[Cs-studio-core] Layouts Re: CSS BOY ideas

[Kasemir, K. <kas...@or...>]

>>* Our GDA team use the window builder ... using SWT
>>layouts.

One thing that we briefly discussed at DLS are layouts.

Programmatically created Eclipse views tend to use layouts. HTML pages use
layouts. Layouts are great for panels that should re-size. Simply zooming
in/out isn't quite as good as automatically wrapping around into the next
line etc., i.e. having a proper layout.

BOY does actually provide a layout: A basic grid layout, N columns.
Fundamentally, there could be more layouts.

I see layouts in a control system display tool have a strong use case for
automatically created displays.

On the other hand, fixed pixel positions also have a strong use case. When
people casually create displays, it is MUCH easier for them to simply
place the widgets in a fixed location, what-you-see-is-all-you-get. With
layouts, you need to worry about layout constraints like
"to-the-right-of-Š with a gap of Š resizing as follows". You need to
actually play with your display, re-size it to test if it works as you
intended. Takes much longer to get it right.
When displays are shown in the control room, it can also be important that
critical components don't "move".
Operators get used to seeing the XYZ in that corner of the display. They
can spot it across the room. Muscle memory takes over: If this indicator
turns yellow, push the bottom that's at 19'o'clock from it. If the display
layout changes depending on the panel size, the XYZ can suddenly be in an
unexpected location.

So there are two basic ideas, somewhat incompatible:

* It has to be like (M)EDM. On login, all those displays must show up as
separate windows in exactly the right location. Operators are used to
this. If things move on the screen, people will die because operators miss
key indicators.

* It should be like a web browser. Each user can open/close displays as
they want. We need layouts so widgets re-flow as panel sizes change.

Thanks,
Kay