python - 在 pyGTK 的 TextView/TextBuffer 中插入粗体字符

Question

我有一个 TextView 和一个与其关联的 TextBuffer。

当用户按下 Ctrl+b 时，我希望文本开始以粗体输入，直到用户再次按下 Ctrl+b。

我尝试了自己的方法，但没有用，然后我在邮件列表中找到了这篇文章: http://www.daa.com.au/pipermail/pygtk/2009-April/016951.html

和我一样的问题，有人给出的解决方案是

Your application will have to handle the bookkeeping required to managethe tags in the TextBuffer. When text is inserted at the cursor your apphas to catch a signal indicating the text is being inserted and thenapply the required tags to the inserted text. I think this can be doneby catching theTextBuffer "insert-text" signal (using connect_after()to make sure the text has already been inserted) and then applying thetags to the text in the callback.

所以我尝试了这个。这是我的 textbuffer.py

import gtk
import pango

class TextBuffer(gtk.TextBuffer):
 def __init__(self):
  gtk.TextBuffer.__init__(self)
  self.connect_after('insert-text', self.text_inserted)
  # A list to hold our active tags
  self.tags_on = []
  # Our Bold tag.
  self.tag_bold = self.create_tag("bold", weight=pango.WEIGHT_BOLD) 

 def get_iter_position(self):
  return self.get_iter_at_mark(self.get_insert())
 
 def make_bold(self, text):
  ''' add "bold" to our active tags list '''
  self.tags_on.append('bold')
 
 def text_inserted(self, buffer, iter, text, length):
  # A text was inserted in the buffer. If there are ny tags in self.tags_on, apply them
  if self.tags_on:
   print self.get_iter_position()
   
   # This sets the iter back N characters
   iter.backward_chars(length)
   
   # And this applies tag from iter to end of buffer
   self.apply_tag_by_name('bold', self.get_iter_position(), self.get_end_iter())
   
   print self.get_iter_position()

每当有人按下 Ctrl+b 时，主脚本就会调用 make_bold() 方法。

从理论上讲，这正是邮件帮助所说的那样。但是没有用。文本在我键入时未显示为粗体。如果我按向左箭头并将光标向后移动，然后键入一个字符，则光标右侧的字符会变为粗体。

我怎样才能完成这个任务？

此外，有人可以向其中添加标签“textbuffer”吗？我无法创建新标签，我觉得该标签比“textview”更准确

Answer 1

在示例代码中，您在 TextBuffer.text_inserted 中调用了 iter.backward_chars但你永远不会使用那个迭代器!，所以我制作了一个示例脚本来向你展示所需的行为并澄清:

import gtk
import pango

class TextBuffer(gtk.TextBuffer):
    def __init__(self):
        gtk.TextBuffer.__init__(self)
        self.connect_after('insert-text', self.text_inserted)
        # A list to hold our active tags
        self.tags_on = []
        # Our Bold tag.
        self.tag_bold = self.create_tag("bold", weight=pango.WEIGHT_BOLD)  

    def get_iter_position(self):
        return self.get_iter_at_mark(self.get_insert())

    def make_bold(self):
        ''' add "bold" to our active tags list '''
        if 'bold' in self.tags_on:
            del self.tags_on[self.tags_on.index('bold')]
        else:
            self.tags_on.append('bold')

    def text_inserted(self, buffer, iter, text, length):
        # A text was inserted in the buffer. If there are ny tags in self.tags_on,   apply them
        if self.tags_on:
            # This sets the iter back N characters
            iter.backward_chars(length)
            # And this applies tag from iter to end of buffer
            self.apply_tag_by_name('bold', self.get_iter_position(), iter)



def main():
    window = gtk.Window()
    window.connect('destroy', lambda _: gtk.main_quit())
    window.resize(300, 300)
    tb = TextBuffer()
    tv = gtk.TextView(buffer=tb)

    accel = gtk.AccelGroup()
    accel.connect_group(gtk.keysyms.b,
                        gtk.gdk.CONTROL_MASK,gtk.ACCEL_LOCKED,
                        lambda a,b,c,d: tb.make_bold())
    window.add_accel_group(accel)
    window.add(tv)
    window.show_all()
    gtk.main()

if __name__ == '__main__':
    main()