Initial revision

Lib/stdwin/TransParent.py

@@ -0,0 +1,96 @@
+# A class that sits transparently between a parent and one child.
+# First create the parent, then this thing, then the child.
+# Use this as a base class for objects that are almost transparent.
+# Don't use as a base class for parents with multiple children.
+
+Error = 'TransParent.Error'	# Exception
+
+class ManageOneChild():
+	#
+	# Upcalls shared with other single-child parents
+	#
+	def addchild(self, child):
+		if self.child:
+			raise Error, 'addchild: one child only'
+		if not child:
+			raise Error, 'addchild: bad child'
+		self.child = child
+	#
+	def delchild(self, child):
+		if not self.child:
+			raise Error, 'delchild: no child'
+		if child <> self.child:
+			raise Error, 'delchild: not my child'
+		self.child = 0
+
+class TransParent() = ManageOneChild():
+	#
+	# Calls from creator
+	# NB derived classes may add parameters to create()
+	#
+	def create(self, parent):
+		parent.addchild(self)
+		self.parent = parent
+		self.child = 0 # No child yet
+	#
+	# Downcalls from parent to child
+	#
+	def destroy(self):
+		del self.parent
+		if self.child: self.child.destroy()
+		del self.child
+	#
+	def minsize(self, m):
+		if not self.child:
+			return 0, 0
+		else:
+			return self.child.minsize(m)
+	def getbounds(self, bounds):
+		if not self.child:
+			raise Error, 'getbounds w/o child'
+		else:
+			return self.child.getbounds()
+	def setbounds(self, bounds):
+		if not self.child:
+			raise Error, 'setbounds w/o child'
+		else:
+			self.child.setbounds(bounds)
+	def draw(self, args):
+		if self.child:
+			self.child.draw(args)
+	#
+	# Downcalls only made after certain upcalls
+	#
+	def mouse_down(self, detail):
+		if self.child: self.child.mouse_down(detail)
+	def mouse_move(self, detail):
+		if self.child: self.child.mouse_move(detail)
+	def mouse_up(self, detail):
+		if self.child: self.child.mouse_up(detail)
+	#
+	def timer(self):
+		if self.child: self.child.timer()
+	#
+	# Upcalls from child to parent
+	#
+	def need_mouse(self, child):
+		self.parent.need_mouse(self)
+	def no_mouse(self, child):
+		self.parent.no_mouse(self)
+	#
+	def need_timer(self, child):
+		self.parent.need_timer(self)
+	def no_timer(self, child):
+		self.parent.no_timer(self)
+	#
+	def begindrawing(self):
+		return self.parent.begindrawing()
+	def beginmeasuring(self):
+		return self.parent.beginmeasuring()
+	#
+	def change(self, area):
+		self.parent.change(area)
+	def scroll(self, args):
+		self.parent.scroll(args)
+	def settimer(self, itimer):
+		self.parent.settimer(itimer)