way to show image sequence without using timer or thread
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wrote on 8 Jan 2021, 15:40 last edited by
Hello,
Try displaying a sequence of image with signal slot but without using timer and thread. Is there a good way to do.
Images are saved somewhere in a partition and are orderly named. I use OpenCV to read each and convert the one read into QImage and show it with QLabel. It is OK for a single image. What if I want to do so for all of them. I didn't find label item can emit signal while its content was changed. -
@Make-it-GREAT-again said in way to show image sequence without using timer or thread:
but without using timer
use a QTimer, everything else will not work.
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@Make-it-GREAT-again said in way to show image sequence without using timer or thread:
but without using timer
use a QTimer, everything else will not work.
wrote on 8 Jan 2021, 15:51 last edited byHi, @Christian-Ehrlicher . Thanks for reply at first. I cannot use QTimer for timer is an option of my project to limit running time of the entire application (or program).
I have just found a virtual function named PaintEvent. Is that possible to re-implement this to do my work like this
https://stackoverflow.com/questions/1242005/what-is-the-most-efficient-way-to-display-decoded-video-frames-in-qt?rq=1 -
@Make-it-GREAT-again said in way to show image sequence without using timer or thread:
I cannot use QTimer for timer is an option of my project to limit running time of the entire application
I don't understand what you mean.
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@Make-it-GREAT-again said in way to show image sequence without using timer or thread:
I cannot use QTimer for timer is an option of my project to limit running time of the entire application
I don't understand what you mean.
wrote on 8 Jan 2021, 16:02 last edited by@Christian-Ehrlicher
I use a checkbox to choose using a timer for controlling the running time of my program. It means that the program should be automatically stopped in a time mannually speicified once the timer is selected via the checkbox. QTimer is simply for couting time down. -
@Christian-Ehrlicher
I use a checkbox to choose using a timer for controlling the running time of my program. It means that the program should be automatically stopped in a time mannually speicified once the timer is selected via the checkbox. QTimer is simply for couting time down.wrote on 8 Jan 2021, 16:27 last edited by@Make-it-GREAT-again said in way to show image sequence without using timer or thread:
It means that the program should be automatically stopped in a time mannually speicified once the timer is selected via the checkbox. QTimer is simply for couting time down.
Again, don't know what you mean here. Don't know what you think the restriction is, if you want to "manually specify a time" for a
QTimeryou can load/reload it with that, stop it, reset, do whatever to it. -
@Make-it-GREAT-again said in way to show image sequence without using timer or thread:
It means that the program should be automatically stopped in a time mannually speicified once the timer is selected via the checkbox. QTimer is simply for couting time down.
Again, don't know what you mean here. Don't know what you think the restriction is, if you want to "manually specify a time" for a
QTimeryou can load/reload it with that, stop it, reset, do whatever to it.wrote on 10 Jan 2021, 03:40 last edited byHi, @JonB. Thanks for your reply. Does that mean I can use several QTimer(s) con-currently for different task in my program.
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Hi, @JonB. Thanks for your reply. Does that mean I can use several QTimer(s) con-currently for different task in my program.
wrote on 10 Jan 2021, 04:01 last edited byWhat made you think, that there can be only one
QTimerin your whole program? -
Hi, @JonB. Thanks for your reply. Does that mean I can use several QTimer(s) con-currently for different task in my program.
wrote on 10 Jan 2021, 07:50 last edited by@Make-it-GREAT-again
You may use as manyQTimers as you wish. (Probably within reason: I don't know what happens if you create 1,000,000 of them!) -
What made you think, that there can be only one
QTimerin your whole program?wrote on 11 Jan 2021, 02:19 last edited by@Pl45m4 . LOL. Do not know Qt very much. I have been thinking multi-Qtimer should be affected by each other.
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@Make-it-GREAT-again
You may use as manyQTimers as you wish. (Probably within reason: I don't know what happens if you create 1,000,000 of them!)wrote on 11 Jan 2021, 02:29 last edited by@JonB . Thanks for this answer.
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