#
# CanvasMixin.py -- enable canvas like capabilities.
#
# This is open-source software licensed under a BSD license.
# Please see the file LICENSE.txt for details.
#
from ginga.canvas.CompoundMixin import CompoundMixin
__all__ = ['CanvasMixin']
class CanvasError(Exception):
pass
[docs]
class CanvasMixin(object):
"""A CanvasMixin is combined with the CompoundMixin to make a
tag-addressible canvas-like interface. This mixin should precede the
CompoundMixin in the inheritance (and so, method resolution) order.
"""
def __init__(self):
assert isinstance(self, CompoundMixin), "Missing CompoundMixin class"
# holds the list of tags
self.tags = {}
self.count = 0
for name in ('modified', ):
self.enable_callback(name)
[docs]
def update_canvas(self, whence=3):
self.make_callback('modified', whence)
[docs]
def redraw(self, whence=3):
self.make_callback('modified', whence)
[docs]
def subcanvas_updated_cb(self, canvas, whence):
"""
This is a notification that a subcanvas (a canvas contained in
our canvas) has been modified. We in turn signal that our canvas
has been modified.
"""
# avoid self-referential loops
if canvas != self:
#print("%s subcanvas %s was updated" % (self.name, canvas.name))
self.make_callback('modified', whence)
[docs]
def add(self, obj, tag=None, tagpfx=None, belowThis=None, redraw=True):
self.count += 1
if tag:
# user supplied a tag
if tag in self.tags:
raise CanvasError("Tag already used: '%s'" % (tag))
else:
if tagpfx:
# user supplied a tag prefix
if tagpfx.startswith('@'):
raise CanvasError("Tag prefix may not begin with '@'")
tag = '%s%d' % (tagpfx, self.count)
else:
# make up our own tag
tag = '@%d' % (self.count)
obj.tag = tag
self.tags[tag] = obj
self.add_object(obj, belowThis=belowThis)
# propagate change notification on this canvas
if obj.has_callback('modified'):
obj.add_callback('modified', self.subcanvas_updated_cb)
if redraw:
self.update_canvas(whence=3)
return tag
[docs]
def delete_objects_by_tag(self, tags, redraw=True):
for tag in tags:
try:
obj = self.tags[tag]
del self.tags[tag]
super(CanvasMixin, self).delete_object(obj)
except Exception as e:
continue
if redraw:
self.update_canvas(whence=3)
[docs]
def delete_object_by_tag(self, tag, redraw=True):
self.delete_objects_by_tag([tag], redraw=redraw)
[docs]
def get_object_by_tag(self, tag):
obj = self.tags[tag]
return obj
[docs]
def lookup_object_tag(self, obj):
# TODO: we may need to have a reverse index eventually
res = list(zip(*self.tags.items()))
if len(res) == 0:
return None
tags, objs = res
try:
idx = objs.index(obj)
return tags[idx]
except ValueError:
return None
[docs]
def has_tag(self, tag):
return tag in self.tags
[docs]
def get_objects_by_tag_pfx(self, tagpfx):
return [self.tags[k] for k in self.get_tags_by_tag_pfx(tagpfx)]
[docs]
def delete_all_objects(self, redraw=True):
self.tags.clear()
CompoundMixin.delete_all_objects(self)
if redraw:
self.update_canvas(whence=3)
[docs]
def delete_objects(self, objects, redraw=True):
res = list(zip(*self.tags.items()))
if len(res) == 0:
tags, objs = [], []
else:
tags, objs = res
for obj in objects:
try:
idx = objs.index(obj)
tag = tags[idx]
except ValueError:
tag = None
if tag is not None:
self.delete_object_by_tag(tag, redraw=False)
else:
CompoundMixin.delete_object(self, obj)
if redraw:
self.update_canvas(whence=3)
[docs]
def delete_object(self, obj, redraw=True):
self.delete_objects([obj], redraw=redraw)
[docs]
def raise_object_by_tag(self, tag, aboveThis=None, redraw=True):
obj1 = self.get_object_by_tag(tag)
if aboveThis is None:
self.raise_object(obj1)
else:
obj2 = self.get_object_by_tag(aboveThis)
self.raise_object(obj1, obj2)
if redraw:
self.update_canvas(whence=3)
[docs]
def lower_object_by_tag(self, tag, belowThis=None, redraw=True):
obj1 = self.get_object_by_tag(tag)
if belowThis is None:
self.lower_object(obj1)
else:
obj2 = self.get_object_by_tag(belowThis)
self.lower_object(obj1, obj2)
if redraw:
self.update_canvas(whence=3)