Sugar Code Snippets

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Toolbar

This snippet shows how an activity would have a toolbar with a button and a gtk.TextView widget embedded in a hippo Canvas:

import logging
import hippo
import gtk

from gettext import gettext as _

from sugar.activity import activity
from sugar.graphics.toolbar import Toolbar
from sugar.graphics.iconbutton import IconButton
from sugar.graphics.entry import Entry
from sugar.graphics.optionmenu import OptionMenu
from sugar.graphics.menu import MenuItem

class FooActivity(activity.Activity):

    _ACTION_ANYTHING = 1
    _ACTION_APPLES = 2
    _ACTION_ORANGES = 3

   def __init__(self, handle):
        activity.Activity.__init__(self, handle)

        vbox = hippo.CanvasBox()
        self.set_root(vbox)

        toolbar = Toolbar()
        vbox.append(toolbar)

        button = IconButton(icon_name='theme:stock-close')
        button.connect("activated", self._button_activated_cb)
        toolbar.append(button)

        entry = Entry()
        button.connect("activated", self._entry_activated_cb)
        toolbar.append(entry)

        option_menu = OptionMenu()
        option_menu.add_item(MenuItem(self._ACTION_ANYTHING, _('Anything')))
        option_menu.add_item(MenuItem(self._ACTION_APPLES, _('Apples'),
                                      'theme:stock-close'))
        option_menu.add_item(MenuItem(self._ACTION_ORANGES, _('Oranges')))
        option_menu.add_separator()
        toolbar.append(option_menu)

        text_view_widget = hippo.CanvasWidget()
        vbox.append(text_view_widget, hippo.PACK_EXPAND)

        text_view = gtk.TextView()
        text_view.get_buffer().set_text('Write here!', -1)
        text_view_widget.props.widget = text_view

    def _button_activated_cb(self, button):
        logging.debug('FooActivity._button_activated_cb')

    def _entry_activated_cb(self, entry):
        logging.debug('FooActivity._entry_activated_cb')

In build 443 (June '07), from sugar.graphics.entry import Entry yields ImportError: No module named entry. MitchellNCharity 19:52, 15 June 2007 (EDT)

Files

This snippet shows how to get a path to files in the running Activity:

from sugar.activity import activity
bundle_path = activity.get_bundle_path()

Images

• Loading an SVG file onto a surface with a transparent background:

target = ctx.get_target()
buf = target.create_similar(cairo.CONTENT_COLOR_ALPHA, w, h)

• Measuring an SVG file's original dimensions

dimensions = handle.get_dimension_data()
width = dimensions[0]
height = dimensions[1]

• Loading a JPEG file onto a surface:

pixbuf = gtk.gdk.pixbuf_new_from_file("foo.jpg")
ctx = # a cairo context
ctx.set_source_pixbuf(pixbuf,0,0)
ctx.paint()

libjpeg is said to be an alternative to using pixbuf. Which is better? Perhaps Sugar/HippoCanvas provides an easier way to do this?

Cairo image expansion is good quality, but expensive. Shrinking is fine and notably faster. So for images rendered large (ie, screen-size), you might want to start with a big image, rather than expanding a small one. A speed/space tradeoff. And use SVG instead if appropriate, of course. MitchellNCharity 10:37, 10 May 2007 (EDT)

Not yet sorted

• Getting a unique ID for the XO user:

from sugar import profile

key = profile.get_pubkey()

# If you want a shorter key, you can hash that like:

from sugar import util

key_hash = util._sha_data(key)
hashed_key = util.printable_hash(key_hash)

Performance Tips

This section belongs on a different, as yet non-existent page. But a good organization for software development tips is currently unclear to me, so I'll stash this here for now. MitchellNCharity 14:05, 10 May 2007 (EDT)

• ctx.stroke() several lines at once. stroke() currently has significant overhead. So it is faster to stroke several, than to stroke them individually. They need not be contiguous. MitchellNCharity 14:05, 10 May 2007 (EDT)