""" Defines the PlotLabel class. """ from __future__ import with_statement from enable.font_metrics_provider import font_metrics_provider from traits.api import DelegatesTo, Enum, Instance, Str, Trait from abstract_overlay import AbstractOverlay from label import Label LabelDelegate = DelegatesTo("_label") class PlotLabel(AbstractOverlay): """ A label used by plots. This class wraps a simple Label instance, and delegates some traits to it. """ # The text of the label. text = LabelDelegate # The color of the label text. color = DelegatesTo("_label") # The font for the label text. font = LabelDelegate # The angle of rotation of the label. angle = DelegatesTo("_label", "rotate_angle") bgcolor = LabelDelegate border_width = LabelDelegate border_color = LabelDelegate border_visible = LabelDelegate margin = LabelDelegate line_spacing = LabelDelegate #------------------------------------------------------------------------ # Layout-related traits #------------------------------------------------------------------------ # Horizontal justification used if the label has more horizontal space # than it needs. hjustify = Enum("center", "left", "right") # Vertical justification used if the label has more vertical space than it # needs. vjustify = Enum("center", "bottom", "top") # The position of this label relative to the object it is overlaying. # Can be "top", "left", "right", "bottom", and optionally can be preceeded # by the words "inside" or "outside", separated by a space. If "inside" # and "outside" are not provided, then defaults to "outside". # Examples: # inside top # outside right overlay_position = Trait("outside top", Str, None) # Should this PlotLabel modify the padding on its underlying component # if there is not enough room to lay out the text? # FIXME: This could cause cycles in layout, so not implemented for now #modify_component = Bool(True) # By default, this acts like a component and will render on the main # "plot" layer unless its **component** attribute gets set. draw_layer = "plot" #------------------------------------------------------------------------ # Private traits #------------------------------------------------------------------------ # The label has a fixed height and can be resized horizontally. (Overrides # PlotComponent.) resizable = "h" # The Label instance this plot label is wrapping. _label = Instance(Label, args=()) def __init__(self, text="", *args, **kw): super(PlotLabel, self).__init__(*args, **kw) self.text = text return def overlay(self, component, gc, view_bounds=None, mode="normal"): """ Draws this label overlaid on another component. Overrides AbstractOverlay. """ self._draw_overlay(gc, view_bounds, mode) return def get_preferred_size(self): """ Returns the label's preferred size. Overrides PlotComponent. """ dummy_gc = font_metrics_provider() size = self._label.get_bounding_box(dummy_gc) return size def do_layout(self): """ Tells this component to do layout. Overrides PlotComponent. """ if self.component is not None: self._layout_as_overlay() else: self._layout_as_component() return def _draw_overlay(self, gc, view_bounds=None, mode="normal"): """ Draws the overlay layer of a component. Overrides PlotComponent. """ # Perform justification and compute the correct offsets for # the label position width, height = self._label.get_bounding_box(gc) if self.hjustify == "left": x_offset = 0 elif self.hjustify == "right": x_offset = self.width - width elif self.hjustify == "center": x_offset = int((self.width - width) / 2) if self.vjustify == "bottom": y_offset = 0 elif self.vjustify == "top": y_offset = self.height - height elif self.vjustify == "center": y_offset = int((self.height - height) / 2) with gc: # XXX: Uncomment this after we fix kiva GL backend's clip stack #gc.clip_to_rect(self.x, self.y, self.width, self.height) # We have to translate to our position because the label # tries to draw at (0,0). gc.translate_ctm(self.x + x_offset, self.y + y_offset) self._label.draw(gc) return def _draw_plot(self, gc, view_bounds=None, mode="normal"): if self.component is None: # We are not overlaying anything else, so we should render # on this layer self._draw_overlay(gc, view_bounds, mode) def _layout_as_component(self, size=None, force=False): pass def _layout_as_overlay(self, size=None, force=False): """ Lays out the label as an overlay on another component. """ if self.component is not None: orientation = self.overlay_position outside = True if "inside" in orientation: tmp = orientation.split() tmp.remove("inside") orientation = tmp[0] outside = False elif "outside" in orientation: tmp = orientation.split() tmp.remove("outside") orientation = tmp[0] if orientation in ("left", "right"): self.y = self.component.y self.height = self.component.height if not outside: gc = font_metrics_provider() self.width = self._label.get_bounding_box(gc)[0] if orientation == "left": if outside: self.x = self.component.outer_x self.width = self.component.padding_left else: self.outer_x = self.component.x elif orientation == "right": if outside: self.x = self.component.x2 + 1 self.width = self.component.padding_right else: self.x = self.component.x2 - self.outer_width elif orientation in ("bottom", "top"): self.x = self.component.x self.width = self.component.width if not outside: gc = font_metrics_provider() self.height = self._label.get_bounding_box(gc)[1] if orientation == "bottom": if outside: self.y = self.component.outer_y self.height = self.component.padding_bottom else: self.outer_y = self.component.y elif orientation == "top": if outside: self.y = self.component.y2 + 1 self.height = self.component.padding_top else: self.y = self.component.y2 - self.outer_height else: # Leave the position alone pass return def _text_changed(self, old, new): self._label.text = new self.do_layout() return def _font_changed(self, old, new): self._label.font = new self.do_layout() return def _angle_changed(self, old, new): self._label.rotate_angle = new self.do_layout() return def _overlay_position_changed(self): self.do_layout() def _component_changed(self, old, new): if new: self.draw_layer = "overlay" else: self.draw_layer = "plot" return # EOF