Difference between revisions of "TextBackground"

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(Moved and edited contents of Underlining_With_TextBackgrounds)
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{{todo|Add more examples of usage of textbackgrounds.}}
 
{{todo|Add more examples of usage of textbackgrounds.}}
  
Pages, paragraphs, words can have a background: color or screen.
+
Pages, paragraphs, words can have a background color or frame. ConTeXt creates these using [[MetaPost]].
 +
 
 +
(See, eventually, the [[manual:details.pdf| details]] manual or the {{src|anch-bck.mkvi|source}} for further explanations.)
  
 
== Example: multi-page backgrounded text ==
 
== Example: multi-page backgrounded text ==
  
Perhaps one might like to offset examples from the running text, or signal to the reader that the following paragraphs contain secondary, detailed information that is of interest only to the specialists. This can be achieved using textbackgrounds.
+
Perhaps one might like to offset examples from the running text, or signal to the reader that the following paragraphs contain secondary, detailed information that is of interest only to the specialists. This can be achieved using textbackground.
  
 
In contrast, [[Framed]] creates text blocks that do not span columns or pages.
 
In contrast, [[Framed]] creates text blocks that do not span columns or pages.
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In the following example, we also reduce the textwidth and bodyfont size.
 
In the following example, we also reduce the textwidth and bodyfont size.
 
<context source="yes">
 
<context source="yes">
\setupcolors[state=start]
 
 
 
\definetextbackground[secondary][
 
\definetextbackground[secondary][
        location=paragraph,
+
  location=paragraph,
        %background=screen, %doesn't work??
+
  background=color,
background=color,backgroundscreen=middlegray,
+
  backgroundcolor=lightgray,
        leftoffset=.5\bodyfontsize,rightoffset=.5\bodyfontsize,
+
  leftoffset=.5\bodyfontsize,
        topoffset=.5\bodyfontsize,bottomoffset=.5\bodyfontsize,
+
  rightoffset=.5\bodyfontsize,
        before={\startnarrower\switchtobodyfont[small]},
+
  topoffset=.5\bodyfontsize,
        after={\switchtobodyfont[normal]\stopnarrower},
+
  bottomoffset=.5\bodyfontsize,
        frame=off]
+
  before={\startnarrower\switchtobodyfont[small]},
 
+
  after={\stopnarrower},
\starttext
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  frame=off,]
  
 
\input knuth
 
\input knuth
  
 
\startsecondary
 
\startsecondary
\input knuth
+
\input knuth
 
\stopsecondary
 
\stopsecondary
  
 
\input knuth
 
\input knuth
 
\stoptext
 
 
</context>
 
</context>
  
{{todo|The background does not show here using the live, online conTeXt processor. Why?}}
+
== Background Offset ==
 
 
== backgroundoffset ==
 
  
 
The options left, right, top, bottomoffset can be replaced by backgroundoffset yielding a different result:
 
The options left, right, top, bottomoffset can be replaced by backgroundoffset yielding a different result:
  
 
<context source="yes">
 
<context source="yes">
\setupcolors[state=start]
 
 
 
\definetextbackground[secondary][
 
\definetextbackground[secondary][
        location=paragraph,
+
  location=paragraph,
        %background=screen, %doesn't work??
+
  background=color,
background=color,backgroundscreen=middlegray,
+
  backgroundcolor=lightgray,
        backgroundoffset=.5\bodyfontsize,
+
  backgroundoffset=.5\bodyfontsize,
        before={\startnarrower\switchtobodyfont[small]},
+
  before={\startnarrower\switchtobodyfont[small]},
        after={\switchtobodyfont[normal]\stopnarrower},
+
  after={\stopnarrower},
        frame=off]
+
  frame=off,]
 
 
\starttext
 
  
 
\input knuth
 
\input knuth
  
 
\startsecondary
 
\startsecondary
\input knuth
+
\input knuth
 
\stopsecondary
 
\stopsecondary
  
 
\input knuth
 
\input knuth
 +
</context>
 +
 +
== Underlining with Text Backgrounds ==
 +
 +
Underlining is generally frowned upon by experienced TeXnicians. Occasionally,
 +
however, it is necessary and <cmd>ul</cmd> or <cmd>underbar</cmd> doesn’t do what you want. In those
 +
cases using  <cmd>definetextbackground</cmd> for the underlining may also be tried.
 +
 +
<context source="yes">
 +
\definetextbackground[underline]
 +
  [location=text,alternative=1,background=,frame=off]
 +
\definestartstop[underline]
 +
  [before={\starttextbackground[underline]},
 +
  after=\stoptextbackground]
  
\stoptext
+
An example with \startunderline underlined\stopunderline\ text.
 
</context>
 
</context>
 +
 +
If desired, the location of the line can also be adjusted.
 +
 +
<context source="yes">
 +
\startuseMPgraphic{mpos:par:columnset} % Shift underlining down a touch
 +
  \iftracepositions show_multi_pars \else draw_multi_pars \fi ;
 +
  path p ; p := boundingbox currentpicture ;
 +
  currentpicture := currentpicture shifted (0,-StrutDepth/3) ;
 +
  setbounds currentpicture to p ;
 +
\stopuseMPgraphic
 +
\definetextbackground[underline]
 +
  [location=text,alternative=1,background=,frame=off]
 +
\definestartstop[underline]
 +
  [before={\starttextbackground[underline]},
 +
  after=\stoptextbackground]
 +
An example with \startunderline underlined\stopunderline\ text.
 +
</context>
 +
 +
 +
=== Example: dashed underbar ===
 +
(by WS, 4/2011)
 +
 +
<context source="yes">
 +
\definetextbackground
 +
  [dashed]
 +
  [location=text,
 +
  framecolor=black,
 +
  alternative=1,
 +
  voffset=-\strutdp,
 +
  background=,
 +
  frame=off,
 +
  dash=1]
 +
 +
\startdashed
 +
\input ward
 +
\stopdashed
 +
</context>
 +
 +
== What if textbackground doesn’t work? (MkII) ==
 +
 +
The textbackground commands require [[write18]] to be enabled; see that page for more information.

Revision as of 10:38, 5 February 2019

< Main Page | Visuals >


TODO: Add more examples of usage of textbackgrounds. (See: To-Do List)


Pages, paragraphs, words can have a background color or frame. ConTeXt creates these using MetaPost.

(See, eventually, the details manual or the source for further explanations.)

Example: multi-page backgrounded text

Perhaps one might like to offset examples from the running text, or signal to the reader that the following paragraphs contain secondary, detailed information that is of interest only to the specialists. This can be achieved using textbackground.

In contrast, Framed creates text blocks that do not span columns or pages.

In the following example, we also reduce the textwidth and bodyfont size.

\definetextbackground[secondary][
  location=paragraph,
  background=color,
  backgroundcolor=lightgray,
  leftoffset=.5\bodyfontsize,
  rightoffset=.5\bodyfontsize,
  topoffset=.5\bodyfontsize,
  bottomoffset=.5\bodyfontsize,
  before={\startnarrower\switchtobodyfont[small]},
  after={\stopnarrower},
  frame=off,]

\input knuth

\startsecondary
\input knuth
\stopsecondary

\input knuth

Background Offset

The options left, right, top, bottomoffset can be replaced by backgroundoffset yielding a different result:

\definetextbackground[secondary][
  location=paragraph,
  background=color,
  backgroundcolor=lightgray,
  backgroundoffset=.5\bodyfontsize,
  before={\startnarrower\switchtobodyfont[small]},
  after={\stopnarrower},
  frame=off,]

\input knuth

\startsecondary
\input knuth
\stopsecondary

\input knuth

Underlining with Text Backgrounds

Underlining is generally frowned upon by experienced TeXnicians. Occasionally, however, it is necessary and \ul or \underbar doesn’t do what you want. In those cases using \definetextbackground for the underlining may also be tried.

\definetextbackground[underline]
  [location=text,alternative=1,background=,frame=off]
\definestartstop[underline]
  [before={\starttextbackground[underline]},
   after=\stoptextbackground]

An example with \startunderline underlined\stopunderline\ text.

If desired, the location of the line can also be adjusted.

\startuseMPgraphic{mpos:par:columnset} % Shift underlining down a touch
   \iftracepositions show_multi_pars \else draw_multi_pars \fi ;
   path p ; p := boundingbox currentpicture ;
   currentpicture := currentpicture shifted (0,-StrutDepth/3) ;
   setbounds currentpicture to p ;
\stopuseMPgraphic
\definetextbackground[underline]
  [location=text,alternative=1,background=,frame=off]
\definestartstop[underline]
  [before={\starttextbackground[underline]},
   after=\stoptextbackground]
An example with \startunderline underlined\stopunderline\ text.


Example: dashed underbar

(by WS, 4/2011)

\definetextbackground
  [dashed]
  [location=text,
   framecolor=black,
   alternative=1,
   voffset=-\strutdp,
   background=,
   frame=off,
   dash=1]

\startdashed
\input ward
\stopdashed

What if textbackground doesn’t work? (MkII)

The textbackground commands require write18 to be enabled; see that page for more information.