# Speak.activity
# A simple front end to the espeak text-to-speech engine on the XO laptop
# http://wiki.laptop.org/go/Speak
#
# Copyright (C) 2008  Joshua Minor
# This file is part of Speak.activity
#
# Parts of Speak.activity are based on code from Measure.activity
# Copyright (C) 2007  Arjun Sarwal - arjun@laptop.org
# 
#     Speak.activity is free software: you can redistribute it and/or modify
#     it under the terms of the GNU General Public License as published by
#     the Free Software Foundation, either version 3 of the License, or
#     (at your option) any later version.
# 
#     Speak.activity 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 General Public License for more details.
# 
#     You should have received a copy of the GNU General Public License
#     along with Speak.activity.  If not, see <http://www.gnu.org/licenses/>.

import pygtk
import gtk
import gtk.gdk
import gobject
import cairo
import math

class Eye(gtk.DrawingArea):
    def __init__(self, fill_color):
        gtk.DrawingArea.__init__(self)
        self.connect("expose_event", self.expose)
        self.frame = 0
        self.blink = False
        self.x, self.y = 0,0
        self.fill_color = fill_color

        # listen for clicks
        self.add_events(gtk.gdk.BUTTON_PRESS_MASK)
        self.add_events(gtk.gdk.BUTTON_RELEASE_MASK)
        self.connect("button_press_event", self._mouse_pressed_cb)
        self.connect("button_release_event", self._mouse_released_cb)

    def _mouse_pressed_cb(self, widget, event):
        self.blink = True
        self.queue_draw()

    def _mouse_released_cb(self, widget, event):
        self.blink = False
        self.queue_draw()

    def look_at(self, x, y):
        self.x = x
        self.y = y
        self.queue_draw()

    def look_ahead(self):
        self.x = None
        self.y = None
        self.queue_draw()

    # Thanks to xeyes :)
    def computePupil(self):
        a = self.get_allocation()

        if self.x is None or self.y is None:
            # look ahead, but not *directly* in the middle
            if a.x + a.width/2 < self.parent.get_allocation().width/2:
                cx = a.width * 0.6
            else:
                cx = a.width * 0.4
            return cx, a.height * 0.6

        EYE_X, EYE_Y = self.translate_coordinates(
                self.get_toplevel(), a.width/2, a.height/2)
        EYE_HWIDTH = a.width
        EYE_HHEIGHT = a.height
        BALL_DIST = EYE_HWIDTH/4

        dx = self.x - EYE_X
        dy = self.y - EYE_Y

        if dx or dy:
            angle = math.atan2(dy, dx)
            cosa = math.cos(angle)
            sina = math.sin(angle)
            h = math.hypot(EYE_HHEIGHT * cosa, EYE_HWIDTH * sina)
            x = (EYE_HWIDTH * EYE_HHEIGHT) * cosa / h
            y = (EYE_HWIDTH * EYE_HHEIGHT) * sina / h
            dist = BALL_DIST * math.hypot(x, y)

            if dist < math.hypot(dx, dy):
                dx = dist * cosa
                dy = dist * sina

        return a.width/2 + dx, a.height/2 + dy

    def expose(self, widget, event):
        self.frame += 1
        bounds = self.get_allocation()

        eyeSize = min(bounds.width, bounds.height)
        outlineWidth = eyeSize/20.0
        pupilSize = eyeSize/10.0
        pupilX, pupilY = self.computePupil()
        dX = pupilX - bounds.width/2.
        dY = pupilY - bounds.height/2.
        distance = math.sqrt(dX*dX + dY*dY)
        limit = eyeSize/2 - outlineWidth*2 - pupilSize
        if distance > limit:
            pupilX = bounds.width/2 + dX*limit/distance
            pupilY = bounds.height/2 + dY*limit/distance

        self.context = widget.window.cairo_create()
        #self.context.set_antialias(cairo.ANTIALIAS_NONE)

        #set a clip region for the expose event. This reduces redrawing work (and time)
        self.context.rectangle(event.area.x, event.area.y, event.area.width, event.area.height)
        self.context.clip()

        # background
        self.context.set_source_rgba(*self.fill_color.get_rgba())
        self.context.rectangle(0,0,bounds.width,bounds.height)
        self.context.fill()

        # eye ball
        self.context.arc(bounds.width/2,bounds.height/2, eyeSize/2-outlineWidth/2, 0,360)
        self.context.set_source_rgb(1,1,1)
        self.context.fill()

        # outline
        self.context.set_line_width(outlineWidth)
        self.context.arc(bounds.width/2,bounds.height/2, eyeSize/2-outlineWidth/2, 0,360)
        self.context.set_source_rgb(0,0,0)
        self.context.stroke()

        # pupil
        self.context.arc(pupilX,pupilY,pupilSize,0,360)
        self.context.set_source_rgb(0,0,0)
        self.context.fill()

        self.blink = False

        return True