From 58bfc9f886ed037eb89aed59f192489d68b4e653 Mon Sep 17 00:00:00 2001
From: Matthew D Jones <Matthew.D.Jones@tessella.com>
Date: Mon, 10 Aug 2015 15:44:04 +0100
Subject: [PATCH] Re #11422 Scale transformation now of correct form
---
.../src/plot2D/PowerScaleEngine.cpp | 33 ++++++++++++-------
.../MantidPlot/src/plot2D/PowerScaleEngine.h | 4 ++-
2 files changed, 24 insertions(+), 13 deletions(-)
diff --git a/Code/Mantid/MantidPlot/src/plot2D/PowerScaleEngine.cpp b/Code/Mantid/MantidPlot/src/plot2D/PowerScaleEngine.cpp
index 04e2d11d390..5bd32be0915 100644
--- a/Code/Mantid/MantidPlot/src/plot2D/PowerScaleEngine.cpp
+++ b/Code/Mantid/MantidPlot/src/plot2D/PowerScaleEngine.cpp
@@ -4,7 +4,7 @@
--------------------------------------------------------------------
Copyright : (C) 2009 by Ion Vasilief
Email (use @ for *) : ion_vasilief*yahoo.fr
- Description : Return a transformation for reciprocal (1/t) scales
+ Description : Return a transformation for power (X^n) scales
***************************************************************************/
@@ -141,15 +141,6 @@ void PowerScaleEngine::buildTicks(
for ( int i = 0; i < QwtScaleDiv::NTickTypes; i++ )
{
ticks[i] = strip(ticks[i], interval);
-
- // ticks very close to 0.0 are
- // explicitely set to 0.0
-
- for ( int j = 0; j < (int)ticks[i].count(); j++ )
- {
- if ( QwtScaleArithmetic::compareEps(ticks[i][j], 0.0, stepSize) == 0 )
- ticks[i][j] = 0.0;
- }
}
}
@@ -244,15 +235,33 @@ QwtScaleTransformation *PowerScaleTransformation::copy() const
return new PowerScaleTransformation(d_engine);
}
+/*
+ * Transform a value between 2 linear intervals
+ *
+ * \param s value related to the interval [s1, s2]
+ * \param s1 first border of scale interval
+ * \param s2 second border of scale interval
+ * \param p1 first border of target interval
+ * \param p2 second border of target interval
+ */
double PowerScaleTransformation::xForm(
double s, double s1, double s2, double p1, double p2) const
{
- return p1 + (p2 - p1) * s2 * (s1 - s)/(s * (s1 - s2));
+ return p1 + (p2 - p1) / (pow(s2, nth_power) - pow(s1, nth_power)) * (pow(s, nth_power) - pow(s1, nth_power));
}
+/*
+ * Transform a value from a linear to a power scale interval
+ *
+ * \param p value related to the linear interval [p1, p2]
+ * \param p1 first border of linear interval
+ * \param p2 second border of linear interval
+ * \param s1 first border of logarithmic interval
+ * \param s2 second border of logarithmic interval
+ */
double PowerScaleTransformation::invXForm(double p, double p1, double p2,
double s1, double s2) const
{
- return s1*s2*(p2 - p1)/(s2*(p2 - p) + s1*(p - p1));
+ return pow((p - p1) / (p2 - p1) * (pow(s2, nth_power) - pow(s1, nth_power)), 1.0/nth_power) * s1;
}
diff --git a/Code/Mantid/MantidPlot/src/plot2D/PowerScaleEngine.h b/Code/Mantid/MantidPlot/src/plot2D/PowerScaleEngine.h
index b910d4b9263..03602089d91 100644
--- a/Code/Mantid/MantidPlot/src/plot2D/PowerScaleEngine.h
+++ b/Code/Mantid/MantidPlot/src/plot2D/PowerScaleEngine.h
@@ -37,10 +37,12 @@
class PowerScaleTransformation: public ScaleTransformation
{
public:
- PowerScaleTransformation(const ScaleEngine *engine):ScaleTransformation(engine){};
+ PowerScaleTransformation(const ScaleEngine *engine):ScaleTransformation(engine){nth_power = 2.0;};
virtual double xForm(double x, double, double, double p1, double p2) const;
virtual double invXForm(double x, double s1, double s2, double p1, double p2) const;
QwtScaleTransformation* copy() const;
+private:
+ double nth_power;
};
/*!
--
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