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namedwindow not defined

asked 2019-01-13 12:00:59 -0500

IanB gravatar image

Hi, I'm just starting, I made a UWP app with an opencv helper project according to this:

link text

I got the blur example working fine.

I thought I would try HoughCircles based on this: link text and I think it is working but I am struggling with display the results. At the end I have

namedWindow("circles", 1);
imshow("circles", img);

.. but it won't compile, namedWindow and imshow are undefined.if I type "cv::" I get code completion showing loads and loads of things but not namedWindow or imshow.

I'd appreciated some assistance with this, Thanks

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I made a UWP app

afaik, none of opencv's highgui code is supported / used there

berak gravatar imageberak ( 2019-01-13 12:05:05 -0500 )edit

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answered 2019-01-13 12:27:08 -0500

berak gravatar image

if you want my 2 ct: no, don't try with UWP, ever. all of opencv's codebase is plain, unmanaged c++

if you're just starting, don't go on such an adventure, instead please try with https://github.com/opencv/opencv/tree...

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Like @berak stated, UWP works not nicely together with C++. It is possible, but it gives you tons of headaches on the way there.

StevenPuttemans gravatar imageStevenPuttemans ( 2019-01-16 04:46:09 -0500 )edit
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^^ hmm, have a look at the links below, it seems the ms folks have changed a relevant detail.

while the prev. attempts (like the UWP samples in opencv) tried to do it ALL in managed c++ (gulp !), the newer attempt seems to be: let opencv work, as it is intended (all unmanaged), then run away with a pixel pointer, and do any gui from c# !

seems much less frragile, this way to me !

berak gravatar imageberak ( 2019-01-16 05:48:41 -0500 )edit
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answered 2019-01-16 05:28:33 -0500

IanB gravatar image

I found a sample which does everything, it is very impressive, doing blur, houghlines, etc in uwp from webcam smoothly at full framerate 30fps. https://docs.microsoft.com/en-us/wind...

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yea, you probably meant this one, but again:

for showing images, you will have to use, whatever UWP comes with, not highgui

berak gravatar imageberak ( 2019-01-16 05:40:39 -0500 )edit
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yes I think it's that one - but the drawing commands that uses are into opencv (line, drawContours, etc) which just work. So maybe the sample I first started with was an old one and namedWindow and imshow just aren't needed anymore and don't exist. Anyway, I have an excellent platform to start from. Thanks everyone, might be some more silly questions from me soon

IanB gravatar imageIanB ( 2019-01-16 06:12:58 -0500 )edit

you never told us, which opencv you installed, and how.

did you use the ms branch ? (it probably does not come with highgui)

berak gravatar imageberak ( 2019-01-16 06:17:26 -0500 )edit

literally download from the link above, it has loads of sample projects, open the solution CameraOpenCV, and it just works. Unfortunately I have been distracted by some other things so have not got further than that yet

IanB gravatar imageIanB ( 2019-01-16 08:47:32 -0500 )edit
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Asked: 2019-01-13 12:00:59 -0500

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Last updated: Jan 16