How can I know the value of an angle ???

[ivan louette]

Hi,

the question is how can we know precisely the angle between a straight line (or a pair of points) which is part of an arbitrary positioned object and the horizontal ???
That may be very helpfull for those who would re-orient an object and snap it correctly side to side to another without modify it !!! Be sure there are a lot of other applications to that.
Thank you in advance,
ivan

[myles]

Hi Ivan,

A few steps to get the answer :

If you create a line (2 clicks with the pen tool),
then select the last point on the line with the Shape Editor tool, the information bar above gives you the angle the line makes to the horizontal.
(the box with an "A" beside it).

By snapping the line to the edges of both objects, you can then calculate the angle you need to rotate the object in order to align the two edges.

Once aligned, moving the objects so they touch is also aided by the magnet/snap tool if you grab the object near its edge when moving.

Regards, Myles

[ivan louette]

Thanks so much, Myles !!!

Did you see that an old user of Xara and this forum can miss si important things !!!!! I know about snapping but I never saw about angles !!!!!

(but I have no time before this evening)

Thank you again,
ivan

[Clements]

I have used Xara for quite a while and never noticed it could do this. I did not realize that any node of a line segment in multi-node line can be selected and its "absolute" angular measurement is displayed.

What is new in Xara X is the "Reverse Paths" icon (the curved arrow) directly to the left of the angle readout in the Info Bar. This will really come in handy when using arrowheads.

Below is a little diagram of how Xara assigns the angles to selected nodes. Negative values above the horizon and positive below.

[tonylondon]

I have a feeling that angles are not always given depending on the type of node. When given, the angle field is perfect for adjusting lines to horizontal or vertical. Tab round each node and set each angle to the nearest multiple of 90, being sure to leave in any negative signs if present.

Tony

[This message was edited by tonylondon on January 10, 2001 at 01:44 AM.]

[Clements]

Hi Tony, from the brief "testing" I did it, yes, appears only for nodes which define line segments.

I don't know of any other illustration app that can do this. When you change the angle value for a node in essence you are ROTATING it around the previous node because the linear distance ("radius" if you will) between it and the previous node remains the same. A very useful and unique editing feature.

[This message was edited by John S. Clements on January 10, 2001 at 08:12 AM.]

[pj3]

Myles...
"By snapping the line to the edges of both objects, you can then calculate the angle"

details please on snapping that line to another object

PJ

[myles]

Up on the Xara top toolbar, between the view quality slider and the gallery icons (assuming you're still using the default Xara toolbars), there is a "snap to objects" button with a magnet icon - one of those old stereotype cartoon magnets like a red horseshoe with white tips.

When that feature is turned on, many of the Xara manipulators will snap to other objects - so in this case:

Turn on the magnet, select the line, change to the Shape Editor tool, then drag each node of the line - as it gets close to the edge or vertex of another object a little magnet icon shows up near the cursor. Releasing the node at this point will automatically snap it to the edge or vertex of the other object.

Repeat for the node on the other end of the line.

More information in the Xara help index under "snapping".

Regards, Myles.

[pj3]

Myles... I was able to get the line to snap to the irregular poly... found out what the angle was and then selected the box and rotated it to the exact angle that the line was... now here is the question... I was not able to get the box to snap to the polygon. How do I snap the rotated box to the polygon?

Thanks again
PJ

[myles]

PJ, greetings again.

1. Use the selector tool.
2. Make sure object snapping is turned on.
3. Grab right on the edge of the object you want to move.
4. Drag it to the edge you want to snap to, and release when you see the magnet/snap icon appear near your cursor.

Note that you can tell if you are right on the edge (step 3) when selecting the first object because when object snapping is turned on the magnet icon in the bottom right corner of Xara window lights up red and rotates to the vertical when you are near enough to an edge or vertex, even when your cursor is just hovering rather than dragging.

Alternatively, if you don't like looking in the bottom corner, you can also change to the lowest quality (wireframe) view setting - that way you can only select an object by its edges, you can't just grab it anywhere and drag.

Regards, Myles.