tst_qiconhighdpi.cpp

// Copyright (C) 2017 The Qt Company Ltd.

// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only

#include <QIcon>

#include <QTemporaryFile>

#include <QTest>

class tst_QIconHighDpi : public QObject

    Q_OBJECT

public:

    tst_QIconHighDpi();

private slots:

    void initTestCase();

    void fromTheme_data();

    void fromTheme();

    void addPixmap_data();

    void addPixmap();

    void ninePatch();

    void preferUpscale();

    void dontModifyDprInCacheEntry();

};

tst_QIconHighDpi::tst_QIconHighDpi()

void tst_QIconHighDpi::initTestCase()

void tst_QIconHighDpi::fromTheme_data()

    QTest::addColumn<int>("requestedSize");

    QTest::addColumn<qreal>("requestedDpr");

    QTest::addColumn<int>("expectedSize");

    QTest::addColumn<qreal>("expectedDpr");

    // The pixmaps that we have available can be found in tst_qiconhighdpi.qrc.

    // Currently we only have @1 and @2 icons available, which limits the expected

    // devicePixelRatio when testing at e.g. devicePixelRatio 3.

    // We have an @2 high DPI version of the 22x22 size of this icon.

    QTest::newRow("22x22,dpr=1") << 22 << 1.0 << 22 << 1.0;

    QTest::newRow("22x22,dpr=2") << 22 << 2.0 << 44 << 2.0;

    QTest::newRow("22x22,dpr=3") << 22 << 3.0 << 44 << 2.0;

    // We don't have a high DPI version of the 16x16 size of this icon,

    // so directoryMatchesSize() will return false for all directories.

    // directorySizeDelta() is then called to find the best match.

    // The table below illustrates the results for our available images at various DPRs:

    // Available size | Available scale | Requested size | Requested scale | Delta

    //        22      *        2        -       16       *        1        =    28

    //        22      *        1        -       16       *        1        =     6

    //        16      *        1        -       16       *        1        =     0 < (16x16)

    // Available size | Available scale | Requested size | Requested scale | Delta

    //        22      *        2        -       16       *        2        =    12 < (22x22, prefer downscale)

    //        22      *        1        -       16       *        2        =   -10

    //        16      *        1        -       16       *        2        =   -16

    // Available size | Available scale | Requested size | Requested scale | Delta

    //        22      *        2        -       16       *        3        =    -4 < (22x22@2)

    //        22      *        1        -       16       *        3        =   -26

    //        16      *        1        -       16       *        3        =   -32

    // Both of these functions are implementations of the freedesktop icon theme spec,

    // which dictates that if there is no matching scale, directorySizeDistance() determines

    // the winner, regardless of whether or not the scale is too low for the requested scale.

    QTest::newRow("16x16,dpr=1") << 16 << 1.0 << 16 << 1.0;

    QTest::newRow("16x16,dpr=2") << 16 << 2.0 << 32 << 2.0;

    QTest::newRow("16x16,dpr=3") << 16 << 3.0 << 44 << 2.75;

    // We don't have an 8x8 size of this icon, so:

    // Available size | Available scale | Requested size | Requested scale | Delta

    //        22      *        2        -       8        *        1        =    36

    //        22      *        1        -       8        *        1        =    14

    //        16      *        1        -       8        *        1        =     8 < (16x16)

    // Available size | Available scale | Requested size | Requested scale | Delta

    //        22      *        2        -       8        *        2        =    28

    //        22      *        1        -       8        *        2        =     6

    //        16      *        1        -       8        *        2        =     0 < (16x16)

    // Available size | Available scale | Requested size | Requested scale | Delta

    //        22      *        2        -       8        *        3        =    20 < (22x22, prefer downscale)

    //        22      *        1        -       8        *        3        =    -2

    //        16      *        1        -       8        *        3        =    -8

    QTest::newRow("8x8,dpr=1") << 8 << 1.0 << 8 << 1.0;

    QTest::newRow("8x8,dpr=2") << 8 << 2.0 << 16 << 2.0;

    QTest::newRow("8x8,dpr=3") << 8 << 3.0 << 24 << 3.0;

    // We don't have a 44x44 size of this icon, so:

    // Available size | Available scale | Requested size | Requested scale | Delta

    //        22      *        2        -       44       *        1        =     0 < (22x22@2)

    //        22      *        1        -       44       *        1        =   -22

    //        16      *        1        -       44       *        1        =   -28

    // Available size | Available scale | Requested size | Requested scale | Delta

    //        22      *        2        -       44       *        2        =   -44 < (22x22@2)

    //        22      *        1        -       44       *        2        =   -66

    //        16      *        1        -       44       *        2        =   -72

    // Available size | Available scale | Requested size | Requested scale | Delta

    //        22      *        2        -       44       *        3        =   -88 < (22x22@2)

    //        22      *        1        -       44       *        3        =  -110

    //        16      *        1        -       44       *        3        =  -116

    QTest::newRow("44x44,dpr=1") << 44 << 1.0 << 44 << 1.0;

    QTest::newRow("44x44,dpr=2") << 44 << 2.0 << 44 << 1.0;

    QTest::newRow("44x44,dpr=3") << 44 << 3.0 << 44 << 1.0;

    // We don't have a 20x20 size of this icon, so:

    // Available size | Available scale | Requested size | Requested scale | Delta

    //        22      *        2        -       20       *        1        =    24

    //        22      *        1        -       20       *        1        =     2 < (22x22)

    //        16      *        1        -       20       *        1        =    -4

    // Available size | Available scale | Requested size | Requested scale | Delta

    //        22      *        2        -       20       *        2        =     4 < (22x22@2)

    //        22      *        1        -       20       *        2        =   -18

    //        16      *        1        -       20       *        2        =   -24

    // Available size | Available scale | Requested size | Requested scale | Delta

    //        22      *        2        -       20       *        3        =   -16 < (22x22@2)

    //        22      *        1        -       20       *        3        =   -38

    //        16      *        1        -       20       *        3        =   -44

    QTest::newRow("20x20,dpr=1") << 20 << 1.0 << 20 << 1.0;

    // PixmapEntry::pixmap() will only downscale the pixmap if actualSize.width() > size.width().

    // In this case, 44 > 40 is true, so the 44x44 pixmap is downscaled to 40x40.

    QTest::newRow("20x20,dpr=2") << 20 << 2.0 << 40 << 2.0;

    QTest::newRow("20x20,dpr=3") << 20 << 3.0 << 44 << 2.2;

void tst_QIconHighDpi::fromTheme()

    QFETCH(int, requestedSize);

    QFETCH(qreal, requestedDpr);

    QFETCH(int, expectedSize);

    QFETCH(qreal, expectedDpr);

    QString searchPath = QLatin1String(":/icons");

    QIcon::setThemeSearchPaths(QStringList() << searchPath);

    QCOMPARE(QIcon::themeSearchPaths().size(), 1);

    QCOMPARE(searchPath, QIcon::themeSearchPaths()[0]);

    QString themeName("testtheme");

    QIcon::setThemeName(themeName);

    QCOMPARE(QIcon::themeName(), themeName);

    QIcon appointmentIcon = QIcon::fromTheme("appointment-new");

    QVERIFY(!appointmentIcon.isNull());

    QVERIFY(!appointmentIcon.availableSizes(QIcon::Normal, QIcon::Off).isEmpty());

    QVERIFY(appointmentIcon.availableSizes().contains(QSize(16, 16)));

    QVERIFY(appointmentIcon.availableSizes().contains(QSize(22, 22)));

    const QPixmap pixmap = appointmentIcon.pixmap(QSize(requestedSize, requestedSize), requestedDpr);

    QCOMPARE(pixmap.size(), QSize(expectedSize, expectedSize));

    // We should get the high DPI version of an image if it exists in the correct directory.

    QCOMPARE(pixmap.devicePixelRatio(), expectedDpr);

void tst_QIconHighDpi::addPixmap_data()

    // fromTheme() and addPixmap() test the QIconLoaderEngine and QPixmapIconEngine

    // QIcon backend, repsectively. We want these to have identical behavior and

    // re-use the same test data here.

    fromTheme_data();

void tst_QIconHighDpi::addPixmap()

    QFETCH(int, requestedSize);

    QFETCH(qreal, requestedDpr);

    QFETCH(int, expectedSize);

    QFETCH(qreal, expectedDpr);

    QIcon icon;

    // manual pixmap adder for full control of devicePixelRatio

    auto addPixmapWithDpr = [&icon](const QString &path, qreal dpr) {

        QImage image(path);

        image.setDevicePixelRatio(dpr);

        icon.addPixmap(QPixmap::fromImage(image));

};

    addPixmapWithDpr(":icons/testtheme/16x16/actions/appointment-new.png", 1);

    addPixmapWithDpr(":icons/testtheme/22x22/actions/appointment-new.png", 1);

    addPixmapWithDpr(":icons/testtheme/22x22@2/actions/appointment-new.png", 2);

    QVERIFY(icon.availableSizes().contains(QSize(16, 16)));

    QVERIFY(icon.availableSizes().contains(QSize(22, 22)));

    if (qstrcmp(QTest::currentDataTag(), "44x44,dpr=1") == 0)

        QSKIP("broken corner case"); // expect 44x44, get 22x22

    const QPixmap pixmap = icon.pixmap(QSize(requestedSize, requestedSize), requestedDpr);

    QCOMPARE(pixmap.size(), QSize(expectedSize, expectedSize));

    QCOMPARE(pixmap.devicePixelRatio(), expectedDpr);

void tst_QIconHighDpi::ninePatch()

    const QIcon icon(":/icons/misc/button.9.png");

    const int dpr = qCeil(qApp->devicePixelRatio());

    switch (dpr) {

    case 1:

        QCOMPARE(icon.availableSizes().size(), 1);

        QCOMPARE(icon.availableSizes().at(0), QSize(42, 42));

        break;

    case 2:

        QCOMPARE(icon.availableSizes().size(), 2);

        QCOMPARE(icon.availableSizes().at(0), QSize(42, 42));

        QCOMPARE(icon.availableSizes().at(1), QSize(82, 82));

        break;

void tst_QIconHighDpi::preferUpscale()

    QIcon icon;

    // manual pixmap adder for full control of devicePixelRatio

    auto addPixmapWithDpr = [&icon](const QString &path, qreal dpr) {

        QImage image(path);

        image.setDevicePixelRatio(dpr);

        icon.addPixmap(QPixmap::fromImage(image));

};

    addPixmapWithDpr(":/icons/testtheme/22x22/actions/appointment-new.png", 1);

    addPixmapWithDpr(":/icons/testtheme/22x22@2/actions/appointment-new.png", 2);

    QCOMPARE(icon.pixmap(QSize(22, 22), 1.25f).devicePixelRatio(), 1.25f);

void tst_QIconHighDpi::dontModifyDprInCacheEntry()

    std::vector<std::unique_ptr<QTemporaryFile>> files;

    QIcon icon;

    const auto createImage = [&](int size, QColor col) {

        QImage img(QSize(size, size), QImage::Format_ARGB32);

        img.fill(col);

        files.emplace_back(std::make_unique<QTemporaryFile>());

        QTemporaryFile *f = files.back().get();

        if (!f->open() || !img.save(f, "PNG"))

            return false;

        icon.addFile(f->fileName());

        return true;

};

    QVERIFY(createImage(16, Qt::red));

    QVERIFY(createImage(20, Qt::green));

    QVERIFY(createImage(32, Qt::blue));

    auto checkPixmap = [&](qreal dpr) {

        constexpr QSize reqSize(16, 16);

        const QPixmap pm = icon.pixmap(icon.actualSize(reqSize), dpr);

        const QRgb c = pm.toImage().pixel(pm.rect().center());

        return QColor(c);

};

    QCOMPARE(checkPixmap(1.25), Qt::green);

    QCOMPARE(checkPixmap(2.00), Qt::blue);

    QCOMPARE(checkPixmap(1.25), Qt::green);

int main(int argc, char *argv[])

    QGuiApplication app(argc, argv);

    Q_UNUSED(app);

    tst_QIconHighDpi test;

    QTEST_SET_MAIN_SOURCE_PATH

    return QTest::qExec(&test, argc, argv);

#include "tst_qiconhighdpi.moc"

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