File indexing completed on 2024-05-12 15:28:17

 /***************************************************************************
     File             : ExpressionTextEdit.cpp
     Project          : LabPlot
     --------------------------------------------------------------------
     Copyright        : (C) 2014-2017 Alexander Semke (alexander.semke@web.de)
     Description      : widget for defining mathematical expressions
     modified version of https://doc.qt.io/qt-5/qtwidgets-tools-customcompleter-example.html
  ***************************************************************************/
 
 /***************************************************************************
  *                                                                         *
  *  This program is free software; you can redistribute it and/or modify   *
  *  it under the terms of the GNU General Public License as published by   *
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  *  (at your option) any later version.                                    *
  *                                                                         *
  *  This program is distributed in the hope that it will be useful,        *
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  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the          *
  *  GNU General Public License for more details.                           *
  *                                                                         *
  *   You should have received a copy of the GNU General Public License     *
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  *   Foundation, Inc., 51 Franklin Street, Fifth Floor,                    *
  *   Boston, MA  02110-1301  USA                                           *
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  ***************************************************************************/
 
 /****************************************************************************
  **
  ** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
  ** Contact: http://www.qt-project.org/legal
  **
  ** This file is part of the examples of the Qt Toolkit.
  **
  ** $QT_BEGIN_LICENSE:BSD$
  ** You may use this file under the terms of the BSD license as follows:
  **
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  ** modification, are permitted provided that the following conditions are
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 #include "ExpressionTextEdit.h"
 #include "backend/gsl/ExpressionParser.h"
 #include "tools/EquationHighlighter.h"
 
 #include <QCompleter>
 #include <QKeyEvent>
 #include <QAbstractItemView>
 #include <QScrollBar>
 
 /*!
   \class ExpressionTextEdit
   \brief  Provides a widget for defining mathematical expressions
           Supports syntax-highlighting and completion.
 
           Modified version of https://doc.qt.io/qt-5/qtwidgets-tools-customcompleter-example.html
 
   \ingroup kdefrontend
 */
 ExpressionTextEdit::ExpressionTextEdit(QWidget* parent) : KTextEdit(parent),
     m_highlighter(new EquationHighlighter(this)) {
 
     QStringList list = ExpressionParser::getInstance()->functions();
     list.append(ExpressionParser::getInstance()->constants());
 
     setTabChangesFocus(true);
 
     m_completer = new QCompleter(list, this);
     m_completer->setWidget(this);
     m_completer->setCompletionMode(QCompleter::PopupCompletion);
     m_completer->setCaseSensitivity(Qt::CaseInsensitive);
 
     connect(m_completer, QOverload<const QString&>::of(&QCompleter::activated), this, &ExpressionTextEdit::insertCompletion);
     connect(this, &ExpressionTextEdit::textChanged, this, [=](){ validateExpression();});
     connect(this, &ExpressionTextEdit::cursorPositionChanged, m_highlighter, &EquationHighlighter::rehighlight);
 }
 
 EquationHighlighter* ExpressionTextEdit::highlighter() {
     return m_highlighter;
 }
 
 bool ExpressionTextEdit::isValid() const {
     return (!document()->toPlainText().simplified().isEmpty() && m_isValid);
 }
 
 void ExpressionTextEdit::setExpressionType(XYEquationCurve::EquationType type) {
     m_expressionType = type;
     m_variables.clear();
     if (type == XYEquationCurve::EquationType::Cartesian)
         m_variables << "x";
     else if (type == XYEquationCurve::EquationType::Polar)
         m_variables << "phi";
     else if (type == XYEquationCurve::EquationType::Parametric)
         m_variables << "t";
     else if (type == XYEquationCurve::EquationType::Implicit)
         m_variables << "x" << "y";
 
     m_highlighter->setVariables(m_variables);
 }
 
 void ExpressionTextEdit::setVariables(const QStringList& vars) {
     m_variables = vars;
     m_highlighter->setVariables(m_variables);
     validateExpression(true);
 }
 
 void ExpressionTextEdit::insertCompletion(const QString& completion) {
     QTextCursor tc{ textCursor() };
     int extra{ completion.length() - m_completer->completionPrefix().length() };
     tc.movePosition(QTextCursor::Left);
     tc.movePosition(QTextCursor::EndOfWord);
     tc.insertText(completion.right(extra));
     setTextCursor(tc);
 }
 
 /*!
  * \brief Validates the current expression if the text was changed and highlights the text field red if the expression is invalid.
  * \param force forces the validation and highlighting when no text changes were made, used when new parameters/variables were provided
  */
 void ExpressionTextEdit::validateExpression(bool force) {
     //check whether the expression was changed or only the formatting
     QString text = toPlainText().simplified();
     bool textChanged{ (text != m_currentExpression) ? true : false };
 
     if (textChanged || force) {
         m_isValid = ExpressionParser::getInstance()->isValid(text, m_variables);
         if (!m_isValid)
             setStyleSheet("QTextEdit{background: red;}");
         else
             setStyleSheet(QString());
 
         m_currentExpression = text;
     }
     if (textChanged)
         emit expressionChanged();
 }
 
 //##############################################################################
 //####################################  Events   ###############################
 //##############################################################################
 void ExpressionTextEdit::focusInEvent(QFocusEvent* e) {
     m_completer->setWidget(this);
     QTextEdit::focusInEvent(e);
 }
 
 void ExpressionTextEdit::focusOutEvent(QFocusEvent* e) {
     //when loosing focus, rehighlight to remove potential highlighting of opening and closing brackets
     m_highlighter->rehighlight();
     QTextEdit::focusOutEvent(e);
 }
 
 void ExpressionTextEdit::keyPressEvent(QKeyEvent* e) {
     switch (e->key()) {
         case Qt::Key_Enter:
         case Qt::Key_Return:
             e->ignore();
             return;
         default:
             break;
     }
 
     const bool isShortcut = ((e->modifiers() & Qt::ControlModifier) && e->key() == Qt::Key_E); // CTRL+E
     if (!isShortcut) // do not process the shortcut when we have a completer
         QTextEdit::keyPressEvent(e);
 
     const bool ctrlOrShift = e->modifiers() & (Qt::ControlModifier | Qt::ShiftModifier);
     if ((ctrlOrShift && e->text().isEmpty()))
         return;
 
     static QString eow("~!@#$%^&*()_+{}|:\"<>?,./;'[]\\-="); // end of word
     const bool hasModifier = (e->modifiers() != Qt::NoModifier) && !ctrlOrShift;
     QTextCursor tc = textCursor();
     tc.select(QTextCursor::WordUnderCursor);
     const QString& completionPrefix = tc.selectedText();
 
     if (!isShortcut && (hasModifier || e->text().isEmpty()|| completionPrefix.length() < 1
                     || eow.contains(e->text().right(1)))) {
         m_completer->popup()->hide();
         return;
     }
 
     if (completionPrefix != m_completer->completionPrefix()) {
         m_completer->setCompletionPrefix(completionPrefix);
         m_completer->popup()->setCurrentIndex(m_completer->completionModel()->index(0, 0));
     }
     QRect cr{ cursorRect() };
     cr.setWidth(m_completer->popup()->sizeHintForColumn(0)
                 + m_completer->popup()->verticalScrollBar()->sizeHint().width());
     m_completer->complete(cr); // popup it up!
 }
 
 void ExpressionTextEdit::mouseMoveEvent(QMouseEvent* e) {
     QTextCursor tc = cursorForPosition(e->pos());
     tc.select(QTextCursor::WordUnderCursor);
 
     const QString& token = tc.selectedText();
     if (token.isEmpty()) {
         setToolTip(QString());
         return;
     }
 
     //try to find the token under the mouse cursor in the list of constants first
     static const QStringList& constants = ExpressionParser::getInstance()->constants();
     int index = constants.indexOf(token);
 
     if (index != -1) {
         static const QStringList& names = ExpressionParser::getInstance()->constantsNames();
         static const QStringList& values = ExpressionParser::getInstance()->constantsValues();
         static const QStringList& units = ExpressionParser::getInstance()->constantsUnits();
         setToolTip(names.at(index) + ": " + constants.at(index) + " = " + values.at(index) + ' ' + units.at(index));
     } else {
         //text token was not found in the list of constants -> check functions as next
         static const QStringList& functions = ExpressionParser::getInstance()->functions();
         index = functions.indexOf(token);
         if (index != -1) {
             static const QStringList& names = ExpressionParser::getInstance()->functionsNames();
             setToolTip(functions.at(index) + " - " + names.at(index));
         } else
             setToolTip(QString());
     }
 
     KTextEdit::mouseMoveEvent(e);
 }