Re: [Texmacs-dev] Drawing mode feature request: Annotation of .eps graphics.

[Henri Lesourd]

Karl Hegbloom wrote:

> On Tue, 2005-11-08 at 22:09 +0100, Henri Lesourd wrote:
>  
>
> > In practice, what I do is that I have a list, and then I
> > implement the features one after the other (or sometimes
> > I don't add such or such a feature, because i.e. I discover
> > that I would need some other thing implemented first).
> >    
>
> Another item for a sublist...  I'd like to show dimensions in some
> constructions.  There's two ways to show them.  One is the dimension
> lines as used in blueprints, where you draw line segments in line with
> the end points of the item you are measuring, and then draw a line with
> arrows on the ends that has a break in the center where the dimension is
> written.
That is an interesting idea, I will have to think about how
to do it best.

>  Another nice way to show it is to use a large {, as in the
> \choice macro of TeXmacs, or like a large opened calipers.
>  
I see.

> For the 3-d constructions, perhaps a nice way to do a projection drawing
> would be nice.  Have you ever learned to do one point or two point
> projections?
I did technical drawing (long time ago).

>  It's where you tape down your sheet of paper, then pick
> one or two points off to the upper right of your page, the distance they
> are from your paper determines your viewing angle.  You then draw the
> "going away from you" parts so that their lines always converge towards
> those chosen points. The things you draw that you can see the left side
> of have their lines converging toward the right dot, and the ones you
> can see the right side of converge toward the left dot.  It can also be
> done with a single point.  Think of a railroad track that extends from
> where you are standing off across a very flat plain to the horizon.  It
> appears to come to a point at the horizon.  If you are standing off to
> one side of it, it converges also, but farther toward the right,
> depending on where you are 'standing'...  If the two points are far
> enough away, they converge into one.  So when your clipping box, the
> page, shows only part of that track, you use two points.  If it shows
> the horizon, you use one point at the horizon.
>
> It probably works well enough for the simple kind of geometric diagram
> required for schematic illustrations of physics problems, I think.
>  
What would be easy to do right now would be something similar
to VRML markup, that you would input in source mode, and
that would become activated at some point. On the other
hand, interactive editing would raise a lot of (interesting,
indeed) other problems.