Quote Originally Posted by bcastalia View Post
The advent of Qwt 6 which replaces Qwt 5 without providing full backwards compatibility has caused me some consternation about the merits of moving to the new version. The existing classes that I have implemented that use Qwt depend on the old data model based on the QwtData class. Because QwtData is not provided with Qwt 6 these classes would need to be revised, perhaps significantly.
Instead of QwtData you have QwtSeriesData<QPointF> - the API is more or less equivalent. Renaming a couple of methods is trivial and absolutely no reason for any consternation.

Much more substantial is that the render engine has been moved from ints to doubles. In the end this is a delayed Qt3 -> Qt4 port, but I can't support Qt3 forever.

Uwe

PS1: when moving to a new version I recommend to port to Qwt from SVN trunk ( or to wait until there is an official release - planned after Qt5 is available ).
PS2: and yes the scene graph of Qt5 means again changing APIs sooner or later significantly ( coming with Qwt 7.x )