Visual Debugging

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).

Unordered

\tracefiles : ?

\tracepositions : ?

\traceposstring : ?

\traceboxplacement : ?

\traceotr : output routine?

\showboxes : show boxes

Layout

\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]

\starttext

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

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

\stoptext

Grid, Layers and Column Sets

\tracelayers : show boxes of layers

\tracecolumnset : ?

\tracetextareas : ?

\showgrid : make line grid visible

\tracegridsnapping : ?

Tables

\tracetables : ?

\traceTABLE : ?

\tracetabulate : ?

Math

\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

\tracemathcollectiontrue
\tracemathsymbol{Re}
\tracemathsymbol{Im}

\tracemathcharacter : ?

Bookmarks and References

\tracebookmarks : ?

\tracelinenotes : ?

\tracereferences : ?

\tracelabels : ?

Fonts and Type

\showbodyfont : actual bodyfont family with all variants

\showbodyfont[pagella,7pt]

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

\showbodyfontenvironment[pagella,7pt]

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

\showsymbolset[navigation 1]

\ShowCompleteFont from module fnt-10 : list of available chars of actual bodyfont encoding (for MkII, \showcharacters lists the available chars of actual bodyfont encoding )

\usemodule[fnt-10]
\setupcolors[state=start]
\starttext
\ShowCompleteFont{name:texgyrepagella}{8pt}{1}
\stoptext

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

\usemodule[math-characters]
\setupcolors[state=start]
\setupbodyfont[pagella,7pt]
\starttext
\showmathfontcharacters
\stoptext

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

(Make a better, slightly more complex example.)

\setupbodyfont[pagella,7pt]
\framed[frame=off,align=normal]{\showstruts
This will display \strut struts.\crlf
A frame with strut \framed[strut=yes]{xxx} and frame without \framed[strut=no]{xxx}}

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

\setupbodyfont[pagella,7pt]
\framed[frame=off]{\showfontstrip}

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

\setupbodyfont[pagella,7pt]
\framed[frame=off]{\tracedfontname{Bold}}

Colors

\showcolor : see Color

\showcolorgroup : ?

\showpalet : ?

\tracedgreymode : ?

\tracedgreycolormode : ?

\tracedrgbcolormode : ?

\tracedcmykcolormode : ?

\tracedspotcolormode : ?

Figures

\showexternalfigures : ?

\traceexternalfigures : ?

\tracesidefloats : ?

Interaction

\showfields : ?

\tracefields : ?

\traceJScode : trace JavaScript code

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