Style Scheme Definition Reference

Reference to the GtkSourceView style scheme definition file format


This is an overview of the Style Scheme Definition XML format, describing the meaning and usage of every element and attribute. The formal definition is stored in the RelaxNG schema file style.rng which should be installed on your system in the directory ${PREFIX}/share/gtksourceview-5/ (where ${PREFIX} can be /usr/ or /usr/local/ if you have installed from source).

The toplevel tag in a style scheme file is <style-scheme>. It has the following attributes:

  • id (mandatory)

Identifier for the style scheme. This is must be unique among style schemes.

  • name (mandatory)

Name of the style scheme. This is the name of the scheme to display to user, e.g. in a preferences dialog.

  • _name

This is the same as name attribute, except it will be translated. name and _name may not be used simultaneously.

  • parent-scheme (optional)

Style schemes may have parent schemes: all styles but those specified in the scheme will be taken from the parent scheme. In this way a scheme may be customized without copying all its content.

  • version (mandatory)

Style scheme format identifier. At the moment it must be “1.0”.

  • style-scheme tag may contain the following tags:

  • author Name of the style scheme author.

  • description Description of the style scheme.

  • _description Same as description except it will be localized.

  • color tags

    These define color names to be used in style tags. It has two attributes: name and value. value is the hexadecimal color specification like “#000000” or named color understood by Gdk prefixed with “#”, e.g. “#beige”.

  • style tags

    See below for their format description.

Each style tag describes a single element of style scheme (it corresponds to GtkSourceStyle object). It has the following attributes:

  • name (mandatory)

Name of the style. It can be anything, syntax highlighting uses lang-id:style-id, and there are few special styles which are used to control general appearance of the text. Style scheme may contain other names to be used in an application. For instance, it may define color to highlight compilation errors in a build log or a color for bookmarks.

  • foreground

Foreground color. It may be name defined in one of color tags, or value in hexadecimal format, e.g. “#000000”, or symbolic name understood by Gdk, prefixed with “#”, e.g. “#magenta” or “#darkred”.

  • background

Background color.

  • italic: true or false

  • bold: true or false

  • weight

The weight attribute was added in GtkSourceView 5.4.

The weight of the matched text block. The default value is “normal” but you may use any of the PangoWeight nicks or optionally a numeric value equivalent to the weights of CSS.

Setting this value will override any setting of “bold”.

  • underline

Accepts the values supported by PangoUnderline (“none”, “single”, “double”, “low”, “error”). GtkSourceView versions <= 3.16 only supported true or false and such value are still accepted for backward compatibility.

  • underline-color

Underline color.

  • strikethrough: true or false

  • scale

Scale the matched text block. Possible values are a float number as factor (e.g. "1.75") or one of the values "xx-small", "x-small", "small", "medium", "large","x-large","xx-large".

The following are names of styles which control GtkSourceView appearance:

  • text

Default style of text.

  • selection

Style of selected text.

  • selection-unfocused

Style of selected text when the widget doesn’t have input focus.

  • cursor

Text cursor style. Only the foreground attribute is used for this style.

  • secondary-cursor

Secondary cursor style (used in bidirectional text). Only the foreground attribute is used for this style. If this is not set while “cursor” is, then a color between text background and cursor colors is chosen, so it is enough to use “cursor” style only.

  • current-line

Current line style. Only the background attribute is used.

  • line-numbers

Text and background colors for the left margin, on which line numbers are drawn.

  • line-numbers-border

Background color for the border between the left gutter and textview.

  • current-line-number

Current line style for the left margin, on which the current line number is drawn. The background, foreground, and bold attributes may be used. foreground and bold were added in GtkSourceView 5.4. If bold is unset, it defaults to true.

  • bracket-match

Style to use for matching brackets.

  • bracket-mismatch

Style to use for mismatching brackets.

  • right-margin

Style to use for the right margin. The foreground attribute is used for drawing the vertical line. And the background attribute is used for the background on the right side of the margin. An alpha channel is applied to the two colors. For a light style scheme, a good color for both attributes is black. For a dark style scheme, white is a good choice.

  • draw-spaces

Style to use for drawing spaces (special symbols for a space, a tabulation, etc). Only the foreground attribute is used.

  • background-pattern

Style to use for drawing a background pattern, for example a grid. Only the background attribute is used.

Default style schemes

The GtkSourceView team prefers to just keep a small number of style schemes distributed with the library. To add a new style scheme in GtkSourceView itself, the style scheme must be very popular, and ideally a GtkSourceView-based application must use it by default.