3 Controlling Screen Display

It is often desirable to get visual help of what markup code in a text actually does without having to decipher it explicitly. For this purpose Emacs and AUCTeX provide font locking (also known as syntax highlighting) which visually sets off markup code like macros or environments by using different colors or fonts. For example text to be typeset in italics can be displayed with an italic font in the editor as well, or labels and references get their own distinct color.

While font locking helps you grasp the purpose of markup code and separate markup from content, the markup code can still be distracting. AUCTeX lets you hide those parts and show them again at request with its built-in support for hiding macros and environments which we call folding here.

Besides folding of macros and environments, AUCTeX provides support for Emacs’ outline mode which lets you narrow the buffer content to certain sections of your text by hiding the parts not belonging to these sections.

Moreover, you can focus in a specific portion of the code by narrowing the buffer to the desired region. AUCTeX provides also functions to narrow the buffer to the current group and to LaTeX environments.

AUCTeX also provides some WYSIWYG features.

First, you can customize font-latex-fontify-script to enable special formatting of ^ superscripts and _ subscripts (see Font Locking).

Secondly, AUCTeX with GNU Emacs 25 or later can display certain math macros using Unicode characters, e.g., \alpha as α. This is called prettification and is lightweight and reasonable robust (see Prettifying).

A more accurate approach is provided by preview-latex, a subsystem of AUCTeX, see Introduction in The preview-latex Manual. This system uses LaTeX to generate images that are then displayed in your buffer. It is extremely accurate but can be fragile with some packages (like older pgf versions).

Please note that you can use prettification and preview-latex together.

3.1 Font Locking

Font locking is supposed to improve readability of the source code by highlighting certain keywords with different colors or fonts. It thereby lets you recognize the function of markup code to a certain extent without having to read the markup command. For general information on controlling font locking with Emacs’ Font Lock mode, see Font Lock Mode in GNU Emacs Manual.

User Option: TeX-install-font-lock

Once font locking is enabled globally or for the major modes provided by AUCTeX, the font locking patterns and functionality of font-latex are activated by default. You can switch to a different font locking scheme or disable font locking in AUCTeX by customizing the variable TeX-install-font-lock.

Besides font-latex AUCTeX ships with a scheme which is derived from Emacs’ default LaTeX mode and activated by choosing tex-font-setup. Be aware that this scheme is not coupled with AUCTeX’s style system and not the focus of development. Therefore and due to font-latex being much more feature-rich the following explanations will only cover font-latex.

In case you want to hook in your own fontification scheme, you can choose other and insert the name of the function which sets up your font locking patterns. If you want to disable fontification in AUCTeX completely, choose ignore.

font-latex provides many options for customization which are accessible with M-x customize-group RET font-latex RET. For this description the various options are explained in conceptional groups.

3.1.1 Fontification of macros

Highlighting of macros can be customized by adapting keyword lists which can be found in the customization group font-latex-keywords.

Three types of macros can be handled differently with respect to fontification:

1. Commands of the form ‘\foo[bar]{baz}’ which consist of the macro itself, optional arguments in square brackets and mandatory arguments in curly braces. For the command itself the face font-lock-keyword-face will be used and for the optional arguments the face font-lock-variable-name-face. The face applied to the mandatory argument depends on the macro class represented by the respective built-in variables.
2. Declaration macros of the form ‘{\foo text}’ which consist of the macro which may be enclosed in a TeX group together with text to be affected by the macro. In case a TeX group is present, the macro will get the face font-lock-keyword-face and the text will get the face configured for the respective macro class. If no TeX group is present, the latter face will be applied to the macro itself.
3. Simple macros of the form ‘\foo’ which do not have any arguments or groupings. The respective face will be applied to the macro itself.

Customization variables for ‘\foo[bar]{baz}’ type macros allow both the macro name and the sequence of arguments to be specified. The latter is done with a string which can contain the characters

‘*’

indicating the existence of a starred variant for the macro,

‘[’

for optional arguments in brackets,

‘{’

for mandatory arguments in braces,

‘\’

for mandatory arguments consisting of a single macro and

‘|’

as a prefix indicating that two alternatives are following.

For example the specifier for ‘\documentclass’ would be ‘[{’ because the macro has one optional followed by one mandatory argument. The specifier for ‘\newcommand’ would be ‘*|{\[[{’ because there is a starred variant, the mandatory argument following the macro name can be a macro or a TeX group which can be followed by two optional arguments and the last token is a mandatory argument in braces.

Customization variables for the ‘{\foo text}’ and ‘\foo’ types are simple lists of strings where each entry is a macro name (without the leading backslash).

General macro classes

font-latex provides keyword lists for different macro classes which are described in the following table:

font-latex-match-function-keywords

Keywords for macros defining or related to functions, like ‘\newcommand’.
Type: ‘\macro[...]{...}’
Face: font-lock-function-name-face

font-latex-match-reference-keywords

Keywords for macros defining or related to references, like ‘\ref’.
Type: ‘\macro[...]{...}’
Face: font-lock-constant-face

font-latex-match-textual-keywords

Keywords for macros specifying textual content, like ‘\caption’.
Type: ‘\macro[...]{...}’
Face: font-lock-type-face

font-latex-match-variable-keywords

Keywords for macros defining or related to variables, like ‘\setlength’.
Type: ‘\macro[...]{...}’
Face: font-lock-variable-name-face

font-latex-match-warning-keywords

Keywords for important macros, e.g. affecting line or page break, like ‘\clearpage’.
Type: ‘\macro’
Face: font-latex-warning-face

Sectioning commands

Sectioning commands are macros like ‘\chapter’ or ‘\section’. For these commands there are two fontification schemes which may be selected by customizing the variable font-latex-fontify-sectioning.

User Option: font-latex-fontify-sectioning

Per default sectioning commands will be shown in a larger, proportional font, which corresponds to a number for this variable. The font size varies with the sectioning level, e.g. ‘\part’ (font-latex-sectioning-0-face) has a larger font than ‘\paragraph’ (font-latex-sectioning-5-face). Typically, values from 1.05 to 1.3 for font-latex-fontify-sectioning give best results, depending on your font setup. If you rather like to use the base font and a different color, set the variable to the symbol ‘color’. In this case the face font-lock-type-face will be used to fontify the argument of the sectioning commands.

You can make font-latex aware of your own sectioning commands be adding them to the keyword lists: font-latex-match-sectioning-0-keywords (font-latex-sectioning-0-face) … font-latex-match-sectioning-5-keywords (font-latex-sectioning-5-face).

Related to sectioning there is special support for slide titles which may be fontified with the face font-latex-slide-title-face. You can add macros which should appear in this face by customizing the variable font-latex-match-slide-title-keywords.

Commands for changing fonts

LaTeX provides various macros for changing fonts or font attributes. For example, you can select an italic font with ‘\textit{...}’ or bold with ‘\textbf{...}’. An alternative way to specify these fonts is to use special macros in TeX groups, like ‘{\itshape ...}’ for italics and ‘{\bfseries ...}’ for bold. As mentioned above, we call the former variants commands and the latter declarations.

Besides the macros for changing fonts provided by LaTeX there is an infinite number of other macros—either defined by yourself for logical markup or defined by macro packages—which affect the font in the typeset text. While LaTeX’s built-in macros and macros of packages known by AUCTeX are already handled by font-latex, different keyword lists per type style and macro type are provided for entering your own macros which are listed in the table below.

font-latex-match-bold-command-keywords

Keywords for commands specifying a bold type style.
Face: font-latex-bold-face

font-latex-match-italic-command-keywords

Keywords for commands specifying an italic font.
Face: font-latex-italic-face

font-latex-match-math-command-keywords

Keywords for commands specifying a math font.
Face: font-latex-math-face

font-latex-match-type-command-keywords

Keywords for commands specifying a typewriter font.
Face: font-lock-type-face

font-latex-match-bold-declaration-keywords

Keywords for declarations specifying a bold type style.
Face: font-latex-bold-face

font-latex-match-italic-declaration-keywords

Keywords for declarations specifying an italic font.
Face: font-latex-italic-face

font-latex-match-type-declaration-keywords

Keywords for declarations specifying a typewriter font.
Face: font-latex-type-face

Deactivating defaults of built-in keyword classes

font-latex ships with predefined lists of keywords for the classes described above. You can disable these defaults per class by customizing the variable font-latex-deactivated-keyword-classes. This is a list of strings for keyword classes to be deactivated. Valid entries are "warning", "variable", "biblatexnoarg", "biblatex", "reference", "function" , "sectioning-0", "sectioning-1", "sectioning-2", "sectioning-3", "sectioning-4", "sectioning-5", "slide-title", "textual", "bold-command", "italic-command", "math-command", "type-command", "bold-declaration", "italic-declaration", "type-declaration".

You can also get rid of certain keywords only. For example if you want to remove highlighting of footnotes as references you can put the following stanza into your init file:

(eval-after-load "font-latex"
  '(setq-default
    font-latex-match-reference-keywords-local
    (remove (assoc-string "footnote"
            font-latex-match-reference-keywords-local)
                font-latex-match-reference-keywords-local)))

But note that this means fiddling with font-latex’s internals and is not guaranteed to work in future versions of font-latex.

User-defined keyword classes

In case the customization options explained above do not suffice for your needs, you can specify your own keyword classes by customizing the variable font-latex-user-keyword-classes.

User Option: font-latex-user-keyword-classes

Every keyword class consists of four parts, a name, a list of keywords, a face and a specifier for the type of macros to be highlighted.

When adding new entries, you have to use unique values for the class names, i.e. they must not clash with names of the built-in keyword classes or other names given by you. Additionally the names must not contain spaces.

The list of keywords defines which commands and declarations should be covered by the keyword class. A keyword can either be a simple command name omitting the leading backslash or a list consisting of the command name and a string specifying the sequence of arguments for the command.

The face argument can either be an existing face or face attributes made by you.

There are three alternatives for the type of keywords—“Command with arguments”, “Declaration inside TeX group” and “Command without arguments”—which correspond with the macro types explained above.

3.1.2 Fontification of quotes

Text in quotation marks is displayed with the face font-latex-string-face. Besides the various forms of opening and closing double and single quotation marks, so-called guillemets (<<, >>) can be used for quoting. Because there are two styles of using them—French style: << text >>; German style: >>text<<—you can customize the variable font-latex-quotes to tell font-latex which type you are using if the correct value cannot be derived from document properties.

User Option: font-latex-quotes

The default value of font-latex-quotes is ‘auto’ which means that font-latex will try to derive the correct type of quotation mark matching from document properties like the language option supplied to the babel LaTeX package.

If the automatic detection fails for you and you mostly use one specific style you can set it to a specific language-dependent value as well. Set the value to ‘german’ if you are using >>German quotes<< and to ‘french’ if you are using << French quotes >>. font-latex will recognize the different ways these quotes can be given in your source code, i.e. (‘"<’, ‘">’), (‘<<’, ‘>>’) and the respective 8-bit variants.

If you set font-latex-quotes to nil, quoted content will not be fontified.

3.1.3 Fontification of mathematical constructs

In LaTeX mathematics can be indicated by a variety of different methods: toggles (like dollar signs), macros and environments. Math constructs known by font-latex are displayed with the face font-latex-math-face. Support for dollar signs and shorthands like ‘\(...\)’ or ‘\[...\]’ is built-in and not customizable. Support for other math macros and environments can be adapted by customizing the variables font-latex-match-math-command-keywords and font-latex-math-environments respectively.

In order to make math constructs more readable, font-latex displays subscript and superscript parts in a smaller font and raised or lowered respectively. This fontification feature can be controlled with the variables font-latex-fontify-script and font-latex-script-display.

User Option: font-latex-fontify-script

If non-nil, fontify subscript and superscript strings. Concretely, this means that the scripts are raised or lowered.

Another possiblity is setting this variable to the symbol multi-level. In this case, in a formula x^{y^z}, y is raised above and smaller than x, and z is raised above and smaller than y. With many script levels, the text might become too small to be readable. (See font-latex-fontify-script-max-level below.)

Lastly, you can set this variable to invisible whose behavior is like multi-level, and in addition the super-/subscript characters ^ and _ are not displayed.

User Option: font-latex-fontify-script-max-level

Maximum scriptification level for which script faces are applied.

The faces font-latex-superscript-face and font-latex-subscript-face define custom :height values < 1.0. Therefore, scripts are displayed with a slightly smaller font than normal math text. If font-latex-fontify-script is multi-level or invisible, the font size becomes too small to be readable after a few levels. This option allows to specify the maximum level after which the size of the script text won’t be shrunken anymore.

For example, in the expression x^{y^{z^a_b}}, x has scriptification level 0, y has level 1, z has level 2, and both a and b have scriptification level 3.

If font-latex-fontify-script-max-level was 2, then z, a, and b would have the same font size. If it was 3 or more, then a and b were smaller than z just in the same way as z is smaller than y and y is smaller than x.

The script characters ‘^’ and ‘_’ themselves are also fontified with an own face named font-latex-script-char-face.

User Option: font-latex-script-display

Display specification for subscript and superscript content. The car is used for subscript, the cdr is used for superscript. The feature is implemented using so-called display properties. For information on what exactly to specify for the values, see Other Display Specifications in GNU Emacs Lisp Reference Manual.

3.1.4 Verbatim macros and environments

Usually it is not desirable to have content to be typeset verbatim highlighted according to LaTeX syntax. Therefore this content will be fontified uniformly with the face font-latex-verbatim-face.

font-latex differentiates three different types of verbatim constructs for fontification. Macros with special characters like | as delimiters, macros with braces, and environments. Which macros and environments are recognized is controlled by the variables LaTeX-verbatim-macros-with-delims, LaTeX-verbatim-macros-with-braces, and LaTeX-verbatim-environments respectively.

3.1.5 Faces used by font-latex

In case you want to change the colors and fonts used by font-latex please refer to the faces mentioned in the explanations above and use M-x customize-face RET <face> RET. All faces defined by font-latex are accessible through a customization group by typing M-x customize-group RET font-latex-highlighting-faces RET.

3.1.6 Known fontification problems

In certain cases the fontification machinery fails to interpret buffer contents correctly. This can lead to color bleed, i.e. large parts of a buffer get fontified with an inappropriate face. A typical situation for this to happen is the use of a dollar sign (‘$’) in a verbatim macro or environment. If font-latex is not aware of the verbatim construct, it assumes the dollar sign to be a toggle for mathematics and fontifies the following buffer content with the respective face until it finds a closing dollar sign or till the end of the buffer.

As a remedy you can make the verbatim construct known to font-latex, see Verbatim content. If this is not possible, you can insert a commented dollar sign (‘%$’) at the next suitable end of line as a quick workaround.

3.2 Folding Macros and Environments

A popular complaint about markup languages like TeX and LaTeX is that there is too much clutter in the source text and that one cannot focus well on the content. There are macros where you are only interested in the content they are enclosing, like font specifiers where the content might already be fontified in a special way by font locking. Or macros the content of which you only want to see when actually editing it, like footnotes or citations. Similarly you might find certain environments or comments distracting when trying to concentrate on the body of your document.

With AUCTeX’s folding functionality you can collapse those items and replace them by a fixed string, the content of one of their arguments, or a mixture of both. If you want to make the original text visible again in order to view or edit it, move point sideways onto the placeholder (also called display string) or left-click with the mouse pointer on it. (The latter is currently only supported on Emacs.) The macro or environment will unfold automatically, stay open as long as point is inside of it and collapse again once you move point out of it. (Note that folding of environments currently does not work in every AUCTeX mode.)

In order to use this feature, you have to activate TeX-fold-mode which will activate the auto-reveal feature and the necessary commands to hide and show macros and environments. You can activate the mode in a certain buffer by typing the command M-x TeX-fold-mode RET or using the keyboard shortcut C-c C-o C-f. If you want to use it every time you edit a LaTeX document, add it to a hook:

(add-hook 'LaTeX-mode-hook (lambda ()
                             (TeX-fold-mode 1)))

If it should be activated in all AUCTeX modes, use TeX-mode-hook instead of LaTeX-mode-hook.

Once the mode is active there are several commands available to hide and show macros, environments and comments:

Command: TeX-fold-buffer

(C-c C-o C-b) Hide all foldable items in the current buffer according to the setting of TeX-fold-type-list.

If you want to have this done automatically every time you open a file, add it to a hook and make sure the function is called after font locking is set up for the buffer. The following code should accomplish this:

(add-hook 'find-file-hook 'TeX-fold-buffer t)

The command can be used any time to refresh the whole buffer and fold any new macros and environments which were inserted after the last invocation of the command.

User Option: TeX-fold-type-list

List of symbols determining the item classes to consider for folding. This can be macros, environments and comments. Per default only macros and environments are folded.

User Option: TeX-fold-force-fontify

In order for all folded content to get the right faces, the whole buffer has to be fontified before folding is carried out. TeX-fold-buffer therefore will force fontification of unfontified regions. As this will prolong the time folding takes, you can prevent forced fontification by customizing the variable TeX-fold-force-fontify.

User Option: TeX-fold-auto

By default, a macro inserted with TeX-insert-macro (C-c C-m) will not be folded. Set this variable to a non-nil value to aumatically fold macros as soon as they are inserted.

User Option: TeX-fold-preserve-comments

By default items found in comments will be folded. If your comments often contain unfinished code this might lead to problems. Give this variable a non-nil value and foldable items in your comments will be left alone.

User Option: TeX-fold-unfold-around-mark

When this variable is non-nil and there is an active regione, text around the mark will be kept unfolded.

Command: TeX-fold-region

(C-c C-o C-r) Hide all configured macros in the marked region.

Command: TeX-fold-paragraph

(C-c C-o C-p) Hide all configured macros in the paragraph containing point.

Command: TeX-fold-macro

(C-c C-o C-m) Hide the macro on which point currently is located. If the name of the macro is found in TeX-fold-macro-spec-list, the respective display string will be shown instead. If it is not found, the name of the macro in sqare brackets or the default string for unspecified macros (TeX-fold-unspec-macro-display-string) will be shown, depending on the value of the variable TeX-fold-unspec-use-name.

Command: TeX-fold-env

(C-c C-o C-e) Hide the environment on which point currently is located. The behavior regarding the display string is analogous to TeX-fold-macro and determined by the variables TeX-fold-env-spec-list and TeX-fold-unspec-env-display-string respectively.

Command: TeX-fold-math

Hide the math macro on which point currently is located. If the name of the macro is found in TeX-fold-math-spec-list, the respective display string will be shown instead. If it is not found, the name of the macro in sqare brackets or the default string for unspecified macros (TeX-fold-unspec-macro-display-string) will be shown, depending on the value of the variable TeX-fold-unspec-use-name.

Command: TeX-fold-comment

(C-c C-o C-c) Hide the comment point is located on.

Command: TeX-fold-clearout-buffer

(C-c C-o b) Permanently unfold all macros and environments in the current buffer.

Command: TeX-fold-clearout-region

(C-c C-o r) Permanently unfold all macros and environments in the marked region.

Command: TeX-fold-clearout-paragraph

(C-c C-o p) Permanently unfold all macros and environments in the paragraph containing point.

Command: TeX-fold-clearout-item

(C-c C-o i) Permanently show the macro or environment on which point currently is located. In contrast to temporarily opening the macro when point is moved sideways onto it, the macro will be permanently unfolded and will not collapse again once point is leaving it.

Command: TeX-fold-dwim

(C-c C-o C-o) Hide or show items according to the current context. If there is folded content, unfold it. If there is a marked region, fold all configured content in this region. If there is no folded content but a macro or environment, fold it.

In case you want to use a different prefix than C-c C-o for these commands you can customize the variable TeX-fold-command-prefix. (Note that this will not change the key binding for activating the mode.)

The commands above will only take macros or environments into consideration which are specified in the variables TeX-fold-macro-spec-list or TeX-fold-env-spec-list respectively.

User Option: TeX-fold-macro-spec-list

List of replacement specifiers and macros to fold. The specifier can be a string, an integer or a function symbol.

If you specify a string, it will be used as a display replacement for the whole macro. Numbers in braces, brackets, parens or angle brackets will be replaced by the respective macro argument. For example ‘{1}’ will be replaced by the first mandatory argument of the macro. One can also define alternatives within the specifier which are used if an argument is not found. Alternatives are separated by ‘||’. They are most useful with optional arguments. As an example, the default specifier for ‘\item’ is ‘[1]:||*’ which means that if there is an optional argument, its value is shown followed by a colon. If there is no optional argument, only an asterisk is used as the display string.

If you specify a number as the first element, the content of the respective mandatory argument of a LaTeX macro will be used as the placeholder.

If the first element is a function symbol, the function will be called with all mandatory arguments of the macro and the result of the function call will be used as a replacement for the macro.

The placeholder is made by copying the text from the buffer together with its properties, i.e. its face as well. If fontification has not happened when this is done (e.g. because of lazy font locking) the intended fontification will not show up. As a workaround you can leave Emacs idle a few seconds and wait for stealth font locking to finish before you fold the buffer. Or you just re-fold the buffer with TeX-fold-buffer when you notice a wrong fontification.

User Option: TeX-fold-env-spec-list

List of display strings or argument numbers and environments to fold. Argument numbers refer to the ‘\begin’ statement. That means if you have e.g. ‘\begin{tabularx}{\linewidth}{XXX} ... \end{tabularx}’ and specify 3 as the argument number, the resulting display string will be “XXX”.

User Option: TeX-fold-math-spec-list

List of display strings and math macros to fold.

The variables TeX-fold-macro-spec-list, TeX-fold-env-spec-list, and TeX-fold-math-spec-list apply to any AUCTeX mode. If you want to make settings which are only applied to LaTeX mode, you can use the mode-specific variables LaTeX-fold-macro-spec-list, LaTeX-fold-env-spec-list, and LaTeX-fold-math-spec-list

User Option: TeX-fold-unspec-macro-display-string

Default display string for macros which are not specified in TeX-fold-macro-spec-list.

User Option: TeX-fold-unspec-env-display-string

Default display string for environments which are not specified in TeX-fold-env-spec-list.

User Option: TeX-fold-unspec-use-name

If non-nil the name of the macro or environment surrounded by square brackets is used as display string, otherwise the defaults specified in TeX-fold-unspec-macro-display-string or TeX-fold-unspec-env-display-string respectively.

When you hover with the mouse pointer over folded content, its original text will be shown in a tooltip or the echo area depending on Tooltip mode being activate. In order to avoid exorbitantly big tooltips and to cater for the limited space in the echo area the content will be cropped after a certain amount of characters defined by the variable TeX-fold-help-echo-max-length.

User Option: TeX-fold-help-echo-max-length

Maximum length of original text displayed in a tooltip or the echo area for folded content. Set it to zero in order to disable this feature.

3.3 Outlining the Document

AUCTeX supports the standard outline minor mode using LaTeX/ConTeXt sectioning commands as header lines. See Outline Mode in GNU Emacs Manual.

You can add your own headings by setting the variable TeX-outline-extra.

Variable: TeX-outline-extra

List of extra TeX outline levels.

Each element is a list with two entries. The first entry is the regular expression matching a header, and the second is the level of the header. A ‘^’ is automatically prepended to the regular expressions in the list, so they must match text at the beginning of the line.

See LaTeX-section-list or ConTeXt-INTERFACE-section-list for existing header levels.

The following example add ‘\item’ and ‘\bibliography’ headers, with ‘\bibliography’ at the same outline level as ‘\section’, and ‘\item’ being below ‘\subparagraph’.

(setq TeX-outline-extra
      '(("[ \t]*\\\\\\(bib\\)?item\\b" 7)
	("\\\\bibliography\\b" 2)))

You may want to check out the unbundled out-xtra package for even better outline support. It is available from your favorite emacs lisp archive.

3.4 Narrowing

Sometimes you want to focus your attention to a limited region of the code. You can do that by restricting the text addressable by editing commands and hiding the rest of the buffer with the narrowing functions, see Narrowing in GNU Emacs Manual. In addition, AUCTeX provides a couple of other commands to narrow the buffer to a group, i.e. a region enclosed in a pair of curly braces, and to LaTeX environments.

Command: TeX-narrow-to-group

(C-x n g) Make text outside current group invisible.

Command: LaTeX-narrow-to-environment count

(C-x n e) Make text outside current environment invisible. With optional argument count keep visible that number of enclosing environmens.

Like other standard narrowing functions, the above commands are disabled. Attempting to use them asks for confirmation and gives you the option of enabling them; if you enable the commands, confirmation will no longer be required for them.

3.5 Prettifying

Emacs 25 is able to prettify symbols in programming language buffers, see Misc for Programs in GNU Emacs Manual. The canonical example is to display (lambda () ...) as (λ () ...) in Lisp buffers.

AUCTeX can use this feature in order to display certain math macros and greek letters using their Unicode representation, too. For example, the TeX code \alpha \times \beta will be displayed as α × β. When point is on one of the characters, it’ll be unprettified automatically, meaning you see the verbatim text again. For this behaviour however you need to set prettify-symbols-unprettify-at-point to t or right-edge which will unprettify the symbol when point moves into or near it.

To enable prettification in AUCTeX, simply add prettify-symbols-mode to TeX-mode-hook. If you enabled prettification globally with global-prettify-symbols-mode, then it’s automatically enabled in AUCTeX, too.

You can also add custom symbol unicode-character pairs for prettification by adding to tex--prettify-symbols-alist. Note that this variable is part of Emacs’ stock tex-mode.el and used by that and AUCTeX.