Re: epicsQt/caWtDM and sliders

["Jemian, Pete R." <jemian@anl.gov>]

John:

Your use of the keyboard to adjust a slider is a common use case.  Selection of the slider widget can also be obtained by using the tab key in some user interfaces.

Pete

Sent from my Samsung Galaxy Note® II

-------- Original message --------
From: John Dobbins <john.dobbins@cornell.edu>
Date: 2015/04/24 8:37 AM (GMT-06:00)
To: Andrew Rhyder <Andrew.Rhyder@synchrotron.org.au>,tech-talk@aps.anl.gov
Subject: Re: epicsQt/caWtDM and sliders

Andrew,

I was unaware of the QEAnalogSlider - I installed epicsQt 3.0.2 which doesn't include this. 

Our use of the slider is a little idiosyncratic in that we mostly use it via the keyboard which provides controlled steps (as opposed to actually dragging the slider). The ability to set the size of the step is thus important. One could reasonable ask why use a slider in this case. The slider is also acting as a visual indicator showing where you are in the control range. 

I am certainly open to considering alternative approaches to these sorts of details. My principle motivation for checking out Qt based display managers is thinking about how to do a better job of presenting screen based controls. I am trying to figure out how Qt based displays might figure into our future controls. So my thanks to you and to everyone who has contributed to epicsQt and caQtDM. Obviously a lot of work has gone into these projects.

Regards,

John Dobbins

---

From: Andrew Rhyder <Andrew.Rhyder@synchrotron.org.au>
Sent: Friday, April 24, 2015 5:59 AM
To: John Dobbins; tech-talk@aps.anl.gov
Subject: RE: epicsQt/caWtDM and sliders

 

Hi John

 

Firstly, you may not be aware there are two slider controls in the EPCISQ t framework – QESlider that is intended to function just like a standard Qt slider but be connected to a PV, and QEAnalogSlider which is intended to allow slider control but give much richer feedback with a separate readback scale, alarm limits, set points, etc.

 

Regarding incremental adjustment, both these allow incremental movement using the mouse. Did that not work for you, or is the problem setting the appropriate increments, etc?

 

Regarding the slider not stopping if the mouse pointer moves off the slider knob, as Emmanuel mentioned the intention is not to emulate MEDM/EDM, but to provide modern style controls, and generally people are now used to the mouse holding onto the control no matter how far the pointer wanders from it (sliders, scroll bars, window edges, etc). Apart from providing familiar interaction I feel that this also allows the user to focus on more important things than exactly where the pointer is in relation to the control. The user knows they have control until they release the button. That said, while the aim is not to emulate medm/edm, the aim IS to provide controls with the required functionality, and I’m happy to discuss any potential changes that make the controls more functional. While I’d argue against this behaviour in a modern GUI, one justification for it may be to ensure slider widgets from both the EPICSQt and caQtDm widget sets can be mixed and matched more comfortably.

 

Regards

 

Andrew

 

 

From: tech-talk-bounces@aps.anl.gov [mailto:tech-talk-bounces@aps.anl.gov] On Behalf Of John Dobbins
Sent: Wednesday, 22 April 2015 1:47 AM
To: tech-talk@aps.anl.gov
Subject: epicsQt/caWtDM and sliders

 

All,

 

I am exploring the Qt display managers options. One of the first things I was interested in checking out were the sliders. (We have several development machines where manual adjustment is a daily part of operations) I find:

 

1) The epicQt slide has no increment adjustment (? ) Is there anything that would preclude adding this. I don't know where the default increment is set (methods inherited from Abstract Slider?)

 

2) The caQtDm slider stops following if the mouse pointer moves off the slider knob (?)  If one attempts to move too fast the slider stops following. (Different behavior than EDM/MEDM/CSS.)

 

Regards,

 

John Dobbins