Qt window does not update (Bug #812)

Added by Jason Hirata about 14 years ago. Updated over 12 years ago.

Status:Cancelled Start date:
Priority:Normal Due date:
Assignee:Ilya Lysenkov % Done:

0%
Category:highgui-gui
Target version:-
Affected version: Operating System:
Difficulty: HW Platform:
Pull request:

Description

when opening two windows using the opencv highgui, with opencv compiled with the WITH_QT flag and WITH_QT_OPENGL flag ON, the first one opened does not update with call so cv::imshow, but the second one will.

example
cv::VideoCapture vc( some_file );
while(vc.grab()) {
cv::Mat frame, result;
vc.retrieve(frame);

// do something with frame and get an image result, that is      compatible with imshow
  cv::Mat result = foo(frame);
// frame will not update
  cv::imshow("Frame", frame);
// result will update
  cv::imshow("Result", result);
}

this doesn't seem to occur if you compile with WITH_QT_OPENGL=OFF

Associated revisions

Revision f7641be4
Added by Andrey Kamaev almost 12 years ago

Merge pull request #812 from bitwangyaoyao:master_uhp

History

#1
Updated by Ilya Lysenkov over 13 years ago

  • Status deleted (Open)

#2
Updated by Ilya Lysenkov over 13 years ago

Thank you for the ticket.

I've compiled the OpenCV trunk WITH_QT flag and WITH_QT_OPENGL flag ON but I can't reproduce this problem by running OpenCV samples. Your example doesn't show me any images at all but this should be solved by adding something like cv::waitKey(30) to the end of the loop:

cv::VideoCapture vc( some_file );
while(vc.grab()) {
  cv::Mat frame, result;
  vc.retrieve(frame);
  // do something with frame and get an image result, that is compatible with imshow
  cv::Mat result = foo(frame);
  // frame will not update
  cv::imshow("Frame", frame);
  // result will update
  cv::imshow("Result", result);

  cv::waitKey(30);
}

This version works fine for me. So try to add cv::waitKey(30) to your code and let me know if the problem still persists and how to reproduce it.

  • Status set to Done
  • (deleted custom field) set to worksforme

#3
Updated by Andrey Kamaev over 12 years ago

  • Status changed from Done to Cancelled
  • Category changed from highgui-images to highgui-gui

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