Qt-embedded-interest Archive, April 2007
RE: .png image display problem on ARM
Message 1 in thread
> Hi all,
>
> I have created a GUI application for OMAP5912 on Linux.It is working
> fine,besides one problem. The problem is that a " .png image is not
> disalaying on the screen". I have checked the code, but found nothing
> wrong.The .png image is also in the directory. When i am running the
> application on Virtual frame buffer, the image is displaying
> perfectly,but not on the OMAP5912 hardware. Any help or
> suggestion will
> be appriciated.
> Thank you.
>
>
> regards,
> Sandeep
>
Sandeep,
I had a problem like this, although I didn't try the Virtual Frame
Buffer.
It turned out that the linker was optimizing away the
qmake_image_collection.cpp code.
I got things to work by calling the function that should be implicitly
called by a constructor:
// The following declaration is necessary to force the linker
// to include the qmake_image_collection.cpp code, which is
// "optimized" away otherwise.
void qInitImages_projectname();
And in the initialization code:
// force initialization of static images
qInitImages_projectname();
Where "projectname" is the name of your project.
This is a function in the code generated by the moc compiler to manage
the embedded images.
Ralph Walden
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Message 2 in thread
The changes I'm referring to are not in Qt, but in your application.
If you add the code I describe into your main.cpp, that would be fine.
When you build your project, you have some project file called:
myproject.pro
Qmake creates a Makefile which builds your project, executing moc for
your ui files, etc.
Embedding images in your GUI design using Qt Designer causes this
process to create a .cpp file which contains the images. This is
probably the file "qmake_image_collection.cpp" most likely located in a
".ui" subdirectory in your project directory.
This qmake_image_collection.cpp code depends on a constructor of a
object which is statically declarared to call an initialization function
"qInitImages_projectname()" in the same file.
Well, since the cross-linker sees no explicit reference to this function
(or any qmake_image_collection.cpp code) it assumes that it is dead code
and so "optimizes" it away.
That's why (I think) I had to add an explicit call to this function
(qInitImages_projectname()) in MY code. I added a call to this function
in my "main()" function.
Is anyone else familiar with this problem? Trolltech guys?
Ralph Walden
> -----Original Message-----
> From: sandeep bihal [mailto:sandeepbihal@xxxxxxxxx]
> Sent: Wednesday, April 04, 2007 12:58 AM
> To: Ralph Walden
> Subject: Re: .png image display problem on ARM
>
> Ralph Walden wrote:
>
> >>Hi all,
> >>
> >>I have created a GUI application for OMAP5912 on Linux.It
> is working
> >>fine,besides one problem. The problem is that a " .png image is not
> >>disalaying on the screen". I have checked the code, but
> found nothing
> >>wrong.The .png image is also in the directory. When i am
> running the
> >>application on Virtual frame buffer, the image is displaying
> >>perfectly,but not on the OMAP5912 hardware. Any help or
> >>suggestion will
> >>be appriciated.
> >>Thank you.
> >>
> >>
> >>regards,
> >>Sandeep
> >>
> >>
> >>
> >
> >Sandeep,
> >
> >I had a problem like this, although I didn't try the Virtual Frame
> >Buffer.
> >
> >It turned out that the linker was optimizing away the
> >qmake_image_collection.cpp code.
> >
> >I got things to work by calling the function that should be
> implicitly
> >called by a constructor:
> >
> >// The following declaration is necessary to force the linker
> >// to include the qmake_image_collection.cpp code, which is
> >// "optimized" away otherwise.
> >void qInitImages_projectname();
> >
> >And in the initialization code:
> >
> > // force initialization of static images
> > qInitImages_projectname();
> >
> >Where "projectname" is the name of your project.
> >
> >This is a function in the code generated by the moc compiler
> to manage
> >the embedded images.
> >
> >
> >Ralph Walden
> >
> >
> >
> Ralph,
> i did not understand,where to make changes.(in which files).
> Can you be
> more specific..?
>
> regards,
> Sandeep
>
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