diff layer/ColourScale.h @ 1068:521f7e8b0559 spectrogram-minor-refactor

Introduce ColourScale to handle colour mapping for both spectrogram and colour 3d plot layers

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/layer/ColourScale.h	Thu Jun 23 14:42:37 2016 +0100
@@ -0,0 +1,96 @@
+/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
+
+/*
+    Sonic Visualiser
+    An audio file viewer and annotation editor.
+    Centre for Digital Music, Queen Mary, University of London.
+    This file copyright 2006-2016 Chris Cannam and QMUL.
+    
+    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 the Free Software Foundation; either version 2 of the
+    License, or (at your option) any later version.  See the file
+    COPYING included with this distribution for more information.
+*/
+
+#ifndef COLOUR_SCALE_H
+#define COLOUR_SCALE_H
+
+#include "ColourMapper.h"
+
+/**
+ * Map values within a range onto a set of colours, with a given
+ * distribution (linear, log etc) and optional colourmap rotation.
+ */
+class ColourScale
+{
+public:
+    enum Scale {
+	LinearColourScale,
+	MeterColourScale,
+	LogColourScale,
+	PhaseColourScale,
+        PlusMinusOneScale,
+        AbsoluteScale
+    };
+
+    /**
+     * Create a ColourScale with the given parameters:
+     * 
+     * @param colourMap A colour map index as used by ColourMapper
+     * @param scale Distribution for the scale
+     * @param minValue Minimum value in range
+     * @param maxValue Maximum value in range. Must be > minValue
+     * @param threshold Threshold below which every value is mapped to
+     *   background pixel 0
+     * @param gain Gain to apply before clamping and mapping, typically 1
+     *
+     * Note that some parameters may be ignored for some scale
+     * distribution settings. For example, min and max are ignored for
+     * PlusMinusOneScale and PhaseColourScale and threshold and gain
+     * are ignored for PhaseColourScale.
+     */
+    ColourScale(int colourMap,
+		Scale scale,
+		double minValue,
+		double maxValue,
+		double threshold,
+		double gain);
+
+    /**
+     * Return a pixel number (in the range 0-255 inclusive)
+     * corresponding to the given value.  The pixel 0 is used only for
+     * values below the threshold supplied in the constructor. All
+     * other values are mapped onto the range 1-255.
+     */
+    int getPixel(double value);
+
+    /**
+     * Return the colour for the given pixel number (which must be in
+     * the range 0-255). The pixel 0 is always the background
+     * colour. Other pixels are mapped taking into account the given
+     * colourmap rotation (which is also a value in the range 0-255).
+     */
+    QColor getColourForPixel(int pixel, int rotation);
+    
+    /**
+     * Return the colour corresponding to the given value. This is
+     * equivalent to getColourForPixel(getPixel(value), rotation).
+     */
+    QColor getColour(double value, int rotation) {
+	return getColourForPixel(getPixel(value), rotation);
+    }
+
+private:
+    ColourMapper m_mapper;
+    Scale m_scale;
+    double m_min;
+    double m_max;
+    double m_mappedMin;
+    double m_mappedMax;
+    double m_threshold;
+    double m_gain;
+    static int m_maxPixel;
+};
+
+#endif