--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/engine/python/fife/extensions/pychan/widgets/layout.py	Mon Jan 11 23:34:52 2010 +0000
@@ -0,0 +1,309 @@
+# -*- coding: utf-8 -*-
+
+# ####################################################################
+#  Copyright (C) 2005-2009 by the FIFE team
+#  http://www.fifengine.de
+#  This file is part of FIFE.
+#
+#  FIFE 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.,
+#  51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+# ####################################################################
+
+from fife.extensions.pychan.attrs import IntAttr
+
+AlignTop, AlignBottom, AlignLeft, AlignRight, AlignCenter = range(5)
+def isLayouted(widget):
+	return isinstance(widget,LayoutBase)
+
+class LayoutBase(object):
+	"""
+	This class is at the core of the layout engine. The two MixIn classes L{VBoxLayoutMixin}
+	and L{HBoxLayoutMixin} specialise on this by reimplementing the C{resizeToContent} and
+	the C{expandContent} methods.
+
+	Dynamic Layouting
+	-----------------
+
+	The layout is calculated in the L{Widget.show} method. Thus if you modify the layout,
+	by adding or removing child widgets for example, you have to call L{widgets.Widget.adaptLayout}
+	so that the changes ripple through the widget hierachy.
+
+	Internals
+	---------
+
+	At the core the layout engine works in two passes:
+
+	Before a root widget loaded by the XML code is shown, its resizeToContent method
+	is called recursively (walking the widget containment relation in post order).
+	This shrinks all HBoxes and VBoxes to their minimum heigt and width.
+	After that the expandContent method is called recursively in the same order,
+	which will re-align the widgets if there is space left AND if a Spacer is contained.
+
+	Inside bare Container instances (without a Layout MixIn) absolute positioning
+	can be used.
+	"""
+	def __init__(self,align = (AlignLeft,AlignTop), **kwargs):
+		self.align = align
+		self.spacer = []
+		super(LayoutBase,self).__init__(**kwargs)
+
+	def addSpacer(self,spacer):
+		self.spacer.append(spacer)
+		spacer.index = len(self.children)
+
+	def xdelta(self,widget):return 0
+	def ydelta(self,widget):return 0
+
+	def _applyHeight(self, spacers = []):
+		y = self.border_size + self.margins[1]
+		ydelta = map(self.ydelta,self.children)
+		for index, child in enumerate(self.children):
+			while spacers and spacers[0].index == index:
+				y += spacers.pop(0).size
+			child.y = y
+			y += ydelta.pop(0)
+
+	def _adjustHeightWithSpacer(self):
+		pass
+
+	def _applyWidth(self, spacers = []):
+		x = self.border_size + self.margins[0]
+		xdelta = map(self.xdelta,self.children)
+		for index, child in enumerate(self.children):
+			while spacers and spacers[0].index == index:
+				x += spacers.pop(0).size
+			child.x = x
+			x += xdelta.pop(0)
+
+	def _expandWidthSpacer(self):
+		xdelta = map(self.xdelta,self.children)
+		xdelta += [spacer.min_size for spacer in self.spacer]
+
+		available_space = self.width - 2*self.margins[0] - 2*self.border_size - self._extra_border[0]
+
+		used_space = sum(xdelta)
+		if self.children:
+			used_space -= self.padding
+		if used_space >= available_space:
+			return
+
+		expandable_items = self._getExpanders(vertical=False)
+		#print "AS/US - before",self,[o.width for o in expandable_items]
+		#print "SPACERS",self.spacer
+
+		index = 0
+		n = len(expandable_items)
+		while used_space < available_space and expandable_items:
+			index = index % n
+			delta = (available_space - used_space) / n
+			if delta == 0:
+				delta = 1
+
+			expander = expandable_items[index]
+			old_width = expander.width
+			expander.width += delta
+			delta = expander.width - old_width
+			if delta == 0:
+				expandable_items.pop(index)
+				n -= 1
+			else:
+				used_space += delta
+				index += 1
+		#print "AS/US - after",self,[o.width for o in expandable_items]
+		#print "SPACERS",self.spacer
+		self._applyWidth(spacers = self.spacer[:])
+
+	def _expandHeightSpacer(self):
+		ydelta = map(self.ydelta,self.children)
+		ydelta += [spacer.min_size for spacer in self.spacer]
+
+		available_space = self.height - 2*self.margins[1] - 2*self.border_size - self._extra_border[1]
+
+		used_space = sum(ydelta)
+		if self.children:
+			used_space -= self.padding
+
+		if used_space >= available_space:
+			return
+
+		expandable_items = self._getExpanders(vertical=True)
+		#print "AS/US - before",self,[o.height for o in expandable_items]
+
+		index = 0
+		n = len(expandable_items)
+		while used_space < available_space and expandable_items:
+			index = index % n
+			delta = (available_space - used_space) / n
+			if delta == 0:
+				delta = 1
+
+			expander = expandable_items[index]
+			old_height = expander.height
+			expander.height += delta
+			delta = expander.height - old_height
+			if delta == 0:
+				expandable_items.pop(index)
+				n -= 1
+			else:
+				used_space += delta
+				index += 1
+
+		#print "AS/US - after",self,[o.height for o in expandable_items]
+		self._applyHeight(spacers = self.spacer[:])
+
+
+	def _getExpanders(self,vertical=True):
+		expanders = []
+		spacers = self.spacer[:]
+		for index, child in enumerate(self.children):
+			if spacers and spacers[0].index == index:
+				expanders.append( spacers.pop(0) )
+			if child.vexpand and vertical:
+				expanders += [child]*child.vexpand
+			if child.hexpand and not vertical:
+				expanders += [child]*child.hexpand
+		return expanders + spacers
+
+	def _resetSpacers(self):
+		for spacer in self.spacer:
+			spacer.size = 0
+
+class VBoxLayoutMixin(LayoutBase):
+	"""
+	A mixin class for a vertical layout. Do not use directly.
+	"""
+	def __init__(self,**kwargs):
+		super(VBoxLayoutMixin,self).__init__(**kwargs)
+
+	def resizeToContent(self, recurse = True):
+		self._resetSpacers()
+
+		max_w = self.getMaxChildrenWidth()
+		x = self.margins[0] + self.border_size
+		y = self.margins[1] + self.border_size
+		for widget in self.children:
+			widget.width = max_w
+			y += widget.height + self.padding
+
+		if self.children:
+			y -= self.padding
+
+		y += sum([spacer.min_size for spacer in self.spacer])
+
+		self.height = y + self.margins[1] + self.border_size + self._extra_border[1]
+		self.width = max_w + 2*x + self._extra_border[0]
+
+		self._applyHeight(spacers = self.spacer[:])
+		self._applyWidth()
+
+	def expandContent(self):
+		self._expandHeightSpacer()
+		if not self.hexpand and self.parent:return
+		for widget in self.children:
+			widget.width = self.width - 2*self.margins[0] - 2*self.border_size - self._extra_border[0]
+
+
+	def ydelta(self,widget):return widget.height + self.padding
+
+class HBoxLayoutMixin(LayoutBase):
+	"""
+	A mixin class for a horizontal layout. Do not use directly.
+	"""
+	def __init__(self,**kwargs):
+		super(HBoxLayoutMixin,self).__init__(**kwargs)
+
+	def resizeToContent(self, recurse = True):
+		self._resetSpacers()
+
+		max_h = self.getMaxChildrenHeight()
+		x = self.margins[0] + self.border_size
+		y = self.margins[1] + self.border_size
+		for widget in self.children:
+			widget.height = max_h
+			x += widget.width + self.padding
+		if self.children:
+			x -= self.padding
+		x += sum([spacer.min_size for spacer in self.spacer])
+
+		self.width = x + self.margins[0] + self._extra_border[0]
+		self.height = max_h + 2*y + self._extra_border[1]
+
+		self._applyHeight()
+		self._applyWidth(spacers = self.spacer[:])
+
+	def expandContent(self):
+		self._expandWidthSpacer()
+		if not self.vexpand and self.parent:return
+		for widget in self.children:
+			widget.height = self.height - 2*self.margins[1] - 2*self.border_size - self._extra_border[1]
+
+	def xdelta(self,widget):return widget.width + self.padding
+
+class Spacer(object):
+	""" A spacer represents expandable or fixed 'whitespace' in the GUI.
+
+	In a XML file you can get this by adding a <Spacer /> inside a VBox or
+	HBox element (Windows implicitly are VBox elements).
+
+	Attributes
+	----------
+
+	As with widgets a number of attributes can be set on a spacer (inside the XML definition).
+	
+	  - min_size: Int: The minimal size this Spacer is allowed to have.
+	  - max_size: Int: The maximal size this Spacer is allowed to have.
+	  - fixed_size: Int: Set min_size and max_size to the same vale - effectively a Fixed size spacer. 
+
+	"""
+
+	ATTRIBUTES = [
+		IntAttr('min_size'), IntAttr('size'), IntAttr('max_size'),
+		IntAttr('fixed_size'),
+	]
+
+	def __init__(self,parent=None,**kwargs):
+		self.parent = parent
+		self.min_size = 0
+		self.max_size = 1000
+		self.size = 0
+
+	def __str__(self):
+		return "Spacer(parent.name='%s')" % getattr(self.parent,'name','None')
+
+	def __repr__(self):
+		return "<Spacer(parent.name='%s') at %x>" % (getattr(self.parent,'name','None'),id(self))
+
+	def _getSize(self):
+		self.size = self._size
+		return self._size
+	def _setSize(self,size):
+		self._size = max(self.min_size, min(self.max_size,size))
+	size = property(_getSize,_setSize)
+
+	# Alias for size
+	width = property(_getSize,_setSize)
+	height = property(_getSize,_setSize)
+
+	def _setFixedSize(self,size):
+		self.min_size = self.max_size = size
+		self.size = size
+	fixed_size = property(fset=_setFixedSize)
+
+	def _isExpanding(self):
+		if self.min_size < self.max_size:
+			return 1
+		return 0
+	vexpand = property(_isExpanding)
+	hexpand = property(_isExpanding)