[Qt-interest] Can I draw Qt objects directly to Win32 DC (Device Context)?

[Anders Bakken]

On Fri, May 28, 2010 at 06:36:15AM +0100, Long Cheng wrote:
> I can draw Qt objects to an QImage and then draw the image to HDC or
> CDC. This may hurt our application's performance. It would be great if
> I can draw Qt objects directly to Win32 HDC or MFC CDC. I expect that
> there is a class, say QWin32Image for clear, then I can use it in this
> way:
>
>       QWin32Image image(hdc, 100, 100, Format_ARGB32_Premultiplied);
>       QPainter painter(&image);
>       painter.drawText(....);
>
> Is it possible for my thought? Or is there a better way to do that?
>
> Thanks,
> Long
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> Qt-interest mailing list
> Qt-interest at trolltech.com
> http://lists.trolltech.com/mailman/listinfo/qt-interest

Presumably there's an API that lets you construct an image of some sort
from a ARGB buffer of pixels.

If so you could do something this.

NativeWindowsImage img;
QImage foo(...);
QPainter p(&foo);
p.draw.*;
NativeWindowsImage temp;
temp.initFrom(foo.bits(), foo.width(), foo.height());
DrawImageOnImage(img, temp);

--
Anders Bakken

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