Source code for seamm_widgets.scrolled_columns
# -*- coding: utf-8 -*-
"""A ttk-based widget for columns of widgets, with fixed titles and scrolling
This widgets has two areas: a row of titles across the top and a scrolled frame
below it. It is used to make a table of widgets with fixed column headers.
"""
import seamm_widgets as sw
import tkinter as tk
from tkinter import ttk
[docs]class ScrolledColumns(ttk.Frame):
def __init__(self, parent, *args, **kwargs):
"""Initialize the widget
"""
class_ = kwargs.pop('class_', 'MScrolledColumns')
super().__init__(parent, class_=class_)
columns = kwargs.pop('columns', [])
self.min_sizes = kwargs.pop('minsize', [])
self._after_id = None
# list (vector) of the header widgets, _ncolumns long
self._header_widgets = []
# list of lists (row x column) of widgets in the table
self._widgets = []
# Create the two subframes, linking them both to the
# horizontal scrollbar at the bottom
# self.headers = ttk.Frame(self)
self.table = sw.ScrolledFrame(
self, scroll_vertically=True, borderwidth=2, relief=tk.SUNKEN
)
self.headers = sw.ScrolledFrame(
self,
scroll_vertically=False,
borderwidth=2,
relief=tk.RAISED,
xscrollbar=self.table.xscrollbar,
height=22
)
# and patch up the horizontal scrolling
self.table.xscrollbar['command'] = self.xview
self.headers.grid(row=0, column=0, sticky=tk.EW)
self.table.grid(row=1, column=0, sticky=tk.NSEW)
self.columnconfigure(0, weight=1)
self.rowconfigure(1, weight=1)
# Put in the column titles if given
col = 0
header = self.headers.interior()
for item in columns:
if isinstance(item, str):
item = ttk.Label(header, text=item)
item.grid(row=0, column=col)
col += 1
self._header_widgets.append(item)
[docs] def cell(self, row, column, value=None):
"""Return or set the widget at the given cell
"""
if value is None:
try:
result = self._widgets[row][column]
except Exception:
raise
return result
else:
if column >= self.ncolumns:
# pad the header and each row with None's
extra = [None] * (column - self.ncolumns + 1)
self._header_widgets.extend(extra)
for row_of_widgets in self._widgets:
row_of_widgets.extend(extra)
if row >= self.nrows:
# add rows 'till we get there
extra = [None] * self.ncolumns
for i in range(self.nrows, row + 1):
self._widgets.append(extra)
if isinstance(value, str):
value = ttk.Label(self.table.interior(), text=value)
value.grid(row=row, column=column)
self._widgets[row][column] = value
self._update_widths()
[docs] def clear(self):
"""Clear the contents of the widget.
Returns
-------
None
"""
for row in self._widgets:
for item in row:
if item is not None:
item.destroy()
self._widgets = []
[docs] def delete_row(self, index):
for item in self._widgets[index]:
if item is not None:
item.destroy()
del self._widgets[index]
self._update_widths()
[docs] def delete_column(self, index):
for row in self._widgets:
item = row[index]
if item is not None:
item.destroy()
del row[index]
self._update_widths()
# Provide matrix-like access to the widgets to make
# the code cleaner
def __getitem__(self, index):
"""Allow [row,column] access to the widgets!"""
if isinstance(index, tuple):
row, column = index
return self.cell(row, column)
else:
raise Exception("Row and column indices are required")
def __setitem__(self, index, value):
"""Allow x[row,column] access to the data"""
if isinstance(index, tuple):
row, column = index
self.cell(row, column, value)
else:
raise Exception("Row and column indices are required")
def __delitem__(self, key):
"""Allow deletion of keys"""
if isinstance(key, tuple):
row, column = key
widget = self.cell(row, column)
widget.destroy()
self.cell(row, column, None)
self._update_widths()
else:
raise Exception("Row and column indices are required")
@property
def nrows(self):
return len(self._widgets)
@property
def ncolumns(self):
return len(self._header_widgets)
def _update_widths_now(self):
"""Force the update of the column widths to happen now"""
self._update_widths(when='now')
def _update_widths(self, when='later'):
"""Make the column widths of header and table identical"""
if when == 'later':
if self._after_id is None:
self._after_id = self.after_idle(self._update_widths_now)
return
self.after_cancel(self._after_id)
self._after_id = None
header = self.headers.interior()
table = self.table.interior()
# Remove any widths currently set
for column in range(0, self.ncolumns):
header.columnconfigure(column, minsize=0)
table.columnconfigure(column, minsize=0)
# Let everything settle and finds its size
header.update_idletasks()
# And make the sizes equal
for column in range(0, self.ncolumns):
# bbox returns (x, y, w, h) so we want the third item
w1 = header.grid_bbox(column, 0)[2]
w2 = table.grid_bbox(column, 0)[2]
if w1 < w2:
header.columnconfigure(column, minsize=w2)
else:
table.columnconfigure(column, minsize=w1)
# ensure that the header area is large enough
h = header.grid_bbox(0, 0)[3]
self.headers.height = h + 5
[docs] def xview(self, *args):
"""Connect the subwidgets to the single scrollbar"""
self.headers.canvas.xview(*args)
self.table.canvas.xview(*args)