Difference between revisions of "Activity Team/Sample code/Ruler"
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Latest revision as of 21:43, 23 February 2010
Ruler is a simple activity that uses Cairo graphics. It is also an example of how to use both the new (0.86+) and old (pre-0,86) toolbar, and simple Journal interaction. Not the most beautiful code, but it works.
Misc. imports. Note that we catch an exception if the new 0.86 toolbars aren't available.
import pygtk pygtk.require('2.0') import gtk import gobject import cairo import os.path import sugar from sugar.activity import activity try: # 0.86+ toolbar widgets from sugar.bundle.activitybundle import ActivityBundle from sugar.activity.widgets import ActivityToolbarButton from sugar.activity.widgets import StopButton from sugar.graphics.toolbarbox import ToolbarBox from sugar.graphics.toolbarbox import ToolbarButton except ImportError: pass from sugar.graphics.toolbutton import ToolButton from sugar.graphics.menuitem import MenuItem from sugar.graphics.icon import Icon from sugar.datastore import datastore try: from sugar.graphics import style GRID_CELL_SIZE = style.GRID_CELL_SIZE except: GRID_CELL_SIZE = 0 import logging _logger = logging.getLogger("ruler-activity") from gettext import gettext as _ import util import show_rulers import show_grids import show_checkers import show_angles
The Cairo canvas event handler. All the drawing happens in here.
# Create a GTK+ widget on which we will draw using Cairo class MyCanvas(gtk.DrawingArea): def __init__(self): gtk.DrawingArea.__init__(self) self._draw_ruler = False self._object = None self.connect('expose-event', self.__expose_event_cb) self.dpi = 200 def __expose_event_cb(self, drawing_area, event): cr = self.window.cairo_create() if self._draw_ruler: # draw lines to create a star self._object.draw(cr,self._dpi) # Restrict Cairo to the exposed area; avoid extra work cr.rectangle(event.area.x, event.area.y, event.area.width, event.area.height) cr.clip() def add_a_ruler(self,r): self._draw_ruler = True self._object = r self.queue_draw() def get_dpi(self): return self._dpi def set_dpi(self, dpi): self._dpi = dpi
The main activity.
# # Sugar activity # class RulerActivity(activity.Activity): def __init__(self, handle): super(RulerActivity,self).__init__(handle) _font = 'helvetica 12' _font_bold = 'helvetica bold 12' # # We need a canvas # self._canvas = MyCanvas() self.set_canvas(self._canvas) self._canvas.show()
How to find out the size of the canvas.
_width = gtk.gdk.screen_width() _height = gtk.gdk.screen_height()-GRID_CELL_SIZE
Check to see if there is metadata available. Since we are not using file data, we don't need to use read_file
# Read the dpi from the Journal try: dpi = self.metadata['dpi'] _logger.debug("Read dpi: " + str(dpi)) self._canvas.set_dpi(int(dpi)) except: if os.path.exists('/sys/power/olpc-pm'): self._canvas.set_dpi(200) # OLPC XO else: self._canvas.set_dpi(100) # Just a guess
Initialize the subclasses used for drawing.
# Create instances of our graphics self._r = show_rulers.ScreenOfRulers(_font,_font_bold,_width,_height) self._gcm = show_grids.ScreenGrid_cm(_font,_font_bold,_width,_height) self._gmm = show_grids.ScreenGrid_mm(_font,_font_bold,_width,_height) self._a90 = show_angles.Angles90(_font,_font_bold,_width,_height) self._a360 = show_angles.Angles360(_font,_font_bold,_width,_height) self._c = show_checkers.ScreenOfCircles(_font,_font_bold,_width,_height) # start with a ruler self._current = self._r self._canvas.add_a_ruler(self._current) # other settings self._grids_mode = "cm" self._angles_mode = "90"
We'll get a NameError if the new toolbars are not available.
# # We need some toolbars # try: # Use 0.86 toolbar design toolbar_box = ToolbarBox() # Buttons added to the Activity toolbar activity_button = ActivityToolbarButton(self) toolbar_box.toolbar.insert(activity_button, 0) activity_button.show() # Show rulers self.rulers = ToolButton( "ruler" ) self.rulers.set_tooltip(_('Ruler')) self.rulers.props.sensitive = True self.rulers.connect('clicked', self._rulers_cb) toolbar_box.toolbar.insert(self.rulers, -1) self.rulers.show() # Show grids self.grids = ToolButton( "grid-a" ) self.grids.set_tooltip(_('Grid')) self.grids.props.sensitive = True self.grids.connect('clicked', self._grids_cb) toolbar_box.toolbar.insert(self.grids, -1) self.grids.show() # Show angles self.angles = ToolButton( "angles-90" ) self.angles.set_tooltip(_('Angles')) self.angles.props.sensitive = True self.angles.connect('clicked', self._angles_cb) toolbar_box.toolbar.insert(self.angles, -1) self.angles.show() # Show checker self.checker = ToolButton( "checker" ) self.checker.set_tooltip(_('Checker')) self.checker.props.sensitive = True self.checker.connect('clicked', self._checker_cb) toolbar_box.toolbar.insert(self.checker, -1) self.checker.show() separator = gtk.SeparatorToolItem() separator.show() toolbar_box.toolbar.insert(separator, -1) dpi = self._canvas.get_dpi() self._dpi_spin_adj = gtk.Adjustment(dpi, 72, 200, 2, 32, 0) self._dpi_spin = gtk.SpinButton(self._dpi_spin_adj, 0, 0) self._dpi_spin_id = self._dpi_spin.connect('value-changed', self._dpi_spin_cb) self._dpi_spin.set_numeric(True) self._dpi_spin.show() self.tool_item_dpi = gtk.ToolItem() self.tool_item_dpi.add(self._dpi_spin) toolbar_box.toolbar.insert(self.tool_item_dpi, -1) self.tool_item_dpi.show() separator = gtk.SeparatorToolItem() separator.props.draw = False separator.set_expand(True) separator.show() toolbar_box.toolbar.insert(separator, -1) # The ever-present Stop Button stop_button = StopButton(self) stop_button.props.accelerator = '<Ctrl>Q' toolbar_box.toolbar.insert(stop_button, -1) stop_button.show() self.set_toolbar_box(toolbar_box) toolbar_box.show()
The old toolbars...
except NameError: # Use pre-0.86 toolbar design toolbox = activity.ActivityToolbox(self) self.set_toolbox(toolbox) self.projectToolbar = ProjectToolbar(self) toolbox.add_toolbar( _('Rulers'), self.projectToolbar ) toolbox.show() toolbox.set_current_toolbar(1)
Without this show_all()
the toolbars won't be drawn.
self.show_all()
Button call-backs that talk to the Cairo canvas
# # Button callbacks # def _rulers_cb(self, button): self._current = self._r self._canvas.add_a_ruler(self._current) return True def _grids_cb(self, button): if self._grids_mode == "cm": self._current = self._gcm self.grids.set_icon("grid-c") self._grids_mode = "mm" else: self._current = self._gmm self.grids.set_icon("grid-a") self._grids_mode = "cm" self._canvas.add_a_ruler(self._current) return True def _angles_cb(self, button): if self._angles_mode == "90": self._current = self._a90 self.angles.set_icon("angles-360") self._angles_mode = "360" else: self._current = self._a360 self.angles.set_icon("angles-90") self._angles_mode = "90" self._canvas.add_a_ruler(self._current) return True def _checker_cb(self, button): self._current = self._c self._canvas.add_a_ruler(self._current) return True def _dpi_spin_cb(self, button): self._canvas.set_dpi(self._dpi_spin.get_value_as_int()) self._canvas.add_a_ruler(self._current) return
Saving metadata to the Journal: write_file
gets called automatically when your activity is exited.
""" Write the dpi to the Journal """ def write_file(self, file_path): dpi = self._canvas.get_dpi() _logger.debug("Write dpi: " + str(dpi)) self.metadata['dpi'] = str(dpi)
This code handles the pre-0.86 toolbars
# # Project toolbar for pre-0.86 toolbars # class ProjectToolbar(gtk.Toolbar): def __init__(self, pc): gtk.Toolbar.__init__(self) self.activity = pc # Ruler self.activity.rulers = ToolButton( "ruler" ) self.activity.rulers.set_tooltip(_('Ruler')) self.activity.rulers.props.sensitive = True self.activity.rulers.connect('clicked', self.activity._rulers_cb) self.insert(self.activity.rulers, -1) self.activity.rulers.show() # Grid self.activity.grids = ToolButton( "grid-a" ) self.activity.grids.set_tooltip(_('Grid')) self.activity.grids.props.sensitive = True self.activity.grids.connect('clicked', self.activity._grids_cb) self.insert(self.activity.grids, -1) self.activity.grids.show() # Angles self.activity.angles = ToolButton( "angles-90" ) self.activity.angles.set_tooltip(_('Angles')) self.activity.angles.props.sensitive = True self.activity.angles.connect('clicked', self.activity._angles_cb) self.insert(self.activity.angles, -1) self.activity.angles.show() # Checker self.activity.checker = ToolButton( "checker" ) self.activity.checker.set_tooltip(_('Checker')) self.activity.checker.props.sensitive = True self.activity.checker.connect('clicked', self.activity._checker_cb) self.insert(self.activity.checker, -1) self.activity.checker.show() separator = gtk.SeparatorToolItem() separator.set_draw(True) self.insert(separator, -1) separator.show() dpi = self.activity._canvas.get_dpi() self.activity._dpi_spin_adj = gtk.Adjustment(dpi, 72, 200, 2, 32, 0) self.activity._dpi_spin = \ gtk.SpinButton(self.activity._dpi_spin_adj, 0, 0) self.activity._dpi_spin_id = self.activity._dpi_spin.connect( 'value-changed', self.activity._dpi_spin_cb) self.activity._dpi_spin.set_numeric(True) self.activity._dpi_spin.show() self.activity.tool_item_dpi = gtk.ToolItem() self.activity.tool_item_dpi.add(self.activity._dpi_spin) self.insert(self.activity.tool_item_dpi, -1) self.activity.tool_item_dpi.show()