Draw curved wires for lighting layouts with the new Arc tool

[ispyisail]

For lighting and house-wiring layouts, where the wire from a switch to a lamp is drawn as a curve (issue #408), there is now an Arc button on the drawing toolbar, in PR #1202.

How it works

• Click one end of the arc, then click the other end at the height the arc should reach. Shift gives a true half circle.
• Select the arc and drag the handle in the middle of the curve to make it deeper or flatter. The two ends stay put; drag past them and the arc turns over.
• For a dashed wire, set the line style in the arc's properties, as for any shape.

Until now an arc meant drawing an ellipse and cutting it down with its end handles (#809). That still works.

Questions

1. Is a half arc the right starting shape, or do you mostly draw shallower curves?
2. Should the middle handle also work on arcs that are not half arcs?

[scorpio810]

I would like this to work in the same way as the ‘arc’ primitive does in the ‘element’ editor.

Edit : ok for me.

[arummler]

1.) when I addressed that request I implemented both bezier curves as well as half arcs using handles on the ellipse. For me the bezier curve is more natural and before committing I tried actually such shapes as shown in the issue's example.

[arummler]

I actually tried it and the xml seems to be same. Closing an arc turns it (in the undo list) into an ellipse and vice versa. So just GUI naming changes.

[arummler]

2. I think there is a bit of conflict between the capabilties of ellipses and your proposal. If it stays saving the same - which makes sense. Then the middle point would need to be added to my ellipse tool (third level).

[scorpio810]

I didn’t want to mention it until today, as an industrial circuit diagram requires conductors with sharp corners rather than rounded ones, but given the direction QET has taken with regard to PID diagrams and in other areas, would it be possible to have a function that allows corners to be rounded depending on the domain, the PID, or when representing pneumatic or hydraulic process pipework? What do you think? Would this be sacrilege or a useful idea?

[arummler]

Rounded connector corners only or arcs/bezier curves or even "real simplified pipes" with red/blue background depending on which side of the heat exchanger they sit? I think all doable. To use the right style could be the responsibility of the user, could be bound to a set specific "domain" like FreeCAD has different tool boxes (although someone would come around and want to do a mixed schematic) or the graphical object has not the class "conductor" but something specific so it can be only connected to element connectors of the corresponding type.