def draw(self, cr: cairo.Context) -> None:
polyline = self._polyline
stroke_width = self._stroke_width
stroke_color = self._stroke_color
if polyline is None or len(polyline) == 0:
self._last_drawn_region = None
return
if self._path_cache is not None:
cr.append_path(self._path_cache)
else:
self._show_polyline(cr, polyline)
self._path_cache = cr.copy_path()
extents = Rect2(cr.path_extents())
dx = 1 / cr.get_matrix().xx
dy = 1 / cr.get_matrix().yy
cr.save()
if self._scale_strokes:
stroke_scale = max(dx, dy)
cr.identity_matrix()
else:
stroke_scale = 1.0
cr.set_line_width(stroke_width)
cr.set_source_rgba(*stroke_color)
cr.stroke()
cr.restore()
extents = expand_rect(extents, max(stroke_width * stroke_scale, dx,
dy))
self._last_drawn_region = cairo.Region(
cairo.RectangleInt(
int(math.floor(extents.x)),
int(math.floor(extents.y)),
int(math.ceil(extents.w)),
int(math.ceil(extents.h)),
))
