Adding new syntax highlighting styles

By default, syntax highlit colors and font rules are held in DEFAULT_STYLES variable. You can add new style directly to this variable or make a copy of it, add new style to the copy and pass it around when instantiating editor and settings classes. Below we add new style "Paper" with changed background color and color of some other elements.

from qppte import (
    DEFAULT_STYLES, TextCharFormat, QPythonPlainTextEdit, 
    QPythonPlainTextWidget, QPythonPlainTextSettingsDialog
)

styles = DEFAULT_STYLES.copy()
styles["Paper"] = {
    # text formats for various python syntax elements
    "function_definition": TextCharFormat(foreground_color="#00627A"),
    "special_function": TextCharFormat(foreground_color="#B200B2"),
    "keyword": TextCharFormat(foreground_color="#0033B3"),
    "decorator": TextCharFormat(foreground_color="#9E880D"),
    "keyword_argument": TextCharFormat(foreground_color="#660099"),
    "line_comment": TextCharFormat(foreground_color="#5C5C5C", italic=True),
    "number": TextCharFormat(foreground_color="#1750EB"),
    "function_call": TextCharFormat(),
    "string": TextCharFormat(foreground_color="#067D17"),
    "docstring": TextCharFormat(foreground_color="#5C5C5C", italic=True),
    "self": TextCharFormat(foreground_color="#94558D"),
    "type": TextCharFormat(foreground_color="#660099"),
    "class_definition_name": TextCharFormat(weight=QFont.Weight.Bold),

    # colors to be applied to the common elements of the editor
    # not python syntax specific
    "QPlainTextEdit_default_foreground_color": "#000000",
    "QPlainTextEdit_background_color": "#fff3e5",
    "QPlainTextEdit_line_number_color": "#999999",
    "QPlainTextEdit_current_line_background_color": "#f5f8fe",
}

text_widget = QPythonPlainTextWidget(editor = QPythonPlainTextEdit(None, syntaxHighlightStyles=styles))

file_menu = QMenu("&File", menu_bar)
file_menu.addAction("&Open", open_file)
file_menu.addSeparator()
file_menu.addAction(
    "&Settings",
    lambda: QPythonPlainTextSettingsDialog(
        self,
        text_widget.editor.settings,  # setting to display and chage
        text_widget.editor,  # editor class to which automatically apply new settings
        syntaxHighlightStyles=styles
    ).exec(),
)