view layer/ScrollableImageCache.cpp @ 1509:8145a9c4c253

The default key frame map is not working well at the moment, because its extents are not being properly updated as the models they depend on are loaded. Leave it empty for now.

/* -*- 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 "base/HitCount.h"

#include <iostream>
using namespace std;

//#define DEBUG_SCROLLABLE_IMAGE_CACHE 1

void
ScrollableImageCache::scrollTo(const LayerGeometryProvider *v,
                               sv_frame_t newStartFrame)
{
    static HitCount count("ScrollableImageCache: scrolling");
    
    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
        count.hit();
        return;
    }
        
    m_startFrame = newStartFrame;
        
    if (!isValid()) {
        count.miss();
        return;
    }

    int w = m_image.width();

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

    if (dx <= -w || dx >= w) {
        // scrolled entirely off
        invalidate();
        count.miss();
        return;
    }

    count.partial();
        
    // 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
        }
    }
}