隔久点不用老是会忘，留个笔记。。
Python+PYGObject/PYGtk，加载 CSS 样式的演示代码
demo 运行的效果截图：
#!/usr/bin/env python3
import sys
import gigi.require_version("Gtk", "3.0")
from gi.repository import GLib, Gtk, Gioclass MyApplication(Gtk.Application):def __init__(self):super().__init__(application_id="com.example.MyGtkApplication")GLib.set_application_name('My Gtk Application')def do_activate(self):window = Gtk.ApplicationWindow(application=self, title="Hello World")window.present()button = Gtk.Button(label="Python+PyGObject+CSS修改背景色")button.set_name("bricks-button")button.set_halign(Gtk.Align.CENTER)button.set_valign(Gtk.Align.CENTER)button.set_size_request(250, 84)window.add(button)window.show_all()strcss="""#bricks-button {color: #F55;background-color: #eef;background-image: -gtk-scaled(url('resource://css/brick.png'), url('resource://css/brick2.png'));background-repeat: no-repeat;background-position: center;/* 测试 */}"""strpath="./play.css"fp = open(strpath, 'w')fp.write(strcss)fp.close()provider = Gtk.CssProvider()provider.connect("parsing-error", self.show_css_parsing_error)# fname = Gio.file_new_for_path('play.css')# provider.load_from_file(fname)# https://docs.gtk.org/gtk4/method.CssProvider.load_from_file.html# load_from_path, load_from_file, load_from_stringprovider.load_from_path(strpath)self.apply_css(window, provider)def show_css_parsing_error(self, provider, section, error):print(error.message)def apply_css(self, widget, provider):Gtk.StyleContext.add_provider(widget.get_style_context(), provider, Gtk.STYLE_PROVIDER_PRIORITY_APPLICATION)if isinstance(widget, Gtk.Container):widget.forall(self.apply_css, provider)app = MyApplication()
exit_status = app.run(sys.argv)
sys.exit(exit_status)
官方文档：CssProvider — GNOME Python API
Deprecated since version 4.12: Use load_from_string or load_from_bytes instead
Styling GTK3 in Python with CSS (Shallow Thoughts)
控件对应的CSS选择器名称（Built-in Class Names）
css = 'button { background-color: #f00; }'
CSS选择器名称可以改（User-set Class Names）
button_context = button.get_style_context()button_context.add_class("whitebutton")
控件名称，映射为 HTML 标签的ID，在CSS中使用井号选择器
（Widget Names, like CSS ID）
label = gtk.Label()label.set_use_markup(True)label.set_line_wrap(True)label.set_name("red_label")mainbox.pack_start(label, False, False, 0)css = '#red_label { background-color: #f00; }'dflabel = gtk.Label()
