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# !/usr/bin/python
# -*- coding: utf-8 -*-
# Glitter Toolkit
__authors__ = ["Jan Jokela <janjokela@gmail.com>"]
__licenses__ = ["LICENSE.LGPL"]
__description__ = "Scroll area widget"
import gobject
import clutter
from widget import *
from container import Container
from image import Image
from scrollable import Scrollable
class ScrollArea(Container):
"""
A scroll area offers a scrollable container area which can be horizontal,
vertical, or both. It supports both standard and touch based scrolling.
"""
def __init__(self, area_width=1.0, area_height=1.0):
""" Initialize scroll area """
super(ScrollArea, self).__init__()
# Scroll area dimensions
self.area_width = area_width
self.area_height = area_height
self._items = []
# Set actor reactive and subscribe to scroll event
self.set_reactive(True)
self.connect('scroll-event', self.do_scroll_event)
self._init_elements()
self._init_animations()
self._update_style(self.style)
def _init_elements(self):
""" Initializes graphical elements """
self._background_image = Image()
self.add(self._background_image)
self._scroll_image = Image()
self.add(self._scroll_image)
self._scroll_image.natural_width = self.area_width
self._scroll_image.natural_height = self.area_height
def _init_animations(self):
""" Initializes animations """
self._timeline = None
self._horiz_factor=0.0
self._vert_factor=0.0
def _update_style(self, props=None):
""" Updates style """
super(ScrollArea, self)._update_style(props)
for key, value in props:
if key == 'background-image':
self.background_image = value
self._background_image.set_source(self.background_image)
self._background_image._update_layout()
elif key == 'scroll-image':
self.scroll_image = value
self._scroll_image.set_source(self.scroll_image)
self._scroll_image._update_layout()
def _update_layout(self):
""" Updates layout """
super(ScrollArea, self)._update_layout()
# Subscribe to key-press events
if self.get_stage():
_stage = self.get_stage()
_stage.connect('key-press-event', self.do_key_press_event)
# Update background and scroll image layouts
self._background_image._update_layout()
self._scroll_image._update_layout()
for item in self._items:
item._update_layout()
# Clip the scroll area
self.set_clipu(0, 0, self.get_widthu(), self.get_heightu())
def pack(self, widget):
""" Packs a widget into the scroll area """
self._scroll_image.add(widget)
self._items.append(widget)
self._update_layout()
def unpack(self, widget):
""" Unpacks a widget from the scroll widget """
self._scroll_image.remove(widget)
self._items.remove(widget)
self._update_layout()
def scroll(self, horiz_factor=0.0, vert_factor=0.0):
""" Scroll by a horizontal and/or vertical factor
horiz_factor -- (float) Horizontal factor to scroll
vert_factor -- (float) Vertical factor to scroll
"""
self._horiz_factor += horiz_factor
self._vert_factor += vert_factor
# Determine target x and y values for the scroll image
horiz_factor_as_units = self._horiz_factor * self._scroll_image.get_widthu()
target_x = self._scroll_image.get_xu() + horiz_factor_as_units
vert_factor_as_units = self._vert_factor * self._scroll_image.get_heightu()
target_y = self._scroll_image.get_yu() + vert_factor_as_units
# Normalize targets out of bounds
if target_x > 0:
target_x = 0
elif target_x < self.get_widthu() - self._scroll_image.get_widthu():
target_x = -(self._scroll_image.get_widthu() - self.get_widthu())
if target_y > 0:
target_y = 0
elif target_y < self.get_heightu() - self._scroll_image.get_heightu():
target_y = -(self._scroll_image.get_heightu() - self.get_heightu())
# Neutralize horizontal and/or vertical factors when the scroll area
# hits bounds
right_bound = self.get_widthu() - self._scroll_image.get_widthu()
if self._scroll_image.get_xu() == 0 or \
self._scroll_image.get_xu() == right_bound:
self._horiz_factor = 0.0
right_bound = self.get_heightu() - self._scroll_image.get_heightu()
if self._scroll_image.get_yu() == 0 or \
self._scroll_image.get_yu() == right_bound:
self._vert_factor = 0.0
# Kick-start scroll animations
if self._timeline:
self._timeline.rewind()
else:
self._timeline = clutter.Timeline(fps=60, duration=200)
alpha = clutter.Alpha(self._timeline, clutter.sine_inc_func)
self._behaviour = clutter.BehaviourPath(alpha)
self._behaviour.append_knots(
(self._scroll_image.get_x(), self._scroll_image.get_y()),
(clutter.units_to_device(target_x), clutter.units_to_device(target_y))
)
self._behaviour.apply(self._scroll_image)
self._timeline.start()
def do_scroll_event(self, widget, event):
""" Handles scroll event """
if event.direction == clutter.SCROLL_UP:
self.scroll(vert_factor=0.1)
elif event.direction == clutter.SCROLL_DOWN:
self.scroll(vert_factor=-0.1)
elif event.direction == clutter.SCROLL_LEFT:
self.scroll(0.1)
elif event.direction == clutter.SCROLL_RIGHT:
self.scroll(-0.1)
def do_key_press_event(self, widget, event):
""" Handles key press event """
if event.keyval == clutter.keysyms.Up:
self.scroll(vert_factor=0.1)
elif event.keyval == clutter.keysyms.Down:
self.scroll(vert_factor=-0.1)
elif event.keyval == clutter.keysyms.Left:
self.scroll(0.1)
elif event.keyval == clutter.keysyms.Right:
self.scroll(-0.1)
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