191 lines
8.0 KiB
Python
191 lines
8.0 KiB
Python
# -*- coding: utf-8 -*-
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"""This widget implements a text based input field"""
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from __future__ import division
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from __future__ import absolute_import
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from __future__ import print_function
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from __future__ import unicode_literals
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from builtins import chr
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from re import match
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from asciimatics.event import KeyboardEvent, MouseEvent
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from asciimatics.screen import Screen
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from asciimatics.widgets.utilities import _find_min_start, _enforce_width, _get_offset
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from asciimatics.widgets.widget import Widget
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class Text(Widget):
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"""
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A Text widget is a single line input field.
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It consists of an optional label and an entry box.
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"""
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__slots__ = ["_label", "_column", "_start_column", "_on_change", "_validator", "_hide_char",
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"_max_length", "_readonly"]
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def __init__(self, label=None, name=None, on_change=None, validator=None, hide_char=None,
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max_length=None, readonly=False, **kwargs):
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"""
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:param label: An optional label for the widget.
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:param name: The name for the widget.
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:param on_change: Optional function to call when text changes.
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:param validator: Optional definition of valid data for this widget.
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This can be a function (which takes the current value and returns True for valid
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content) or a regex string (which must match the entire allowed value).
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:param hide_char: Character to use instead of what the user types - e.g. to hide passwords.
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:param max_length: Optional maximum length of the field. If set, the widget will limit
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data entry to this length.
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:param readonly: Whether the widget prevents user input to change values. Default is False.
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Also see the common keyword arguments in :py:obj:`.Widget`.
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"""
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super(Text, self).__init__(name, **kwargs)
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self._label = label
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self._column = 0
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self._start_column = 0
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self._on_change = on_change
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self._validator = validator
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self._hide_char = hide_char
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self._max_length = max_length
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self._readonly = readonly
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def set_layout(self, x, y, offset, w, h):
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# Do the usual layout work. then apply max length to resulting dimensions.
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super(Text, self).set_layout(x, y, offset, w, h)
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if self._max_length:
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# Allow extra char for cursor, so contents don't scroll at required length
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self._w = min(self._w, self._max_length + self._offset + 1)
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def update(self, frame_no):
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self._draw_label()
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# Calculate new visible limits if needed.
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self._start_column = min(self._start_column, self._column)
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self._start_column += _find_min_start(self._value[self._start_column:self._column + 1],
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self.width, self._frame.canvas.unicode_aware,
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self._column >= self.string_len(self._value))
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# Render visible portion of the text.
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(colour, attr, background) = self._pick_colours("readonly" if self._readonly else "edit_text")
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text = self._value[self._start_column:]
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text = _enforce_width(text, self.width, self._frame.canvas.unicode_aware)
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if self._hide_char:
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text = self._hide_char[0] * len(text)
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text += " " * (self.width - self.string_len(text))
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self._frame.canvas.print_at(
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text,
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self._x + self._offset,
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self._y,
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colour, attr, background)
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# Since we switch off the standard cursor, we need to emulate our own
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# if we have the input focus.
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if self._has_focus:
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text_width = self.string_len(text[:self._column - self._start_column])
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self._draw_cursor(
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" " if self._column >= len(self._value) else self._hide_char[0] if self._hide_char
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else self._value[self._column],
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frame_no,
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self._x + self._offset + text_width,
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self._y)
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def reset(self):
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# Reset to original data and move to end of the text.
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self._start_column = 0
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self._column = len(self._value)
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def process_event(self, event):
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if isinstance(event, KeyboardEvent):
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if event.key_code == Screen.KEY_BACK and not self._readonly:
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if self._column > 0:
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# Delete character in front of cursor.
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self._set_and_check_value("".join([self._value[:self._column - 1],
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self._value[self._column:]]))
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self._column -= 1
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elif event.key_code == Screen.KEY_DELETE and not self._readonly:
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if self._column < len(self._value):
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self._set_and_check_value("".join([self._value[:self._column],
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self._value[self._column + 1:]]))
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elif event.key_code == Screen.KEY_LEFT:
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self._column -= 1
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self._column = max(self._column, 0)
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elif event.key_code == Screen.KEY_RIGHT:
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self._column += 1
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self._column = min(len(self._value), self._column)
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elif event.key_code == Screen.KEY_HOME:
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self._column = 0
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elif event.key_code == Screen.KEY_END:
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self._column = len(self._value)
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elif event.key_code >= 32 and not self._readonly:
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# Enforce required max length - swallow event if not allowed
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if self._max_length is None or len(self._value) < self._max_length:
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# Insert any visible text at the current cursor position.
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self._set_and_check_value(chr(event.key_code).join([self._value[:self._column],
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self._value[self._column:]]))
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self._column += 1
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else:
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# Ignore any other key press.
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return event
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elif isinstance(event, MouseEvent):
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# Mouse event - rebase coordinates to Frame context.
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if event.buttons != 0:
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if self.is_mouse_over(event, include_label=False):
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self._column = (self._start_column +
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_get_offset(self._value[self._start_column:],
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event.x - self._x - self._offset,
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self._frame.canvas.unicode_aware))
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self._column = min(len(self._value), self._column)
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self._column = max(0, self._column)
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return None
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# Ignore other mouse events.
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return event
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else:
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# Ignore other events
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return event
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# If we got here, we processed the event - swallow it.
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return None
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def required_height(self, offset, width):
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return 1
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@property
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def frame_update_count(self):
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# Force refresh for cursor if needed.
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return 5 if self._has_focus and not self._frame.reduce_cpu else 0
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@property
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def readonly(self):
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"""
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Whether this widget is readonly or not.
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"""
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return self._readonly
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@readonly.setter
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def readonly(self, new_value):
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self._readonly = new_value
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@property
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def value(self):
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"""
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The current value for this Text.
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"""
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return self._value
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@value.setter
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def value(self, new_value):
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self._set_and_check_value(new_value, reset=True)
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def _set_and_check_value(self, new_value, reset=False):
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# Only trigger the notification after we've changed the value.
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old_value = self._value
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self._value = new_value if new_value else ""
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if reset:
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self.reset()
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if old_value != self._value and self._on_change:
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self._on_change()
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if self._validator:
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if callable(self._validator):
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self._is_valid = self._validator(self._value)
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else:
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self._is_valid = match(self._validator, self._value) is not None
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