# 5. Syntax Highlighter and Color Settings Page
> For the complete documentation index, see [llms.txt](https://plugins.jetbrains.com/docs/intellij/llms.txt).
> **TL;DR**
> Reference: [Syntax and Error Highlighting](syntax-highlighting-and-error-highlighting.html)
>
>
>
> Code: [SimpleSyntaxHighlighter](https://github.com/JetBrains/intellij-sdk-code-samples/tree/main/simple_language_plugin/src/main/java/org/intellij/sdk/language/SimpleSyntaxHighlighter.java), [SimpleSyntaxHighlighterFactory](https://github.com/JetBrains/intellij-sdk-code-samples/tree/main/simple_language_plugin/src/main/java/org/intellij/sdk/language/SimpleSyntaxHighlighterFactory.java), [SimpleColorSettingsPage](https://github.com/JetBrains/intellij-sdk-code-samples/tree/main/simple_language_plugin/src/main/java/org/intellij/sdk/language/SimpleColorSettingsPage.java)
> **Tip:**
> This page is part of multi-step [Custom Language Support Tutorial](custom-language-support-tutorial.html). All previous steps must be executed in sequence for the code to work.
The first level of syntax highlighting is based on the lexer output, and is provided by `SyntaxHighlighter`. A plugin can also define color settings based on `ColorSettingPage` so the user can configure highlight colors.
## Define a Syntax Highlighter
[SimpleSyntaxHighlighter](https://github.com/JetBrains/intellij-sdk-code-samples/tree/main/simple_language_plugin/src/main/java/org/intellij/sdk/language/SimpleSyntaxHighlighter.java) extends [SyntaxHighlighterBase](https://github.com/JetBrains/intellij-community/tree/idea/263.7307.200/platform/editor-ui-api/src/com/intellij/openapi/fileTypes/SyntaxHighlighterBase.java). As recommended in [Color Scheme Management](color-scheme-management.html#text-attribute-key-dependency), the Simple Language highlighting text attributes are specified as a dependency on one of standard IntelliJ Platform keys. For the Simple Language, define only one scheme.
```JAVA
public class SimpleSyntaxHighlighter extends SyntaxHighlighterBase {
public static final TextAttributesKey SEPARATOR =
createTextAttributesKey("SIMPLE_SEPARATOR", DefaultLanguageHighlighterColors.OPERATION_SIGN);
public static final TextAttributesKey KEY =
createTextAttributesKey("SIMPLE_KEY", DefaultLanguageHighlighterColors.KEYWORD);
public static final TextAttributesKey VALUE =
createTextAttributesKey("SIMPLE_VALUE", DefaultLanguageHighlighterColors.STRING);
public static final TextAttributesKey COMMENT =
createTextAttributesKey("SIMPLE_COMMENT", DefaultLanguageHighlighterColors.LINE_COMMENT);
public static final TextAttributesKey BAD_CHARACTER =
createTextAttributesKey("SIMPLE_BAD_CHARACTER", HighlighterColors.BAD_CHARACTER);
private static final TextAttributesKey[] BAD_CHAR_KEYS = new TextAttributesKey[]{BAD_CHARACTER};
private static final TextAttributesKey[] SEPARATOR_KEYS = new TextAttributesKey[]{SEPARATOR};
private static final TextAttributesKey[] KEY_KEYS = new TextAttributesKey[]{KEY};
private static final TextAttributesKey[] VALUE_KEYS = new TextAttributesKey[]{VALUE};
private static final TextAttributesKey[] COMMENT_KEYS = new TextAttributesKey[]{COMMENT};
private static final TextAttributesKey[] EMPTY_KEYS = new TextAttributesKey[0];
@NotNull
@Override
public Lexer getHighlightingLexer() {
return new SimpleLexerAdapter();
}
@Override
public TextAttributesKey @NotNull [] getTokenHighlights(IElementType tokenType) {
if (tokenType.equals(SimpleTypes.SEPARATOR)) {
return SEPARATOR_KEYS;
}
if (tokenType.equals(SimpleTypes.KEY)) {
return KEY_KEYS;
}
if (tokenType.equals(SimpleTypes.VALUE)) {
return VALUE_KEYS;
}
if (tokenType.equals(SimpleTypes.COMMENT)) {
return COMMENT_KEYS;
}
if (tokenType.equals(TokenType.BAD_CHARACTER)) {
return BAD_CHAR_KEYS;
}
return EMPTY_KEYS;
}
}
```
### Define a Syntax Highlighter Factory
The factory provides a standard way for the IntelliJ Platform to instantiate the syntax highlighter for Simple Language files. Here, [SimpleSyntaxHighlighterFactory](https://github.com/JetBrains/intellij-sdk-code-samples/tree/main/simple_language_plugin/src/main/java/org/intellij/sdk/language/SimpleSyntaxHighlighterFactory.java) subclasses [SyntaxHighlighterFactory](https://github.com/JetBrains/intellij-community/tree/idea/263.7307.200/platform/editor-ui-api/src/com/intellij/openapi/fileTypes/SyntaxHighlighterFactory.java).
```JAVA
final class SimpleSyntaxHighlighterFactory extends SyntaxHighlighterFactory {
@NotNull
@Override
public SyntaxHighlighter getSyntaxHighlighter(Project project, VirtualFile virtualFile) {
return new SimpleSyntaxHighlighter();
}
}
```
### Register the Syntax Highlighter Factory
Register the factory with the IntelliJ Platform in the plugin configuration file using the [com.intellij.lang.syntaxHighlighterFactory](https://jb.gg/ipe?extensions=com.intellij.lang.syntaxHighlighterFactory) extension point .
```XML
```
### Run the Project with Default Colors
Open the example Simple Language [properties file](lexer-and-parser-definition.html#run-the-project) (`test.simple`) in the IDE Development Instance. The colors for Simple Language Key, Separator, and Value highlighting default to the IDE Language Defaults for Keyword, Braces, Operators, and Strings, respectively.
## Define a Color Settings Page
The color settings page adds the ability for users to customize color settings for the highlighting in Simple Language files. The [SimpleColorSettingsPage](https://github.com/JetBrains/intellij-sdk-code-samples/tree/main/simple_language_plugin/src/main/java/org/intellij/sdk/language/SimpleColorSettingsPage.java) implements [ColorSettingsPage](https://github.com/JetBrains/intellij-community/tree/idea/263.7307.200/platform/platform-api/src/com/intellij/openapi/options/colors/ColorSettingsPage.java).
```JAVA
final class SimpleColorSettingsPage implements ColorSettingsPage {
private static final AttributesDescriptor[] DESCRIPTORS = new AttributesDescriptor[]{
new AttributesDescriptor("Key", SimpleSyntaxHighlighter.KEY),
new AttributesDescriptor("Separator", SimpleSyntaxHighlighter.SEPARATOR),
new AttributesDescriptor("Value", SimpleSyntaxHighlighter.VALUE),
new AttributesDescriptor("Bad value", SimpleSyntaxHighlighter.BAD_CHARACTER)
};
@Override
public Icon getIcon() {
return SimpleIcons.FILE;
}
@NotNull
@Override
public SyntaxHighlighter getHighlighter() {
return new SimpleSyntaxHighlighter();
}
@NotNull
@Override
public String getDemoText() {
return """
# You are reading the ".properties" entry.
! The exclamation mark can also mark text as comments.
website = https://en.wikipedia.org/
language = English
# The backslash below tells the application to continue reading
# the value onto the next line.
message = Welcome to \\
Wikipedia!
# Add spaces to the key
key\\ with\\ spaces = This is the value that could be looked up with the key "key with spaces".
# Unicode
tab : \\u0009""";
}
@Nullable
@Override
public Map getAdditionalHighlightingTagToDescriptorMap() {
return null;
}
@Override
public AttributesDescriptor @NotNull [] getAttributeDescriptors() {
return DESCRIPTORS;
}
@Override
public ColorDescriptor @NotNull [] getColorDescriptors() {
return ColorDescriptor.EMPTY_ARRAY;
}
@NotNull
@Override
public String getDisplayName() {
return "Simple";
}
}
```
It is supported to group related attributes like operators or braces by separating the nodes with `//`, e.g.:
```JAVA
AttributesDescriptor[] DESCRIPTORS = new AttributesDescriptor[] {
new AttributesDescriptor("Operators//Plus", MySyntaxHighlighter.PLUS),
new AttributesDescriptor("Operators//Minus", MySyntaxHighlighter.MINUS),
new AttributesDescriptor("Operators//Advanced//Sigma", MySyntaxHighlighter.SIGMA),
new AttributesDescriptor("Operators//Advanced//Pi", MySyntaxHighlighter.PI),
//...
};
```
### Register the Color Settings Page
Register the Simple Language color settings page with the IntelliJ Platform in the plugin configuration file using the [com.intellij.colorSettingsPage](https://jb.gg/ipe?extensions=com.intellij.colorSettingsPage) extension point .
```XML
```
> **Note:**
> The Simple Language sample plugin targets a version earlier than 2026.3. Plugins targeting 2026.3 or later should register the page in the `com.intellij.colorSettings` extension point instead. See [Registering a Color Settings Page](syntax-highlighting-and-error-highlighting.html#registering-a-color-settings-page) for details.
### Run the Project
[Run](creating-plugin-project.html#running-the-plugin) the plugin.
In the IDE Development Instance, open the Simple Language highlight settings page: `Settings | Editor | Color Scheme | Simple`. Each color initially inherits from a Language Defaults value.
