TIP: Alignment and Selection behaviors

[jclements]

I've been working with Xara for a very long time, but I discovered a few things I never knew before. I can't believe I did not notice these behaviors before now. I don't believe I've seen them documented either.

Alignment:

The Alignment functions are based on the "edge" of a curve's visible outline, NOT on its centerline/"backbone".

Two curves with EQUAL thickness will align relative to their centerlines. However, curves with DIFFERENT thicknesses will align to the outer most EDGE of the thickest line selected. [Note, don't be fooled if you assign a line weight of 0 (zero), although this value will be displayed in the Standard Toolbar, the line will still be visible and printable.]

It makes no difference if you in Wireframe viewing mode or not or if you have Scale Line Width on or off.

[jclements]

Selection:

Assume Line-1 is 30-points thick, Line-2 is 4-points thick, and Line-3 is 1-point thick.

If in Wireframe viewing mode, you click-n-drag the selector tool in white space within 14-points of the line 1, you will move line 1. The selector tool "knows" the thickness of the line irregardless of the visibility of the line or the view mode.

In the example below, if Line-1 was 60-points thick so that it visibly overlaps Line-2 then, then while in Wireframe mode you could click-n-drag very close to Line-2 and still move line-1 even though it appears to be far away from Line-2.

If you use Wireframe mode as I do to select geometry in a drawing which is densely populated, BE CAREFUL because you could inadvertantly move things you didn't intend to move (particularly when you are zoomed in). Note, it also makes no difference if Scale Line Widths in on or off.

==============================================

I had a project today where I was joining a lot of curve segments and prepositioning them properly was important. I couldn't for the life of me understand why I kept moving the wrong curve. First I thought it was because of their stacking order, then I thought it might be due to a fill being assigned to them. To complicate things further, some of lines had transparency applied to them.

It would have also made life easier if I could have used the Alignment functions to position curves relative to their center lines rather than their thickness.

So, at the risk of being brow beaten for requesting new features (by you know who ):

1- I sure would like an option in the info Bar or in the Alignment Dialog to "ignore line weigth".

2- Likewise, an option to ignore line weight when in Wireframe mode ... after all isn't the purpose of Wireframe mode to make object selection easier?

[raynerj1]

John,

Does it change if you have scale line widths on/off?

[jclements]

John,

No it makes no difference if Scale Line Widths is on or off.

[gwpriester]

Interesting, John.

I'm sure if Charles were to answer this he'd say, "This is the normal behavior and this is just how one would expect it to be."

Maybe not.

Gary

[Xhris]

Hmm, I'd say it was perhaps an oversight; the Scale Line Widths button should (in theory) determine whether the line aligned by its edge (i.e. whether the line thickness was included) or buy its centre (i.e. whether the line thickness was not included). Snapping-based alignment functionality takes SLW into consideration.

EDIT: Actually no, I've changed my mind. I think this is correct behaviour; the alignment is about the selection bounds. It could cause alignment outside the chosen region if SLW had any effect.