Inspired by a recent question and others like it, and not finding an existing duplicate, I ask:
What is the hierarchy of Front End options?
How do they work?
How can their values be set and recalled?
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2 Answers
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4 Option hierarchy
Quoting John Fultz:
Options work on an inheritance model. ... It all starts someplace. That would be the hard-coded option values in the front end C code. The root of the inheritance of options. Then one typically thinks of
$FrontEndas being the next level down, but there's another level in between. That is$DefaultFrontEnd. So, at the global level, it's ->$DefaultFrontEnd->$FrontEnd->$FrontEndSession. But only values set to$FrontEndget written to your preferences file.
In addition to these global settings many Front End options (or their equivalents) can be set at the Notebook level, with e.g. EvaluationNotebook[], and these, when set, take local priority.
Settings made to the Notebook are saved in the Notebook (.nb). Settings made to $FrontEnd are saved in:
FileNameJoin[{$UserBaseDirectory, "FrontEnd", "init.m"}] Settings to either $FrontEndSession or $DefaultFrontEnd do not persist between sessions. Settings made to $FrontEndSession override those to $FrontEnd for the duration of the session, while $DefaultFrontEnd are only used if the same option is specified nowhere else.
Setting and recalling option values
$FrontEnd and Notebook options can be set and cleared using the Option Inspector with the menu selections Global Preferences and Selected Notebook respectively. To clear an option click the x next to its option name:
Options can be set and recalled at all levels with SetOptions and Options.
For example one could make the following settings:
SetOptions[$DefaultFrontEnd, FontColor -> Red ] SetOptions[$FrontEnd, FontColor -> Orange ] SetOptions[$FrontEndSession, FontColor -> Magenta] SetOptions[EvaluationNotebook[], FontColor -> Blue ] Many options are aslo accessible and configurable through CurrentValue. An unqualified CurrentValue will show the value lowest in the hierarchy (with the highest priority):
CurrentValue[FontColor] // InputForm RGBColor[0, 0, 1] (* blue *)
A qualified CurrentValue will show the other settings as well:
CurrentValue[#, FontColor] & /@ {$DefaultFrontEnd, $FrontEnd, $FrontEndSession} // InputForm {RGBColor[1, 0, 0], (* red *) RGBColor[1, 0.5, 0], (* orange *) RGBColor[1, 0, 1]} (* magenta *)
The qualified form may be used to set option values:
CurrentValue[EvaluationNotebook[], FontColor] = Green; If the Notebook option is cleared through the Option Inspector, or a new Notebook is opened, the next setting up the hierarchy is used:
CurrentValue[FontColor] // InputForm RGBColor[1, 0, 1]
After Mathematica is restarted the $FrontEnd setting persists:
CurrentValue[FontColor] // InputForm RGBColor[1, 0.5, 0]
As David Creech noted in a comment it is possible to use Inherited as an option value to un-set that option and revert to the next higher level of the hierarchy. Example:
SetOptions[EvaluationNotebook[], FontColor -> Blue] Options[EvaluationNotebook[]] {FontColor -> RGBColor[0, 0, 1], FrontEndVersion -> . . .}
SetOptions[EvaluationNotebook[], FontColor -> Inherited] Options[EvaluationNotebook[]] {FrontEndVersion -> "10.1 for Microsoft Windows . . .}
Note that the Option has been entirely removed from the Notebook options list.
- $\begingroup$ I hope to make this answer a worthwhile reference. Please let me know of any corrections that are needed and offer any suggestions for improvement or extension that you have. $\endgroup$Mr.Wizard– Mr.Wizard2015-02-01 07:13:10 +00:00Commented Feb 1, 2015 at 7:13
- 1$\begingroup$ You could cover the use of Inherited to unset an option without using the Option Inspector. $\endgroup$David Creech– David Creech2016-02-01 19:08:18 +00:00Commented Feb 1, 2016 at 19:08
- $\begingroup$ Where
Stylesheetscome into play? $\endgroup$ercegovac– ercegovac2017-10-23 14:03:22 +00:00Commented Oct 23, 2017 at 14:03 - 1$\begingroup$ @ercegovac they come after the settings on the
NotebookObject, but before those set at theCelllevel. Essentially you have$FrontEnd > $FrontEndSession | $DefaultFrontEnd > NotebookObject > Cell Style (StyleSheet) > Box Form (e.g. BoxData, TextData) > CellObject > BoxObject. $\endgroup$b3m2a1– b3m2a12018-01-20 23:29:46 +00:00Commented Jan 20, 2018 at 23:29
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0 A useful point on recalling style definitions. These may be queried at the stylesheet level using StyleDefinitions:
CurrentValue[$FrontEndSession, {StyleDefinitions, "Input", FontColor}] Automatic They cannot, however, be set so easily (but I've got code to do that e.g. here):
CurrentValue[$FrontEndSession, {StyleDefinitions, "Input", FontColor}] = Red Automatic One useful thing about this is we can inspect more interesting options programmatically using this:
inspectBoxOptions[element_] := With[{boxo = StringTrim[ StringReplace[SymbolName[element], "Framed" -> "Frame"], "Box"] <> "BoxOptions"}, CurrentValue[$FrontEndSession, {StyleDefinitions, "Input", boxo}] /. s_Symbol?(StringStartsQ[SymbolName[#], boxo] &) :> StringTrim[SymbolName[s], boxo] ] inspectBoxOptions@Checkbox {"BaseStyle" -> {}, "DefaultBaseStyle" -> "Checkbox", "Enabled" -> Automatic, "Appearance" -> {Automatic, None, "Normal", Automatic}, "Background" -> Automatic, "ImageSize" -> All, "ImageMargins" -> Automatic, "FrameMargins" -> Automatic, "ContentPadding" -> True, "BaselinePosition" -> Automatic, "Alignment" -> {Automatic, Automatic}, "AutoAction" -> False, "ContinuousAction" -> False, "Momentary" -> False} 