Hi, @WLOrion said in Introduction in Qwt: I didn't know this behavior of the Qwt Classes. This is nothing Qwt specific, it's part of the C++ basics. As for tutorial, there's a nice online book that is in German but the author claims that online translator should give you a good enough result in your own language.

@BJUN Hi and welcome to devnet forum qwt is an extension of Qt as third party library. It maintains its own mailing list. Please check out there. This might be a faster way to get feedback on the issue.

ok, stupid me! I forgot to include Qwt in the *.pro file: ... CONFIG += qwt INCLUDEPATH +="/usr/include/qwt" LIBS += -L/usr/lib -lqwt

@mrjj Thank you sir for helping me and direction. I am able to solve this issue by setting the clipping area properly on graph. Use QWidget::update() instead of QWidget::repaint().

@Yash001 Hi, i wish i knew the answer but im fairly sure canvas()->width(); just returns the actual widget size and not the zoomed area as such. Had a look in the help but didnt find the answer on how to get the extent on a zoomed canvas.

@DSpider great! please don't forget to mark your post as solved. Thanks.

@SGaist got it.

Perhaps some dll files are missing.

User something like LIBS += -F /path/to/where/qwt_framework_is -framework qwt

@SGaist It worked. Thank you so much.

@vassia Thanks for reply and good to know that I could help. Since the issue has been solved for you, please mark also your post as solved. This helps others to see that there might be a solution. In order to mark as solved, go to the compobox named "Topic Tools" after your first post or after the last post in the thread and select "Mark as Solved".

Edit: Fixed link to image -- @Wieland

Hi to all, I succeded in extracting from the data contours as path. Anyone knows how to plot them using qt charts? http://doc.qt.io/qt-5/qtcharts-areachart-example.html I need to create area charts with empty areas inside.

hmm, not sure about that one... I think I did, but I know I've been putting this laptop into suspend often because it's not the fastest pc I have :-) Anyway, I found this on https://help.ubuntu.com/community/EnvironmentVariables Shell config files such as ~/.bashrc, ~/.bash_profile, and ~/.bash_login are often suggested for setting environment variables. While this may work on Bash shells for programs started from the shell, variables set in those files are not available by default to programs started from the graphical environment in a desktop session So I didn't test any further.

I can come back only to the initial recommendation to check also with the Qwt mailing list. Possibly you hook to a problem of versions. Qwt had to be updated for Qt 5 for instance.

@HappyCoder Out of personal experience I recommend also to ask your question on QWT mailing list AFAIK QWT is still independent and only based on Qt libs. Uwe has been monitoring this forum in the past, but answers are potentially faster through QWT mailing list.

What if you detach the curve and delete it by hand ?