading (1781) Comments (6) EDIT favorite Reference Category: QT custom Widgets

Comment

Use the new features of qt4.5 to implement the cool transparent form [not logged on] "href =" http://www.cppblog.com/biao/archive/2009/06/12/87508.html#88511 ">#re: qtwidget: use the new features of qt4.5 to implement a cool and transparent form [not logged on] Haha Oh? Prepare to try ~ Reply to more comments

# Re: qtwidget: use the new features of qt4.5 to implement a cool and transparent form. Hello, dotboy, I tried your code on the Windows platform, the result is that the background of the main form turns black and the desktop is not displayed... reply to more comments

# Re: qtwidget: use the new features of qt4.5 to implement a cool transparent form at on. In Windows, you have to pass the title bar to display the transparent effect ...{
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Setreplyauhor ("dotboy ")
} 'Href = "http://www.cppblog.com/biao/archive/2009/06/12/87508.html#post"> reply to more comments

# Re: qtwidget: use the new features of qt4.5 to implement a cool transparent form holy GZ file format? It cannot be decompressed with WinRAR!
Please use WinRAR to pack it and reply to more comments.

# Re: qtwidget: use the new features of qt4.5 to implement a cool and transparent form [not logged on] May I ask if the windows system can achieve transparent results? reply to more comments

# Re: qtwidget: use the new features of qt4.5 to implement a cool transparent form [not logged on] 2010-02-23. The key phrase "The translucentbackground attribute of the transparent control is true (inherits the parent attribute ), A non-transparent control forcibly sets translucentbackground to false in the code ,"{
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Setreplyauhor ("Lu Ren jia ")
} 'Href = "http://www.cppblog.com/biao/archive/2009/06/12/87508.html#post"> reply to more comments from: http://www.cppblog.com/biao/archive/2009/06/12/87508.html