rechnungstool/theme.py

# -*- coding: utf-8 -*-
"""Farben nach dem Windows-Theme (hell/dunkel) - inklusive Titelleiste.

Native tk-Menues und -Popups lassen sich unter Windows nicht einfaerben, darum
baut das Programm Menueleiste und Dropdowns selbst; hier stehen nur die Farben.
"""

import sys
import tkinter as tk
from tkinter import ttk


def windows_dark_mode():
    """True, wenn Windows auf das dunkle App-Theme eingestellt ist."""
    if not sys.platform.startswith("win"):
        return False
    try:
        import winreg
        with winreg.OpenKey(winreg.HKEY_CURRENT_USER,
                            r"Software\Microsoft\Windows\CurrentVersion\Themes\Personalize") as k:
            return winreg.QueryValueEx(k, "AppsUseLightTheme")[0] == 0
    except OSError:
        return False


class ThemeMixin:
    """Farben setzen. Erwartet ein tk.Tk als Basis."""

    # ----------------------------------------------------------------- Theme

    def _apply_theme(self):
        """Farben passend zum Windows-Theme (hell/dunkel) setzen."""
        dark = windows_dark_mode()
        self._dark_mode = dark
        if dark:
            self.col_bg = "#23272e"      # Fenster-Hintergrund
            self.col_fg = "#e6e6e6"      # Schrift
            self.col_field = "#2f343c"   # Eingabefelder
            self.col_sel = "#3a4a44"     # aktiv/hover
            self.col_accent = "#5fb98f"  # Akzent (Gruen, hell)
            self.col_line = "#3a3f47"
            self.col_scroll = "#4a505a"  # Scroll-Griff
            self.col_muted = "#8a929c"   # gedaempfte Schrift (z.B. "powered by")
        else:
            self.col_bg = "#f3f3f3"
            self.col_fg = "#1a1a1a"
            self.col_field = "#ffffff"
            self.col_sel = "#cfe3d8"
            self.col_accent = "#1f5c3d"
            self.col_line = "#cccccc"
            self.col_scroll = "#b8b8b8"
            self.col_muted = "#777777"   # gedaempfte Schrift (z.B. "powered by")

        self.configure(bg=self.col_bg)
        style = ttk.Style(self)
        try:
            style.theme_use("clam")
        except tk.TclError:
            pass
        bg, fg, field, sel, accent = (self.col_bg, self.col_fg, self.col_field,
                                      self.col_sel, self.col_accent)
        style.configure(".", background=bg, foreground=fg, fieldbackground=field,
                        bordercolor=self.col_line, lightcolor=bg, darkcolor=bg)
        style.configure("TFrame", background=bg)
        style.configure("TLabel", background=bg, foreground=fg)
        style.configure("TLabelframe", background=bg, bordercolor=self.col_line)
        style.configure("TLabelframe.Label", background=bg, foreground=accent)
        style.configure("TButton", background=field, foreground=fg, bordercolor=self.col_line)
        style.map("TButton", background=[("active", sel)], foreground=[("active", fg)])
        style.configure("Menu.TMenubutton", background=bg, foreground=fg, relief="flat",
                        arrowcolor=bg, padding=(10, 3))
        style.map("Menu.TMenubutton", background=[("active", sel)], foreground=[("active", fg)])
        style.configure("TCheckbutton", background=bg, foreground=fg)
        style.map("TCheckbutton", background=[("active", bg)], foreground=[("active", fg)])
        style.configure("TEntry", fieldbackground=field, foreground=fg, insertcolor=fg)
        # Bei state="readonly" zeichnet die Combobox ihren Text als MARKIERUNG,
        # sobald sie den Fokus hat - ohne diese beiden Farben steht der Wert
        # unsichtbar im Feld.
        style.configure("TCombobox", fieldbackground=field, foreground=fg,
                        background=field, arrowcolor=fg,
                        selectbackground=field, selectforeground=fg)
        style.map("TCombobox", fieldbackground=[("readonly", field)],
                  foreground=[("readonly", fg)], background=[("readonly", field)],
                  selectbackground=[("readonly", field)], selectforeground=[("readonly", fg)])
        # Die aufgeklappte Liste ist ein klassisches tk-Listbox-Widget
        self.option_add("*TCombobox*Listbox.background", field)
        self.option_add("*TCombobox*Listbox.foreground", fg)
        self.option_add("*TCombobox*Listbox.selectBackground", sel)
        self.option_add("*TCombobox*Listbox.selectForeground", fg)
        for sbs in ("Vertical.TScrollbar", "Horizontal.TScrollbar", "TScrollbar"):
            style.configure(sbs, troughcolor=bg, background=self.col_scroll,
                            bordercolor=bg, lightcolor=bg, darkcolor=bg,
                            arrowcolor=fg, relief="flat", gripcount=0)
            style.map(sbs, background=[("active", accent)],
                      troughcolor=[("disabled", bg)])
        style.configure("TSeparator", background=self.col_line)
        # Klassische tk-Widgets (Canvas, Toplevel, Text) erben diese Defaults
        self.option_add("*background", bg)
        self.option_add("*foreground", fg)

    def _style_dialog(self, d):
        """Toplevel-Dialog an das Theme angleichen."""
        d.configure(bg=self.col_bg)
        # erst nach dem Anzeigen setzen, sonst greift DWM noch nicht
        d.after(20, lambda: self._dark_titlebar(d))

    def _dark_titlebar(self, win):
        """Windows-Titelleiste des Fensters dunkel machen (nur im Dark-Mode)."""
        if not (sys.platform.startswith("win") and getattr(self, "_dark_mode", False)):
            return
        try:
            import ctypes
            win.update_idletasks()
            hwnd = ctypes.windll.user32.GetParent(win.winfo_id())
            val = ctypes.c_int(1)
            for attr in (20, 19):  # DWMWA_USE_IMMERSIVE_DARK_MODE (Win11=20, frühes Win10=19)
                ctypes.windll.dwmapi.DwmSetWindowAttribute(
                    hwnd, attr, ctypes.byref(val), ctypes.sizeof(val))
            # Frame neu zeichnen lassen (ohne Flackern/Fokusverlust)
            SWP = 0x0001 | 0x0002 | 0x0004 | 0x0020  # NOSIZE|NOMOVE|NOZORDER|FRAMECHANGED
            ctypes.windll.user32.SetWindowPos(hwnd, 0, 0, 0, 0, 0, SWP)
        except Exception as e:  # noqa: BLE001
            print("[theme] Titelleiste:", e)