# Standard library imports import re from textwrap import dedent # System library imports from PyQt4 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) / 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._hide_later() 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._hide_later() def paintEvent(self, event): """ Reimplemented to paint the background panel. """ painter = QtGui.QStylePainter(self) option = QtGui.QStyleOptionFrame() option.init(self) painter.drawPrimitive(QtGui.QStyle.PE_PanelTipLabel, option) painter.end() super(CallTipWidget, self).paintEvent(event) 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_docstring(self, doc, maxlines=20): """ Attempts to show the specified docstring at the current cursor location. The docstring is dedented and possibly truncated for length. """ doc = dedent(doc.rstrip()).lstrip() match = re.match("(?:[^\n]*\n){%i}" % maxlines, doc) if match: doc = doc[:match.end()] + '\n[Documentation continues...]' 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() qchar = document.characterAt(position) while (position > 0 and qchar.isPrint() and # Need to check explicitly for line/paragraph separators: qchar.unicode() not in (0x2028, 0x2029)): char = qchar.toAscii() 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 qchar = document.characterAt(position) else: position = -1 return position, commas def _hide_later(self): """ Hides the tooltip after some time has passed. """ if not self._hide_timer.isActive(): 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()