view layer/ScrollableImageCache.cpp @ 1127:9fb8dfd7ce4c spectrogram-minor-refactor

Fix threshold in spectrogram -- it wasn't working in the last release.
There is a new protocol for this. Formerly the threshold parameter had a
range from -50dB to 0 with the default at -50, and -50 treated internally
as "no threshold". However, there was a hardcoded, hidden internal threshold
for spectrogram colour mapping at -80dB with anything below this being rounded
to zero. Now the threshold parameter has range -81 to -1 with the default
at -80, -81 is treated internally as "no threshold", and there is no hidden
internal threshold. So the default behaviour is the same as before, an
effective -80dB threshold, but it is now possible to change this in both
directions. Sessions reloaded from prior versions may look slightly different
because, if the session says there should be no threshold, there will now
actually be no threshold instead of having the hidden internal one.

Still need to do something in the UI to make it apparent that the -81dB
setting removes the threshold entirely. This is at least no worse than the
previous, also obscured, magic -50dB setting.

/* -*- 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.
*/

#include "ScrollableImageCache.h"

#include <iostream>
using namespace std;

#define DEBUG_SCROLLABLE_IMAGE_CACHE 1

void
ScrollableImageCache::scrollTo(const LayerGeometryProvider *v,
                               sv_frame_t newStartFrame)
{
    int dx = (v->getXForFrame(m_startFrame) -
	      v->getXForFrame(newStartFrame));
    
#ifdef DEBUG_SCROLLABLE_IMAGE_CACHE
    cerr << "ScrollableImageCache::scrollTo: start frame " << m_startFrame
	 << " -> " << newStartFrame << ", dx = " << dx << endl;
#endif

    if (m_startFrame == newStartFrame) {
	// haven't moved
        return;
    }
	
    m_startFrame = newStartFrame;
	
    if (!isValid()) {
	return;
    }

    int w = m_image.width();

    if (dx == 0) {
	// haven't moved visibly (even though start frame may have changed)
	return;
    }

    if (dx <= -w || dx >= w) {
	// scrolled entirely off
	invalidate();
	return;
    }
	
    // dx is in range, cache is scrollable

    int dxp = dx;
    if (dxp < 0) dxp = -dxp;

    int copylen = (w - dxp) * int(sizeof(QRgb));
    for (int y = 0; y < m_image.height(); ++y) {
	QRgb *line = (QRgb *)m_image.scanLine(y);
	if (dx < 0) {
	    memmove(line, line + dxp, copylen);
	} else {
	    memmove(line + dxp, line, copylen);
	}
    }
	
    // update valid area
        
    int px = m_validLeft;
    int pw = m_validWidth;
	
    px += dx;
	
    if (dx < 0) {
	// we scrolled left
	if (px < 0) {
	    pw += px;
	    px = 0;
	    if (pw < 0) {
		pw = 0;
	    }
	}
    } else {
	// we scrolled right
	if (px + pw > w) {
	    pw = w - px;
	    if (pw < 0) {
		pw = 0;
	    }
	}
    }

    m_validLeft = px;
    m_validWidth = pw;
}

void
ScrollableImageCache::adjustToTouchValidArea(int &left, int &width,
					     bool &isLeftOfValidArea) const
{
#ifdef DEBUG_SCROLLABLE_IMAGE_CACHE
    cerr << "ScrollableImageCache::adjustToTouchValidArea: left " << left
         << ", width " << width << endl;
    cerr << "ScrollableImageCache: my left " << m_validLeft
         << ", width " << m_validWidth << " so right " << (m_validLeft + m_validWidth) << endl;
#endif
    if (left < m_validLeft) {
	isLeftOfValidArea = true;
	if (left + width <= m_validLeft + m_validWidth) {
	    width = m_validLeft - left;
	}
#ifdef DEBUG_SCROLLABLE_IMAGE_CACHE
        cerr << "ScrollableImageCache: we're left of valid area, adjusted width to " << width << endl;
#endif
    } else {
	isLeftOfValidArea = false;
	width = left + width - (m_validLeft + m_validWidth);
	left = m_validLeft + m_validWidth;
	if (width < 0) width = 0;
#ifdef DEBUG_SCROLLABLE_IMAGE_CACHE
        cerr << "ScrollableImageCache: we're right of valid area, adjusted left to " << left << ", width to " << width << endl;
#endif
    }
}
    
void
ScrollableImageCache::drawImage(int left,
				int width,
				QImage image,
				int imageLeft,
				int imageWidth)
{
    if (image.height() != m_image.height()) {
	cerr << "ScrollableImageCache::drawImage: ERROR: Supplied image height "
	     << image.height() << " does not match cache height "
	     << m_image.height() << endl;
	throw std::logic_error("Image height must match cache height in ScrollableImageCache::drawImage");
    }
    if (left < 0 || width < 0 || left + width > m_image.width()) {
	cerr << "ScrollableImageCache::drawImage: ERROR: Target area (left = "
	     << left << ", width = " << width << ", so right = " << left + width
             << ") out of bounds for cache of width " << m_image.width() << endl;
	throw std::logic_error("Target area out of bounds in ScrollableImageCache::drawImage");
    }
    if (imageLeft < 0 || imageWidth < 0 ||
	imageLeft + imageWidth > image.width()) {
	cerr << "ScrollableImageCache::drawImage: ERROR: Source area (left = "
	     << imageLeft << ", width = " << imageWidth << ", so right = "
             << imageLeft + imageWidth << ") out of bounds for image of "
	     << "width " << image.width() << endl;
	throw std::logic_error("Source area out of bounds in ScrollableImageCache::drawImage");
    }
	
    QPainter painter(&m_image);
    painter.drawImage(QRect(left, 0, width, m_image.height()),
		      image,
		      QRect(imageLeft, 0, imageWidth, image.height()));
    painter.end();

    if (!isValid()) {
	m_validLeft = left;
	m_validWidth = width;
	return;
    }
	
    if (left < m_validLeft) {
	if (left + width > m_validLeft + m_validWidth) {
	    // new image completely contains the old valid area --
	    // use the new area as is
	    m_validLeft = left;
	    m_validWidth = width;
	} else if (left + width < m_validLeft) {
	    // new image completely off left of old valid area --
	    // we can't extend the valid area because the bit in
	    // between is not valid, so must use the new area only
	    m_validLeft = left;
	    m_validWidth = width;
	} else {
	    // new image overlaps old valid area on left side --
	    // use new left edge, and extend width to existing
	    // right edge
	    m_validWidth = (m_validLeft + m_validWidth) - left;
	    m_validLeft = left;
	}
    } else {
	if (left > m_validLeft + m_validWidth) {
	    // new image completely off right of old valid area --
	    // we can't extend the valid area because the bit in
	    // between is not valid, so must use the new area only
	    m_validLeft = left;
	    m_validWidth = width;
	} else if (left + width > m_validLeft + m_validWidth) {
	    // new image overlaps old valid area on right side --
	    // use existing left edge, and extend width to new
	    // right edge
	    m_validWidth = (left + width) - m_validLeft;
	    // (m_validLeft unchanged)
	} else {
	    // new image completely contained within old valid
	    // area -- leave the old area unchanged
	}
    }
}