Wiki
Ãëàâíàÿ  >  Python  >  PyGTK  >  PyGTK 2.4
Çàäàòü âîïðîñ íà ôîðóìå...
10.4. Layout Container
Prev Chapter 10. Container Widgets Next

10.4. Layout Container

The Layout container is similar to the Fixed container except that it implements an infinite (where infinity is less than 2^32) scrolling area. The X window system has a limitation where windows can be at most 32767 pixels wide or tall. The Layout container gets around this limitation by doing some exotic stuff using window and bit gravities, so that you can have smooth scrolling even when you have many child widgets in your scrolling area.

A Layout container is created using:

  layout = gtk.Layout(hadjustment=None, vadjustment=None)

As you can see, you can optionally specify the Adjustment objects (see Chapter 7, Adjustments) that the Layout widget will use for its scrolling. If you don't specify the Adjustment objects, new ones will be created.

You can add and move widgets in the Layout container using the following two methods:

  layout.put(child_widget, x, y)

  layout.move(child_widget, x, y)

The size of the Layout container can be set and retrieved using the next methods:

  layout.set_size(width, height)

  size = layout.get_size()

The final four methods for use with Layout widgets are for manipulating the horizontal and vertical adjustment widgets:

  hadj = layout.get_hadjustment()

  vadj = layout.get_vadjustment()

  layout.set_hadjustment(adjustment)

  layout.set_vadjustment(adjustment)

The layout.py example program creates three buttons and puts them in a layout widget. when a button is clicked, it is moved to a random location in the layout. Figure 10.3, “Layout Example” illustrates the starting display of the program:

Figure 10.3. Layout Example

Layout Example

The layout.py source code is:

    1	#!/usr/bin/env python
    2	
    3	# example layout.py
    4	
    5	import pygtk
    6	pygtk.require('2.0')
    7	import gtk
    8	import random
    9	
   10	class LayoutExample:
   11	    def WindowDeleteEvent(self, widget, event):
   12	        # return false so that window will be destroyed
   13	        return False
   14	
   15	    def WindowDestroy(self, widget, *data):
   16	        # exit main loop
   17	        gtk.main_quit()
   18	
   19	    def ButtonClicked(self, button):
   20	        # move the button
   21	        self.layout.move(button, random.randint(0,500),
   22	                         random.randint(0,500))
   23	
   24	    def __init__(self):
   25	        # create the top level window
   26	        window = gtk.Window(gtk.WINDOW_TOPLEVEL)
   27	        window.set_title("Layout Example")
   28	        window.set_default_size(300, 300)
   29	        window.connect("delete-event", self.WindowDeleteEvent)
   30	        window.connect("destroy", self.WindowDestroy)
   31	        # create the table and pack into the window
   32	        table = gtk.Table(2, 2, False)
   33	        window.add(table)
   34	        # create the layout widget and pack into the table
   35	        self.layout = gtk.Layout(None, None)
   36	        self.layout.set_size(600, 600)
   37	        table.attach(self.layout, 0, 1, 0, 1, gtk.FILL|gtk.EXPAND,
   38	                     gtk.FILL|gtk.EXPAND, 0, 0)
   39	        # create the scrollbars and pack into the table
   40	        vScrollbar = gtk.VScrollbar(None)
   41	        table.attach(vScrollbar, 1, 2, 0, 1, gtk.FILL|gtk.SHRINK,
   42	                     gtk.FILL|gtk.SHRINK, 0, 0)
   43	        hScrollbar = gtk.HScrollbar(None)
   44	        table.attach(hScrollbar, 0, 1, 1, 2, gtk.FILL|gtk.SHRINK,
   45	                     gtk.FILL|gtk.SHRINK, 0, 0)	
   46	        # tell the scrollbars to use the layout widget's adjustments
   47	        vAdjust = self.layout.get_vadjustment()
   48	        vScrollbar.set_adjustment(vAdjust)
   49	        hAdjust = self.layout.get_hadjustment()
   50	        hScrollbar.set_adjustment(hAdjust)
   51	        # create 3 buttons and put them into the layout widget
   52	        button = gtk.Button("Press Me")
   53	        button.connect("clicked", self.ButtonClicked)
   54	        self.layout.put(button, 0, 0)
   55	        button = gtk.Button("Press Me")
   56	        button.connect("clicked", self.ButtonClicked)
   57	        self.layout.put(button, 100, 0)
   58	        button = gtk.Button("Press Me")
   59	        button.connect("clicked", self.ButtonClicked)
   60	        self.layout.put(button, 200, 0)
   61	        # show all the widgets
   62	        window.show_all()
   63	
   64	def main():
   65	    # enter the main loop
   66	    gtk.main()
   67	    return 0
   68	
   69	if __name__ == "__main__":
   70	    LayoutExample()
   71	    main()
Prev Up Next
10.3. Fixed Container Home 10.5. Frames