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from itertools import chain, starmap, product, groupby, islice
from functools import reduce
from operator import itemgetter
from typing import List, Tuple, Iterable, Sequence, Optional, Union
from AnyQt.QtCore import (
QModelIndex, QAbstractItemModel, QItemSelectionModel, QItemSelection,
QObject
)
class BlockSelectionModel(QItemSelectionModel):
"""
Item selection model ensuring the selection maintains a simple block
like structure.
e.g.
[a b] c [d e]
[f g] h [i j]
is allowed but this is not
[a] b c d e
[f g] h [i j]
I.e. select the Cartesian product of row and column indices.
"""
def __init__(
self, model: QAbstractItemModel, parent: Optional[QObject] = None,
selectBlocks=True, **kwargs
) -> None:
super().__init__(model, parent, **kwargs)
self.__selectBlocks = selectBlocks
def select(self, selection: Union[QItemSelection, QModelIndex],
flags: QItemSelectionModel.SelectionFlags) -> None:
"""Reimplemented."""
if isinstance(selection, QModelIndex):
selection = QItemSelection(selection, selection)
if not self.__selectBlocks:
super().select(selection, flags)
return
model = self.model()
if flags & QItemSelectionModel.Current: # no current selection support
flags &= ~QItemSelectionModel.Current
if flags & QItemSelectionModel.Toggle: # no toggle support either
flags &= ~QItemSelectionModel.Toggle
flags |= QItemSelectionModel.Select
if flags == QItemSelectionModel.ClearAndSelect:
# extend selection ranges in `selection` to span all row/columns
sel_rows = selection_rows(selection)
sel_cols = selection_columns(selection)
selection = QItemSelection()
for row_range, col_range in \
product(to_ranges(sel_rows), to_ranges(sel_cols)):
qitemselection_select_range(
selection, model, row_range, col_range
)
elif flags & (QItemSelectionModel.Select |
QItemSelectionModel.Deselect):
# extend all selection ranges in `selection` with the full current
# row/col spans
rows, cols = selection_blocks(self.selection())
sel_rows = selection_rows(selection)
sel_cols = selection_columns(selection)
ext_selection = QItemSelection()
for row_range, col_range in \
product(to_ranges(rows), to_ranges(sel_cols)):
qitemselection_select_range(
ext_selection, model, row_range, col_range
)
for row_range, col_range in \
product(to_ranges(sel_rows), to_ranges(cols)):
qitemselection_select_range(
ext_selection, model, row_range, col_range
)
selection.merge(ext_selection, QItemSelectionModel.Select)
super().select(selection, flags)
def selectBlocks(self):
"""Is the block selection in effect."""
return self.__selectBlocks
def setSelectBlocks(self, state):
"""Set the block selection state.
If set to False, the selection model behaves as the base
QItemSelectionModel
"""
self.__selectBlocks = state
def selection_rows(selection):
# type: (QItemSelection) -> List[Tuple[int, int]]
"""
Return a list of ranges for all referenced rows contained in selection
Parameters
----------
selection : QItemSelection
Returns
-------
rows : List[Tuple[int, int]]
"""
spans = set(range(s.top(), s.bottom() + 1) for s in selection)
indices = sorted(set(chain.from_iterable(spans)))
return list(ranges(indices))
def selection_columns(selection):
# type: (QItemSelection) -> List[Tuple[int, int]]
"""
Return a list of ranges for all referenced columns contained in selection
Parameters
----------
selection : QItemSelection
Returns
-------
rows : List[Tuple[int, int]]
"""
spans = {range(s.left(), s.right() + 1) for s in selection}
indices = sorted(set(chain.from_iterable(spans)))
return list(ranges(indices))
def selection_blocks(selection):
# type: (QItemSelection) -> Tuple[List[Tuple[int, int]], List[Tuple[int, int]]]
if selection.count() > 0:
rowranges = {range(span.top(), span.bottom() + 1)
for span in selection}
colranges = {range(span.left(), span.right() + 1)
for span in selection}
else:
return [], []
rows = sorted(set(chain.from_iterable(rowranges)))
cols = sorted(set(chain.from_iterable(colranges)))
return list(ranges(rows)), list(ranges(cols))
def ranges(indices):
# type: (Iterable[int]) -> Iterable[Tuple[int, int]]
"""
Group consecutive indices into `(start, stop)` tuple 'ranges'.
>>> list(ranges([1, 2, 3, 5, 3, 4]))
>>> [(1, 4), (5, 6), (3, 5)]
"""
g = groupby(enumerate(indices), key=lambda t: t[1] - t[0])
for _, range_ind in g:
range_ind = list(range_ind)
_, start = range_ind[0]
_, end = range_ind[-1]
yield start, end + 1
def merge_ranges(
ranges: Iterable[Tuple[int, int]]
) -> Sequence[Tuple[int, int]]:
def merge_range_seq_accum(
accum: List[Tuple[int, int]], r: Tuple[int, int]
) -> List[Tuple[int, int]]:
last_start, last_stop = accum[-1]
r_start, r_stop = r
assert last_start <= r_start
if r_start <= last_stop:
# merge into last
accum[-1] = last_start, max(last_stop, r_stop)
else:
# push a new (disconnected) range interval
accum.append(r)
return accum
ranges = sorted(ranges, key=itemgetter(0))
if ranges:
return reduce(merge_range_seq_accum, islice(ranges, 1, None),
[ranges[0]])
else:
return []
def qitemselection_select_range(
selection: QItemSelection,
model: QAbstractItemModel,
rows: range,
columns: range
) -> None:
assert rows.step == 1 and columns.step == 1
selection.select(
model.index(rows.start, columns.start),
model.index(rows.stop - 1, columns.stop - 1)
)
def to_ranges(spans: Iterable[Tuple[int, int]]) -> Sequence[range]:
return list(starmap(range, spans))
class SymmetricSelectionModel(QItemSelectionModel):
"""
Item selection model ensuring the selection is symmetric
"""
def select(self, selection: Union[QItemSelection, QModelIndex],
flags: QItemSelectionModel.SelectionFlags) -> None:
if isinstance(selection, QModelIndex):
selection = QItemSelection(selection, selection)
if flags & QItemSelectionModel.Current: # no current selection support
flags &= ~QItemSelectionModel.Current
if flags & QItemSelectionModel.Toggle: # no toggle support either
flags &= ~QItemSelectionModel.Toggle
flags |= QItemSelectionModel.Select
model = self.model()
rows, cols = selection_blocks(selection)
sym_ranges = to_ranges(merge_ranges(chain(rows, cols)))
if flags == QItemSelectionModel.ClearAndSelect:
# extend ranges in `selection` to symmetric selection
# row/columns.
selection = QItemSelection()
for rows, cols in product(sym_ranges, sym_ranges):
qitemselection_select_range(selection, model, rows, cols)
elif flags & (QItemSelectionModel.Select |
QItemSelectionModel.Deselect):
# extend ranges in sym_ranges to span all current rows/columns
rows_current, cols_current = selection_blocks(self.selection())
ext_selection = QItemSelection()
for rrange, crange in product(sym_ranges, sym_ranges):
qitemselection_select_range(selection, model, rrange, crange)
for rrange, crange in product(sym_ranges, to_ranges(cols_current)):
qitemselection_select_range(selection, model, rrange, crange)
for rrange, crange in product(to_ranges(rows_current), sym_ranges):
qitemselection_select_range(selection, model, rrange, crange)
selection.merge(ext_selection, QItemSelectionModel.Select)
super().select(selection, flags)
def selectedItems(self) -> Sequence[int]:
"""Return the indices of the the symmetric selection."""
ranges_ = starmap(range, selection_rows(self.selection()))
return sorted(chain.from_iterable(ranges_))
def setSelectedItems(self, inds: Iterable[int]):
"""Set and select the `inds` indices"""
model = self.model()
selection = QItemSelection()
sym_ranges = to_ranges(ranges(inds))
for rows, cols in product(sym_ranges, sym_ranges):
qitemselection_select_range(selection, model, rows, cols)
self.select(selection, QItemSelectionModel.ClearAndSelect)
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