QLabel & Win32 native handle

[leonimas]

I to all,
I need the win32 native handle of a QT Widget, particullary of the
QLabel widget; I've writed the following code:
@
QLabel* qLab = diag.findChild<QLabel*>("label"); // diag is the parent window of QLabel (QTDialog)
QWindow* w = qLab->windowHandle();
HWND h = static_cast<HWND>(inter->nativeResourceForWindow(QByteArrayLiteral("handle"), w);
@
the problem is that w pointer return a ZERO value and, conseguently, h is set to 0 :(

Best Regards
Leonard

[Edit: Please be sure to wrap code in @ tags -- mlong]

[SGaist]

Hi and welcome to devnet,

Isn't "winId":http://qt-project.org/doc/qt-5/qwindow.html#winId what you are looking for ?

[leonimas]

Hi, thanks to reply !
I want use the following acad/Objectarx function:

acdbDisplayPreviewFromDwg(ACHAR*, void*, Adesk::UInt32*)

to display a dwg thumbnail on a dialog; with MFC it works if I set the
second parameter to the HWND of a 'Picture Control' or 'Text Control'.
But I love QT :) and I want use QWinWidget and QTDialog ...

Your suggest doesn't works:

b = acdbDisplayPreviewFromDwg(result->resval.rstring, (HWND)qLab->winId(), &bCol);

:(

Best Regards
Leonard

[quote author="SGaist" date="1395676216"]Hi and welcome to devnet,

Isn't "winId":http://qt-project.org/doc/qt-5/qwindow.html#winId what you are looking for ? [/quote]

[SGaist]

Did you check that winId returns a valid value ?

[leonimas]

[quote author="SGaist" date="1395697547"]Did you check that winId returns a valid value ?[/quote]

Yes I've checked, winId returns a not null value: 0x000605c0

Best Regards
Leonard

[SGaist]

Another thing that you can try is setting Qt::WA_NativeWindow on your widget before calling winId

[leonimas]

Hi :(,
does'nt works ... the code now is:

QLabel* qLab = diag.findChild<QLabel*>("label");
qLab->setAttribute(Qt::WA_NativeWindow);
HWND h = (HWND)qLab->winId();
Adesk::UInt32 bCol = RGB(255,0,255);
b = acdbDisplayPreviewFromDwg(result->resval.rstring, h, &bCol);

With MFC the working code is:

acdbDisplayPreviewFromDwg(wstrFName, m_pStaticWnd->m_hWnd, &bCol)

where 'm_pStaticWnd->m_hWnd' returns an HWND value, and m_pStaticWnd is a 'CWnd*' pointer to the ‘Text Control’ widget ...

Why the QLabel widget doesn't show the bitmap ? Can be a painting
refresh problem ?

Best regards
Leonard

[quote author="SGaist" date="1395788591"]Another thing that you can try is setting Qt::WA_NativeWindow on your widget before calling winId[/quote]

[SGaist]

That I can't say but it might be.

By the way, why do you need to call acdbDisplayPreviewFromDwg ?

[SGaist]

I just saw "this":http://qt-project.org/doc/qt-5/qwidget.html#effectiveWinId that might also be of some help

[leonimas]

I developing an autocad plugin (OBjectArx dll),
and I use the acdbDisplayPreviewFromDwg() function to display
a preview of a dwg file (little thumbnail)

There is a QT function to read dwg file ?

Thanks in advance

[quote author="SGaist" date="1395869296"]I just saw "this":http://qt-project.org/doc/qt-5/qwidget.html#effectiveWinId that might also be of some help[/quote]

[SGaist]

Not to read DWG file. However, if there's a DWG library than is usable somewhere there's always the option of writing a QImageIOPlugin using it.