[Therion] Rope and anchors symbols

[Evaristo Quiroga]

Hi Vladimir,

Finally  I have choose the easy way (see the attached figure). Yours 
comments and other forum members convinced me. And it's more easy  also 
to coordinate with new Topodroid symbols.

Now I have two new user anchor symbols: u:anchor_artificial and 
u:anchor_natural which I combine with rope section with or without 
rebelays and anchors.

I put the mpost code if others users want use it.
I have choose a brown colour to rigging (rope and anchors). As you can 
not choose the color of the user symbols, with "symbol-colour",  I had 
to define it in the mpost.

Thanks,

Evaristo.

-----------------------------------------------------------------------
/def p_u_anchor_artificial(expr pos,theta,sc,al) =//
//  T:=identity shifted pos;//
//  thdraw origin withpen pencircle scaled 0.25u withcolor (0.58, 0.44, 
0.25);//
//enddef;//
// initsymbol ("p_u_anchor_artificial");//
//
//def p_u_anchor_natural(expr pos,theta,sc,al) =//
//    U:=(.2u,.2u);//
//    T:=identity aligned al rotated theta scaled sc shifted pos;//
//    thfill (-.2u,-.2u)--(0,.2u)--(.2u,-.2u)--cycle withcolor (0.58, 
0.44, 0.25); //
//enddef;//
// initsymbol ("p_u_anchor_natural");

//  symbol-colour line rope [58 44 25]//
/-------------------------------------------------------------------------------

El 02/02/2018 a las 16:54, Владимир Георгиев via Therion escribió:
> Hi Evaristo
>
> Indeed the line rope needs some additions in an elegant way :). 
> Occasionally I have also wanted to make a Y-anchor without the dot in 
> the middle. But I hadn't had the time to add this feature. It can be 
> done by adding extra line point options. Similar to "adjust 
> horizontal", "l-size", etc for "line:wall".
> This will require modifications to both the Metapost code to draw the 
> symbol, and to the therion c++ code that parses the options.
> It would be possible to draw different types of anchors depending on 
> the line point option, but I am not sure if it will be easy to reflect 
> the used anchors in the legend.
>
> Actually it would be best if there are both ways of setting an anchor: 
> with a line point option, or with a separate point "anchor" with 
> different options. The "anchor" point already exists, but is only one 
> type.
>
> When I draw a rope I always use it with "rebelays off" now and draw 
> the rebelays with a Bezier line. This allows me better control, 
> because the automatic rebelay curves don't always fit well in the pit 
> shape.
>
> Evaristo, if you want to work on the code, I can try to help. The 
> above are all nice ideas, like many others, but I personally don't 
> have the time to experiment with implementing them.
>
> Vladimir
>
> On Thu, Feb 1, 2018 at 1:57 PM, Evaristo Quiroga via Therion 
> <therion at speleo.sk <mailto:therion at speleo.sk>> wrote:
>
>     Hi,
>
>     I greatly appreciate the improvement made by Vladimir at the rope
>     line symbol.
>
>     https://www.mail-archive.com/therion@speleo.sk/msg05992.html
>     <https://www.mail-archive.com/therion@speleo.sk/msg05992.html>
>
>     With this symbol you can control if the rope section has anchors
>     and rebelays, as line options. This options are global to the
>     line:  have or not rebelays or anchors.
>
>     Now a I need to go more ahead, I want control the anchor type
>     (natural: tree, block, etc or artificial: spit, multimonti,
>     parabolt, etc) in every point and the rebelay in previous section.
>     I want a round point for artificial anchor (like the Vladimir
>     symbol) and a triangle point for natural anchor.
>
>     When we rig with Y knots and deviators you need to control the
>     line section without rebelays and anchors, so that the rope is
>     straight and the knots do not appear as anchors. (see attached
>     figure).
>
>     Now I have to way to implement this in Therion: the easy and the
>     elegant.
>
>     Easy. Create two new point symbols for natural and artificial
>     anchors. And use the rope line symbol with rebelay and anchor OFF
>     in the rope section with Y and deviators, and  ON in the other
>     sections.
>
>     Elegant. Create a new rope line symbol, where I can control in
>     every point the anchor type (Natural, Artificial or None, for
>     knot) and the rebelay rope effect in the previous rope section. I
>     think we can do this by defining options to the line point. I know
>     other have implemented similar option, like "adjust horizontal".
>     To do this a need code examples with similar option implementation
>     to inspire me.
>
>     Thanks,
>
>     Evaristo.
>
>
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>
>
>
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