/usr/lib/python2.7/dist-packages/chaco/legend.py is in python-chaco 4.4.1-1.2.
This file is owned by root:root, with mode 0o644.
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CompositeIconRenderer classes.
"""
from __future__ import with_statement
from numpy import array, zeros_like
from enable.api import black_color_trait, white_color_trait
from enable.font_metrics_provider import font_metrics_provider
from kiva.trait_defs.kiva_font_trait import KivaFont
from traits.api import Any, Dict, Enum, Bool, HasTraits, Int, \
Instance, List, CList, Float, Str
# Local relative imports
from abstract_overlay import AbstractOverlay
from label import Label
from lineplot import LinePlot
from plot_component import PlotComponent
from scatterplot import ScatterPlot
class AbstractCompositeIconRenderer(HasTraits):
""" Abstract class for an icon renderer.
"""
def render_icon(self, plots, gc, x, y, width, height):
""" Renders an icon representing the given list of plots onto the
graphics context, using the given dimensions and at the specified
position.
"""
raise NotImplementedError
class CompositeIconRenderer(AbstractCompositeIconRenderer):
""" Renderer for composite icons.
"""
def render_icon(self, plots, *render_args):
""" Renders an icon for a list of plots. """
types = set(map(type, plots))
if types == set([ScatterPlot]):
self._render_scatterplots(plots, *render_args)
elif types == set([LinePlot]):
self._render_lineplots(plots, *render_args)
elif types == set([ScatterPlot, LinePlot]):
self._render_line_scatter(plots, *render_args)
else:
raise ValueError("Don't know how to render combination plot with " +\
"renderers " + str(types))
return
def _render_scatterplots(self, plots, gc, x, y, width, height):
# Don't support this for now
pass
def _render_lineplots(self, plots, gc, x, y, width, height):
# Assume they are all the same color/appearance and use the first one
plots[0]._render_icon(gc, x, y, width, height)
def _render_line_scatter(self, plots, gc, x, y, width, height):
# Separate plots into line and scatter renderers; render one of each
scatter = [p for p in plots if type(p) == ScatterPlot]
line = [p for p in plots if type(p) == LinePlot]
line[0]._render_icon(gc, x, y, width, height)
scatter[0]._render_icon(gc, x, y, width, height)
class Legend(AbstractOverlay):
""" A legend for a plot.
"""
# The font to use for the legend text.
font = KivaFont("modern 12")
# The amount of space between the content of the legend and the border.
border_padding = Int(10)
# The border is visible (overrides Enable Component).
border_visible = True
# The color of the text labels
color = black_color_trait
# The background color of the legend (overrides AbstractOverlay).
bgcolor = white_color_trait
# The position of the legend with respect to its overlaid component. (This
# attribute applies only if the legend is used as an overlay.)
#
# * ur = Upper Right
# * ul = Upper Left
# * ll = Lower Left
# * lr = Lower Right
align = Enum("ur", "ul", "ll", "lr")
# The amount of space between legend items.
line_spacing = Int(3)
# The size of the icon or marker area drawn next to the label.
icon_bounds = List([24, 24])
# Amount of spacing between each label and its icon.
icon_spacing = Int(5)
# Map of labels (strings) to plot instances or lists of plot instances. The
# Legend determines the appropriate rendering of each plot's marker/line.
plots = Dict
# The list of labels to show and the order to show them in. If this
# list is blank, then the keys of self.plots is used and displayed in
# alphabetical order. Otherwise, only the items in the **labels**
# list are drawn in the legend. Labels are ordered from top to bottom.
labels = List
# Whether or not to hide plots that are not visible. (This is checked during
# layout.) This option *will* filter out the items in **labels** above, so
# if you absolutely, positively want to set the items that will always
# display in the legend, regardless of anything else, then you should turn
# this option off. Otherwise, it usually makes sense that a plot renderer
# that is not visible will also not be in the legend.
hide_invisible_plots = Bool(True)
# If hide_invisible_plots is False, we can still choose to render the names
# of invisible plots with an alpha.
invisible_plot_alpha = Float(0.33)
# The renderer that draws the icons for the legend.
composite_icon_renderer = Instance(AbstractCompositeIconRenderer)
# Action that the legend takes when it encounters a plot whose icon it
# cannot render:
#
# * 'skip': skip it altogether and don't render its name
# * 'blank': render the name but leave the icon blank (color=self.bgcolor)
# * 'questionmark': render a "question mark" icon
error_icon = Enum("skip", "blank", "questionmark")
# Should the legend clip to the bounds it needs, or to its parent?
clip_to_component = Bool(False)
# The legend is not resizable (overrides PlotComponent).
resizable = "hv"
# An optional title string to show on the legend.
title = Str('')
# If True, title is at top, if False then at bottom.
title_at_top = Bool(True)
# The legend draws itself as in one pass when its parent is drawing
# the **draw_layer** (overrides PlotComponent).
unified_draw = True
# The legend is drawn on the overlay layer of its parent (overrides
# PlotComponent).
draw_layer = "overlay"
#------------------------------------------------------------------------
# Private Traits
#------------------------------------------------------------------------
# A cached list of Label instances
_cached_labels = List
# A cached array of label sizes.
_cached_label_sizes = Any
# A cached list of label names.
_cached_label_names = CList
# A list of the visible plots. Each plot corresponds to the label at
# the same index in _cached_label_names. This list does not necessarily
# correspond to self.plots.value() because it is sorted according to
# the plot name and it potentially excludes invisible plots.
_cached_visible_plots = CList
# A cached array of label positions relative to the legend's origin
_cached_label_positions = Any
def is_in(self, x, y):
""" overloads from parent class because legend alignment
and padding does not cooperatate with the basic implementation
This may just be caused byt a questionable implementation of the
legend tool, but it works by adjusting the padding. The Component
class implementation of is_in uses the outer positions which
includes the padding
"""
in_x = (x >= self.x) and (x <= self.x + self.width)
in_y = (y >= self.y) and (y <= self.y + self.height)
return in_x and in_y
def overlay(self, component, gc, view_bounds=None, mode="normal"):
""" Draws this component overlaid on another component.
Implements AbstractOverlay.
"""
self.do_layout()
valign, halign = self.align
if valign == "u":
y = component.y2 - self.outer_height
else:
y = component.y
if halign == "r":
x = component.x2 - self.outer_width
else:
x = component.x
self.outer_position = [x, y]
if self.clip_to_component:
c = self.component
with gc:
gc.clip_to_rect(c.x, c.y, c.width, c.height)
PlotComponent._draw(self, gc, view_bounds, mode)
else:
PlotComponent._draw(self, gc, view_bounds, mode)
return
# The following two methods implement the functionality of the Legend
# to act as a first-class component instead of merely as an overlay.
# The make the Legend use the normal PlotComponent render methods when
# it does not have a .component attribute, so that it can have its own
# overlays (e.g. a PlotLabel).
#
# The core legend rendering method is named _draw_as_overlay() so that
# it can be called from _draw_plot() when the Legend is not an overlay,
# and from _draw_overlay() when the Legend is an overlay.
def _draw_plot(self, gc, view_bounds=None, mode="normal"):
if self.component is None:
self._draw_as_overlay(gc, view_bounds, mode)
return
def _draw_overlay(self, gc, view_bounds=None, mode="normal"):
if self.component is not None:
self._draw_as_overlay(gc, view_bounds, mode)
else:
PlotComponent._draw_overlay(self, gc, view_bounds, mode)
return
def _draw_as_overlay(self, gc, view_bounds=None, mode="normal"):
""" Draws the overlay layer of a component.
Overrides PlotComponent.
"""
# Determine the position we are going to draw at from our alignment
# corner and the corresponding outer_padding parameters. (Position
# refers to the lower-left corner of our border.)
# First draw the border, if necesssary. This sort of duplicates
# the code in PlotComponent._draw_overlay, which is unfortunate;
# on the other hand, overlays of overlays seem like a rather obscure
# feature.
with gc:
gc.clip_to_rect(int(self.x), int(self.y),
int(self.width), int(self.height))
edge_space = self.border_width + self.border_padding
icon_width, icon_height = self.icon_bounds
icon_x = self.x + edge_space
text_x = icon_x + icon_width + self.icon_spacing
y = self.y2 - edge_space
if self._cached_label_positions is not None:
if len(self._cached_label_positions) > 0:
self._cached_label_positions[:,0] = icon_x
for i, label_name in enumerate(self._cached_label_names):
# Compute the current label's position
label_height = self._cached_label_sizes[i][1]
y -= label_height
self._cached_label_positions[i][1] = y
# Try to render the icon
icon_y = y + (label_height - icon_height) / 2
#plots = self.plots[label_name]
plots = self._cached_visible_plots[i]
render_args = (gc, icon_x, icon_y, icon_width, icon_height)
try:
if isinstance(plots, list) or isinstance(plots, tuple):
# TODO: How do we determine if a *group* of plots is
# visible or not? For now, just look at the first one
# and assume that applies to all of them
if not plots[0].visible:
# TODO: the get_alpha() method isn't supported on the Mac kiva backend
#old_alpha = gc.get_alpha()
old_alpha = 1.0
gc.set_alpha(self.invisible_plot_alpha)
else:
old_alpha = None
if len(plots) == 1:
plots[0]._render_icon(*render_args)
else:
self.composite_icon_renderer.render_icon(plots, *render_args)
elif plots is not None:
# Single plot
if not plots.visible:
#old_alpha = gc.get_alpha()
old_alpha = 1.0
gc.set_alpha(self.invisible_plot_alpha)
else:
old_alpha = None
plots._render_icon(*render_args)
else:
old_alpha = None # Or maybe 1.0?
icon_drawn = True
except:
icon_drawn = self._render_error(*render_args)
if icon_drawn:
# Render the text
gc.translate_ctm(text_x, y)
gc.set_antialias(0)
self._cached_labels[i].draw(gc)
gc.set_antialias(1)
gc.translate_ctm(-text_x, -y)
# Advance y to the next label's baseline
y -= self.line_spacing
if old_alpha is not None:
gc.set_alpha(old_alpha)
return
def _render_error(self, gc, icon_x, icon_y, icon_width, icon_height):
""" Renders an error icon or performs some other action when a
plot is unable to render its icon.
Returns True if something was actually drawn (and hence the legend
needs to advance the line) or False if nothing was drawn.
"""
if self.error_icon == "skip":
return False
elif self.error_icon == "blank" or self.error_icon == "questionmark":
with gc:
gc.set_fill_color(self.bgcolor_)
gc.rect(icon_x, icon_y, icon_width, icon_height)
gc.fill_path()
return True
else:
return False
def get_preferred_size(self):
"""
Computes the size and position of the legend based on the maximum size of
the labels, the alignment, and position of the component to overlay.
"""
# Gather the names of all the labels we will create
if len(self.plots) == 0:
return [0, 0]
plot_names, visible_plots = map(list, zip(*sorted(self.plots.items())))
label_names = self.labels
if len(label_names) == 0:
if len(self.plots) > 0:
label_names = plot_names
else:
self._cached_labels = []
self._cached_label_sizes = []
self._cached_label_names = []
self._cached_visible_plots = []
self.outer_bounds = [0, 0]
return [0, 0]
if self.hide_invisible_plots:
visible_labels = []
visible_plots = []
for name in label_names:
# If the user set self.labels, there might be a bad value,
# so ensure that each name is actually in the plots dict.
if name in self.plots:
val = self.plots[name]
# Rather than checking for a list/TraitListObject/etc., we just check
# for the attribute first
if hasattr(val, 'visible'):
if val.visible:
visible_labels.append(name)
visible_plots.append(val)
else:
# If we have a list of renderers, add the name if any of them are
# visible
for renderer in val:
if renderer.visible:
visible_labels.append(name)
visible_plots.append(val)
break
label_names = visible_labels
# Create the labels
labels = [self._create_label(text) for text in label_names]
# For the legend title
if self.title_at_top:
labels.insert(0, self._create_label(self.title))
label_names.insert(0, 'Legend Label')
visible_plots.insert(0, None)
else:
labels.append(self._create_label(self.title))
label_names.append(self.title)
visible_plots.append(None)
# We need a dummy GC in order to get font metrics
dummy_gc = font_metrics_provider()
label_sizes = array([label.get_width_height(dummy_gc) for label in labels])
if len(label_sizes) > 0:
max_label_width = max(label_sizes[:, 0])
total_label_height = sum(label_sizes[:, 1]) + (len(label_sizes)-1)*self.line_spacing
else:
max_label_width = 0
total_label_height = 0
legend_width = max_label_width + self.icon_spacing + self.icon_bounds[0] \
+ self.hpadding + 2*self.border_padding
legend_height = total_label_height + self.vpadding + 2*self.border_padding
self._cached_labels = labels
self._cached_label_sizes = label_sizes
self._cached_label_positions = zeros_like(label_sizes)
self._cached_label_names = label_names
self._cached_visible_plots = visible_plots
if "h" not in self.resizable:
legend_width = self.outer_width
if "v" not in self.resizable:
legend_height = self.outer_height
return [legend_width, legend_height]
def get_label_at(self, x, y):
""" Returns the label object at (x,y) """
for i, pos in enumerate(self._cached_label_positions):
size = self._cached_label_sizes[i]
corner = pos + size
if (pos[0] <= x <= corner[0]) and (pos[1] <= y <= corner[1]):
return self._cached_labels[i]
else:
return None
def _do_layout(self):
if self.component is not None or len(self._cached_labels) == 0 or \
self._cached_label_sizes is None or len(self._cached_label_names) == 0:
width, height = self.get_preferred_size()
self.outer_bounds = [width, height]
return
def _create_label(self, text):
""" Returns a new Label instance for the given text. Subclasses can
override this method to customize the creation of labels.
"""
return Label(text=text, font=self.font, margin=0, color=self.color_,
bgcolor="transparent", border_width=0)
def _composite_icon_renderer_default(self):
return CompositeIconRenderer()
#-- trait handlers --------------------------------------------------------
def _anytrait_changed(self, name, old, new):
if name in ("font", "border_padding", "padding", "line_spacing",
"icon_bounds", "icon_spacing", "labels", "plots",
"plots_items", "labels_items", "border_width", "align",
"position", "position_items", "bounds", "bounds_items",
"label_at_top"):
self._layout_needed = True
if name == "color":
self.get_preferred_size()
return
def _plots_changed(self):
""" Invalidate the caches.
"""
self._cached_labels = []
self._cached_label_sizes = None
self._cached_label_names = []
self._cached_visible_plots = []
self._cached_label_positions = None
def _title_at_top_changed(self, old, new):
""" Trait handler for when self.title_at_top changes. """
if old == True:
indx = 0
else:
indx = -1
if old != None:
self._cached_labels.pop(indx)
self._cached_label_names.pop(indx)
self._cached_visible_plots.pop(indx)
# For the legend title
if self.title_at_top:
self._cached_labels.insert(0, self._create_label(self.title))
self._cached_label_names.insert(0, '__legend_label__')
self._cached_visible_plots.insert(0, None)
else:
self._cached_labels.append(self._create_label(self.title))
self._cached_label_names.append(self.title)
self._cached_visible_plots.append(None)
#-- end Legend ----------------------------------------------------------------
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