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# -*- coding: utf-8 -*-
"""
Created on Aug 29, 2015
Looper that only shows visible elements
@author: jrm
"""
from atom.api import ContainerList, Instance, List, observe
from enaml.core.declarative import d_
from enaml.core.looper import Looper, new_scope, recursive_expand, sortedmap
from enamlx.widgets.abstract_item_view import AbstractItemView
class ListLooper(Looper):
"""A looper handles ContainerList updates"""
items = ContainerList()
_expanded = List()
def _observe_iterable(self, change):
if not self.is_initialized:
return
elif change["type"] == "update":
self.refresh_items()
elif change["type"] == "container":
if change["operation"] == "append":
self.append_items([change["item"]])
elif change["operation"] == "extend":
self.append_items(change["items"])
elif change["operation"] == "insert":
self.insert_item(change["index"], change["item"])
elif change["operation"] == "remove":
self.remove_items([change["item"]])
elif change["operation"] == "pop":
self.pop_item(change["index"])
elif change["operation"] in ["reverse", "sort"]:
self.refresh_items()
def remove_items(self, old_items):
for item in old_items:
index = self.items.index(item)
self.pop_item(index)
def pop_item(self, index):
for iteration in self.items.pop(index):
for old in iteration:
if not old.is_destroyed:
old.destroy()
def insert_item(self, loop_index, loop_item):
iteration = []
self._iter_data[loop_item] = iteration
for nodes, key, f_locals in self.pattern_nodes:
with new_scope(key, f_locals) as f_locals:
f_locals["loop_index"] = loop_index
f_locals["loop_item"] = loop_item
for node in nodes:
child = node(None)
if isinstance(child, list):
iteration.extend(child)
else:
iteration.append(child)
expanded = []
recursive_expand(sum([iteration], []), expanded)
# Where do I insert it!
self.parent.insert_children(self, expanded)
self.items.insert(loop_index, iteration)
def append_item(self, item):
self.insert_item(len(self.items), item)
def refresh_items(self):
"""Refresh the items of the pattern.
This method destroys the old items and creates and initializes
the new items.
"""
old_items = self.items[:] # if self._dirty else []
old_iter_data = self._iter_data # if self._dirty else {}
iterable = self.iterable
pattern_nodes = self.pattern_nodes
new_iter_data = sortedmap()
new_items = []
if iterable is not None and len(pattern_nodes) > 0:
for loop_index, loop_item in enumerate(iterable):
iteration = old_iter_data.get(loop_item)
if iteration is not None:
new_iter_data[loop_item] = iteration
new_items.append(iteration)
old_items.remove(iteration)
continue
iteration = []
new_iter_data[loop_item] = iteration
new_items.append(iteration)
for nodes, key, f_locals in pattern_nodes:
with new_scope(key, f_locals) as f_locals:
f_locals["loop_index"] = loop_index
f_locals["loop_item"] = loop_item
for node in nodes:
child = node(None)
if isinstance(child, list):
iteration.extend(child)
else:
iteration.append(child)
for iteration in old_items:
for old in iteration:
if not old.is_destroyed:
old.destroy()
if len(new_items) > 0:
expanded = []
recursive_expand(sum(new_items, []), expanded)
self._expanded = expanded
self.parent.insert_children(self, expanded)
self.items = new_items
self._iter_data = new_iter_data
class ItemViewLooper(Looper):
"""A looper that only creates the objects
in the visible window.
"""
item_view = d_(Instance(AbstractItemView))
# --------------------------------------------------------------------------
# Observers
# --------------------------------------------------------------------------
@observe("item_view.iterable")
def _observe_iterable(self, change):
super(ItemViewLooper, self)._observe_iterable(change)
def _observe_item_view(self, change):
"""A private observer for the `window_size` attribute.
If the iterable changes while the looper is active, the loop
items will be refreshed.
"""
self.iterable = self.item_view.iterable
@observe(
"item_view.iterable_index",
"item_view.iterable_fetch_size",
"item_view.iterable_prefetch",
)
def _refresh_window(self, change):
if change["type"] == "update" and self.is_initialized:
self.refresh_items()
@observe("item_view.visible_rect")
def _prefetch_items(self, change):
"""When the current_row in the model changes (whether from scrolling) or
set by the application. Make sure the results are loaded!
"""
if self.is_initialized:
view = self.item_view
upper_limit = (
view.iterable_index + view.iterable_fetch_size - view.iterable_prefetch
)
lower_limit = max(0, view.iterable_index + view.iterable_prefetch)
offset = int(view.iterable_fetch_size / 2.0)
upper_visible_row = view.visible_rect[2]
lower_visible_row = view.visible_rect[0]
print("Visible rect = %s" % view.visible_rect)
if upper_visible_row >= upper_limit:
next_index = max(0, upper_visible_row - offset) # Center on current row
# Going up works...
if next_index > view.iterable_index:
print("Auto prefetch upper limit %s!" % upper_limit)
view.iterable_index = next_index
# view.model().reset()
# But doewn doesnt?
elif view.iterable_index > 0 and lower_visible_row < lower_limit:
next_index = max(0, lower_visible_row - offset) # Center on current row
# Going down works
if next_index < view.iterable_index:
print(
"Auto prefetch lower limit=%s, iterable=%s, setting next=%s!"
% (lower_limit, view.iterable_index, next_index)
)
view.iterable_index = next_index
# view.model().reset()
@property
def windowed_iterable(self):
"""That returns only the window"""
# Seek to offset
effective_offset = max(0, self.item_view.iterable_index)
for i, item in enumerate(self.iterable):
if i < effective_offset:
continue
elif i >= (effective_offset + self.item_view.iterable_fetch_size):
return
yield item
def refresh_items(self):
"""Refresh the items of the pattern.
This method destroys the old items and creates and initializes
the new items.
"""
old_items = self.items[:] # if self._dirty else []
old_iter_data = self._iter_data # if self._dirty else {}
iterable = self.windowed_iterable
pattern_nodes = self.pattern_nodes
new_iter_data = sortedmap()
new_items = []
if iterable is not None and len(pattern_nodes) > 0:
for loop_index, loop_item in enumerate(iterable):
iteration = old_iter_data.get(loop_item)
if iteration is not None:
new_iter_data[loop_item] = iteration
new_items.append(iteration)
old_items.remove(iteration)
continue
iteration = []
new_iter_data[loop_item] = iteration
new_items.append(iteration)
for nodes, key, f_locals in pattern_nodes:
with new_scope(key, f_locals) as f_locals:
f_locals["loop_index"] = loop_index
f_locals["loop_item"] = loop_item
for node in nodes:
child = node(None)
if isinstance(child, list):
iteration.extend(child)
else:
iteration.append(child)
# Add to old items list
# self.old_items.extend(old_items)
# if self._dirty:
for iteration in old_items:
for old in iteration:
if not old.is_destroyed:
old.destroy()
if len(new_items) > 0:
expanded = []
recursive_expand(sum(new_items, []), expanded)
self.parent.insert_children(self, expanded)
self.items = new_items # if self._dirty else new_items+old_items
self._iter_data = new_iter_data
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