Visual Debugging

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Revision as of 11:03, 9 February 2021 by Jano Kula (talk | contribs) (typos)
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Page is focused on the old Mark II ConTeXt version, though \show... commands are still the same. Work-in-progress page on current LMTX version is Debugging.

There's a whole lot of commands that help you analyzing and debugging your ConTeXt documents. Most of them start with \show... or \trace.... While \showsomething is a command that immediately inserts something, \tracesomethingtrue or ...false is a switch that influences the behaviour of some other commands. You can check the setting with \iftrace.... In the following we leave out the boolean value (true or false).


\tracefiles : ?

\tracepositions : ?

\traceposstring : ?

\traceboxplacement : ?

\traceotr : output routine?

\showboxes : show boxes


\showlayout : add four pages that show margins, layout sizes etc.

\showsetups : typeset a list of all defined sizes (variables) and their values

\showmakeup : show some otherwise invisible markup

\showframe : show frames of text area, layers, boxes etc.

\showlayoutcomponents : To allow Acrobat Reader users (among others?) to make layers visible/invisible at will, add this command at the start of your file.

Show attributes of visual elements

\usemodule [setups]


% \setuphead [..,..=..,..]
\showrootvalues [head]

% \setuphead [chapter] [..,..=..,..]
\showinstancevalues [head] [chapter]


Grid, Layers and Column Sets

\tracelayers : show boxes of layers

\tracecolumnset : ?

\tracetextareas : ?

\showgrid : make line grid visible

\tracegridsnapping : ?


\tracetables : ?

\traceTABLE : ?

\tracetabulate : ?


\tracemathtrue : show the layout boxes for left, middle, or right-aligned formulas.

\tracemathcommand : ?

\tracemathcollection : ?

\tracemathsymbol{name of math symbol} : show the command (name of symbol) and the symbol itself


\tracemathcharacter : ?

Bookmarks and References

\tracebookmarks : ?

\tracelinenotes : ?

\tracereferences : ?

\tracelabels : ?

Fonts and Type

\showbodyfont : actual bodyfont family with all variants

\showbodyfontenvironment : draws a table that shows which point sizes match the relative sizes

\showsymbolset[symbolset name] : shows all the symbols within a given symbol set

\showsymbolset[navigation 1]

\showcharacters : list of available chars of actual bodyfont encoding (approx. 4 pages, MkII only)

\showmathcharacters : list of all the available math (non-alphabetical) characters available in math, now including all the AMS characters. MkII only

\showaccents : shows A-Z and a-z with all available accents, MkII only

\showstruts : display struts (invisible placeholders for proper minimum line heights)

(Make a better, slightly more complex example.)

This will display \strut struts.\crlf
Frame with struts: \framed{xxx}\crlf
And frame without them: \framed[strut=no]{xxx}

\showfontstrip : the current typeface combination, with roman, sans, math, and teletype families visualised, with x-heights

\tracefonthandling :

\tracechinese : ?

\tracedfontname{Font Name} : Chain of synonyms for the given font name


\tracedfontencoding : ?

Colors and Graphics


\showcolor : see Color

\showcolorgroup : ?

\showpalet : ?

\tracedgreymode : ?

\tracedgreycolormode : ?

\tracedrgbcolormode : ?

\tracedcmykcolormode : ?

\tracedspotcolormode : ?


\showexternalfigures : ?

\traceexternalfigures : ?

\tracesidefloats : ?


\showfields : ?

\tracefields : ?

\traceJScode : trace JavaScript code

TODO: A lot of commands and switches are still unexplained. (See: To-Do List)