Chris@1030: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
Chris@1030: 
Chris@1030: /*
Chris@1030:     Sonic Visualiser
Chris@1030:     An audio file viewer and annotation editor.
Chris@1030:     Centre for Digital Music, Queen Mary, University of London.
Chris@1030:     
Chris@1030:     This program is free software; you can redistribute it and/or
Chris@1030:     modify it under the terms of the GNU General Public License as
Chris@1030:     published by the Free Software Foundation; either version 2 of the
Chris@1030:     License, or (at your option) any later version.  See the file
Chris@1030:     COPYING included with this distribution for more information.
Chris@1030: */
Chris@1030: 
Chris@1030: #ifndef SCROLLABLE_IMAGE_CACHE_H
Chris@1030: #define SCROLLABLE_IMAGE_CACHE_H
Chris@1030: 
Chris@1030: #include "base/BaseTypes.h"
Chris@1030: 
Chris@1077: #include "LayerGeometryProvider.h"
Chris@1030: 
Chris@1030: #include <QImage>
Chris@1030: #include <QRect>
Chris@1030: #include <QPainter>
Chris@1030: 
Chris@1030: /**
Chris@1030:  * A cached image for a view that scrolls horizontally, primarily the
Chris@1030:  * spectrogram. The cache object holds an image, reports the size of
Chris@1030:  * the image (likely the same as the underlying view, but it's the
Chris@1030:  * caller's responsibility to set the size appropriately), can scroll
Chris@1030:  * the image, and can report and update which contiguous horizontal
Chris@1030:  * range of the image is valid.
Chris@1030:  *
Chris@1030:  * The only way to *update* the valid area in a cache is to draw to it
Chris@1030:  * using the drawImage call.
Chris@1030:  */
Chris@1030: class ScrollableImageCache
Chris@1030: {
Chris@1030: public:
Chris@1030:     ScrollableImageCache(const LayerGeometryProvider *v = 0) :
Chris@1030: 	m_v(v),
Chris@1030: 	m_left(0),
Chris@1030: 	m_width(0),
Chris@1030: 	m_startFrame(0),
Chris@1030: 	m_zoomLevel(0)
Chris@1030:     {}
Chris@1030: 
Chris@1030:     void invalidate() {
Chris@1030: 	m_width = 0;
Chris@1030:     }
Chris@1030:     
Chris@1030:     bool isValid() const {
Chris@1030: 	return m_width > 0;
Chris@1030:     }
Chris@1030: 
Chris@1030:     QSize getSize() const {
Chris@1030: 	return m_image.size();
Chris@1030:     }
Chris@1030:     
Chris@1030:     void resize(QSize newSize) {
Chris@1079:         if (getSize() != newSize) {
Chris@1079:             m_image = QImage(newSize, QImage::Format_ARGB32_Premultiplied);
Chris@1079:             invalidate();
Chris@1079:         }
Chris@1030:     }
Chris@1030: 	
Chris@1030:     int getValidLeft() const {
Chris@1030: 	return m_left;
Chris@1030:     }
Chris@1030:     
Chris@1030:     int getValidWidth() const {
Chris@1030: 	return m_width;
Chris@1030:     }
Chris@1030: 
Chris@1030:     int getValidRight() const {
Chris@1030: 	return m_left + m_width;
Chris@1030:     }
Chris@1030: 
Chris@1030:     QRect getValidArea() const {
Chris@1030: 	return QRect(m_left, 0, m_width, m_image.height());
Chris@1030:     }
Chris@1030:     
Chris@1030:     int getZoomLevel() const {
Chris@1030: 	return m_zoomLevel;
Chris@1030:     }
Chris@1031:     
Chris@1031:     void setZoomLevel(int zoom) {
Chris@1079:         if (m_zoomLevel != zoom) {
Chris@1079:             m_zoomLevel = zoom;
Chris@1079:             invalidate();
Chris@1079:         }
Chris@1031:     }
Chris@1030: 
Chris@1030:     sv_frame_t getStartFrame() const {
Chris@1030: 	return m_startFrame;
Chris@1030:     }
Chris@1031: 
Chris@1031:     /**
Chris@1031:      * Set the start frame and invalidate the cache. To scroll,
Chris@1031:      * i.e. to set the start frame while retaining cache validity
Chris@1031:      * where possible, use scrollTo() instead.
Chris@1031:      */
Chris@1031:     void setStartFrame(sv_frame_t frame) {
Chris@1079:         if (m_startFrame != frame) {
Chris@1079:             m_startFrame = frame;
Chris@1079:             invalidate();
Chris@1079:         }
Chris@1030:     }
Chris@1030:     
Chris@1030:     const QImage &getImage() const {
Chris@1030: 	return m_image;
Chris@1030:     }
Chris@1030: 
Chris@1031:     /**
Chris@1031:      * Set the new start frame for the cache, if possible also moving
Chris@1031:      * along any existing valid data within the cache so that it
Chris@1031:      * continues to be valid for the new start frame.
Chris@1031:      */
Chris@1031:     void scrollTo(sv_frame_t newStartFrame);
Chris@1030: 
Chris@1031:     /**
Chris@1031:      * Take a left coordinate and width describing a region, and
Chris@1031:      * adjust them so that they are contiguous with the cache valid
Chris@1031:      * region and so that the union of the adjusted region with the
Chris@1031:      * cache valid region contains the supplied region.
Chris@1031:      */
Chris@1031:     void adjustToTouchValidArea(int &left, int &width,
Chris@1031: 				bool &isLeftOfValidArea) const;
Chris@1031:     /**
Chris@1031:      * Draw from an image onto the cache. The supplied image must have
Chris@1031:      * the same height as the cache and the full height is always
Chris@1031:      * drawn. The left and width parameters determine the target
Chris@1031:      * region of the cache, the imageLeft and imageWidth parameters
Chris@1031:      * the source region of the image.
Chris@1031:      */
Chris@1030:     void drawImage(int left,
Chris@1030: 		   int width,
Chris@1030: 		   QImage image,
Chris@1030: 		   int imageLeft,
Chris@1031: 		   int imageWidth);
Chris@1030:     
Chris@1030: private:
Chris@1030:     const LayerGeometryProvider *m_v;
Chris@1030:     QImage m_image;
Chris@1030:     int m_left;  // of valid region
Chris@1030:     int m_width; // of valid region
Chris@1030:     sv_frame_t m_startFrame;
Chris@1030:     int m_zoomLevel;
Chris@1030: };
Chris@1030: 
Chris@1030: #endif