Source code for enable.container

# (C) Copyright 2005-2021 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
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""" 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 = 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()