#!/usr/bin/python # magFocusTracker # # Copyright 2009 Sun Microsystems Inc. # Copyright 2010 Willie Walker # Copyright 2011-2012 Igalia, S. L. # Copyright 2011-2012 Inclusive Design Research Centre, OCAD University # # This library is free software; you can redistribute it and/or # modify it under the terms of the GNU Lesser General Public # License as published by the Free Software Foundation; either # version 2.1 of the License, or (at your option) any later version. # # This library is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU # Lesser General Public License for more details. # # You should have received a copy of the GNU Lesser General Public # License along with this library; if not, write to the # Free Software Foundation, Inc., Franklin Street, Fifth Floor, # Boston MA 02110-1301 USA. # # * Contributor: Joanie Diggs # * Contributor: Joseph Scheuhammer """Proof-of-concept standalone application that shows how: 1. to track keyboard focus and the caret using AT-SPI events, and 2. use D-Bus to drive the magnifier to insure the tracked object is within the magnified view. """ __copyright__ = \ "Copyright (c) 2009 Sun Microsystems Inc." \ "Copyright (c) 2010 Willie Walker" \ "Copyright (c) 2011-2012 Igalia, S.L." \ "Copyright (c) 2011-2012 Inclusive Design Research Centre, OCAD University" __license__ = "LGPL" import dbus import pyatspi import sys from dbus.mainloop.glib import DBusGMainLoop from gi.repository import Gdk from gi.repository.Gio import Settings _screenWidth = 0 _screenHeight = 0 _magnifier = None _zoomer = None class RoiHandler: """For handling D-Bus calls to zoomRegion.getRoi() asynchronously""" def __init__(self, left=0, top=0, width=0, height=0, centerX=0, centerY=0, edgeMarginX=0, edgeMarginY=0): self.left = left self.top = top self.width = width self.height = height self.centerX = centerX self.centerY = centerY self.edgeMarginX = edgeMarginX self.edgeMarginY = edgeMarginY def setRoiCenter(self, reply): """Given a region of interest, put that at the center of the magnifier. Arguments: - reply: an array defining a rectangle [left, top, right, bottom] """ roiWidth = reply[2] - reply[0] roiHeight = reply[3] - reply[1] if self.width > roiWidth: self.centerX = self.left if self.height > roiHeight: self.centerY = self.top _setROICenter(self.centerX, self.centerY) def setRoiCursorPush(self, reply): """Given a region of interest, nudge it if the caret or control is not visible. Arguments: - reply: an array defining a rectangle [left, top, right, bottom] """ roiLeft = reply[0] roiTop = reply[1] roiWidth = reply[2] - roiLeft roiHeight = reply[3] - roiTop leftOfROI = (self.left - self.edgeMarginX) <= roiLeft rightOfROI = \ (self.left + self.width + self.edgeMarginX) >= (roiLeft + roiWidth) aboveROI = (self.top - self.edgeMarginY) <= roiTop belowROI = \ (self.top + self.height + self.edgeMarginY) >= (roiTop + roiHeight) x1 = roiLeft x2 = roiLeft + roiWidth y1 = roiTop y2 = roiTop + roiHeight if leftOfROI: x1 = max(0, self.left - self.edgeMarginX) x2 = x1 + roiWidth elif rightOfROI: self.left = min(_screenWidth, self.left + self.edgeMarginX) if self.width > roiWidth: x1 = self.left x2 = x1 + roiWidth else: x2 = self.left + self.width x1 = x2 - roiWidth if aboveROI: y1 = max(0, self.top - self.edgeMarginY) y2 = y1 + roiHeight elif belowROI: self.top = min(_screenHeight, self.top + self.edgeMarginY) if self.height > roiHeight: y1 = self.top y2 = y1 + roiHeight else: y2 = self.top + self.height y1 = y2 - roiHeight _setROICenter((x1 + x2) / 2, (y1 + y2) / 2) def setRoiCenterErr(self, error): _dbusCallbackError('_setROICenter()', error) def setRoiCursorPushErr(self, error): _dbusCallbackError('_setROICursorPush()', error) def magnifyAccessibleErr(self, error): _dbusCallbackError('magnifyAccessible()', error) def _dbusCallbackError(funcName, error): """Log D-Bus errors Arguments: - funcName: The name of the gsmag function that made the D-Bus call. - error: The error that D-Bus returned. """ logLine = funcName + ' failed: ' + str(error) debug.println(debug.LEVEL_WARNING, logLine) def _setROICenter(x, y): """Centers the region of interest around the given point. Arguments: - x: integer in unzoomed system coordinates representing x component - y: integer in unzoomed system coordinates representing y component """ _zoomer.shiftContentsTo(x, y, ignore_reply=True) def _setROICursorPush(x, y, width, height): """Nudges the ROI if the caret or control is not visible. Arguments: - x: integer in unzoomed system coordinates representing x component - y: integer in unzoomed system coordinates representing y component - width: integer in unzoomed system coordinates representing the width - height: integer in unzoomed system coordinates representing the height """ roiPushHandler = RoiHandler(x, y, width, height) _zoomer.getRoi(reply_handler=roiPushHandler.setRoiCursorPush, error_handler=roiPushHandler.setRoiCursorPushErr) def magnifyAccessible(event, obj=None, extents=None): """Sets the region of interest to the upper left of the given accessible, if it implements the Component interface. Otherwise, does nothing. Arguments: - event: the Event that caused this to be called - obj: the accessible """ if event.type.startswith("object:state-changed") and not event.detail1: # This object just became unselected or unfocused, and we're not # big on nostalgia. return obj = obj or event.source haveSomethingToMagnify = False if extents: [x, y, width, height] = extents haveSomethingToMagnify = True elif event and event.type.startswith("object:text-caret-moved"): try: text = obj.queryText() if text and (text.caretOffset >= 0): offset = text.caretOffset if offset == text.characterCount: offset -= 1 [x, y, width, height] = \ text.getCharacterExtents(offset, 0) haveSomethingToMagnify = (width + height > 0) except: haveSomethingToMagnify = False if haveSomethingToMagnify: _setROICursorPush(x, y, width, height) return if not haveSomethingToMagnify: try: extents = obj.queryComponent().getExtents(0) [x, y, width, height] = \ [extents.x, extents.y, extents.width, extents.height] haveSomethingToMagnify = True except: haveSomethingToMagnify = False if haveSomethingToMagnify: _setROICursorPush(x, y, width, height) def startTracking(): global _screenWidth global _screenHeight global _magnifier global _zoomer if _magnifier and _zoomer: screen = Gdk.Screen.get_default() _screenWidth = screen.width() _screenHeight = screen.height() pyatspi.Registry.registerEventListener(magnifyAccessible, "object:text-caret-moved", "object:state-changed:focused", "object:state-changed:selected") def stopTracking(): pyatspi.Registry.deregisterEventListener(magnifyAccessible, "object:text-caret-moved", "object:state-changed:focused", "object:state-changed:selected") def onEnabledChanged(gsetting, key): if key != 'screen-magnifier-enabled': return enabled = gsetting.get_boolean(key) if enabled: startTracking() else: stopTracking() def _initMagDbus(): global _magnifier global _zoomer available = False try: bus = dbus.SessionBus(mainloop=DBusGMainLoop()) proxy = \ bus.get_object('org.gnome.Magnifier', '/org/gnome/Magnifier') _magnifier = dbus.Interface(proxy, 'org.gnome.Magnifier') zoomerPaths = _magnifier.getZoomRegions() if zoomerPaths: proxy = bus.get_object('org.gnome.Magnifier', zoomerPaths[0]) _zoomer = dbus.Interface(proxy, 'org.gnome.Magnifier.ZoomRegion') available = True except: available = False return available def main(): magServiceAvailable = _initMagDbus() if magServiceAvailable: a11yAppSettings = Settings('org.gnome.desktop.a11y.applications') a11yAppSettings.connect('changed', onEnabledChanged) if a11yAppSettings.get_boolean('screen-magnifier-enabled'): startTracking() pyatspi.Registry.start() else: print('Magnification service not available. Exiting.') return 0 if __name__ == "__main__": sys.exit(main())