comparison layer/LayerGeometryProvider.h @ 1216:dc2af6616c83

Merge from branch 3.0-integration

+/* -*- 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 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 LAYER_GEOMETRY_PROVIDER_H
+#define LAYER_GEOMETRY_PROVIDER_H
+
+#include "base/BaseTypes.h"
+
+#include <QMutex>
+#include <QMutexLocker>
+#include <QPainter>
+
+class ViewManager;
+class View;
+class Layer;
+
+/**
+ * Interface for classes that provide geometry information (such as
+ * size, start frame, and a large number of other properties) about
+ * the disposition of a layer. The main implementor of this interface
+ * is the View class, but other implementations may be used in
+ * different circumstances, e.g. as a proxy to handle hi-dpi
+ * coordinate mapping.
+ *
+ * Note it is expected that some implementations of this may be
+ * disposable, created on-the-fly for a single use. Code that receives
+ * a LayerGeometryProvider pointer as an argument to something should
+ * not, in general, store that pointer as it may be invalidated before
+ * the next use. Use getId() to instead obtain a persistent identifier
+ * for a LayerGeometryProvider, for example to establish whether the
+ * same one is being provided in two separate calls.
+ */
+class LayerGeometryProvider
+{
+protected:
+    static int getNextId() {
+        static QMutex idMutex;
+        static int nextId = 1;
+        static int maxId = INT_MAX;
+        QMutexLocker locker(&idMutex);
+        int id = nextId;
+        if (nextId == maxId) {
+            // we don't expect this to happen in the lifetime of a
+            // process, but it would be undefined behaviour if it did
+            // since we're using a signed int, so we should really
+            // guard for it...
+            nextId = 1;
+        } else {
+            nextId++;
+        }
+        return id;
+    }            
+    
+public:
+    LayerGeometryProvider() { }
+    
+    /**
+     * Retrieve the id of this object.
+     */
+    virtual int getId() const = 0;
+
+    /**
+     * Retrieve the first visible sample frame on the widget.
+     * This is a calculated value based on the centre-frame, widget
+     * width and zoom level.  The result may be negative.
+     */
+    virtual sv_frame_t getStartFrame() const = 0;
+
+    /**
+     * Return the centre frame of the visible widget.  This is an
+     * exact value that does not depend on the zoom block size.  Other
+     * frame values (start, end) are calculated from this based on the
+     * zoom and other factors.
+     */
+    virtual sv_frame_t getCentreFrame() const = 0;
+
+    /**
+     * Retrieve the last visible sample frame on the widget.
+     * This is a calculated value based on the centre-frame, widget
+     * width and zoom level.
+     */
+    virtual sv_frame_t getEndFrame() const = 0;
+
+    /**
+     * Return the pixel x-coordinate corresponding to a given sample
+     * frame (which may be negative).
+     */
+    virtual int getXForFrame(sv_frame_t frame) const = 0;
+
+    /**
+     * Return the closest frame to the given pixel x-coordinate.
+     */
+    virtual sv_frame_t getFrameForX(int x) const = 0;
+
+    virtual sv_frame_t getModelsStartFrame() const = 0;
+    virtual sv_frame_t getModelsEndFrame() const = 0;
+
+    /**
+     * Return the closest pixel x-coordinate corresponding to a given
+     * view x-coordinate.
+     */
+    virtual int getXForViewX(int viewx) const = 0;
+    
+    /**
+     * Return the closest view x-coordinate corresponding to a given
+     * pixel x-coordinate.
+     */
+    virtual int getViewXForX(int x) const = 0;
+    
+    /**
+     * Return the (maybe fractional) pixel y-coordinate corresponding
+     * to a given frequency, if the frequency range is as specified.
+     * This does not imply any policy about layer frequency ranges,
+     * but it might be useful for layers to match theirs up if
+     * desired.
+     *
+     * Not thread-safe in logarithmic mode.  Call only from GUI thread.
+     */
+    virtual double getYForFrequency(double frequency,
+                                    double minFreq, double maxFreq, 
+                                    bool logarithmic) const = 0;
+
+    /**
+     * Return the closest frequency to the given (maybe fractional)
+     * pixel y-coordinate, if the frequency range is as specified.
+     *
+     * Not thread-safe in logarithmic mode.  Call only from GUI thread.
+     */
+    virtual double getFrequencyForY(double y,
+                                    double minFreq, double maxFreq,
+                                    bool logarithmic) const = 0;
+
+    virtual int getTextLabelHeight(const Layer *layer, QPainter &) const = 0;
+
+    virtual bool getValueExtents(QString unit, double &min, double &max,
+                                 bool &log) const = 0;
+
+    /**
+     * Return the zoom level, i.e. the number of frames per pixel
+     */
+    virtual int getZoomLevel() const = 0;
+
+    /**
+     * To be called from a layer, to obtain the extent of the surface
+     * that the layer is currently painting to. This may be the extent
+     * of the view (if 1x display scaling is in effect) or of a larger
+     * cached pixmap (if greater display scaling is in effect).
+     */
+    virtual QRect getPaintRect() const = 0;
+
+    virtual QSize getPaintSize() const { return getPaintRect().size(); }
+    virtual int getPaintWidth() const { return getPaintRect().width(); }
+    virtual int getPaintHeight() const { return getPaintRect().height(); }
+
+    virtual bool hasLightBackground() const = 0;
+    virtual QColor getForeground() const = 0;
+    virtual QColor getBackground() const = 0;
+
+    virtual ViewManager *getViewManager() const = 0;
+
+    virtual bool shouldIlluminateLocalFeatures(const Layer *, QPoint &) const = 0;
+    virtual bool shouldShowFeatureLabels() const = 0;
+
+    virtual void drawMeasurementRect(QPainter &p, const Layer *,
+                                     QRect rect, bool focus) const = 0;
+
+    virtual void updatePaintRect(QRect r) = 0;
+    
+    virtual View *getView() = 0;
+    virtual const View *getView() const = 0;
+};
+
+#endif