view widgets/IconLoader.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 file copyright 2007 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 "IconLoader.h"

#include <QPixmap>
#include <QApplication>
#include <QPainter>
#include <QPalette>
#include <QFile>
#include <QSvgRenderer>

#include <vector>
#include <set>

#include "base/Debug.h"

using namespace std;

static set<QString> autoInvertExceptions {
    // These are the icons that look OK in their default colours, even
    // in a colour scheme with a black background.  (They may also be
    // icons that would look worse if we tried to auto-invert them.)
    // If we have icons that look bad when auto-inverted but that are
    // not suitable for use without being inverted, we'll need to
    // supply inverted versions -- the loader will load xx_inverse.png
    // in preference to xx.png if a dark background is found.)
    "fileclose",
    "filenew",
    "fileopen",
    "fileopenaudio",
    "fileopensession",
    "filesave",
    "filesaveas",
    "filesaveas-sv",
    "help",
    "editcut",
    "editcopy",
    "editpaste",
    "editdelete",
    "exit",
    "zoom-fit",
    "zoom-in",
    "zoom-out",
    "zoom"
};

static vector<int> sizes { 0, 16, 22, 24, 32, 48, 64, 128 };

QIcon
IconLoader::load(QString name)
{
    QIcon icon;
    for (int sz: sizes) {
        QPixmap pmap(loadPixmap(name, sz));
        if (!pmap.isNull()) icon.addPixmap(pmap);
    }
    return icon;
}

bool
IconLoader::shouldInvert() const
{
    QColor bg = QApplication::palette().window().color();
    bool darkBackground = (bg.red() + bg.green() + bg.blue() <= 384);
    return darkBackground;
}

bool
IconLoader::shouldAutoInvert(QString name) const
{
    if (shouldInvert()) {
        return (autoInvertExceptions.find(name) == autoInvertExceptions.end());
    } else {
        return false;
    }
}

QPixmap
IconLoader::loadPixmap(QString name, int size)
{
    bool invert = shouldInvert();

    QString scalableName, nonScalableName;
    QPixmap pmap;

    nonScalableName = makeNonScalableFilename(name, size, invert);
    pmap = QPixmap(nonScalableName);
    if (!pmap.isNull()) return pmap;

    if (size > 0) {
        scalableName = makeScalableFilename(name, invert);
        pmap = loadScalable(scalableName, size);
        if (!pmap.isNull()) return pmap;
    }

    if (invert && shouldAutoInvert(name)) {

        nonScalableName = makeNonScalableFilename(name, size, false);
        pmap = QPixmap(nonScalableName);
        if (!pmap.isNull()) return invertPixmap(pmap);

        if (size > 0) {
            scalableName = makeScalableFilename(name, false);
            pmap = loadScalable(scalableName, size);
            if (!pmap.isNull()) return invertPixmap(pmap);
        }
    }

    return QPixmap();
}

QPixmap
IconLoader::loadScalable(QString name, int size)
{
    if (!QFile(name).exists()) {
//        cerr << "loadScalable: no such file as: \"" << name << "\"" << endl;
        return QPixmap();
    }
    QPixmap pmap(size, size);
    pmap.fill(Qt::transparent);
    QSvgRenderer renderer(name);
    QPainter painter;
    painter.begin(&pmap);
//    cerr << "calling renderer for " << name << " at size " << size << "..." << endl;
    renderer.render(&painter);
//    cerr << "renderer completed" << endl;
    painter.end();
    return pmap;
}

QString
IconLoader::makeNonScalableFilename(QString name, int size, bool invert)
{
    if (invert) {
        if (size == 0) {
            return QString(":icons/%1_inverse.png").arg(name);
        } else {
            return QString(":icons/%1-%2_inverse.png").arg(name).arg(size);
        }
    } else {
        if (size == 0) {
            return QString(":icons/%1.png").arg(name);
        } else {
            return QString(":icons/%1-%2.png").arg(name).arg(size);
        }
    }
}

QString
IconLoader::makeScalableFilename(QString name, bool invert)
{
    if (invert) {
        return QString(":icons/scalable/%1_inverse.svg").arg(name);
    } else {
        return QString(":icons/scalable/%1.svg").arg(name);
    }
}

QPixmap
IconLoader::invertPixmap(QPixmap pmap)
{
    // No suitable inverted icon found for black background; try to
    // auto-invert the default one

    QImage img = pmap.toImage().convertToFormat(QImage::Format_ARGB32);

    for (int y = 0; y < img.height(); ++y) {
        for (int x = 0; x < img.width(); ++x) {

            QRgb rgba = img.pixel(x, y);
            QColor colour = QColor
                (qRed(rgba), qGreen(rgba), qBlue(rgba), qAlpha(rgba));

            int alpha = colour.alpha();
            if (colour.saturation() < 5 && colour.alpha() > 10) {
                colour.setHsv(colour.hue(),
                              colour.saturation(),
                              255 - colour.value());
                colour.setAlpha(alpha);
                img.setPixel(x, y, colour.rgba());
            }
        }
    }

    pmap = QPixmap::fromImage(img);
    return pmap;
}