pango markup_markup公式_markup用法(3)

from TextWidget import TextWidget
from sugar.graphics.notebook import Notebook
...
        top_container = Notebook()
        
        #Create pages for the notebook
        first_page = gtk.VBox()
        #Create a TextWidget object that can display pango markup text and add it to the first page
        tw = TextWidget()
        first_page.pack_start(tw)

        second_page = gtk.VBox()
        third_page = gtk.Frame()

        #Add the pages to the notebook. 
        top_container.add_page('First Page', first_page)
        top_container.add_page('Second Page', second_page)
        top_container.add_page('Third Page', third_page)
        return top_container

You will often want to change or reset the text in a pango layout during the life of your activity. To create such dynamic layouts, the main thing you need to do is reset the text or markup for your pango layout (usually using set_markup()) and to then call the queue_draw() method which schedules a redraw (effectively forcing an expose_event signal to be thrown).

The code below uses a standard timeout code pattern to call a method every 1 second. So the text in the Pango is updated to give the current time roughly every 1 second.

import gtk

from gtk import gdk
import cairo
import pango
import gobject
import datetime

class TextWidget(gtk.DrawingArea):

	def __init__(self):

		self.repeat_period_msec = 1000 
		
		gtk.DrawingArea.__init__(self)
		self.context = None

		#create a pango layout. Leave text argument to be empty string since we want to use markup
		self.pango_context = self.create_pango_context()
		self.pango_layout = self.create_pango_layout('')
		
		#Use pango markup to set the text within the pango layout
		self.pango_layout.set_markup('<span foreground=\"blue\">This is some sample markup</span> <sup>text</sup> that <u>is displayed with pango</u>')

		#Make sure to detect and handle the expose_event signal so you can always
		#redraw the pango layout as appropriate. 
		self.connect("expose_event", self.expose_cb)
		self.set_size_request(450, -1)
		self.repeatedly_update_time()


	#The expose method is automatically called when the widget
	#needs to be redrawn
	def expose_cb(self, widget, event):
		
		#create a CAIRO context (to use with pango)
		self.context = widget.window.cairo_create()
		
		#Show the pango_layout in the Cairo context just created. 
		self.context.show_layout(self.pango_layout)

	#This method calls itself every 1 second and updates the time displayed. 
	def repeatedly_update_time(self):
		now = datetime.datetime.now()
		self.pango_layout.set_markup("<u>Current time:</u> " + str(now))
		self.queue_draw()
		gobject.timeout_add(self.repeat_period_msec, self.repeatedly_update_time)

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