# \setupsidebar

## Summary

The command \setupsidebar is used to customize vertical bars that are used to "vertically underline" portions of text.

## Settings

 \setupsidebar[...,...][...=...,...] [...,...] name rulethickness dimension rulecolor color alternative number topoffset dimension bottomoffset dimension distance dimension leftmargindistance dimension level number

OptionExplanation
rulethickness
 thickness of the bar, i.e. 1pt
rulecolor
 the bar's color
alternative
 a number specifying the style of the bar (currently 0=solid bar, 1=dashed bar) number 0 = solid bar 1 = dashed bar
topoffset
 offset to start drawing the bar, from the top of the first line of text between \startsidebar...\stopsidebar
bottomoffset
 offset to stop drawing the bar from the bottom of the last line of text between \startsidebar...\stopsidebar
distance
 the distance from the left edge of the text or from the previous bar, in case of nested \startsidebar...\stopsidebar
leftmargindistance
 distance from the left edge of the text; if it's zero, it's made equal to distance
level
 a number specifying a sort of layer on which the bar is drawn; when a bar is already drawn in the same level, the next one will be drawn with a distance offset; if you draw a second bar in a higher level, it will overlap bars of lower levels

## Description

\setupsidebar customizes the appearance of vertical bars drawn along the portions of text between \startsidebar[...] and \stopsidebar.

\startsidebar[...] ... \stopsidebar can be placed inside the text of a paragraph to "vertically underline" portions of text. They are drawn from the top of the first line to the bottom of the last line of the text between the two commands.

You can fine-tune the starting and ending points of a bar with topoffset and bottomoffset.

\startsidebar[...] ... \stopsidebar can be nested: in this case the distance parameter is used to move the second bar (the inner one) relatively to the first one. The first one is drawn at distance distance from the left edge of the text, each of the next ones will be drawn at distance distance from the previous one.

In case you specify a non zero length for the leftmargindistance parameter, you can discriminate the distance from the text (leftmargindistance) from the distance between bars (distance).

The level parameter lets you define sidebars on different layers. The bars with higher values of level are drawn on top.

From LMTX 2021-10-28, you can use the location parameter: it defaults to left, but it can be right, inner or outer. right draws the sidebar on the right. inner and outer are used with \setuppagenumbering[alternative=doublesided], to get bars that are always in the inner or in the outer margin.

## Examples

### Example 1

\definesidebar[simple][rulethickness=1pt,distance=4pt]
\starttext
\hsize=4cm
The sidebar follows the text between \type{\startsidebar[simple]} and \type{\stopsidebar},
\startsidebar[simple] {\blue from the top of the first line to the bottom of the last line.}\stopsidebar
Here the text between \type{\startsidebar[simple]} and \type{\stopsidebar} has been colored in blue.

\blank

When the \startsidebar[simple] same bar is started twice on the same text, \startsidebar[simple]
a second bar \stopsidebar will be drawn, with an offset equal to the \type{distance} parameter.\stopsidebar

\blank

\setupsidebar[simple][leftmargindistance=0pt,distance=4pt]
When \type{leftmargindistance} is zero, \startsidebar[simple]
the bar is drawn at distance \type{distance} from the left edge
of the text,\stopsidebar which means 4pt in this example.

\blank

\setupsidebar[simple][leftmargindistance=0.1pt,distance=4pt]
When \type{leftmargindistance} is not zero, \startsidebar[simple]
the bar is drawn at distance \type{leftmargindistance} from the left edge
of the text, which means 0.1pt in this example.
\startsidebar[simple] A second bar will be drawn at distance \type{distance}
from the first one.\stopsidebar\stopsidebar

\blank

\setupsidebar[simple][leftmargindistance=0pt,distance=4mm,rulethickness=2mm,level=1]
\definesidebar[over][distance=4mm,rulethickness=1mm,rulecolor=green,level=1]
When \startsidebar[simple]\startsidebar[over] two sidebars are in the same level,
they are drawn at distance \type{distance}.\stopsidebar\stopsidebar

\blank

\setupsidebar[over][level=2]
When \startsidebar[simple]\startsidebar[over] two sidebars are in different levels,
they are drawn as if they were in different layers.\stopsidebar\stopsidebar

\blank

\setupsidebar[simple][rulethickness=1pt,leftmargindistance=\dimexpr -\hsize - 4pt\relax]
\startsidebar[simple] You can put a bar in the right margin.\stopsidebar

\stoptext


### Custom fancy sidebars

You can define fancy, zig zag bars redefining the anch_sidebars_draw macro:

\definesidebar[zigzag1][rulecolor=black,distance=4pt,rulethickness=1pt,alternative=2]
\definesidebar[zigzag2][rulecolor=red,distance=4pt,rulethickness=1pt,alternative=3]
\definesidebar[wave1][rulecolor=blue,distance=4pt,rulethickness=1pt,alternative=4]
\definesidebar[wave2][rulecolor=cyan,distance=4pt,rulethickness=1pt,alternative=5]
\definesidebar[obliquedashes][rulecolor=darkgreen,distance=4pt,rulethickness=1pt,alternative=6]

\startMPcode
% draws a bar repeating a pattern defined from (0,0) to (0,1)
def draw_pattern_bar(expr a, b, pattern, patternlength, patternheight, linewidth, linecolor) =
draw image (
begingroup ;
save p, q, stp ;
pair p, q, stp ;
stp := ( ( b - a ) / arclength( a -- b ) ) * patternlength ;
path q ; q := pattern xscaled patternlength yscaled patternheight rotated (angle(stp)) ;
p := a ;
forever :
draw
q shifted p
withpen pencircle scaled linewidth
withcolor linecolor ;
p := p + stp ;
exitif arclength( a -- p ) > arclength( a -- b ) ;
endfor ;
endgroup ;
clip currentpicture to
(xpart llcorner currentpicture, ypart b) --
(xpart lrcorner currentpicture, ypart b) --
(xpart urcorner currentpicture, ypart a) --
(xpart ulcorner currentpicture, ypart a) -- cycle ;
) ;
enddef ;

% modified from metapost/context/base/mpiv/mp-apos.mpiv to add alternatives
def anch_sidebars_draw (expr p_b_self, p_e_self, y_b_self, y_e_self, h_b_self, d_e_self,
x, y, w, h, alternative, distance, linewidth, linecolor, topoffset, bottomoffset) =
% beware, we anchor at (x,y)
begingroup ;
if alternative = 1 :
interim linecap := rounded ;
else :
interim linecap := butt ;
fi ;
save a, b ; pair a, b ;
if p_b_self = p_e_self :
a := (-distance,y_b_self+h_b_self-y) ;
b := (-distance,y_e_self-d_e_self-y) ;
elseif RealPageNumber = p_b_self :
a := (-distance,y_b_self+h_b_self-y) ;
b := (-distance,0) ;
elseif RealPageNumber = p_e_self :
a := (-distance,h) ;
b := (-distance,y_e_self-d_e_self-y) ;
else :
a := (-distance,h) ;
b := (-distance,0) ;
fi ;
a := (xpart a, min(ypart a + topoffset,   h)) ;
b := (xpart b, max(ypart b - bottomoffset,0)) ;
if alternative = 2 :
draw_pattern_bar( a, b, ((0,0)--(0.25,-0.5)--(0.75,0.5)--(1,0)), 2pt, 2pt, linewidth, linecolor ) ;
elseif alternative = 3 :
draw_pattern_bar( a, b, ((0,0)--(0.25,-0.5)--(0.75,0.5)--(1,0)), 4pt, 1.5pt, linewidth, linecolor ) ;
elseif alternative = 4 :
draw_pattern_bar( a, b, ( ((0,0) .. controls (0,0.5) and (0.5,0.5) .. (0.5,0)) -- ((0.5,0) .. controls (0.5,-0.5) and (1,-0.5) .. (1,0)) ), 6pt, 4pt, linewidth, linecolor ) ;
elseif alternative = 5 :
draw_pattern_bar( a, b, ( (0,0) .. controls (0,1) and (1,1) .. (1,0) ), 4pt, 2pt, linewidth, linecolor ) ;
elseif alternative = 6 :
draw_pattern_bar( a, b, ( (0,0.5) .. (1,-0.5) ), 4pt, 2pt, linewidth, linecolor ) ;
else :
draw
a -- b
if alternative = 1 :
dashed (withdots scaled (linewidth/2))
fi
withpen pencircle scaled linewidth
withcolor linecolor ;
fi ;
endgroup ;
enddef ;
\stopMPcode

\def\samplewithbar#1{The sidebar follows the text
between \type{\startsidebar[...]} and \type{\stopsidebar},
\startsidebar[#1] {\blue from the top of the first line to the bottom of the last line.}\stopsidebar
Here the text between \type{\startsidebar[...]} and \type{\stopsidebar} has been colored in blue.\par
\blank}
\starttext
\hsize=4cm
\samplewithbar{zigzag1}
\samplewithbar{zigzag2}
\samplewithbar{wave1}
\samplewithbar{wave2}
\samplewithbar{obliquedashes}
\stoptext


The metapost macro draw_pattern_bar draws a repeating pattern along the bar length. The pattern is a sort of waveform defined with a path from (0,0) to (1,0). Its bounding box should have a height of 1, so that the base waveform has amplitude 1.

The length of the pattern and its "amplitude" are magnified according to patternlength and patternheight.

### The location parameter

The default \setupsidebar[location=left] and \setupsidebar[location=right]:

In doublesided typesetting with \setuppagenumbering[alternative=doublesided], \setupsidebar[location=inner] puts the sidebars always in the inner margin, while \setupsidebar[location=outer] puts them in the outer margin: