Source code for enable.container
# (C) Copyright 2005-2022 Enthought, Inc., Austin, TX
# All rights reserved.
#
# This software is provided without warranty under the terms of the BSD
# license included in LICENSE.txt and may be redistributed only under
# the conditions described in the aforementioned license. The license
# is also available online at http://www.enthought.com/licenses/BSD.txt
#
# Thanks for using Enthought open source!
""" Defines the basic Container class """
# Major library imports
import warnings
# Enthought library imports
from kiva import affine
from traits.api import Bool, Enum, Instance, List, Property, Tuple
# Local, relative imports
from .base import empty_rectangle, intersect_bounds
from .component import Component
from .events import BlobEvent, BlobFrameEvent, DragEvent, MouseEvent
[docs]class Container(Component):
""" A Container is a logical container that holds other Components within
it and provides an origin for Components to position themselves. Containers
can be "nested" (although "overlayed" is probably a better term).
If auto_size is True, the container will automatically update its bounds to
enclose all of the components handed to it, so that a container's bounds
serve as abounding box (although not necessarily a minimal bounding box) of
its contained components.
"""
# The list of components within this frame
components = Property # List(Component)
# Whether or not the container should automatically maximize itself to
# fit inside the Window, if this is a top-level container.
#
# NOTE: the way that a Container determines that it's a top-level window is
# that someone has explicitly set its .window attribute. If you need to do
# this for some other reason, you may want to turn fit_window off.
fit_window = Bool(True)
# Dimensions in which this container can resize to fit its components.
# This trait only applies to dimensions that are also resizable; if the
# container is not resizable in a certain dimension, then fit_components
# has no effect.
#
# Also, note that the container does not *automatically* resize itself
# based on the value of this trait. Rather, this trait determines
# what value is reported in get_preferred_size(); it is up to the parent
# of this container to make sure that it is allocated the size that it
# needs by setting its bounds appropriately.
#
# TODO: Merge resizable and this into a single trait? Or have a separate
# "fit" flag for each dimension in the **resizable** trait?
# TODO: This trait is used in layout methods of various Container
# subclasses in Chaco. We need to move those containers into
# Enable.
fit_components = Enum("", "h", "v", "hv")
# Whether or not the container should auto-size itself to fit all of its
# components.
# Note: This trait is still used, but will be eventually removed in favor
# of **fit_components**.
auto_size = Bool(False)
# The default size of this container if it is empty.
default_size = Tuple(0, 0)
# The layers that the container will draw first, so that they appear
# under the component layers of the same name.
container_under_layers = Tuple(
"background", "image", "underlay", "mainlayer"
)
# ------------------------------------------------------------------------
# Private traits
# ------------------------------------------------------------------------
# Shadow trait for self.components
_components = List # List(Component)
# Set of components that last handled a mouse event. We keep track of
# this so that we can generate mouse_enter and mouse_leave events of
# our own.
_prev_event_handlers = Instance(set, ())
# This container can render itself in a different mode than what it asks of
# its contained components. This attribute stores the rendering mode that
# this container requests of its children when it does a _draw(). If the
# attribute is set to "default", then whatever mode is handed in to _draw()
# is used.
_children_draw_mode = Enum("default", "normal", "overlay", "interactive")
# ------------------------------------------------------------------------
# Public methods
# ------------------------------------------------------------------------
def __init__(self, *components, **traits):
Component.__init__(self, **traits)
for component in components:
self.add(component)
if "bounds" in traits and "auto_size" not in traits:
self.auto_size = False
[docs] def add(self, *components):
""" Adds components to this container """
for component in components:
if component.container is not None:
component.container.remove(component)
component.container = self
self._components.extend(components)
# Expand our bounds if necessary
if self._should_compact():
self.compact()
self.invalidate_draw()
[docs] def remove(self, *components):
""" Removes components from this container """
for component in components:
if component in self._components:
component.container = None
self._components.remove(component)
else:
raise RuntimeError(
"Unable to remove component from container."
)
# Check to see if we need to compact.
if self.auto_size:
if ((component.outer_x2 == self.width)
or (component.outer_y2 == self.height)
or (component.x == 0)
or (component.y == 0)):
self.compact()
self.invalidate_draw()
[docs] def insert(self, index, component):
"Inserts a component into a specific position in the components list"
if component.container is not None:
component.container.remove(component)
component.container = self
self._components.insert(index, component)
self.invalidate_draw()
[docs] def components_at(self, x, y):
"""
Returns a list of the components underneath the given point (given in
the parent coordinate frame of this container).
"""
result = []
if self.is_in(x, y):
xprime = x - self.position[0]
yprime = y - self.position[1]
for component in self._components[::-1]:
if component.is_in(xprime, yprime):
result.append(component)
return result
[docs] def raise_component(self, component):
""" Raises the indicated component to the top of the Z-order """
c = self._components
ndx = c.index(component)
if len(c) > 1 and ndx != len(c) - 1:
self._components = c[:ndx] + c[ndx + 1:] + [component]
[docs] def lower_component(self, component):
""" Puts the indicated component to the very bottom of the Z-order """
raise NotImplementedError
[docs] def cleanup(self, window):
"""When a window viewing or containing a component is destroyed,
cleanup is called on the component to give it the opportunity to
delete any transient state it may have (such as backbuffers)."""
if self._components:
for component in self._components:
component.cleanup(window)
[docs] def compact(self):
"""
Causes this container to update its bounds to be a compact bounding
box of its components. This may cause the container to recalculate
and adjust its position relative to its parent container (and adjust
the positions of all of its contained components accordingly).
"""
# Loop over our components and determine the bounding box of all of
# the components.
ll_x, ll_y, ur_x, ur_y = self._calc_bounding_box()
if len(self._components) > 0:
# Update our position and the positions of all of our components,
# but do it quietly
for component in self._components:
component.trait_setq(
position=[component.x - ll_x, component.y - ll_y]
)
# Change our position (in our parent's coordinate frame) and
# update our bounds
self.position = [self.x + ll_x, self.y + ll_y]
self.bounds = [ur_x - ll_x, ur_y - ll_y]
# ------------------------------------------------------------------------
# Protected methods
# ------------------------------------------------------------------------
def _calc_bounding_box(self):
"""
Returns a 4-tuple (x,y,x2,y2) of the bounding box of all our contained
components. Expressed as coordinates in our local coordinate frame.
"""
if len(self._components) == 0:
return (0.0, 0.0, 0.0, 0.0)
else:
comp = self._components[0]
ll_x = comp.outer_x
ll_y = comp.outer_y
ur_x = comp.outer_x2
ur_y = comp.outer_y2
for component in self._components[1:]:
if component.x < ll_x:
ll_x = component.x
if component.x2 > ur_x:
ur_x = component.x2
if component.y < ll_y:
ll_y = component.y
if component.y2 > ur_y:
ur_y = component.y2
return (ll_x, ll_y, ur_x, ur_y)
def _dispatch_draw(self, layer, gc, view_bounds, mode):
""" Renders the named *layer* of this component.
"""
new_bounds = self._transform_view_bounds(view_bounds)
if new_bounds == empty_rectangle:
return
if self.layout_needed:
self.do_layout()
# Give the container a chance to draw first for the layers that are
# considered "under" or "at" the main layer level
if layer in self.container_under_layers:
my_handler = getattr(self, "_draw_container_" + layer, None)
if my_handler:
my_handler(gc, view_bounds, mode)
# Now transform coordinates and draw the children
visible_components = self._get_visible_components(new_bounds)
if visible_components:
with gc:
gc.translate_ctm(*self.position)
for component in visible_components:
if component.unified_draw:
# Plot containers that want unified_draw only get
# called if their draw_layer matches the current layer
# we're rendering
if component.draw_layer == layer:
component._draw(gc, new_bounds, mode)
else:
component._dispatch_draw(layer, gc, new_bounds, mode)
# The container's annotation and overlay layers draw over those of
# its components.
# FIXME: This needs to be abstracted so that when subclasses override
# the draw_order list, these are pulled from the subclass list instead
# of hardcoded here.
if layer in ("annotation", "overlay", "border"):
my_handler = getattr(self, "_draw_container_" + layer, None)
if my_handler:
my_handler(gc, view_bounds, mode)
def _draw_container(self, gc, mode="default"):
"Draw the container background in a specified graphics context"
pass
def _draw_container_background(self, gc, view_bounds=None, mode="normal"):
self._draw_background(gc, view_bounds, mode)
def _draw_container_overlay(self, gc, view_bounds=None, mode="normal"):
self._draw_overlay(gc, view_bounds, mode)
def _draw_container_underlay(self, gc, view_bounds=None, mode="normal"):
self._draw_underlay(gc, view_bounds, mode)
def _draw_container_border(self, gc, view_bounds=None, mode="normal"):
self._draw_border(gc, view_bounds, mode)
def _get_visible_components(self, bounds):
""" Returns a list of this plot's children that are in the bounds. """
if bounds is None:
return [c for c in self.components if c.visible]
visible_components = []
for component in self.components:
if not component.visible:
continue
tmp = intersect_bounds(
component.outer_position + component.outer_bounds, bounds
)
if tmp != empty_rectangle:
visible_components.append(component)
return visible_components
def _should_layout(self, component):
""" Returns True if it is appropriate for the container to lay out
the component; False if not.
"""
if (not component
or (not component.visible and not component.invisible_layout)):
return False
else:
return True
def _should_compact(self):
""" Returns True if the container needs to call compact(). Subclasses
can overload this method as needed.
"""
if self.auto_size:
width = self.width
height = self.height
for component in self.components:
x, y = component.outer_position
x2 = component.outer_x2
y2 = component.outer_y2
if (x2 >= width) or (y2 >= height) or (x < 0) or (y < 0):
return True
else:
return False
def _transform_view_bounds(self, view_bounds):
"""
Transforms the given view bounds into our local space and computes a
new region that can be handed off to our children. Returns a 4-tuple
of the new position+bounds, or None (if None was passed in), or the
value of empty_rectangle (from enable.base) if the intersection
resulted in a null region.
"""
if view_bounds:
# Check if we are visible
tmp = intersect_bounds(self.position + self.bounds, view_bounds)
if tmp == empty_rectangle:
return empty_rectangle
# Compute new_bounds, which is the view_bounds transformed into
# our coordinate space
v = view_bounds
new_bounds = (v[0] - self.x, v[1] - self.y, v[2], v[3])
else:
new_bounds = None
return new_bounds
def _component_bounds_changed(self, component):
"Called by contained objects when their bounds change"
# For now, just punt and call compact()
if self.auto_size:
self.compact()
def _component_position_changed(self, component):
"Called by contained objects when their position changes"
# For now, just punt and call compact()
if self.auto_size:
self.compact()
# ------------------------------------------------------------------------
# Property setters & getters
# ------------------------------------------------------------------------
def _get_components(self):
return self._components
def _set_components(self, new):
self._components = new
def _get_layout_needed(self):
# Override the parent implementation to take into account whether any
# of our contained components need layout.
if self._layout_needed:
return True
else:
for c in self.components:
if c.layout_needed:
return True
else:
return False
# ------------------------------------------------------------------------
# Interactor interface
# ------------------------------------------------------------------------
[docs] def normal_mouse_leave(self, event):
event.push_transform(self.get_event_transform(event), caller=self)
for component in self._prev_event_handlers:
component.dispatch(event, "mouse_leave")
self._prev_event_handlers = set()
event.pop(caller=self)
def _container_handle_mouse_event(self, event, suffix):
"""
This method allows the container to handle a mouse event before its
children get to see it. Once the event gets handled, its .handled
should be set to True, and contained components will not be called
with the event.
"""
# super()._dispatch_stateful_event(event, suffix)
Component._dispatch_stateful_event(self, event, suffix)
[docs] def get_event_transform(self, event=None, suffix=""):
return affine.affine_from_translation(-self.x, -self.y)
def _dispatch_stateful_event(self, event, suffix):
"""
Dispatches a mouse event based on the current event_state. Overrides
the default Interactor._dispatch_stateful_event by adding some default
behavior to send all events to our contained children.
"suffix" is the name of the mouse event as a suffix to the event state
name, e.g. "_left_down" or "_window_enter".
"""
if not event.handled:
if isinstance(event, BlobFrameEvent):
# This kind of event does not have a meaningful location. Just
# let all of the child components see it.
for component in self._components[::-1]:
component.dispatch(event, suffix)
return
components = self.components_at(event.x, event.y)
# Translate the event's location to be relative to this container
event.push_transform(
self.get_event_transform(event, suffix), caller=self
)
try:
new_component_set = set(components)
# For "real" mouse events (i.e., not pre_mouse_* events),
# notify the previous listening components of a mouse or
# drag leave
if not suffix.startswith("pre_"):
components_left = (
self._prev_event_handlers - new_component_set
)
if components_left:
leave_event = None
if isinstance(event, MouseEvent):
leave_event = event
leave_suffix = "mouse_leave"
elif isinstance(event, DragEvent):
leave_event = event
leave_suffix = "drag_leave"
elif isinstance(event, (BlobEvent, BlobFrameEvent)):
# Do not generate a 'leave' event.
pass
else:
# TODO: think of a better way to handle this rare
# case?
leave_event = MouseEvent(
x=event.x, y=event.y, window=event.window
)
leave_suffix = "mouse_leave"
if leave_event is not None:
for component in components_left:
component.dispatch(
leave_event, "pre_" + leave_suffix
)
component.dispatch(leave_event, leave_suffix)
event.handled = False
# Notify new components of a mouse enter, if the event is
# not a mouse_leave or a drag_leave
if suffix not in ("mouse_leave", "drag_leave"):
components_entered = (
new_component_set - self._prev_event_handlers
)
if components_entered:
enter_event = None
if isinstance(event, MouseEvent):
enter_event = event
enter_suffix = "mouse_enter"
elif isinstance(event, DragEvent):
enter_event = event
enter_suffix = "drag_enter"
elif isinstance(event, (BlobEvent, BlobFrameEvent)): # noqa: E501
# Do not generate an 'enter' event.
pass
if enter_event:
for component in components_entered:
component.dispatch(
enter_event, "pre_" + enter_suffix
)
component.dispatch(
enter_event, enter_suffix
)
event.handled = False
# Handle the actual event
# Only add event handlers to the list of previous event
# handlers if they actually receive the event (and the event
# is not a pre_* event).
if not suffix.startswith("pre_"):
self._prev_event_handlers = set()
for component in components:
component.dispatch(event, suffix)
if not suffix.startswith("pre_"):
self._prev_event_handlers.add(component)
if event.handled:
break
finally:
event.pop(caller=self)
if not event.handled:
self._container_handle_mouse_event(event, suffix)
# ------------------------------------------------------------------------
# Event handlers
# ------------------------------------------------------------------------
def _auto_size_changed(self, old, new):
# For safety, re-compute our bounds
if new is True:
self.compact()
else:
pass
def _window_resized(self, event):
newsize = event.new
if newsize is not None:
self.bounds = [newsize[0] - self.x, newsize[1] - self.y]
# FIXME: Need a _window_changed to remove this handler if the window
# changes
def _fit_window_changed(self, old, new):
if self._window is not None:
if not self.fit_window:
self._window.observe(
self._window_resized, "resized", remove=True
)
else:
self._window.observe(self._window_resized, "resized")
def _bounds_changed(self, old, new):
# crappy... calling our parent's handler seems like a common traits
# event handling problem
super()._bounds_changed(old, new)
self._layout_needed = True
self.invalidate_draw()
def _bounds_items_changed(self, event):
super()._bounds_items_changed(event)
self._layout_needed = True
self.invalidate_draw()
def _bgcolor_changed(self):
self.invalidate_draw()
self.request_redraw()
def __components_items_changed(self, event):
self._layout_needed = True
def __components_changed(self, event):
self._layout_needed = True
self.invalidate_draw()
