class TransactionalToolChain(ToolChain):
"""
In addition to a normal toolchain, this chain begins an undo-transaction
at button-press and commits the transaction at button-release.
"""
def __init__(self, event_manager, view=None):
super().__init__(view)
self.event_manager = event_manager
self._tx = None
def handle(self, event):
# For double click: button_press, double_click, button_release
# print 'event', self.EVENT_HANDLERS.get(event.type)
if self.EVENT_HANDLERS.get(event.type) in ("on_button_press", ):
assert not self._tx
self._tx = Transaction(self.event_manager)
try:
return super().handle(event)
finally:
if self._tx and self.EVENT_HANDLERS.get(event.type) in (
"on_button_release",
"on_double_click",
"on_triple_click",
):
self._tx.commit()
self._tx = None
class TransactionalToolChain(ToolChain):
"""
In addition to a normal toolchain, this chain begins an undo-transaction
at button-press and commits the transaction at button-release.
"""
def __init__(self, view=None):
super(TransactionalToolChain, self).__init__(view)
self._tx = None
def handle(self, event):
# For double click: button_press, double_click, button_release
# print 'event', self.EVENT_HANDLERS.get(event.type)
if self.EVENT_HANDLERS.get(event.type) in ("on_button_press",):
assert not self._tx
self._tx = Transaction()
try:
super(TransactionalToolChain, self).handle(event)
finally:
if self._tx and self.EVENT_HANDLERS.get(event.type) in (
"on_button_release",
"on_double_click",
"on_triple_click",
):
self._tx.commit()
self._tx = None
class PlacementTool(_PlacementTool):
"""
PlacementTool is used to place items on the canvas.
"""
def __init__(self,
view,
item_factory,
after_handler=None,
handle_index=-1):
"""
item_factory is a callable. It is used to create a CanvasItem
that is displayed on the diagram.
"""
_PlacementTool.__init__(self,
view,
factory=item_factory,
handle_tool=ConnectHandleTool(),
handle_index=handle_index)
self.after_handler = after_handler
self._tx = None
@transactional
def create_item(self, pos):
return self._create_item(pos)
def on_button_press(self, event):
assert not self._tx
self._tx = Transaction()
view = self.view
view.unselect_all()
if _PlacementTool.on_button_press(self, event):
try:
opposite = self.new_item.opposite(
self.new_item.handles()[self._handle_index])
except (KeyError, AttributeError):
pass
else:
# Connect opposite handle first, using the HandleTool's
# mechanisms
# First make sure all matrices are updated:
view.canvas.update_matrix(self.new_item)
view.update_matrix(self.new_item)
vpos = event.x, event.y
item = self.handle_tool.glue(self.new_item, opposite, vpos)
if item:
self.handle_tool.connect(self.new_item, opposite, vpos)
return True
return False
def on_button_release(self, event):
try:
if self.after_handler:
self.after_handler(self.new_item)
return _PlacementTool.on_button_release(self, event)
finally:
self._tx.commit()
self._tx = None
class PlacementTool(_PlacementTool):
"""
PlacementTool is used to place items on the canvas.
"""
def __init__(self, view, item_factory, after_handler=None, handle_index=-1):
"""
item_factory is a callable. It is used to create a CanvasItem
that is displayed on the diagram.
"""
_PlacementTool.__init__(
self,
view,
factory=item_factory,
handle_tool=ConnectHandleTool(),
handle_index=handle_index,
)
self.after_handler = after_handler
self._tx = None
@transactional
def create_item(self, pos):
return self._create_item(pos)
def on_button_press(self, event):
assert not self._tx
self._tx = Transaction()
view = self.view
view.unselect_all()
if _PlacementTool.on_button_press(self, event):
try:
opposite = self.new_item.opposite(
self.new_item.handles()[self._handle_index]
)
except (KeyError, AttributeError):
pass
else:
# Connect opposite handle first, using the HandleTool's
# mechanisms
# First make sure all matrices are updated:
view.canvas.update_matrix(self.new_item)
view.update_matrix(self.new_item)
vpos = event.x, event.y
item = self.handle_tool.glue(self.new_item, opposite, vpos)
if item:
self.handle_tool.connect(self.new_item, opposite, vpos)
return True
return False
def on_button_release(self, event):
try:
if self.after_handler:
self.after_handler(self.new_item)
return _PlacementTool.on_button_release(self, event)
finally:
self._tx.commit()
self._tx = None
