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call_tip_widget.py
230 lines | 8.7 KiB | text/x-python | PythonLexer
# Standard library imports
import re
from textwrap import dedent
from unicodedata import category
# System library imports
from IPython.external.qt import QtCore, QtGui
class CallTipWidget(QtGui.QLabel):
""" Shows call tips by parsing the current text of Q[Plain]TextEdit.
"""
#--------------------------------------------------------------------------
# 'QObject' interface
#--------------------------------------------------------------------------
def __init__(self, text_edit):
""" Create a call tip manager that is attached to the specified Qt
text edit widget.
"""
assert isinstance(text_edit, (QtGui.QTextEdit, QtGui.QPlainTextEdit))
super(CallTipWidget, self).__init__(None, QtCore.Qt.ToolTip)
self._hide_timer = QtCore.QBasicTimer()
self._text_edit = text_edit
self.setFont(text_edit.document().defaultFont())
self.setForegroundRole(QtGui.QPalette.ToolTipText)
self.setBackgroundRole(QtGui.QPalette.ToolTipBase)
self.setPalette(QtGui.QToolTip.palette())
self.setAlignment(QtCore.Qt.AlignLeft)
self.setIndent(1)
self.setFrameStyle(QtGui.QFrame.NoFrame)
self.setMargin(1 + self.style().pixelMetric(
QtGui.QStyle.PM_ToolTipLabelFrameWidth, None, self))
self.setWindowOpacity(self.style().styleHint(
QtGui.QStyle.SH_ToolTipLabel_Opacity, None, self, None) / 255.0)
def eventFilter(self, obj, event):
""" Reimplemented to hide on certain key presses and on text edit focus
changes.
"""
if obj == self._text_edit:
etype = event.type()
if etype == QtCore.QEvent.KeyPress:
key = event.key()
if key in (QtCore.Qt.Key_Enter, QtCore.Qt.Key_Return):
self.hide()
elif key == QtCore.Qt.Key_Escape:
self.hide()
return True
elif etype == QtCore.QEvent.FocusOut:
self.hide()
elif etype == QtCore.QEvent.Enter:
self._hide_timer.stop()
elif etype == QtCore.QEvent.Leave:
self._leave_event_hide()
return super(CallTipWidget, self).eventFilter(obj, event)
def timerEvent(self, event):
""" Reimplemented to hide the widget when the hide timer fires.
"""
if event.timerId() == self._hide_timer.timerId():
self._hide_timer.stop()
self.hide()
#--------------------------------------------------------------------------
# 'QWidget' interface
#--------------------------------------------------------------------------
def enterEvent(self, event):
""" Reimplemented to cancel the hide timer.
"""
super(CallTipWidget, self).enterEvent(event)
self._hide_timer.stop()
def hideEvent(self, event):
""" Reimplemented to disconnect signal handlers and event filter.
"""
super(CallTipWidget, self).hideEvent(event)
self._text_edit.cursorPositionChanged.disconnect(
self._cursor_position_changed)
self._text_edit.removeEventFilter(self)
def leaveEvent(self, event):
""" Reimplemented to start the hide timer.
"""
super(CallTipWidget, self).leaveEvent(event)
self._leave_event_hide()
def paintEvent(self, event):
""" Reimplemented to paint the background panel.
"""
painter = QtGui.QStylePainter(self)
option = QtGui.QStyleOptionFrame()
option.initFrom(self)
painter.drawPrimitive(QtGui.QStyle.PE_PanelTipLabel, option)
painter.end()
super(CallTipWidget, self).paintEvent(event)
def setFont(self, font):
""" Reimplemented to allow use of this method as a slot.
"""
super(CallTipWidget, self).setFont(font)
def showEvent(self, event):
""" Reimplemented to connect signal handlers and event filter.
"""
super(CallTipWidget, self).showEvent(event)
self._text_edit.cursorPositionChanged.connect(
self._cursor_position_changed)
self._text_edit.installEventFilter(self)
#--------------------------------------------------------------------------
# 'CallTipWidget' interface
#--------------------------------------------------------------------------
def show_call_info(self, call_line=None, doc=None, maxlines=20):
""" Attempts to show the specified call line and docstring at the
current cursor location. The docstring is possibly truncated for
length.
"""
if doc:
match = re.match("(?:[^\n]*\n){%i}" % maxlines, doc)
if match:
doc = doc[:match.end()] + '\n[Documentation continues...]'
else:
doc = ''
if call_line:
doc = '\n\n'.join([call_line, doc])
return self.show_tip(doc)
def show_tip(self, tip):
""" Attempts to show the specified tip at the current cursor location.
"""
# Attempt to find the cursor position at which to show the call tip.
text_edit = self._text_edit
document = text_edit.document()
cursor = text_edit.textCursor()
search_pos = cursor.position() - 1
self._start_position, _ = self._find_parenthesis(search_pos,
forward=False)
if self._start_position == -1:
return False
# Set the text and resize the widget accordingly.
self.setText(tip)
self.resize(self.sizeHint())
# Locate and show the widget. Place the tip below the current line
# unless it would be off the screen. In that case, place it above
# the current line.
padding = 3 # Distance in pixels between cursor bounds and tip box.
cursor_rect = text_edit.cursorRect(cursor)
screen_rect = QtGui.qApp.desktop().screenGeometry(text_edit)
point = text_edit.mapToGlobal(cursor_rect.bottomRight())
point.setY(point.y() + padding)
tip_height = self.size().height()
if point.y() + tip_height > screen_rect.height():
point = text_edit.mapToGlobal(cursor_rect.topRight())
point.setY(point.y() - tip_height - padding)
self.move(point)
self.show()
return True
#--------------------------------------------------------------------------
# Protected interface
#--------------------------------------------------------------------------
def _find_parenthesis(self, position, forward=True):
""" If 'forward' is True (resp. False), proceed forwards
(resp. backwards) through the line that contains 'position' until an
unmatched closing (resp. opening) parenthesis is found. Returns a
tuple containing the position of this parenthesis (or -1 if it is
not found) and the number commas (at depth 0) found along the way.
"""
commas = depth = 0
document = self._text_edit.document()
char = document.characterAt(position)
# Search until a match is found or a non-printable character is
# encountered.
while category(char) != 'Cc' and position > 0:
if char == ',' and depth == 0:
commas += 1
elif char == ')':
if forward and depth == 0:
break
depth += 1
elif char == '(':
if not forward and depth == 0:
break
depth -= 1
position += 1 if forward else -1
char = document.characterAt(position)
else:
position = -1
return position, commas
def _leave_event_hide(self):
""" Hides the tooltip after some time has passed (assuming the cursor is
not over the tooltip).
"""
if (not self._hide_timer.isActive() and
# If Enter events always came after Leave events, we wouldn't need
# this check. But on Mac OS, it sometimes happens the other way
# around when the tooltip is created.
QtGui.qApp.topLevelAt(QtGui.QCursor.pos()) != self):
self._hide_timer.start(300, self)
#------ Signal handlers ----------------------------------------------------
def _cursor_position_changed(self):
""" Updates the tip based on user cursor movement.
"""
cursor = self._text_edit.textCursor()
if cursor.position() <= self._start_position:
self.hide()
else:
position, commas = self._find_parenthesis(self._start_position + 1)
if position != -1:
self.hide()