Live video and crosshair overlay

Bengt 0

Hi!

I am writing a live video desktop application, very simple function, a live window with digital zoom..
I am putting the video handle from the USB camera SDK into a GraphicsView ui element. This is working fine.

But now I need to put a cross-hair marker in the live video frame to identify the exact center.
What is the best/simplest way to do this?

BN

SGaist

Hi,

What are you using to show the video feed on the QGraphicsView ?

Bengt 0

HWND display;
HIDS m_hCam;

The graphicsView is defined in the ui file.

display = (HWND)ui->graphicsView->winId();
is_InitCamera(&m_hCam, (void*)&display); // supplied from the camera API

Is this what you are asking for?

Bengt 0

I try to follow https://stackoverflow.com/questions/54802254/qt-making-a-panel-that-overlaps-a-qgraphicsview
but none of the added items are visible in the video. If I start the application with the camera unplugged, the added items show up as expected. So locking a graphicsview to an video feed seems to override everything else.
Is there any way to control the foreground/background relation for the widgets?

SGaist

You are overwriting the graphics view painting. I would rather move that part to a dedicated widget. However mixing native windows painting and Qt painting is not something I have done so I don't know at which level of feasibility it can be found.