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# -*- coding: UTF-8 -*-
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"""Cell renderer for directed graph.
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This module contains the implementation of a custom GtkCellRenderer that
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draws part of the directed graph based on the lines suggested by the code
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Because we're shiny, we use Cairo to do this, and because we're naughty
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we cheat and draw over the bits of the TreeViewColumn that are supposed to
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just be for the background.
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__copyright__ = "Copyright © 2005-2011 Canonical Ltd."
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__author__ = "Scott James Remnant <scott@ubuntu.com>"
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from gi.repository import Gtk
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from gi.repository import GObject
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from gi.repository import Pango
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from gi.repository import PangoCairo
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# Cairo constants are not exported yet. These are taken from documentation.
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CAIRO_LINE_CAP_BUTT = 0
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CAIRO_LINE_CAP_ROUND = 1
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CAIRO_LINE_CAP_SQUARE = 2
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CAIRO_FILL_RULE_WINDING = 0
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CAIRO_FILL_RULE_EVEN_ODD = 1
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# Macro from Pango header.
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return (d + 512) / 1000
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class CellRendererGraph(Gtk.CellRendererPixbuf):
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"""Cell renderer for directed graph.
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node (column, colour) tuple to draw revision node,
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in_lines (start, end, colour) tuple list to draw inward lines,
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out_lines (start, end, colour) tuple list to draw outward lines.
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"node": ( GObject.TYPE_PYOBJECT, "node",
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"revision node instruction",
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GObject.PARAM_WRITABLE
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"tags": ( GObject.TYPE_PYOBJECT, "tags",
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"list of tags associated with the node",
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GObject.PARAM_WRITABLE
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"in-lines": ( GObject.TYPE_PYOBJECT, "in-lines",
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"instructions to draw lines into the cell",
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GObject.PARAM_WRITABLE
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"out-lines": ( GObject.TYPE_PYOBJECT, "out-lines",
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"instructions to draw lines out of the cell",
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GObject.PARAM_WRITABLE
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def do_set_property(self, property, value):
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"""Set properties from GObject properties."""
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if property.name == "node":
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elif property.name == "tags":
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elif property.name == "in-lines":
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elif property.name == "out-lines":
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self.out_lines = value
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raise AttributeError, "no such property: '%s'" % property.name
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def box_size(self, widget):
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"""Calculate box size based on widget's font.
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Cache this as it's probably expensive to get. It ensures that we
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draw the graph at least as large as the text.
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except AttributeError:
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pango_ctx = widget.get_pango_context()
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font_desc = widget.get_style_context().get_font(
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metrics = pango_ctx.get_metrics(font_desc, None)
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ascent = PANGO_PIXELS(metrics.get_ascent())
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descent = PANGO_PIXELS(metrics.get_descent())
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self._box_size = ascent + descent + 6
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def set_colour(self, ctx, colour, bg, fg):
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"""Set the context source colour.
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Picks a distinct colour based on an internal wheel; the bg
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parameter provides the value that should be assigned to the 'zero'
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colours and the fg parameter provides the multiplier that should be
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applied to the foreground colours.
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mainline_color = ( 0.0, 0.0, 0.0 )
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colour_rgb = mainline_color
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colour_rgb = colours[colour % len(colours)]
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red = (colour_rgb[0] * fg) or bg
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green = (colour_rgb[1] * fg) or bg
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blue = (colour_rgb[2] * fg) or bg
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ctx.set_source_rgb(red, green, blue)
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def do_activate(event, widget, path, bg_area, cell_area, flags):
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"""Renderers cannot be activated; always return True."""
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def do_editing_started(event, widget, path, fb_area, cell_area, flags):
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"""Renderers cannot be edited; always return None."""
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def do_get_size(self, widget, cell_area):
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"""Return the size we need for this cell.
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Each cell is drawn individually and is only as wide as it needs
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to be, we let the TreeViewColumn take care of making them all
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box_size = self.box_size(widget) + 1
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width = box_size * (self.columns_len + 1)
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# FIXME I have no idea how to use cell_area properly
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return (0, 0, width, height)
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def do_render(self, ctx, widget, bg_area, cell_area, flags):
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"""Render an individual cell.
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Draws the cell contents using cairo, taking care to clip what we
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do to within the background area so we don't draw over other cells.
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Note that we're a bit naughty there and should really be drawing
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in the cell_area (or even the exposed area), but we explicitly don't
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We try and be a little clever, if the line we need to draw is going
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to cross other columns we actually draw it as in the .---' style
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instead of a pure diagonal ... this reduces confusion by an
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ctx.rectangle(bg_area.x, bg_area.y, bg_area.width, bg_area.height)
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box_size = self.box_size(widget)
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ctx.set_line_width(box_size / 8)
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# Draw lines into the cell
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for start, end, colour in self.in_lines:
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self.render_line (ctx, cell_area, box_size,
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bg_area.y, bg_area.height,
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start, end, colour, flags)
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# Draw lines out of the cell
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for start, end, colour in self.out_lines:
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self.render_line (ctx, cell_area, box_size,
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bg_area.y + bg_area.height, bg_area.height,
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start, end, colour, flags)
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# Draw the revision node in the right column
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(column, colour) = self.node
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ctx.arc(cell_area.x + box_size * column + box_size / 2,
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cell_area.y + cell_area.height / 2,
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box_size / 4, 0, 2 * math.pi)
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if flags & Gtk.CellRendererState.SELECTED:
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ctx.set_source_rgb(1.0, 1.0, 1.0)
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ctx.set_line_width(box_size / 4)
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ctx.stroke_preserve()
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ctx.set_line_width(box_size / 8)
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self.set_colour(ctx, colour, 0.0, 0.5)
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ctx.stroke_preserve()
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self.set_colour(ctx, colour, 0.5, 1.0)
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self.render_tags(ctx, widget.create_pango_context(), cell_area, box_size)
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def render_line(self, ctx, cell_area, box_size,
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mid, height, start, end, colour, flags):
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ctx.set_line_cap(CAIRO_LINE_CAP_ROUND)
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x = cell_area.x + box_size * end + box_size / 2
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ctx.move_to(x, mid + height / 3)
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ctx.line_to(x, mid + height / 3)
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ctx.move_to(x, mid + height / 6)
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ctx.line_to(x, mid + height / 6)
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ctx.set_line_cap(CAIRO_LINE_CAP_ROUND)
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x = cell_area.x + box_size * start + box_size / 2
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ctx.move_to(x, mid - height / 3)
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ctx.line_to(x, mid - height / 3)
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ctx.move_to(x, mid - height / 6)
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ctx.line_to(x, mid - height / 6)
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ctx.set_line_cap(CAIRO_LINE_CAP_BUTT)
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startx = cell_area.x + box_size * start + box_size / 2
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endx = cell_area.x + box_size * end + box_size / 2
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ctx.move_to(startx, mid - height / 2)
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if start - end == 0 :
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ctx.line_to(endx, mid + height / 2 + 1)
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ctx.curve_to(startx, mid - height / 5,
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startx, mid - height / 5,
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startx + (endx - startx) / 2, mid)
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ctx.curve_to(endx, mid + height / 5,
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endx, mid + height / 5 ,
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endx, mid + height / 2 + 1)
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if flags & Gtk.CellRendererState.SELECTED:
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ctx.set_source_rgb(1.0, 1.0, 1.0)
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ctx.set_line_width(box_size / 5)
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ctx.stroke_preserve()
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ctx.set_line_width(box_size / 8)
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self.set_colour(ctx, colour, 0.0, 0.65)
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def render_tags(self, ctx, pango_ctx, cell_area, box_size):
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# colour ID used in self.set_colour on the tags
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(column, colour) = self.node
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font_desc = Pango.FontDescription()
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font_desc.set_size(Pango.SCALE * 7)
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tag_layout = Pango.Layout(pango_ctx)
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tag_layout.set_font_description(font_desc)
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# The width of the tag label stack
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for tag_idx, tag in enumerate(self.tags):
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tag_layout.set_text(" " + tag + " ", -1)
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text_width, text_height = tag_layout.get_pixel_size()
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box_size * (column + 1.3) + width
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cell_area.height / 2 - \
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width += text_width + 5
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# Draw the tag border
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ctx.move_to(x0 - box_size / 3, y0 + text_height / 2)
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ctx.line_to(x0 + text_width, y0)
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ctx.line_to(x0 + text_width, y0 + text_height)
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ctx.line_to(x0, y0 + text_height)
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ctx.line_to(x0 - box_size / 3, y0 + text_height / 2)
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ctx.arc(x0 - box_size / 12,
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y0 + text_height / 2,
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self.set_colour(ctx, TAG_COLOUR_ID, 0.0, 0.5)
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ctx.stroke_preserve()
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ctx.set_fill_rule (CAIRO_FILL_RULE_EVEN_ODD)
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self.set_colour(ctx, TAG_COLOUR_ID, 0.5, 1.0)
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self.set_colour(ctx, 0, 0.0, 0.0)
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PangoCairo.show_layout(ctx, tag_layout)