Fixed root-finding: was ignoring the type of plot (it was assuming the plot

was not a derivative or integral).

svn path=/trunk/KDE/kdeedu/kmplot/; revision=530483

kmplot/View.cpp

@@ -252,10 +252,10 @@ double View::value( Equation * eq, Function::PMode mode, double x )
 			return XParser::self()->fkt( eq, x );
 			
 		case Function::Derivative1:
-			return XParser::self()->derivative1( eq, x, dx );
+			return XParser::self()->derivative( 0, Function::Derivative1, eq, x, dx );
 			
 		case Function::Derivative2:
-			return XParser::self()->derivative2( eq, x, dx );
+			return XParser::self()->derivative( 0, Function::Derivative2, eq, x, dx );
 			
 		case Function::Integral:
 			return XParser::self()->integral( eq, x, dx );
@@ -456,7 +456,18 @@ void View::plotFunction(Function *ufkt, QPainter *pDC)
 						if(mflg<=1)
 						{
 							if ( drawIntegral && (x >= m_integralDrawSettings.dmin) && (x <= m_integralDrawSettings.dmax) )
-								pDC->drawRect( QRectF( p1, QSizeF( p2.x()-p1.x(), p2.y() - CDiagr::self()->yToPixel( 0 ) ) ) );
+							{
+								double y0 = CDiagr::self()->yToPixel( 0 );
+								
+								QPointF points[4];
+								points[0] = QPointF( p1.x(), y0 );
+								points[1] = QPointF( p2.x(), y0 );
+								points[2] = QPointF( p2.x(), p2.y() );
+								points[3] = QPointF( p1.x(), p1.y() );
+								
+								pDC->drawPolygon( points, 4 );
+// 								pDC->drawRect( QRectF( p1, QSizeF( p2.x()-p1.x(), CDiagr::self()->yToPixel( 0 ) - p2.y() ) ) );
+							}
 							else
 							{
 								if ( penShouldDraw( totalLength, ufkt, p_mode ) )
@@ -779,7 +790,7 @@ void View::setpi(QString *s)
 }
 
 
-bool View::root(double *x0, Equation *it)
+bool View::findRoot( double *x0, Function::PMode plot, Equation *it )
 {
 	if(m_haveRoot)
 		return false;
@@ -797,13 +808,13 @@ bool View::root(double *x0, Equation *it)
 	double dx;
 	do
 	{
-		double df = XParser::self()->derivative1( it, *x0, (m_xmax-m_xmin)*1e-5 );
+		double df = XParser::self()->derivative( 1, plot, it, *x0, (m_xmax-m_xmin)*1e-5 );
 		if ( qAbs(df) < 1e-20 )
 			df = 1e-20 * ((df < 0) ? -1 : 1);
 		
 		dx = y / df;
 		*x0 -= dx;
-		y = XParser::self()->fkt( it, *x0 );
+		y = value( it, plot, *x0 );
 		
 		kDebug() << "k="<<k<<": ("<<*x0<<","<<y<<")\n";
 		
@@ -1409,7 +1420,7 @@ bool View::updateCrosshairPosition()
 			else if(fabs(CDiagr::self()->yToReal(ptl.y())) < (m_ymax-m_ymin)/80)
 			{
 				double x0;
-				if ( root( &x0, it->eq[0] ) )
+				if ( findRoot( &x0, m_currentFunctionPlot, it->eq[0] ) )
 				{
 					QString str="  ";
 					str+=i18n("root");

kmplot/View.h

@@ -147,7 +147,9 @@ class View : public QWidget, virtual public ViewIface
 		KToggleAction * m_menuSliderAction;
 		void updateSliders(); /// show only needed sliders
 		
-		/// Convert a width in mm to a suitable QPen width for drawing
+		/**
+		 * Convert a width in mm to a suitable QPen width for drawing.
+		 */
 		double mmToPenWidth( double width_mm, bool antialias ) const;
 
 		/** Current plot range endge. */
@@ -200,12 +202,12 @@ protected slots:
 signals:
 	void setStatusBarText(const QString &);
 	
-protected:
-	/// called when focus is lost
-	virtual void focusOutEvent( QFocusEvent * );
-	/// called when focus is gained
-	virtual void focusInEvent( QFocusEvent * );
-
+	protected:
+		/// called when focus is lost
+		virtual void focusOutEvent( QFocusEvent * );
+		/// called when focus is gained
+		virtual void focusInEvent( QFocusEvent * );
+	
 	private:
 		/**
 		* Print out table with additional information. Only for printing.
@@ -233,7 +235,7 @@ protected:
 		 * \p x (which is then set to the exact root if found).
 		 * \returns whether a root was found.
 		 */
-		bool root( double * x, Equation * eq );
+		bool findRoot( double * x, Function::PMode plot, Equation * eq );
 		///return the inverted color
 		void invertColor(QColor &, QColor &);
 		/// Changes the text in the statusbar
@@ -273,17 +275,16 @@ protected:
 		 * \return the function position of the closest plot if one was found.
 		*/
 		QPointF getPlotUnderMouse();
-	/**
-	 * Finds the closest point to \p pos to the given function.
-	 * \return the parametization (angle or t) that gives the closest point.
-	 */
-	double getClosestPoint( const QPointF & pos, Function * function, Function::PMode mode );
-	/**
-	 * Calculates the pixel distance from \p pos to the display point of the
-	 * given function at \p x.
-	 */
-	double pixelDistance( const QPointF & pos, Function * function, Function::PMode mode, double x );
-	
+		/**
+		* Finds the closest point to \p pos to the given function.
+		* \return the parametization (angle or t) that gives the closest point.
+		*/
+		double getClosestPoint( const QPointF & pos, Function * function, Function::PMode mode );
+		/**
+		* Calculates the pixel distance from \p pos to the display point of the
+		* given function at \p x.
+		*/
+		double pixelDistance( const QPointF & pos, Function * function, Function::PMode mode, double x );
 		/**
 		 * Convenience function for calculating the value of \p eq using the
 		 * given \p mode

kmplot/functioneditor.cpp

@@ -458,7 +458,7 @@ void FunctionEditor::createParametric()
 	m_functionID = XParser::self()->addFunction( QString("x%1(t)=0").arg( name ), QString("y%1(t)=0").arg( name ), Function::Parametric ); 
 	assert( m_functionID != -1 );
 
-	kDebug() << "Created parametric, so requestion state save.\n";
+	kDebug() << "Created parametric, so requesting state save.\n";
 	MainDlg::self()->requestSaveCurrentState();
 }
 

kmplot/xparser.cpp

@@ -138,16 +138,49 @@ bool XParser::getext( Function *item, const QString fstr )
 		return true;
 }
 
-double XParser::derivative1( Equation *u_item, double x, double h )
-{
-	return ( fkt(u_item, x + h ) - fkt( u_item, x ) ) / h;
-}
 
-double XParser::derivative2( Equation *u_item, double x, double h )
+double XParser::derivative( unsigned n, Function::PMode plot, Equation * eq, double x, double h )
 {
-	return ( fkt( u_item, x + h + h ) - 2 * fkt( u_item, x + h ) + fkt( u_item, x ) ) / h / h;
+	switch ( plot )
+	{
+		case Function::Derivative0:
+			break;
+			
+		case Function::Derivative1:
+			n += 1;
+			break;
+			
+		case Function::Derivative2:
+			n += 2;
+			break;
+			
+		case Function::Integral:
+		{
+			if ( n == 0 )
+				return integral( eq, x, h );
+			
+			n -= 1;
+			break;
+		}
+	}
+	
+	switch ( n )
+	{
+		case 0:
+			return fkt( eq, x );
+			
+		case 1:
+			return ( fkt(eq, x + (h/2) ) - fkt( eq, x - (h/2) ) ) / h;
+			
+		case 2:
+			return ( fkt( eq, x + h ) - 2 * fkt( eq, x ) + fkt( eq, x - h ) ) / (h*h);
+			
+		default:
+			return ( derivative( n-1, Function::Derivative0, eq, x+(h/2), (h/4) ) - derivative( n-1, Function::Derivative0, eq, x-(h/2), (h/4) ) ) / h;
+	}
 }
 
+
 void XParser::findFunctionName(QString &function_name, int const id, int const type)
 {
   char last_character;

kmplot/xparser.h

@@ -47,18 +47,25 @@ class XParser : public Parser
 		static XParser * self( bool * modified = 0 );
 		
 		~XParser();
-		/// Evaluates the 1st dreivative of the function with intex \a ix
-		double derivative1( Equation * eq, double x, double h );
-		/// Evaluates the 2nd dreivative of the function with intex \a ix
-		double derivative2( Equation * eq, double x, double h );
+		/**
+		 * Evaluates the \p n th derivative of the function using numerical
+		 * stepsize \p h .
+		 * \param plot This should be the plot to take the derivative of, and
+		 * it adjusts \p n accordingly. For example, passing \p plot =
+		 * Derivative1 and \p n = 1 is the same as passing \p plot = Derivative0
+		 * and \p n = 2.
+		 */
+		double derivative( unsigned n, Function::PMode plot, Equation * eq, double x, double h );
 		/**
 		 * Calculates the value of the equation using numerical integration
 		 * with the given step size \p h (which is only used as a hint).
 		 */
 		double integral( Equation * eq, double x, double h );
-        
-	/// Line width default
-	QColor defaultColor(int function);
+		/**
+		 * The settings contain 10 default function colors. This returns the
+		 * (function % 10)th color.
+		 */
+		QColor defaultColor(int function);
 	
 	virtual int addFunction( QString, QString, Function::Type type );