comparison layer/WaveformLayer.h @ 0:2a4f26e85b4c

initial import

+/* -*- c-basic-offset: 4 -*-  vi:set ts=8 sts=4 sw=4: */
+
+/*
+    A waveform viewer and audio annotation editor.
+    Chris Cannam, Queen Mary University of London, 2005
+    
+    This is experimental software.  Not for distribution.
+*/
+
+#ifndef _WAVEFORM_VIEW_H_
+#define _WAVEFORM_VIEW_H_
+
+#include <QRect>
+#include <QColor>
+
+#include "base/Layer.h"
+
+#include "model/RangeSummarisableTimeValueModel.h"
+
+class View;
+class QPainter;
+class QPixmap;
+
+class WaveformLayer : public Layer
+{
+    Q_OBJECT
+
+public:
+    WaveformLayer(View *w);
+    ~WaveformLayer();
+
+    virtual const ZoomConstraint *getZoomConstraint() const { return m_model; }
+    virtual const Model *getModel() const { return m_model; }
+    virtual void paint(QPainter &paint, QRect rect) const;
+
+    virtual int getVerticalScaleWidth(QPainter &) const;
+    virtual void paintVerticalScale(QPainter &paint, QRect rect) const;
+
+    void setModel(const RangeSummarisableTimeValueModel *model);
+
+    virtual PropertyList getProperties() const;
+    virtual PropertyType getPropertyType(const PropertyName &) const;
+    virtual QString getPropertyGroupName(const PropertyName &) const;
+    virtual int getPropertyRangeAndValue(const PropertyName &,
+					   int *min, int *max) const;
+    virtual QString getPropertyValueLabel(const PropertyName &,
+					  int value) const;
+    virtual void setProperty(const PropertyName &, int value);
+
+    /**
+     * Set the gain multiplier for sample values in this view.
+     *
+     * The default is 1.0.
+     */
+    void setGain(float gain);
+    float getGain() const { return m_gain; }
+
+    /**
+     * Set the basic display colour for waveforms.
+     *
+     * The default is black.
+     *!!! NB should default to white if the associated View !hasLightBackground()
+     */
+    void setBaseColour(QColor);
+    QColor getBaseColour() const { return m_colour; }
+
+    /**
+     * Set whether to display mean values as a lighter-coloured area
+     * beneath the peaks.  Rendering will be slightly faster without
+     * but arguably prettier with.
+     *
+     * The default is to display means.
+     */
+    void setShowMeans(bool);
+    bool getShowMeans() const { return m_showMeans; }
+
+    /**
+     * Set whether to use shades of grey (or of the base colour) to
+     * provide additional perceived vertical resolution (i.e. using
+     * half-filled pixels to represent levels that only just meet the
+     * pixel unit boundary).  This provides a small improvement in
+     * waveform quality at a small cost in rendering speed.
+     * 
+     * The default is to use greyscale.
+     */
+    void setUseGreyscale(bool);
+    bool getUseGreyscale() const { return m_greyscale; }
+
+
+    enum ChannelMode { SeparateChannels, MergeChannels };
+
+    /**
+     * Specify whether multi-channel audio data should be displayed
+     * with a separate axis per channel (SeparateChannels), or with a
+     * single synthetic axis showing channel 0 above the axis and
+     * channel 1 below (MergeChannels).
+     * 
+     * MergeChannels does not work for files with more than 2
+     * channels.
+     * 
+     * The default is SeparateChannels.
+     */
+    void setChannelMode(ChannelMode);
+    ChannelMode getChannelMode() const { return m_channelMode; }
+
+
+    /**
+     * Specify the channel to use from the source model.  A value of
+     * -1 means to show all available channels (laid out to the
+     * channel mode). The default is -1.
+     */
+    void setChannel(int);
+    int getChannel() const { return m_channel; }
+
+
+    enum Scale { LinearScale, MeterScale, dBScale };
+
+    /**
+     * Specify the vertical scale for sample levels.  With LinearScale,
+     * the scale is directly proportional to the raw [-1, +1)
+     * floating-point audio sample values.  With dBScale the
+     * vertical scale is proportional to dB level (truncated at
+     * -50dB).  MeterScale provides a hybrid variable scale based on
+     * IEC meter scale, intended to provide a clear overview at
+     * relatively small heights.
+     *
+     * Note that the effective gain (see setGain()) is applied before
+     * vertical scaling.
+     *
+     * The default is LinearScale.
+     */
+    void setScale(Scale);
+    Scale getScale() const { return m_scale; }
+
+    /**
+     * Enable or disable aggressive pixmap cacheing.  If enabled,
+     * waveforms will be rendered to an off-screen pixmap and
+     * refreshed from there instead of being redrawn from the peak
+     * data each time.  This may be faster if the data and zoom level
+     * do not change often, but it may be slower for frequently zoomed
+     * data and it will only work if the waveform is the "bottom"
+     * layer on the displayed widget, as each refresh will erase
+     * anything beneath the waveform.
+     *
+     * This is intended specifically for a panner widget display in
+     * which the waveform never moves, zooms, or changes, but some
+     * graphic such as a panner outline is frequently redrawn over the
+     * waveform.  This situation would necessitate a lot of waveform
+     * refresh if the default cacheing strategy was used.
+     *
+     * The default is not to use aggressive cacheing.
+     */
+    void setAggressiveCacheing(bool);
+    bool getAggressiveCacheing() const { return m_aggressive; }
+
+    virtual int getCompletion() const;
+
+    virtual QString getPropertyContainerIconName() const { return "waveform"; }
+
+protected:
+    int dBscale(float sample, int m) const;
+
+    const RangeSummarisableTimeValueModel *m_model; // I do not own this
+
+    /// Return value is number of channels displayed
+    size_t getChannelArrangement(size_t &min, size_t &max, bool &merging) const;
+
+    float m_gain;
+    QColor m_colour;
+    bool m_showMeans;
+    bool m_greyscale;
+    ChannelMode m_channelMode;
+    int m_channel;
+    Scale m_scale;
+    bool m_aggressive;
+
+    mutable QPixmap *m_cache;
+    mutable bool m_cacheValid;
+    mutable int m_cacheZoomLevel;
+};
+
+#endif