[Therion] Need metapost wizard: new text label

[Benedikt Hallinger]

Hello Tarquin,

i tweaked and fiddled around and now have a version that correctly 
scales, rotates and aligns.
Your wiki page hint helped, but i already found it in the past... The 
example code there does not work here for some reason (compile error).

But anyhow, to answer your question regarding the "0.001" rotation 
parameter in the label calling:
if i use "0.0" or "0" or also "0.0001", it puts my label text in the 
center of the generated map with rotation of the scrap-rotation applied. 
I don't know why and found by try-and-error that this value works.


Here is the updated code:, enhanced with a nicer legend output:
-----------------------------------
     # Symbol to denote assigned survey.
     #   Option "-attr text <string>" shows given text; otherwise current 
survey is shown.
     #   Option "-attr bordersmooth <num>" overrides edge smoothness (0 
for sharp edges)
     #   Option "-attr bordermargin <num>" overrides margin text/border
     #   Option "-attr basescale <num>" overrides basic text sizing 
factor (default text size)
     def p_u_mappe(expr pos, theta, sc, al) =
       T:=identity aligned al rotated theta scaled sc shifted pos;
       begingroup;
         % Basic config
         bordersmooth:=4;         % smoothness of box corners  (0=90° 
edges)
         bordermargin:=5.0bp;     % padding border->text
         basescale:=1.0;          % basic scaling of default-sized text
         if known(ATTR_bordersmooth): 
bordersmooth:=scantokens(ATTR_bordersmooth); fi;
         if known(ATTR_bordermargin): 
bordermargin:=scantokens(ATTR_bordermargin); fi;
         if known(ATTR_basescale):    
basescale:=scantokens(ATTR_basescale);       fi;

         % GET LABEL TEXT:
         string txt;
         if known(ATTR_text):
             txt := ATTR_text;
         else:
                 txt := ATTR__survey;
         fi;

         % DRAW LABEL:
         lab:=thelabel(txt, (0.0,0.0));
         pickup PenA;                       % border thickness
         interim bboxmargin:=bordermargin;  % padding border->text
         q:=((bbox lab) smoothed bordersmooth) aligned al scaled (sc * 
basescale) rotated theta shifted pos;
         draw q;
         lab:=lab aligned al;
         lab:=lab scaled (sc * basescale);
         lab:=lab rotated theta;
         lab:=lab shifted pos;
         process_label(pos, 0.001);   % for some weird reason "0.0" does 
not work here and puts the label to map-center at scrap-rotation.

       endgroup;
     enddef;
     def p_u_mappe_legend =
         begingroup;
         save ATTR_text;
         string ATTR_text;
         ATTR_text:="028";
         p_u_mappe((.5,.5) inscale, 0, 1.0, (0,0));
         endgroup;
     enddef;

-----------------------------------





Am 2020-03-01 22:23, schrieb Tarquin Wilton-Jones via Therion:
>>> thelabel(txt, pos);
>> 
>> I notice in the main Therion Metapost, it uses
>> lab:=thelabel@#(txt, pos);
>> to make sure that it can respect alignment, which your code cannot.
>> Don't suppose you worked out how to pass the correct alignment value 
>> to
>> it, did you?
> 
> I have worked it out, see my thread "Metapost variable macro suffixes".
> I will add it to my existing function which takes the point alignment
> parameter and turns it into the right suffix in the "thelabel" call or
> p_label call, whichever one ends up getting used.
> 
> Your code also didn't apply rotation to the ornamentation. You need
> something like this:
> draw ((bbox lab) smoothed 4) rotatedaround (pos,rotation);
> 
> Note that this applies the rotation around the point position, so
> alignment and rotation at the same time is weird. This is the same with
> regular labels though - Therion bug that Bruce is fond of :) - so at
> least this is consistent with Therion itself.
> 
> Your code hardcoded rotation to a very specific 0.001 degrees, which 
> was
> weird. I assume you had intended to use 0 or a variable (my code uses
> the rotation parameter of the point symbol).
> 
>>> interim bboxmargin:=6.5bp;    % padding border->text
>> 
>> Just checking, since I don't know the "interim" keyword very well ...
>> Doesn't it need to be inside a "begingroup/endgroup" pair, in order to
>> know when to stop applying the "interim" value to the internal
>> bboxmargin variable?
>> 
>> As far as I can tell, you are modifying the global value of it, so all
>> subsequent uses of that internal variable will end up with your 
>> padding.
>> At least until the next "endgroup" happens somewhere above your code 
>> in
>> the stack.
> 
> This was correct. You needed to use begingroup+endgroup or use a vardef
> instead of a def (with vardef, it automatically applies a
> begingroup+endgroup). Therion's Metapost uses both of these approaches
> to avoid the problem.
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