Here're the basics of how I'd like a "fixed scale" to behave:
1. When encountering a symbol for the first time, autoscale and autoposition it, just to get things started. This is what QT does now.
2. Then leave it up to the user to adjust the vertical scale factor and the vertical positioning, independently, and remember these two parameters for that symbol forever (or some reasonable amount of time).
That's all there is to it, at its simplest.
Possible fiddles (since you guys are so good at features):
1. Turn on/off some kind of autopositioning, like perhaps keeping the last bar near the middle of the chart.
2. Turn on/off a synchonization the VS across all concurrent views of the same symbol
3. Possibly expire the remembered VS and VP settings of a symbol that hasn't been viewed for some settable amount of time.
The key is to leave the vertical scale, and the vertical position, under the control of the user.
QCharts works this way, but its ability to remember a symbol's settings seems broken. At least I can't get it to work after all kinds of fiddling. The help available for QCharts is total and absolute CRAP (i.e., non-existent), yet I put up with QCharts because I can adjust the VS and VP.
QT, as it is now, is like having a stereo that measures the incoming sound level of every passage of every tune it is playing, and plays it at maximum volume (no matter how soft or loud it originally was).
Thanks for listening.
BTW, add my voice to those who sing the praises of QT -- there is a LOT of good stuff in your program and I use it 1) as a backup to QCharts and 2) to view tick charts, and 3) to keep live data going for a large number of symbols.