-- goal is to use leaders to have pointers with text indicating for instance heights or name materials, etc.
use skethup tool Text (leader with text) not attacing it to any object.

link to definition:
https://documentation.help/AutoCAD-DXF/WS1a9193826455f5ff18cb41610ec0a2e719-7a02.htm


Possible values for Code 73 Leader creation flag (default = 3):
0 = Created with text annotation
1 = Created with tolerance annotation
2 = Created with block reference annotation
3 = Created without any annotation


Example values are taken from the file "dxf issues with special chars.dxf"


Example of a hooked leader line with text:
...
0   --class
LEADER  -- LEADER class
  5  -- handle
45D
...
100
AcDbEntity
  8  -- layer
01_Linien
...
100
AcDbLeader
  3  -- Dimension style name
ERSTELLTER_STIL__8
 73  -- Leader creation flag (default = 3 - leader without annotation ):
     0 -- create with text annotation. 
 74  -- Hookline direction flag: (probably we do not need)
     -- 0 = Hookline (or end of tangent for a splined leader) is the opposite direction from the horizontal vector
     -- 1 = Hookline (or end of tangent for a splined leader) is the same direction as horizontal vector (see code 75)
     0
 40 -- height of text annotation box
0.1861200073957443
 41 -- width of text annotation box
2.365020093977451
 76  -- number of vertices in leader line 
     2   -- here we have two vertices. a beginning and end point
 10 -- there are multiple (x,y,z) points (10,20,30). Only use the first one as this is the starting point
0.2350246010019716
 20
23.23973242126534
 30
0.0
 10 -- x coord of second point. use the last one to calc the vector needed in SketchUp
2.156191826437881
 20 -- y coord of second point 
23.71269979155023
 30 -- z coord of second point 
0.0
340 -- hard link to MTEXT or block or INSERT. but we should support only MTEXT link
45E -- search vor code 5 with same value to find MTEXT
211 --“Horizontal” direction for leader
0.9693654083247027
221
0.2456230957045413
231
0.0
...
  0
MTEXT
  5  -- handle, links back to code 340 in Leader object
45E
...
100
AcDbEntity
  8  -- layer
01_Linien
...
100
AcDbMText
...
  1
\A1;{\fArial|b0|i0|c0|p34;OK Mauer ca. 549.79}
...


# Transform to SketchUp:
# DXF codes indicated in variables staring with p (point) or v(vector) or c(any code):

# leader type
c73 = 0 
# number of verices , take the firs and the last, ignroe the ones in between
c76 = 2 
# starting point of SketchUp Text
p10s = "0.2350246010019716m".to_l
p20s = "23.71269979155023m".to_l
p30s = "0.0m".to_l
# end point of SketchUp Text this the occurrence of the point (10,20,30) indicated in Code 76
p10e = "2.156191826437881m".to_l
p20e = "23.71269979155023m".to_l
p30e = "0.0m".to_l
# annotation text, not needed, if we only draw the leader line
c1 = "\A1;{\fArial|b0|i0|c0|p34;OK Mauer ca. 549.79}"





  0
LEADER
  5
455
...
100
AcDbEntity
  8  -- layer
01_Linien
...
100
AcDbLeader
  3  -- style
ERSTELLTER_STIL__8
 73  -- leader type
     0
...
 76  -- number of vertices
     2
 10  -- start point
0.8933383387278445
 20
20.07616254294711
 30
0.0
 10  -- end point
1.843283190558974
 20
20.0556887295855
 30
0.0
340  -- hande of related MText
456
...
  0
MTEXT
  5
456
...
100
AcDbEntity
  8
01_Linien
...
100
AcDbMText
...
  1
\A1;\A1;\A1;{\fArial|b0|i0|c0|p34;547.32}
...


# Transform to SketchUp:
# DXF codes indicated in variables staring with p (point) or v(vector) or c(any code):

# leader type
c73 = 0 
# number of verices , take the firs and the last, ignroe the ones in between
c76 = 2 
# starting point of SketchUp Text
p10s = "0.8933383387278445m".to_l
p20s = "20.07616254294711m".to_l
p30s = "0.0m".to_l
# end point of SketchUp Text this the occurrence of the point (10,20,30) indicated in Code 76
p10e = "1.843283190558974m".to_l
p20e = "20.0556887295855m".to_l
p30e = "0.0m".to_l
# annotation text, not needed, if we only draw the leader line
c1 = "\A1;\A1;\A1;{\fArial|b0|i0|c0|p34;547.32}"





  0
LEADER
  5
459
...
100
AcDbEntity
  8  -- layer
01_Linien
...
100
AcDbLeader
  3  -- stye
ERSTELLTER_STIL__8
 73  -- leader type
     0
...
 76  --  number of vertices
     2
 10
0.2357477944377185
 20
17.524072953701
 30
0.0
 10
2.214148233044702
 20
17.50141582001132
 30
0.0
340
45A
...
  0
MTEXT
  5
45A
...
100
AcDbEntity
  8
01_Linien
...
100
AcDbMText
...
  1
\A1;\A1;\A1;{\fArial|b0|i0|c0|p34;OK Mauer ca. 548.80}
...



# Transform to SketchUp:
# DXF codes indicated in variables staring with p (point) or v(vector) or c(any code):

# leader type
c73 = 0 
# number of verices , take the firs and the last, ignroe the ones in between
c76 = 2 
# starting point of SketchUp Text
p10s = "0.2357477944377185m".to_l
p20s = "17.524072953701m".to_l
p30s = "0.0m".to_l
# end point of SketchUp Text this the occurrence of the point (10,20,30) indicated in Code 76
p10e = "2.214148233044702m".to_l
p20e = "17.50141582001132m".to_l
p30e = "0.0m".to_l
# annotation text, not needed, if we only draw the leader line
c1 = "\A1;\A1;\A1;{\fArial|b0|i0|c0|p34;OK Mauer ca. 548.80}"





  0
LEADER
  5
461
330
1F
100
AcDbEntity
  8
0_WP_Plankopf_1_50_(AaA)
...
100
AcDbLeader
  3  -- style
ERSTELLTER_STIL__9
 73  -- leader type
     0
 75  -- Hookline flag: 0 = No hookline; 1 = Has a hookline. This seems to set if MORE than two verices in Code 76. but we do not need
     1
...
 76  -- number of vertices in leader, take only first and last
     3
 10  -- start position
0.9616737862169167
 20
16.05730627056626
 30
0.0
 10
0.8016737862169165
 20
16.16410309801638
 30
0.0
 10  -- end position
0.6876737862169165
 20
16.16410309801638
 30
0.0
340  -- link to MTEXT handle
462
...
  0
MTEXT
  5
462  -- MTEXT handle
...
100
AcDbEntity
  8  -- layer
0_WP_Plankopf_1_50_(AaA)
...
100
AcDbMText
...
  1
\A1;\A1;\A1;{\fArial|b0|i0|c0|p34;Knickarmmarkise}
...





# Transform to SketchUp:
# DXF codes indicated in variables staring with p (point) or v(vector) or c(any code):

# leader type
c73 = 0 
# number of verices , take the firs and the last, ignroe the ones in between
c76 = 3 
# starting point of SketchUp Text
p10s = "0.9616737862169167m".to_l
p20s = "16.05730627056626m".to_l
p30s = "0.0m".to_l
# end point of SketchUp Text this the occurrence of the point (10,20,30) indicated in Code 76
p10e = "0.6876737862169165m".to_l
p20e = "16.16410309801638m".to_l
p30e = "0.0m".to_l
# annotation text, not needed, if we only draw the leader line
c1 = "\A1;\A1;\A1;{\fArial|b0|i0|c0|p34;Knickarmmarkise}"







# create sketchup text with leader based on the above done variable assignment:


entities = Sketchup.active_model.entities

# start and end point are the first and last (10,20,30) coordinates from dxf Leader
p0s = Geom::Point3d.new(p10s, p20s, p30s)
p0e = Geom::Point3d.new(p10e, p20e, p30e)

v0s = Geom::Vector3d.new(p0s.to_a)
v0e = Geom::Vector3d.new(p0e.to_a)

# v0 corresponds to the vector between the start and end point.
v0 = v0e - v0s

#text corresponds to the MText value stored in code 1
t = c1

# create SketchUp text
text = entities.add_text t, p0s, v0
# but we could also leave the text empty and just draw the leader, as MText is already imported. 
# Disadvanage is that the SketchUp Text changes when orbiting, so adding the text would be nicer.
# text = entities.add_text "", p0s, v0


#Text font: 
# change to the one in dxf as already read during the import.
# use as well a font size in mm/inch and not pixels, because then the leader zooms in and out like the other 3DText imported


# Leader type: 
# Valid leader types are 0 for none, 1 for View-based, and 2 for Pushpin
# is always 2 
text.leader_type=2


# Arrow Type: 
# Valid arrow types are 0 for none, 2 for dot, 3 for closed arrow, 4 for open arrow.
# not sure what to do here. I would leave the sketchUp default set by the user
text.arrow_type = 2


# Line weight in pixels: Default is 1
# take from style, if easily available, otherwise leave the default
text.line_weight = 3