How do I set the text attributes on an empty line in a PyGtk TextView? - pygtk

Question

The first section of code is the original code posted. The second code is modification of Bob's answer who led me in the right direction.
I need the user, when they reach a specific line (where this is a new line, which of course is empty) in the gtk.TextBuffer to be typing in a bold font.
If possible, what change is necessary in the code below that would make the font bold from where the user begins to type?
import gtk, pango
class BoldTestWindow(gtk.Window):
def __init__(self):
gtk.Window.__init__(self)
self.connect( "destroy", lambda *w: gtk.main_quit() )
self.set_default_size(280, 80)
# Create a text view and get it's buffer.
self.tv = gtk.TextView()
buffer = self.tv.get_buffer()
# Create the Tags and add them to the Tag Table.
tags = [["weight", pango.WEIGHT_BOLD], ]
for tag in tags:
newTag = gtk.TextTag(name=tag[0])
newTag.set_property(tag[0], tag[1])
textTable = buffer.get_tag_table()
textTable.add(newTag)
# Grab an Iter to insert text.
startIter = buffer.get_start_iter()
# Insert some text in which to apply the bold attribute.
buffer.insert(startIter, "A Bold Statement.")
# startIter must be asked for again, because text was inserted.
startIter = buffer.get_start_iter()
endIter = buffer.get_end_iter()
# Apply the tags to entire range of TextBuffer
tags = ["weight",]
for tag in tags:
buffer.apply_tag_by_name(tag, startIter, endIter)
# Let's see what happens.
self.add(self.tv)
self.tv.grab_focus()
self.set_position(gtk.WIN_POS_CENTER)
self.show_all()
if __name__ == "__main__":
bww = BoldTestWindow()
gtk.main()
Bob's answer was the expose event, accept the expose event floods with thousands of calls to change the attributes, where only one call is neccessary per character added.
In order to stop a flooding of events, I experimented with key events.
I tried using key-press-event, but the character was not modified until the next event round, which left no style changes for the last character pressed.
I tried key-release-event and this worked, but there was a small delay in adding the attributes. The character would be no attribute for a split second, then the bold attribute would be added.
Finally, I tried a mix of key-press-event with expose-event, but that bottle necked some, then Juhaz from irc #pygtk recommended changed event which seems to work well. I believe the anser is close, I will use the following section to post it when done. I still have to work out line justification properties, they are still buggy.
import gtk, pango
# TaggedCursorTextView attempts to only add one feature to gtk.TextView: make the cursor dynamically settable
# to a list of tags. This forces the current text being typed to the set of tags set.
class TaggedCursorTextView(gtk.TextView):
def __init__(self):
gtk.TextView.__init__(self)
# Create buffer variable that point to it's internal TextBuffer.
self.buffer = self.get_buffer()
# Listen for the changed event. (User types, deletes or pastes text, etc.)
self.connect("key-press-event", self.on_key_press_event)
# What ever tags are place in here determines the text attributes (font type, bold, etc.)
# That is being typed by the user at any given moment.
# Default should be kept empty, no styles.
self.cursorTags = []
self.handlerID = None
def addTags(self, tagList):
# Create the Tags and add them to the Tag Table. Ignores duplicate tag names.
for tag in tagList:
newTag = gtk.TextTag(name=tag[0])
textTable = self.buffer.get_tag_table()
tagNameFound = textTable.lookup(tag[0])
if not tagNameFound:
newTag.set_property(tag[1], tag[2])
textTable.add(newTag)
def removeTags(self, tagNameList):
pass
def setCursorTags(self, tagList):
self.cursorTags = tagList
def on_key_press_event(self, widget, event):
self.handlerID = self.buffer.connect("changed", self.on_changed_event)
def on_changed_event(self, widget):
"""This method updates the last character type to the cursor style."""
self.buffer.disconnect(self.handlerID)
# Get the iter that falls before and after the last char typed.
endIter = self.buffer.get_end_iter()
offset = endIter.get_offset() - 1
startIter = self.buffer.get_iter_at_offset(offset)
# Apply the tags to the newly typed char
for tag in self.cursorTags:
self.buffer.apply_tag_by_name(tag, startIter, endIter)
class TaggedCurserTextViewTestWindow(gtk.Window):
def __init__(self):
gtk.Window.__init__(self)
self.connect( "destroy", lambda *w: gtk.main_quit() )
self.set_default_size(280, 80)
# Create a TaggedCursorTextView.
tctv = TaggedCursorTextView()
# Add some cursors tags that will be used at some point later in the app.
# Each tag element list is: [tag name, tag property, tag value]
tagList = [["Italic", "style", pango.STYLE_ITALIC], ["Bold", "weight", pango.WEIGHT_BOLD], ["Center", "justification", gtk.JUSTIFY_CENTER]]
tctv.addTags(tagList)
# Use the names of the tags in a list to set the cursor tags.
tctv.setCursorTags(["Italic", "Bold", "Center"]) # Comment out this line for no style.
# Let's see what happens.
self.add(tctv)
tctv.grab_focus()
self.set_position(gtk.WIN_POS_CENTER)
self.show_all()
if __name__ == "__main__":
TaggedCurserTextViewTestWindow()
gtk.main()

Answer 1

Here's a rather crude modification of your code. I've just created an expose-event handler for your textview and whenever expose-event is invoked (i.e. when your textview requests to redraw), it redraws everything with bold font.
I'm not sure, if this is what you wanted; please explain in more detail your purpose, if it's not (I'm in IRC).
import gtk, pango
class BoldTestWindow(gtk.Window):
def __init__(self):
gtk.Window.__init__(self)
self.connect( "destroy", lambda *w: gtk.main_quit() )
self.set_default_size(280, 80)
# Create a text view and get it's buffer.
self.tv = gtk.TextView()
buffer = self.tv.get_buffer()
# Create the Tags and add them to the Tag Table.
tags = [["weight", pango.WEIGHT_BOLD], ]
for tag in tags:
newTag = gtk.TextTag(name=tag[0])
newTag.set_property(tag[0], tag[1])
textTable = buffer.get_tag_table()
textTable.add(newTag)
# Grab an Iter to insert text.
startIter = buffer.get_start_iter()
# Insert some text in which to apply the bold attribute.
buffer.insert(startIter, "A Bold Statement.")
# startIter must be asked for again, because text was inserted.
startIter = buffer.get_start_iter()
endIter = buffer.get_end_iter()
# Apply the tags to entire range of TextBuffer
tags = ["weight",]
for tag in tags:
buffer.apply_tag_by_name(tag, startIter, endIter)
# Let's see what happens.
self.add(self.tv)
self.tv.grab_focus()
self.set_position(gtk.WIN_POS_CENTER)
self.show_all()
def on_expose_event(self, widget, event, data=None):
buffer = self.tv.get_buffer()
startIter = buffer.get_start_iter()
endIter = buffer.get_end_iter()
# Apply the tags to entire range of TextBuffer
tags = ["weight",]
for tag in tags:
buffer.apply_tag_by_name(tag, startIter, endIter)
if __name__ == "__main__":
bww = BoldTestWindow()
bww.tv.connect("expose-event", bww.on_expose_event)
gtk.main()