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# Enthought package imports
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from enthought.traits.api import Event, HasTraits, Instance, List, Str, This, Trait
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# Local relative imports
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from stylesheets import Style, StyleSheet
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class Stylable(HasTraits):
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A mix-in class to give objects the ability to participate in Chaco's Style
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The primary functions of the Stylable mix-in class is it:
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1. provide a mechanism for style lookup on parents
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2. cache styles information (automatically invalidated when the stylesheet changes)
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3. allow for objects to only
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# The parent stylable, or None
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style_parent = Trait(None, None, This)
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# The stylesheet that this component is using
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stylesheet = Instance(StyleSheet, args=())
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# The style for this component
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style = Instance(Style, args=())
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# The ID of this stylable object; this ID should be unique across the entire
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# The class name of this stylable object, e.g. axis, grid, box, text, etc.
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# This is defined at the class level and defaults to "component".
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style_class = "component"
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# This event is fired when our style changes, or when any of our ancestors'
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#------------------------------------------------------------------------
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#------------------------------------------------------------------------
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# The cached Style object from our previous query to the stylesheet. Also
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# includes the parent's stylesheet merged in. Local changes made to our
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# Style dict are not committed.
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cached_style = Instance(Style, args=())
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cached_ancestors = List
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#------------------------------------------------------------------------
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#------------------------------------------------------------------------
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def save_style(self, style_id=None, as_class=False):
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Saves our style to the stylesheet, using style_id as the identifier
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(or self.style_id if one is not provided). Alternatively, if as_class
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is True, then saves to the stylesheet using self.style_class.
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def _cache_style_ancestors(self):
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if self.style_parent is not None:
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self.cached_ancestors = [self.style_parent] + self.style_parent.cached_ancestors
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self.cached_ancestors = []
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#print "updated ancestors for", self.name + ":", [a.name for a in self.cached_ancestors]
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#------------------------------------------------------------------------
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#------------------------------------------------------------------------
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def _style_parent_changed(self, old, new):
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self._cache_style_ancestors()
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# Re-wire the event handlers
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old.on_trait_event(self._parent_style_updated, "style_updated", remove=True)
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new.on_trait_event(self._parent_style_updated, "style_updated")
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# We have to do the same thing as if the parent style_updated had fired
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self._parent_style_updated()
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def _stylesheet_changed(self, old, new):
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self.cached_style = self.stylesheet.query(self, self.cached_ancestors)
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self.style_updated = True
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def _parent_style_updated(self):
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if self.style_parent is not None:
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self.set(stylesheet=self.style_parent.stylesheet, trait_change_notify=False)
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self.cached_style = Style(self.style_parent.cached_style)
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self.cached_style.update(self.stylesheet.query(self, self.cached_ancestors))
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print "cached style:", self.cached_style
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self.cached_style = self.stylesheet.query(self, self.cached_ancestors)
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self.style.set_dict(self.cached_style)
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# Now that we have a valid, updated style, fire the event handler to
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# notify our children.
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self.style_updated = True
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#------------------------------------------------------------------------
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#------------------------------------------------------------------------
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# TODO: add stuff here!
added
removed
enthought/chaco/attic/stylable.py
