annotate layer/Colour3DPlotRenderer.cpp @ 1160:a429b2acb45d 3.0-integration

Make SVDEBUG always write to a log file -- formerly this was disabled in NDEBUG builds. I think there's little use to that, it just means that we keep adding more cerr debug output because we aren't getting the log we need. And SVDEBUG logging is not usually used in tight loops, I don't think the performance overhead is too serious.

Also update the About box.

/* -*- 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 file copyright 2006-2016 Chris Cannam and QMUL.
    
    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 "Colour3DPlotRenderer.h"
#include "RenderTimer.h"

#include "base/Profiler.h"

#include "data/model/DenseThreeDimensionalModel.h"
#include "data/model/Dense3DModelPeakCache.h"
#include "data/model/FFTModel.h"

#include "LayerGeometryProvider.h"
#include "VerticalBinLayer.h"
#include "PaintAssistant.h"
#include "ImageRegionFinder.h"

#include "view/ViewManager.h" // for main model sample rate. Pity

#include <vector>

//#define DEBUG_COLOUR_PLOT_REPAINT 1

using namespace std;

Colour3DPlotRenderer::RenderResult
Colour3DPlotRenderer::render(const LayerGeometryProvider *v, QPainter &paint, QRect rect)
{
    return render(v, paint, rect, false);
}

Colour3DPlotRenderer::RenderResult
Colour3DPlotRenderer::renderTimeConstrained(const LayerGeometryProvider *v,
                                            QPainter &paint, QRect rect)
{
    return render(v, paint, rect, true);
}

QRect
Colour3DPlotRenderer::getLargestUncachedRect(const LayerGeometryProvider *v)
{
    RenderType renderType = decideRenderType(v);

    if (renderType == DirectTranslucent) {
        return QRect(); // never cached
    }

    int h = m_cache.getSize().height();

    QRect areaLeft(0, 0, m_cache.getValidLeft(), h);
    QRect areaRight(m_cache.getValidRight(), 0,
                    m_cache.getSize().width() - m_cache.getValidRight(), h);

    if (areaRight.width() > areaLeft.width()) {
        return areaRight;
    } else {
        return areaLeft;
    }
}

bool
Colour3DPlotRenderer::geometryChanged(const LayerGeometryProvider *v)
{
    RenderType renderType = decideRenderType(v);

    if (renderType == DirectTranslucent) {
        return true; // never cached
    }

    if (m_cache.getSize() == v->getPaintSize() &&
        m_cache.getZoomLevel() == v->getZoomLevel() &&
        m_cache.getStartFrame() == v->getStartFrame()) {
        return false;
    } else {
        return true;
    }
}

Colour3DPlotRenderer::RenderResult
Colour3DPlotRenderer::render(const LayerGeometryProvider *v,
                             QPainter &paint, QRect rect, bool timeConstrained)
{
    RenderType renderType = decideRenderType(v);

    if (renderType != DrawBufferPixelResolution) {
        // Rendering should be fast in bin-resolution and direct draw
        // cases because we are quite well zoomed-in, and the sums are
        // easier this way. Calculating boundaries later will be
        // fiddly for partial paints otherwise.
        timeConstrained = false;
    }

    int x0 = v->getXForViewX(rect.x());
    int x1 = v->getXForViewX(rect.x() + rect.width());
    if (x0 < 0) x0 = 0;
    if (x1 > v->getPaintWidth()) x1 = v->getPaintWidth();

    sv_frame_t startFrame = v->getStartFrame();
    
    m_cache.resize(v->getPaintSize());
    m_cache.setZoomLevel(v->getZoomLevel());

    m_magCache.resize(v->getPaintSize().width());
    m_magCache.setZoomLevel(v->getZoomLevel());
    
    if (renderType == DirectTranslucent) {
        MagnitudeRange range = renderDirectTranslucent(v, paint, rect);
        return { rect, range };
    }
    
#ifdef DEBUG_COLOUR_PLOT_REPAINT
    cerr << "cache start " << m_cache.getStartFrame()
         << " valid left " << m_cache.getValidLeft()
         << " valid right " << m_cache.getValidRight()
         << endl;
    cerr << " view start " << startFrame
         << " x0 " << x0
         << " x1 " << x1
         << endl;
#endif
    
    if (m_cache.isValid()) { // some part of the cache is valid

        if (v->getXForFrame(m_cache.getStartFrame()) ==
            v->getXForFrame(startFrame) &&
            m_cache.getValidLeft() <= x0 &&
            m_cache.getValidRight() >= x1) {

#ifdef DEBUG_COLOUR_PLOT_REPAINT
            cerr << "cache hit" << endl;
#endif
            
            // cache is valid for the complete requested area
            paint.drawImage(rect, m_cache.getImage(), rect);

            MagnitudeRange range = m_magCache.getRange(x0, x1 - x0);

            return { rect, range };

        } else {
#ifdef DEBUG_COLOUR_PLOT_REPAINT
            cerr << "cache partial hit" << endl;
#endif
            
            // cache doesn't begin at the right frame or doesn't
            // contain the complete view, but might be scrollable or
            // partially usable
            m_cache.scrollTo(v, startFrame);
            m_magCache.scrollTo(v, startFrame);

            // if we are not time-constrained, then we want to paint
            // the whole area in one go; we don't return a partial
            // paint. To avoid providing the more complex logic to
            // handle painting discontiguous areas, if the only valid
            // part of cache is in the middle, just make the whole
            // thing invalid and start again.
            if (!timeConstrained) {
                if (m_cache.getValidLeft() > x0 &&
                    m_cache.getValidRight() < x1) {
                    m_cache.invalidate();
                }
            }
        }
    } else {
        // cache is completely invalid
        m_cache.setStartFrame(startFrame);
        m_magCache.setStartFrame(startFrame);
    }

    bool rightToLeft = false;

    int reqx0 = x0;
    int reqx1 = x1;
    
    if (!m_cache.isValid() && timeConstrained) {
        // When rendering the whole area, in a context where we might
        // not be able to complete the work, start from somewhere near
        // the middle so that the region of interest appears first

        //!!! (perhaps we should avoid doing this if past repaints
        //!!! have been fast enough to do the whole in one shot)
        if (x0 == 0 && x1 == v->getPaintWidth()) {
            x0 = int(x1 * 0.3);
        }
    }

    if (m_cache.isValid()) {
            
        // When rendering only a part of the cache, we need to make
        // sure that the part we're rendering is adjacent to (or
        // overlapping) a valid area of cache, if we have one. The
        // alternative is to ditch the valid area of cache and render
        // only the requested area, but that's risky because this can
        // happen when just waving the pointer over a small part of
        // the view -- if we lose the partly-built cache every time
        // the user does that, we'll never finish building it.
        int left = x0;
        int width = x1 - x0;
        bool isLeftOfValidArea = false;
        m_cache.adjustToTouchValidArea(left, width, isLeftOfValidArea);
        x0 = left;
        x1 = x0 + width;

        // That call also told us whether we should be painting
        // sub-regions of our target region in right-to-left order in
        // order to ensure contiguity
        rightToLeft = isLeftOfValidArea;
    }
    
    // Note, we always paint the full height to cache. We want to
    // ensure the cache is coherent without having to worry about
    // vertical matching of required and valid areas as well as
    // horizontal.

    if (renderType == DrawBufferBinResolution) {

        renderToCacheBinResolution(v, x0, x1 - x0);

    } else { // must be DrawBufferPixelResolution, handled DirectTranslucent earlier

        renderToCachePixelResolution(v, x0, x1 - x0, rightToLeft, timeConstrained);
    }

    QRect pr = rect & m_cache.getValidArea();
    paint.drawImage(pr.x(), pr.y(), m_cache.getImage(),
                    pr.x(), pr.y(), pr.width(), pr.height());

    if (!timeConstrained && (pr != rect)) {
        cerr << "WARNING: failed to render entire requested rect "
             << "even when not time-constrained" << endl;
    }

    MagnitudeRange range = m_magCache.getRange(reqx0, reqx1 - reqx0);
    
    return { pr, range };
}

Colour3DPlotRenderer::RenderType
Colour3DPlotRenderer::decideRenderType(const LayerGeometryProvider *v) const
{
    const DenseThreeDimensionalModel *model = m_sources.source;
    if (!model || !v || !(v->getViewManager())) {
        return DrawBufferPixelResolution; // or anything
    }

    int binResolution = model->getResolution();
    int zoomLevel = v->getZoomLevel();
    sv_samplerate_t modelRate = model->getSampleRate();

    double rateRatio = v->getViewManager()->getMainModelSampleRate() / modelRate;
    double relativeBinResolution = binResolution * rateRatio;

    if (m_params.binDisplay == BinDisplay::PeakFrequencies) {
        // no alternative works here
        return DrawBufferPixelResolution;
    }

    if (!m_params.alwaysOpaque && !m_params.interpolate) {

        // consider translucent option -- only if not smoothing & not
        // explicitly requested opaque & sufficiently zoomed-in
        
        if (model->getHeight() * 3 < v->getPaintHeight() &&
            relativeBinResolution >= 3 * zoomLevel) {
            return DirectTranslucent;
        }
    }

    if (relativeBinResolution > zoomLevel) {
        return DrawBufferBinResolution;
    } else {
        return DrawBufferPixelResolution;
    }
}

ColumnOp::Column
Colour3DPlotRenderer::getColumn(int sx, int minbin, int nbins) const
{
    // order:
    // get column -> scale -> normalise -> record extents ->
    // peak pick -> distribute/interpolate -> apply display gain

    // we do the first bit here:
    // get column -> scale -> normalise

    ColumnOp::Column column;
                
    if (m_params.colourScale.getScale() == ColourScaleType::Phase &&
        m_sources.fft) {

        ColumnOp::Column fullColumn = m_sources.fft->getPhases(sx);

        column = vector<float>(fullColumn.data() + minbin,
                               fullColumn.data() + minbin + nbins);

    } else {
                    
        ColumnOp::Column fullColumn = m_sources.source->getColumn(sx);
                
        column = vector<float>(fullColumn.data() + minbin,
                               fullColumn.data() + minbin + nbins);

        column = ColumnOp::applyGain(column, m_params.scaleFactor);

        column = ColumnOp::normalize(column, m_params.normalization);
    }

    return column;
}

MagnitudeRange
Colour3DPlotRenderer::renderDirectTranslucent(const LayerGeometryProvider *v,
                                              QPainter &paint,
                                              QRect rect)
{
    Profiler profiler("Colour3DPlotRenderer::renderDirectTranslucent");

    MagnitudeRange magRange;
    
    QPoint illuminatePos;
    bool illuminate = v->shouldIlluminateLocalFeatures
        (m_sources.verticalBinLayer, illuminatePos);

    const DenseThreeDimensionalModel *model = m_sources.source;
    
    int x0 = rect.left();
    int x1 = rect.right() + 1;

    int h = v->getPaintHeight();

    sv_frame_t modelStart = model->getStartFrame();
    sv_frame_t modelEnd = model->getEndFrame();
    int modelResolution = model->getResolution();

    double rateRatio =
        v->getViewManager()->getMainModelSampleRate() / model->getSampleRate();

    // the s-prefix values are source, i.e. model, column and bin numbers
    int sx0 = int((double(v->getFrameForX(x0)) / rateRatio - double(modelStart))
                  / modelResolution);
    int sx1 = int((double(v->getFrameForX(x1)) / rateRatio - double(modelStart))
                  / modelResolution);

    int sh = model->getHeight();

    const int buflen = 40;
    char labelbuf[buflen];

    int minbin = m_sources.verticalBinLayer->getIBinForY(v, h);
    if (minbin >= sh) minbin = sh - 1;
    if (minbin < 0) minbin = 0;
    
    int nbins  = m_sources.verticalBinLayer->getIBinForY(v, 0) - minbin + 1;
    if (minbin + nbins > sh) nbins = sh - minbin;

    int psx = -1;

    vector<float> preparedColumn;

    int modelWidth = model->getWidth();

    for (int sx = sx0; sx <= sx1; ++sx) {

        if (sx < 0 || sx >= modelWidth) {
            continue;
        }

        if (sx != psx) {

            // order:
            // get column -> scale -> normalise -> record extents ->
            // peak pick -> distribute/interpolate -> apply display gain

            // this does the first three:
            preparedColumn = getColumn(sx, minbin, nbins);
            
            magRange.sample(preparedColumn);

            if (m_params.binDisplay == BinDisplay::PeakBins) {
                preparedColumn = ColumnOp::peakPick(preparedColumn);
            }

            // Display gain belongs to the colour scale and is
            // applied by the colour scale object when mapping it

            psx = sx;
        }

	sv_frame_t fx = sx * modelResolution + modelStart;

	if (fx + modelResolution <= modelStart || fx > modelEnd) continue;

        int rx0 = v->getXForFrame(int(double(fx) * rateRatio));
	int rx1 = v->getXForFrame(int(double(fx + modelResolution + 1) * rateRatio));

	int rw = rx1 - rx0;
	if (rw < 1) rw = 1;

	bool showLabel = (rw > 10 &&
			  paint.fontMetrics().width("0.000000") < rw - 3 &&
			  paint.fontMetrics().height() < (h / sh));
        
	for (int sy = minbin; sy < minbin + nbins; ++sy) {

            int ry0 = m_sources.verticalBinLayer->getIYForBin(v, sy);
            int ry1 = m_sources.verticalBinLayer->getIYForBin(v, sy + 1);

            if (m_params.invertVertical) {
                ry0 = h - ry0 - 1;
                ry1 = h - ry1 - 1;
            }
                    
            QRect r(rx0, ry1, rw, ry0 - ry1);

            float value = preparedColumn[sy - minbin];
            QColor colour = m_params.colourScale.getColour(value,
                                                           m_params.colourRotation);

            if (rw == 1) {
                paint.setPen(colour);
                paint.setBrush(Qt::NoBrush);
                paint.drawLine(r.x(), r.y(), r.x(), r.y() + r.height() - 1);
                continue;
            }

	    QColor pen(255, 255, 255, 80);
	    QColor brush(colour);

            if (rw > 3 && r.height() > 3) {
                brush.setAlpha(160);
            }

	    paint.setPen(Qt::NoPen);
	    paint.setBrush(brush);

	    if (illuminate) {
		if (r.contains(illuminatePos)) {
		    paint.setPen(v->getForeground());
		}
	    }
            
#ifdef DEBUG_COLOUR_3D_PLOT_LAYER_PAINT
//            cerr << "rect " << r.x() << "," << r.y() << " "
//                      << r.width() << "x" << r.height() << endl;
#endif

	    paint.drawRect(r);

	    if (showLabel) {
                double value = model->getValueAt(sx, sy);
                snprintf(labelbuf, buflen, "%06f", value);
                QString text(labelbuf);
                PaintAssistant::drawVisibleText
                    (v,
                     paint,
                     rx0 + 2,
                     ry0 - h / sh - 1 + 2 + paint.fontMetrics().ascent(),
                     text,
                     PaintAssistant::OutlinedText);
	    }
	}
    }

    return magRange;
}

void
Colour3DPlotRenderer::renderToCachePixelResolution(const LayerGeometryProvider *v,
                                                   int x0, int repaintWidth,
                                                   bool rightToLeft,
                                                   bool timeConstrained)
{
    Profiler profiler("Colour3DPlotRenderer::renderToCachePixelResolution");
#ifdef DEBUG_COLOUR_PLOT_REPAINT
    cerr << "renderToCachePixelResolution" << endl;
#endif
    
    // Draw to the draw buffer, and then copy from there. The draw
    // buffer is at the same resolution as the target in the cache, so
    // no extra scaling needed.

    const DenseThreeDimensionalModel *model = m_sources.source;
    if (!model || !model->isOK() || !model->isReady()) {
	throw std::logic_error("no source model provided, or model not ready");
    }

    int h = v->getPaintHeight();

    clearDrawBuffer(repaintWidth, h);

    vector<int> binforx(repaintWidth);
    vector<double> binfory(h);
    
    bool usePeaksCache = false;
    int binsPerPeak = 1;
    int zoomLevel = v->getZoomLevel();
    int binResolution = model->getResolution();

    for (int x = 0; x < repaintWidth; ++x) {
        sv_frame_t f0 = v->getFrameForX(x0 + x);
        double s0 = double(f0 - model->getStartFrame()) / binResolution;
        binforx[x] = int(s0 + 0.0001);
    }

    if (m_sources.peaks) { // peaks cache exists

        binsPerPeak = m_sources.peaks->getColumnsPerPeak();
        usePeaksCache = (binResolution * binsPerPeak) < zoomLevel;
        
        if (m_params.colourScale.getScale() ==
            ColourScaleType::Phase) {
            usePeaksCache = false;
        }
    }

#ifdef DEBUG_COLOUR_PLOT_REPAINT
    cerr << "[PIX] zoomLevel = " << zoomLevel
         << ", binResolution " << binResolution 
         << ", binsPerPeak " << binsPerPeak
         << ", peak cache " << m_sources.peaks
         << ", usePeaksCache = " << usePeaksCache
         << endl;
#endif
    
    for (int y = 0; y < h; ++y) {
        binfory[y] = m_sources.verticalBinLayer->getBinForY(v, h - y - 1);
    }

    int attainedWidth;

    if (m_params.binDisplay == BinDisplay::PeakFrequencies) {
        attainedWidth = renderDrawBufferPeakFrequencies(v,
                                                        repaintWidth,
                                                        h,
                                                        binforx,
                                                        binfory,
                                                        rightToLeft,
                                                        timeConstrained);

    } else {
        attainedWidth = renderDrawBuffer(repaintWidth,
                                         h,
                                         binforx,
                                         binfory,
                                         usePeaksCache,
                                         rightToLeft,
                                         timeConstrained);
    }

    if (attainedWidth == 0) return;

    // draw buffer is pixel resolution, no scaling factors or padding involved
    
    int paintedLeft = x0;
    if (rightToLeft) {
        paintedLeft += (repaintWidth - attainedWidth);
    }

    m_cache.drawImage(paintedLeft, attainedWidth,
                      m_drawBuffer,
                      paintedLeft - x0, attainedWidth);

    for (int i = 0; in_range_for(m_magRanges, i); ++i) {
        m_magCache.sampleColumn(i, m_magRanges.at(i));
    }
}

void
Colour3DPlotRenderer::renderToCacheBinResolution(const LayerGeometryProvider *v,
                                                 int x0, int repaintWidth)
{
    Profiler profiler("Colour3DPlotRenderer::renderToCacheBinResolution");
#ifdef DEBUG_COLOUR_PLOT_REPAINT
    cerr << "renderToCacheBinResolution" << endl;
#endif
    
    // Draw to the draw buffer, and then scale-copy from there. Draw
    // buffer is at bin resolution, i.e. buffer x == source column
    // number. We use toolkit smooth scaling for interpolation.

    const DenseThreeDimensionalModel *model = m_sources.source;
    if (!model || !model->isOK() || !model->isReady()) {
	throw std::logic_error("no source model provided, or model not ready");
    }

    // The draw buffer will contain a fragment at bin resolution. We
    // need to ensure that it starts and ends at points where a
    // time-bin boundary occurs at an exact pixel boundary, and with a
    // certain amount of overlap across existing pixels so that we can
    // scale and draw from it without smoothing errors at the edges.

    // If (getFrameForX(x) / increment) * increment ==
    // getFrameForX(x), then x is a time-bin boundary.  We want two
    // such boundaries at either side of the draw buffer -- one which
    // we draw up to, and one which we subsequently crop at.

    sv_frame_t leftBoundaryFrame = -1, leftCropFrame = -1;
    sv_frame_t rightBoundaryFrame = -1, rightCropFrame = -1;

    int drawBufferWidth;
    int binResolution = model->getResolution();

    for (int x = x0; ; --x) {
        sv_frame_t f = v->getFrameForX(x);
        if ((f / binResolution) * binResolution == f) {
            if (leftCropFrame == -1) leftCropFrame = f;
            else if (x < x0 - 2) {
                leftBoundaryFrame = f;
                break;
            }
        }
    }
    for (int x = x0 + repaintWidth; ; ++x) {
        sv_frame_t f = v->getFrameForX(x);
        if ((f / binResolution) * binResolution == f) {
            if (rightCropFrame == -1) rightCropFrame = f;
            else if (x > x0 + repaintWidth + 2) {
                rightBoundaryFrame = f;
                break;
            }
        }
    }
    drawBufferWidth = int
        ((rightBoundaryFrame - leftBoundaryFrame) / binResolution);
    
    int h = v->getPaintHeight();

    // For our purposes here, the draw buffer needs to be exactly our
    // target size (so we recreate always rather than just clear it)
    
    recreateDrawBuffer(drawBufferWidth, h);

    vector<int> binforx(drawBufferWidth);
    vector<double> binfory(h);
    
    for (int x = 0; x < drawBufferWidth; ++x) {
        binforx[x] = int(leftBoundaryFrame / binResolution) + x;
    }

#ifdef DEBUG_COLOUR_PLOT_REPAINT
    cerr << "[BIN] binResolution " << binResolution 
         << endl;
#endif
    
    for (int y = 0; y < h; ++y) {
        binfory[y] = m_sources.verticalBinLayer->getBinForY(v, h - y - 1);
    }

    int attainedWidth = renderDrawBuffer(drawBufferWidth,
                                         h,
                                         binforx,
                                         binfory,
                                         false,
                                         false,
                                         false);

    if (attainedWidth == 0) return;

    int scaledLeft = v->getXForFrame(leftBoundaryFrame);
    int scaledRight = v->getXForFrame(rightBoundaryFrame);

#ifdef DEBUG_COLOUR_PLOT_REPAINT
    cerr << "scaling draw buffer from width " << m_drawBuffer.width()
         << " to " << (scaledRight - scaledLeft) << " (nb drawBufferWidth = "
         << drawBufferWidth << ")" << endl;
#endif
    
    QImage scaled = m_drawBuffer.scaled
        (scaledRight - scaledLeft, h,
         Qt::IgnoreAspectRatio, (m_params.interpolate ?
                                 Qt::SmoothTransformation :
                                 Qt::FastTransformation));
            
    int scaledLeftCrop = v->getXForFrame(leftCropFrame);
    int scaledRightCrop = v->getXForFrame(rightCropFrame);
    
    int targetLeft = scaledLeftCrop;
    if (targetLeft < 0) {
        targetLeft = 0;
    }
    
    int targetWidth = scaledRightCrop - targetLeft;
    if (targetLeft + targetWidth > m_cache.getSize().width()) {
        targetWidth = m_cache.getSize().width() - targetLeft;
    }
    
    int sourceLeft = targetLeft - scaledLeft;
    if (sourceLeft < 0) {
        sourceLeft = 0;
    }
    
#ifdef DEBUG_COLOUR_PLOT_REPAINT
    cerr << "repaintWidth = " << repaintWidth
         << ", targetWidth = " << targetWidth << endl;
#endif
    
    if (targetWidth > 0) {
        // we are copying from an image that has already been scaled,
        // hence using the same width in both geometries
        m_cache.drawImage(targetLeft, targetWidth,
                          scaled,
                          sourceLeft, targetWidth);
    }
    
    for (int i = 0; i < targetWidth; ++i) {
        // but the mag range vector has not been scaled
        int sourceIx = int((double(i + sourceLeft) / scaled.width())
                           * int(m_magRanges.size()));
        if (in_range_for(m_magRanges, sourceIx)) {
            m_magCache.sampleColumn(i, m_magRanges.at(sourceIx));
        }
    }
}

int
Colour3DPlotRenderer::renderDrawBuffer(int w, int h,
                                       const vector<int> &binforx,
                                       const vector<double> &binfory,
                                       bool usePeaksCache,
                                       bool rightToLeft,
                                       bool timeConstrained)
{
    // Callers must have checked that the appropriate subset of
    // Sources data members are set for the supplied flags (e.g. that
    // peaks model exists if usePeaksCache)
    
    RenderTimer timer(timeConstrained ?
                      RenderTimer::FastRender :
                      RenderTimer::NoTimeout);

    int divisor = 1;
    const DenseThreeDimensionalModel *sourceModel = m_sources.source;
    if (usePeaksCache) {
        divisor = m_sources.peaks->getColumnsPerPeak();
        sourceModel = m_sources.peaks;
    }

    int sh = sourceModel->getHeight();
    
    int minbin = int(binfory[0] + 0.0001);
    if (minbin >= sh) minbin = sh - 1;
    if (minbin < 0) minbin = 0;

    int nbins  = int(binfory[h-1]) - minbin + 1;
    if (minbin + nbins > sh) nbins = sh - minbin;
    
    int psx = -1;

    int start = 0;
    int finish = w;
    int step = 1;

    if (rightToLeft) {
        start = w-1;
        finish = -1;
        step = -1;
    }

    int columnCount = 0;
    
    vector<float> preparedColumn;

    int modelWidth = sourceModel->getWidth();

#ifdef DEBUG_COLOUR_PLOT_REPAINT
    cerr << "modelWidth " << modelWidth << ", divisor " << divisor << endl;
#endif
    
    for (int x = start; x != finish; x += step) {

        // x is the on-canvas pixel coord; sx (later) will be the
        // source column index
        
        ++columnCount;

#ifdef DEBUG_COLOUR_PLOT_REPAINT
        cerr << "x = " << x << ", binforx[x] = " << binforx[x] << endl;
#endif
        
        if (binforx[x] < 0) continue;

        int sx0 = binforx[x] / divisor;
        int sx1 = sx0;
        if (x+1 < w) sx1 = binforx[x+1] / divisor;
        if (sx0 < 0) sx0 = sx1 - 1;
        if (sx0 < 0) continue;
        if (sx1 <= sx0) sx1 = sx0 + 1;

        vector<float> pixelPeakColumn;
        MagnitudeRange magRange;
        
        for (int sx = sx0; sx < sx1; ++sx) {

#ifdef DEBUG_COLOUR_PLOT_REPAINT
            cerr << "sx = " << sx << endl;
#endif

            if (sx < 0 || sx >= modelWidth) {
                continue;
            }

            if (sx != psx) {
                
                // order:
                // get column -> scale -> normalise -> record extents ->
                // peak pick -> distribute/interpolate -> apply display gain

                // this does the first three:
                ColumnOp::Column column = getColumn(sx, minbin, nbins);

                magRange.sample(column);
                
                if (m_params.binDisplay == BinDisplay::PeakBins) {
                    column = ColumnOp::peakPick(column);
                }

                preparedColumn =
                    ColumnOp::distribute(column,
                                         h,
                                         binfory,
                                         minbin,
                                         m_params.interpolate);

                // Display gain belongs to the colour scale and is
                // applied by the colour scale object when mapping it
                
                psx = sx;
            }

            if (sx == sx0) {
                pixelPeakColumn = preparedColumn;
            } else {
                for (int i = 0; in_range_for(pixelPeakColumn, i); ++i) {
                    pixelPeakColumn[i] = std::max(pixelPeakColumn[i],
                                                  preparedColumn[i]);
                }
            }
        }

        if (!pixelPeakColumn.empty()) {

            for (int y = 0; y < h; ++y) {
                int py;
                if (m_params.invertVertical) {
                    py = y;
                } else {
                    py = h - y - 1;
                }
                m_drawBuffer.setPixel
                    (x,
                     py,
                     m_params.colourScale.getPixel(pixelPeakColumn[y]));
            }
            
            m_magRanges.push_back(magRange);
        }

        double fractionComplete = double(columnCount) / double(w);
        if (timer.outOfTime(fractionComplete)) {
            cerr << "out of time" << endl;
            return columnCount;
        }
    }

    return columnCount;
}

int
Colour3DPlotRenderer::renderDrawBufferPeakFrequencies(const LayerGeometryProvider *v,
                                                      int w, int h,
                                                      const vector<int> &binforx,
                                                      const vector<double> &binfory,
                                                      bool rightToLeft,
                                                      bool timeConstrained)
{
    // Callers must have checked that the appropriate subset of
    // Sources data members are set for the supplied flags (e.g. that
    // fft model exists)
    
    RenderTimer timer(timeConstrained ?
                      RenderTimer::FastRender :
                      RenderTimer::NoTimeout);

    const FFTModel *fft = m_sources.fft;

    int sh = fft->getHeight();
    
    int minbin = int(binfory[0] + 0.0001);
    if (minbin >= sh) minbin = sh - 1;
    if (minbin < 0) minbin = 0;

    int nbins  = int(binfory[h-1]) - minbin + 1;
    if (minbin + nbins > sh) nbins = sh - minbin;

    FFTModel::PeakSet peakfreqs;

    int psx = -1;
    
    int start = 0;
    int finish = w;
    int step = 1;

    if (rightToLeft) {
        start = w-1;
        finish = -1;
        step = -1;
    }
    
    int columnCount = 0;
    
    vector<float> preparedColumn;

    int modelWidth = fft->getWidth();
#ifdef DEBUG_COLOUR_PLOT_REPAINT
    cerr << "modelWidth " << modelWidth << endl;
#endif
    
    double minFreq =
        (double(minbin) * fft->getSampleRate()) / fft->getFFTSize();
    double maxFreq =
        (double(minbin + nbins - 1) * fft->getSampleRate()) / fft->getFFTSize();

    bool logarithmic = (m_params.binScale == BinScale::Log);
    
    for (int x = start; x != finish; x += step) {
        
        // x is the on-canvas pixel coord; sx (later) will be the
        // source column index
        
        ++columnCount;
        
        if (binforx[x] < 0) continue;

        int sx0 = binforx[x];
        int sx1 = sx0;
        if (x+1 < w) sx1 = binforx[x+1];
        if (sx0 < 0) sx0 = sx1 - 1;
        if (sx0 < 0) continue;
        if (sx1 <= sx0) sx1 = sx0 + 1;

        vector<float> pixelPeakColumn;
        MagnitudeRange magRange;
        
        for (int sx = sx0; sx < sx1; ++sx) {

            if (sx < 0 || sx >= modelWidth) {
                continue;
            }

            if (sx != psx) {
                preparedColumn = getColumn(sx, minbin, nbins);
                magRange.sample(preparedColumn);
                psx = sx;
            }

            if (sx == sx0) {
                pixelPeakColumn = preparedColumn;
                peakfreqs = fft->getPeakFrequencies(FFTModel::AllPeaks, sx,
                                                    minbin, minbin + nbins - 1);
            } else {
                for (int i = 0; in_range_for(pixelPeakColumn, i); ++i) {
                    pixelPeakColumn[i] = std::max(pixelPeakColumn[i],
                                                  preparedColumn[i]);
                }
            }
        }

        if (!pixelPeakColumn.empty()) {
            
            for (FFTModel::PeakSet::const_iterator pi = peakfreqs.begin();
                 pi != peakfreqs.end(); ++pi) {

                int bin = pi->first;
                double freq = pi->second;

                if (bin < minbin) continue;
                if (bin >= minbin + nbins) break;
            
                double value = pixelPeakColumn[bin - minbin];
            
                double y = v->getYForFrequency
                    (freq, minFreq, maxFreq, logarithmic);
            
                int iy = int(y + 0.5);
                if (iy < 0 || iy >= h) continue;

                m_drawBuffer.setPixel
                    (x,
                     iy,
                     m_params.colourScale.getPixel(value));
            }

            m_magRanges.push_back(magRange);
        }

        double fractionComplete = double(columnCount) / double(w);
        if (timer.outOfTime(fractionComplete)) {
            return columnCount;
        }
    }

    return columnCount;
}

void
Colour3DPlotRenderer::recreateDrawBuffer(int w, int h)
{
    m_drawBuffer = QImage(w, h, QImage::Format_Indexed8);

    for (int pixel = 0; pixel < 256; ++pixel) {
        m_drawBuffer.setColor
            ((unsigned char)pixel,
             m_params.colourScale.getColourForPixel
             (pixel, m_params.colourRotation).rgb());
    }

    m_drawBuffer.fill(0);
    m_magRanges.clear();
}

void
Colour3DPlotRenderer::clearDrawBuffer(int w, int h)
{
    if (m_drawBuffer.width() < w || m_drawBuffer.height() != h) {
        recreateDrawBuffer(w, h);
    } else {
        m_drawBuffer.fill(0);
        m_magRanges.clear();
    }
}

QRect
Colour3DPlotRenderer::findSimilarRegionExtents(QPoint p) const
{
    QImage image = m_cache.getImage();
    ImageRegionFinder finder;
    QRect rect = finder.findRegionExtents(&image, p);
    return rect;
}