Display of widgets for 'no_write' PVs

[rjwills28]

We've recently been converting some OPI screens to BOB format and noticed that the appearance of a no_write widget looks slightly odd when there is a colored background behind it. For comparison I am showing what it looked like in CSS vs Phoebus.

Left: CSS - text is greyed out.
Right: Phoebus - opacity of the ChoiceButton is set to 40%

As I said, the Phoebus display looks a little odd and makes it look like there is a layering issue. It doesn't look obvious in this case that this is no_write widget.

I was just wondering if there is a better of way of displaying a no_write widget - perhaps changing the font color instead although I am aware that the opacity change is just following what JavaFX does when a widget is disabled.

In addition, I noticed that only some widgets display a red 'x' when you hover over them if the PV is no_write. For example, the ChoiceButton, TextEntry and spinner do, but other Control widgets like the Boolean Button, CheckBox or RadioButton do not. Is there a specific reason for this or should the hover over 'x' also be added here?

[rjwills28]

I have had a look into an alternative to changing the widgets opacity when it should look 'not_enabled' but decided that there isn't really a better option that applies well to all control widgets. Therefore I think changing the opacity as we do now is the best option.

However, while investigating all of this I discovered some current problems with 'not_enabled' widgets:

• I have attached a video of a 'not_enabled' ChoiceButton where even though you cannot write to the PV, it still looks like you can interact with the widget. You can still hover over it and see the buttons change color, you can still click on a button and it looks like it has been clicked, and it appears you can click on the button displaying the current value and 'unselect' it.

no_write_widget_demo.mp4

• Some of the widgets have still been actually disabled (i.e. use the setDisable(true) method), which as noted in the code, removes the context menu. This is true for the BooleanButton and ThumbWheel widgets.

• Some widgets still try to write to a PV that is no_write, that is to say I see exceptions in the log about not being able to write to it, which is not ideal. This is true of the Spinner and Text Entry widgets.

• Some widgets apply the no_write red cross cursor when they are not enabled and other don't.

• An ActionButton with only a single action to write to a PV that is no-write never gets shown as 'not_enabled' when it could be in this case.

I have created a branch where I have addressed all of the above issues and will shortly open a PR for review of these changes.