Changes

< {{todo|Add more examples of usage of textbackgrounds.}} == Basics == Pages, paragraphs, words can have a background color or [[Overlays|overlay]]. ConTeXt creates these using [[Main PageMetaPost]] . But a usual frame is only one object, its contents can’t flow over to the next page. You can use {{cmd|definetextbackground}} to define a named text background. The environment is based on {{cmd| framed}} and understands its parameters, but can contain several paragraphs and page breaks. After `\definetextbackground[Name]` you can use `\startName ... \stopName` (if there’s no name conflict) or `\starttextbackground[VisualsName]... \stoptextbackground`. Usually you won’t need {{cmd|setuptextbackground}}. The `location` parameter changes the behaviour between `text` (highlighting running text) and `paragraph` (boxed paragraphs). (See, eventually, the [[manual:details.pdf| details] >] manual or the {{src|anch-bck.mkvi|source}} for further explanations.)

Pages, paragraphs, words '''Beware''': The examples using {{cmd|startnarrower}} may be misleading – of course you can have a background: color or screenuse {{cmd|startbackground}} without the `narrower` environment; it behaves differently without `\starttext ... \stoptext`.

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 textbackgroundstextbackground.

location=paragraph, % background=screencolor, %doesn't work?? background=color,backgroundscreen backgroundcolor=middlegraylightgray, leftoffset=.5\bodyfontsize, rightoffset=.5\bodyfontsize, topoffset=.5\bodyfontsize, bottomoffset=.5\bodyfontsize, before={\startnarrower\switchtobodyfont[small]}, after={\switchtobodyfont[normal]\stopnarrower}, frame=off,]

 \input samplefile{knuth}

\input samplefile{knuth}

\input samplefile{knuth}

{{todo|The background does not show here using the live, online conTeXt processor. Why?}} == backgroundoffset Background Offset ==

location=paragraph, % background=screencolor, %doesn't work?? background=color,backgroundscreen backgroundcolor=middlegraylightgray, backgroundoffset=.5\bodyfontsize, before={\startnarrower\switchtobodyfont[small]}, after={\switchtobodyfont[normal]\stopnarrower}, frame=off,]

 \input samplefile{knuth}

\input samplefile{knuth}

\input samplefile{knuth}\stoptext</context> == Underlining with Text Backgrounds ==

Underlining is generally frowned upon by experienced TeXnicians. Occasionally,however, it is necessary and {{cmd|ul}} or {{cmd|underbar}} doesn’t do what you want. In thosecases using {{cmd|definetextbackground}} for the underlining may also be tried. <context source="yes">\stoptextdefinetextbackground[underline] [location=text,alternative=1,background=,frame=off] \definestartstop[underline] [before={\starttextbackground[underline]}, after=\stoptextbackground] \startTEXpageAn example with \startunderline underlined\stopunderline\ text.\stopTEXpage</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] \startTEXpageAn example with \startunderline underlined\stopunderline\ text.\stopTEXpage</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\samplefile{ward}\stopdashed