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metapost [2019/11/30 23:14] – [Line Symbols] tarquinwjmetapost [2020/03/01 22:58] – [Adding custom styled labels at any point/linepoint] tarquinwj
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 This can be used to set a minimum pen thickness, so that all other pens take their sizes relative to that pen thickness. This can be useful for publications that mandate a specific pen width, which can be harder to control with scaling. (This can be done by setting the "u" value, but that causes all symbols to be scaled too.) This can be used to set a minimum pen thickness, so that all other pens take their sizes relative to that pen thickness. This can be useful for publications that mandate a specific pen width, which can be harder to control with scaling. (This can be done by setting the "u" value, but that causes all symbols to be scaled too.)
 +
 +[[user:tarquinwj|Tarquin 2019]]
  
 <code> <code>
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 This function simplifies it all. Add it once, and then any of your custom points can call it to add a label. This function simplifies it all. Add it once, and then any of your custom points can call it to add a label.
  
-[[user:tarquinwj|Tarquin 2019]]+[[user:tarquinwj|Tarquin 2019-2020]]
  
 <code> <code>
 code metapost code metapost
   vardef create_styled_label (expr plaintext,P,R,S,A,defaultstyle)=   vardef create_styled_label (expr plaintext,P,R,S,A,defaultstyle)=
-    save textsize, style;+    save textsize, style, thetext;
     string textsize;     string textsize;
     if S = 0.5:     if S = 0.5:
Line 269: Line 271:
 For an example of code making use of this function, see [[#Rope lengths]] below. For an example of code making use of this function, see [[#Rope lengths]] below.
  
 +If you want to add custom label styles, you need to call "thelabel.suffix(thetext,position)" with the right alignment suffix, save the return value in a variable called "lab", then call "process_label(position,rotation)". After that, you can check "bbox lab" to get the bounding box of the text label as a path which can be used to draw the decoration. You can temporarily ("interim") set the internal "bboxmargin" variable to make the bounding box larger than the text, to create some padding between the text and your ornamentation. You should use "begingroup+endroup" within a "def" when using the "interim" operator to make sure it gets reset correctly afterwards, or use a vardef instead of a def.
 +
 +Use "rotatedaround (position,rotation)" when drawing the ornamentation to make sure it gets rotated and aligned the same as the label. 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 - known Therion bug - so at least this is consistent with Therion itself.
 +
 +Since this will require setting the suffix correctly for both the regular label styles and the custom label styles, there ends up being a lot of duplicated code. It is easier to store the suffix name as a string which can then be extracted with scantokens when calling the appropriate macro, which is what the example code below does. The custom decorations are specified using a style number starting from 100, so as not to clash with the numbers used for Therion's internal label styles.
 +
 +<code>
 +code metapost
 +  vardef create_styled_label (expr plaintext,P,R,S,A,defaultstyle)=
 +    save textsize, style, thetext, sufx, athick;
 +    string textsize;
 +    if S = 0.5:
 +      textsize:="\thtinysize";
 +    elseif S = 0.7:
 +      textsize:="\thsmallsize";
 +    elseif S = 1.4:
 +      textsize:="\thlargesize";
 +    elseif S = 2:
 +      textsize:="\thhugesize";
 +    else: % normal is 1
 +      textsize:="\thnormalsize";
 +    fi;
 +    if known ATTR_labelstyle:
 +      style:=scantokens(ATTR_labelstyle);
 +    else:
 +      style:=defaultstyle;
 +    fi;
 +    picture thetext;
 +    thetext:=thTEX("\thframed {" & textsize & plaintext & "}");
 +    % store the alignment suffix as a string, it will be turned back into a suffix with scantokens
 +    string sufx;
 +    if A = (-1,1):
 +      sufx:="ulft";
 +    elseif A = (0,1):
 +      sufx:="top";
 +    elseif A = (1,1):
 +      sufx:="urt";
 +    elseif A = (-1,0):
 +      sufx:="lft";
 +    elseif A = (1,0):
 +      sufx:="rt";
 +    elseif A = (-1,-1):
 +      sufx:="llft";
 +    elseif A = (0,-1):
 +      sufx:="bot";
 +    elseif A = (1,-1):
 +      sufx:="lrt";
 +    else:
 +      sufx:="";
 +    fi;
 +    if style >= 100:
 +      % create the label, passing the alignment as a suffix
 +      lab:=thelabel.scantokens(sufx)(thetext,P);
 +      % process_label looks for a variable called "lab"
 +      process_label(P,R);
 +      % define all the different ornamentations that you want
 +      if style = 100:
 +        pickup PenA;
 +        athick:=(xpart (lrcorner PenA)) - (xpart (llcorner PenA));
 +        % make bounding box measurements temporarily be larger than the object being measured
 +        % "interim" modifies internal variable, must be inside vardef or def+begingroup to make
 +        % sure it gets reset to default correctly afterwards
 +        interim bboxmargin:=5athick;
 +        % rounded rectangle
 +        % rotating around P is undesirable when alignment is also used, but this is what regular labels do
 +        draw ((bbox lab) smoothed 5athick) rotatedaround (P,R) dashed evenly;
 +      fi;
 +    else:
 +      % create the label, passing the alignment as a suffix
 +      p_label.scantokens(sufx)(thetext,P,R,style);
 +    fi;
 +  enddef;
 +endcode
 +</code>
 =====Replacing legend drawings for existing symbols===== =====Replacing legend drawings for existing symbols=====
  
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 The default "anchor" symbol takes up a lot of space. It also resists rotation. This produces a P-hanger icon instead. It respects rotation, so that if the "orientation" arrow points to the right, the P-hanger will point in the chosen direction. In addition, it selects the correct direction to face, so that the loop of the hanger always points down the page. It intentionally has a thinner line pointing into the rock, so that it appears to pierce the wall of the cave (just like a real P-hanger). The default "anchor" symbol takes up a lot of space. It also resists rotation. This produces a P-hanger icon instead. It respects rotation, so that if the "orientation" arrow points to the right, the P-hanger will point in the chosen direction. In addition, it selects the correct direction to face, so that the loop of the hanger always points down the page. It intentionally has a thinner line pointing into the rock, so that it appears to pierce the wall of the cave (just like a real P-hanger).
  
-In elevation view, by default it switches to being a filled circle, a standard symbol for a fixed position hanger, which can be placed on the linepoints of a basic rope line.+In elevation view, by default it switches to being a filled circle, a standard symbol for a fixed position hanger on [[riggingtopos|Rigging topos]], which can be placed on the linepoints of a basic rope line.
  
 By using the "-attr type" option, you can control which type of anchor it will show: By using the "-attr type" option, you can control which type of anchor it will show:
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 ===Magnetic effects=== ===Magnetic effects===
  
-[[user:tarquinwj|Tarquin 2019]]+[[user:tarquinwj|Tarquin 2019-2020]]
  
 Certain rocks can cause a compass to give the wrong reading. This icon can be used to show areas where this happens (ie. where the survey may be unreliable as a result); a spinning compass: Certain rocks can cause a compass to give the wrong reading. This icon can be used to show areas where this happens (ie. where the survey may be unreliable as a result); a spinning compass:
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   % a spinning compass   % a spinning compass
   def p_u_magnetism (expr P,R,S,A)=   def p_u_magnetism (expr P,R,S,A)=
-    scale:=0.5u; +    begingroup; 
-    halfline:=(0.5u/20S); %half thickness of PenC - pen thicknesses do not scale with S +      save scale, cthick, pointheight, pointwidth, cutheight, cutwidth; 
-    pointheight:=scale*.9; +      scale:=0.5u; 
-    pointwidth:=scale*.4; +      cthick:=(xpart (lrcorner PenC)) - (xpart (llcorner PenC)); 
-    U:=(scale,scale); +      pointheight:=scale*.9; 
-    T:=identity aligned A rotated (R-20) scaled S shifted P; +      pointwidth:=scale*.4; 
-    % a circle +      cutheight:=pointheight - (cthick / sind(angle(pointheight,pointwidth))); 
-    thdraw fullcircle scaled 2scale withpen PenC withcolor black; +      cutwidth:=pointwidth - (cthick / sind(angle(pointwidth,pointheight))); 
-    % filled triangle +      U:=(scale,scale); 
-    thfill (0,pointheight)--(pointwidth,0)--(-pointwidth,0)--cycle withcolor black; +      T:=identity aligned A rotated (R-20) scaled S shifted P; 
-    % black triangle outline +      % a circle 
-    thdraw (0,-pointheight+halfline)--(pointwidth-halfline,0) withpen PenC withcolor black; +      thdraw fullcircle scaled 2scale withpen PenC; 
-    thdraw (0,-pointheight+halfline)--(-pointwidth+halfline,0) withpen PenC withcolor black; +      % filled triangle 
-    % spin arcs, a full circle is path 0-8, anticlockwise, starting from the right +      thfill (0,pointheight)--(pointwidth,0)--(-pointwidth,0)--cycle; 
-    thdraw subpath (2.4,3.5) of fullcircle scaled 1.5scale withpen PenC withcolor black; +      % black triangle outline 
-    thdraw subpath (6.4,7.5) of fullcircle scaled 1.5scale withpen PenC withcolor black;+      % this can be drawn with mitred pens, but it still ends up needing calculations to get the centre position of the pen thickness 
 +      % therefore it is easier to just use a filled path 
 +      % pointheight/2 is used to stop the thin unpainted gap between shapes 
 +      thfill (0,-pointheight)--(pointwidth,0)--(0,pointheight/2)--(cutwidth,0)--(0,-cutheight)--(-cutwidth,0)--(0,pointheight/2)--(-pointwidth,0)--cycle; 
 +      % spin arcs, a full circle is path 0-8, anticlockwise, starting from the right 
 +      thdraw subpath (2.4,3.5) of fullcircle scaled 1.5scale withpen PenC; 
 +      thdraw subpath (6.4,7.5) of fullcircle scaled 1.5scale withpen PenC; 
 +    endgroup;
   enddef;   enddef;
   initsymbol("p_u_magnetism");   initsymbol("p_u_magnetism");
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 [[user:tarquinwj|Tarquin 2019]] [[user:tarquinwj|Tarquin 2019]]
  
-A common way to show rope lengths (at least in the UK) is with a number inside a circle. This point relies on you also including the code for [[#Adding custom styled labels at any point/linepoint]]:+A common way to show rope lengths (at least in the UK) on [[riggingtopos|Rigging topos]] is with a number inside a circle. This point relies on you also including the code for [[#Adding custom styled labels at any point/linepoint]]:
  
 <code> <code>
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 [[user:tarquinwj|Tarquin 2019]] [[user:tarquinwj|Tarquin 2019]]
  
-Pits use the same appearance in both plan and elevation views. However, it may be desirable for a pit edge to be drawn as a pitch in plan view, but a ledge in elevation view. This is common with rigging topos, for example, where the plan uses a pit symbol, but the same same drop in the elevation view will normally be shown with a different symbol, such as a dashed line, to indicate that a traverse may be required along a ledge. It is still a pitch, so it should use the same semantic "l_pit" symbol, even though the rendering should be different. This example shows how to show a pit symbol in plan view, but replace it with a dashed ledge line (borrowed from a temporary border) in elevation view:+Pits use the same appearance in both plan and elevation views. However, it may be desirable for a pit edge to be drawn as a pitch in plan view, but a ledge in elevation view. This is common with [[riggingtopos|Rigging topos]], for example, where the plan uses a pit symbol, but the same same drop in the elevation view will normally be shown with a different symbol, such as a dashed line, to indicate that a traverse may be required along a ledge. It is still a pitch, so it should use the same semantic "l_pit" symbol, even though the rendering should be different. This example shows how to show a pit symbol in plan view, but replace it with a dashed ledge line (borrowed from a temporary border) in elevation view:
  
 <code> <code>
Line 1010: Line 1093:
 [[user:tarquinwj|Tarquin 2019]] [[user:tarquinwj|Tarquin 2019]]
  
-The default Therion rope symbol is very pretty, doing fancy rebelays and anchors. This works well for simple cases, but when trying to draw rigging topos, it tries to add anchors and rebelays in places where you were just trying to draw Y-hang knots, and it sometimes fails to draw lines because it decides that they were too short.+The default Therion rope symbol is very pretty, doing fancy rebelays and anchors. This works well for simple cases, but when trying to draw [[riggingtopos|Rigging topos]], it tries to add anchors and rebelays in places where you were just trying to draw Y-hang knots, and it sometimes fails to draw lines because it decides that they were too short.
  
 It is possible to disable the anchors and rebelays by adding two options to a linepoint (not the line itself), and hoping that you never accidentally remove that particular linepoint. These options apply to the whole line rather than an individual linepoint, so you cannot fine control the use of rebelays and linepoints. It is best to just disable them, use the usual Bézier curve controls, and [[#P-hangers that face the right way, and other anchor designs|manually add anchors]]. It is possible to disable the anchors and rebelays by adding two options to a linepoint (not the line itself), and hoping that you never accidentally remove that particular linepoint. These options apply to the whole line rather than an individual linepoint, so you cannot fine control the use of rebelays and linepoints. It is best to just disable them, use the usual Bézier curve controls, and [[#P-hangers that face the right way, and other anchor designs|manually add anchors]].
Line 1054: Line 1137:
 [[user:tarquinwj|Tarquin 2019]] [[user:tarquinwj|Tarquin 2019]]
  
-For rigging topos, one of the most easily recognised symbols used in the UK is a rope reaching from a wall towards the main rope, with a small oval around it, pulling the rope to the side. This symbol shows an example of cutoffafter, used to allow the deviation's rope to share a linepoint with the main rope, but without showing the deviation rope inside the oval (a reverse clipping effect in MetaPost!).+For [[riggingtopos|Rigging topos]], one of the most easily recognised symbols used in the UK is a rope reaching from a wall towards the main rope, with a small oval around it, pulling the rope to the side. This symbol shows an example of cutoffafter, used to allow the deviation's rope to share a linepoint with the main rope, but without showing the deviation rope inside the oval (a reverse clipping effect in MetaPost!).
  
 <code> <code>
Line 1207: Line 1290:
 [[user:tarquinwj|Tarquin 2019]] [[user:tarquinwj|Tarquin 2019]]
  
-Trees are often found in the entrances to caves, and sometimes a survey deserves to show the trees. This is particularly common with rigging topos for surface shafts, where a tree may be used as a rope belay, but it also may be in particularly large entrances which contain forests. A tree may be created as a single point symbol, but this then makes it difficult to scale the heights and widths perfectly, and even harder to attach other lines (like ropes or tethers) to the sides of them. It also means that when trying to draw a particularly distinctive tree which must be used as a belay, it is not possible to show it in a recognisable way.+Trees are often found in the entrances to caves, and sometimes a survey deserves to show the trees. This is particularly common with [[riggingtopos|Rigging topos]] for surface shafts, where a tree may be used as a rope belay, but it also may be in particularly large entrances which contain forests. A tree may be created as a single point symbol, but this then makes it difficult to scale the heights and widths perfectly, and even harder to attach other lines (like ropes or tethers) to the sides of them. It also means that when trying to draw a particularly distinctive tree which must be used as a belay, it is not possible to show it in a recognisable way.
  
 This is therefore a pair of symbols. The first is for the sides of the tree trunk (which could also be used to create jagged shapes for conifers), and the second is for the bushy leaves at the top of a deciduous tree. The sides of the tree can therefore be curved or branched as needed, with linepoints added for attaching rope lines, the surface lines, and the bushy part of the tree to. For plans, the bushy part alone would normally work, as a closed, circular line. This is therefore a pair of symbols. The first is for the sides of the tree trunk (which could also be used to create jagged shapes for conifers), and the second is for the bushy leaves at the top of a deciduous tree. The sides of the tree can therefore be curved or branched as needed, with linepoints added for attaching rope lines, the surface lines, and the bushy part of the tree to. For plans, the bushy part alone would normally work, as a closed, circular line.
Line 1309: Line 1392:
 {{ ::tree.png?nolink |}} {{ ::tree.png?nolink |}}
  
-Select these as line type "u" with "-subtype treetrunk" and "-subtype treetrunk" in their options. Remember to set "-clip off" on the lines if they are going to be used outside of the cave walls. Use it with these lines in your layout:+Select these as line type "u" with "-subtype treetrunk" and "-subtype bush" in their options. Remember to set "-clip off" on the lines if they are going to be used outside of the cave walls. Use it with these lines in your layout:
  
   text en "line u:treetrunk" "tree"   text en "line u:treetrunk" "tree"
Line 1325: Line 1408:
 [[user:tarquinwj|Tarquin 2019]] [[user:tarquinwj|Tarquin 2019]]
  
-Metal bars and wooden beams are a common part of chokes, and are not normally drawn on a survey (though sometimes that are drawn, for particularly special cases). However, sometimes they are also used for rigging, and that is where they become important. Therion does not do anything with the "-scale" option on lines (it is silently ignored), but sometimes it is needed for a line symbol, and this is one of those cases - some shoring deserves a thick line, some does not. This symbol is therefore an example of how to provide an equivalent "-attr scale xs" option which can be used in the symbol code. The values it supports are the same as a regular -scale option (xs, s, m, l, xl).+Metal bars and wooden beams are a common part of chokes, and are not normally drawn on a survey (though sometimes that are drawn, for particularly special cases). However, sometimes they are also used for [[riggingtopos|rigging]], and that is where they become important. Therion does not do anything with the "-scale" option on lines (it is silently ignored), but sometimes it is needed for a line symbol, and this is one of those cases - some shoring deserves a thick line, some does not. This symbol is therefore an example of how to provide an equivalent "-attr scale xs" option which can be used in the symbol code. The values it supports are the same as a regular -scale option (xs, s, m, l, xl).
  
 <code> <code>
Line 1361: Line 1444:
  
   text en "line u:shoring" "shoring/bars"   text en "line u:shoring" "shoring/bars"
 +
 +===Centreline that is only visible when not in a scrap===
 +
 +[[user:tarquinwj|Tarquin 2019]]
 +
 +Sometimes, you might want to show a centreline for a section of the cave where you do not have any wall data, if you are using [[tips#Showing centreline for parts of a cave, and passage walls for others|a map made up from surveys and other maps]]. However, you might not want to show the walls within your regular scraps where you have wall data, since they are distracting and meaningless for viewers. There is no setting for this, since "symbol-hide group centreline" affects all centrelines at once, so it must be done through MetaPost:
 +
 +<code>
 +code metapost
 +  def l_survey_cave_MY(expr P) =
 +    if ATTR__scrap_centerline:
 +      l_survey_cave_SKBB(P);
 +    fi;
 +  enddef;
 +  initsymbol("l_survey_cave_MY");
 +endcode
 +</code>
 +
 +You may notice the misleadingly named "ATTR__scrap_centerline", which does not mean "centreline within a scrap". Instead, it means "a virtual scrap automatically created, made up entirely of centreline", which is what Therion creates when you ask it to include survey data within a map.
 +
 +Use it with this line in your layout:
 +
 +  symbol-assign line survey:cave MY
 +
 +You can use a similar approach for l_survey_surface_MY (surface survey legs), p_station_temporary_MY, p_station_natural_MY, p_station_painted_MY and p_station_fixed_MY (survey stations) if you needed to show those outside too.
 +
 +===Break line===
 +
 +[[user:tarquinwj|Tarquin 2019]]
 +
 +When a section of are omitted or shortened, typically used with [[riggingtopos|rigging topos]], the common approach is to show a double line wherever the passage has been omitted. Usually, it is drawn at an angle of about 45 degrees. This can either be used on a single scrap with a double line over the passage to show that it is much longer than shown, or it is used to end the scrap, then a second double line is used to start the next scrap; this second version is normally used when the passage on either side of the break is of different dimensions.
 +
 +This code is an example of how to extend a line beyond the defined ends, using additional points. It also shows how to cope with the fact that (as of the time of writing) Therion does not offer a variable that allows you to read the "map-bg" colour. It also shows how to cope with Therion trying to recognise keywords inside "code metapost" sections.
 +
 +  code metapost
 +    def l_u_break(expr P)=
 +      begingroup;
 +        save mainpath, parallel, orientation, direction, gapsize;
 +        T:=identity;
 +        gapsize:=u/3;
 +        path mainpath;
 +        %make the ends stick out beyond the passage
 +        mainpath:=( (point 0 of P) + u * unitvector( thdir(P, 0) rotated 180 ) / 2 )
 +                  -- P --
 +                  ( (point (length P) of P) + u * unitvector( thdir(P, arclength P) ) / 2 );
 +        path parallel;
 +        string orientation;
 +        orientation:=if known ATTR_orientation: ATTR_orientation; else: "horizontal"; fi;
 +        if orientation = "vertical":
 +          direction:=if (xpart (point 0 of mainpath)) > (xpart (point (length mainpath) of mainpath)): 1; else: -1; fi;
 +          parallel:=mainpath shifted (0, direction * gapsize);
 +        else:
 +          direction:=if (ypart (point 0 of mainpath)) > (ypart (point (length mainpath) of mainpath)): -1; else: 1; fi;
 +          parallel:=mainpath shifted (direction * gapsize, 0);
 +        fi;
 +        if known fill_l_u_break:
 +          thfill (mainpath -- (reverse parallel) -- cycle) withcolor fill_l_u_break;
 +        else:
 +          thunfill (mainpath -- (reverse parallel) -- cycle);
 +        fi;
 +        pickup PenC;
 +        thdraw mainpath;
 +        thdraw parallel;
 +      endgroup;
 +    enddef;
 +    initsymbol("l_u_break");
 +    def l_u_break_legend =
 +      l_wall_bedrock(((0,.2) .. controls (.3,.2) and (.4,.4) .. (.6,.4)) inscale);
 +      l_wall_bedrock(((.7,.6) .. controls (.4,.6) and (.3,.4) .. (0,.4)) inscale);
 +      l_u_break(((.6,.4) -- (.7,.6)) inscale);
 +    enddef;
 +  endcode
 +
 +{{ :passagebreak.png?nolink |}}
 +
 +Select this as line type "u" with "-subtype break" in its options. You will also need to define it with "-clip off" in its options to allow the ends of the line to show up outside the walls. Typically, you will also need to use "-place top" in its options to allow it to be placed over the top of any walls, so that it can blank out the wall in between the double lines (either that or you need to ensure that it appears before any wall lines in its scrap, but this can make maintenance harder).
 +
 +Use it with this line in your layout:
 +
 +  text en "line u:break" "passage omitted/offset"
 +
 +By default, it will pick up the colour of the scrap background, to put between the double lines. However, it normally looks better with the map-bg colour between them. Unfortunately, Therion does not appear to expose this colour to MetaPost code (it is created in raw Tex). So you will need to do it manually. If you do not specify map-bg, it is white; "(1, 1, 1)" in MetaPost. If you have set it to a colour like "70", this is "(.7, .7, .7)" in MetaPost. If you have set it to a colour like "[70 35 50]", this is "(.7, .35, .5)" in MetaPost. The code will check for a variable called fill_l_u_break, and will try to use it as a fill colour if it exists.
 +
 +You cannot use "color fill_l_u_break;" in a "code metapost" section, because Therion will try to treat the keyword "color" as a Therion command instead of a MetaPost keyword. You can either write ";color fill_l_u_break;" with a leading semicolon which MetaPost will ignore, or use the synonym "rgbcolor fill_l_u_break;" which Metpost understands but Therion will not recognise.
 +
 +  code metapost
 +    rgbcolor fill_l_u_break;
 +    fill_l_u_break:=(1,1,1);
 +  endcode
 +
 +By default, the break line is set up for use along a horizontal passage. This follows the usual style used in the UK; two parallel lines, separated by a horizontal gap, with the tops and bottoms horizontally aligned (no matter whether the lines are drawn vertically or tilted at 45 degrees or more). If you are using it on a vertical section of cave, you can set the "-attr orientation vertical" option on the line. This will cause it to leave a vertical gap between the lines, and to align them horizontally compared with each other. This makes only a tiny difference when tilted at 45 degrees, but it looks better, and matches the normal style used in rigging topos.
 ====Area Symbols====  ====Area Symbols==== 
 ===Show area water in a different color=== ===Show area water in a different color===
  • metapost.txt
  • Last modified: 22 months ago
  • by tarquinwj