qt-everywhere-src-5.14.1/qtdeclarative/tests/auto/quick/shared/visualtestutil.cpp

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** This file is part of the test suite of the Qt Toolkit.
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#include "visualtestutil.h"

#include <QtQuick/QQuickItem>
#include <QtCore/QDebug>

bool QQuickVisualTestUtil::delegateVisible(QQuickItem *item)
{
    return item->isVisible() && !QQuickItemPrivate::get(item)->culled;
}

QQuickItem *QQuickVisualTestUtil::findVisibleChild(QQuickItem *parent, const QString &objectName)
{
    QQuickItem *item = 0;
    QList<QQuickItem*> items = parent->findChildren<QQuickItem*>(objectName);
    for (int i = 0; i < items.count(); ++i) {
        if (items.at(i)->isVisible() && !QQuickItemPrivate::get(items.at(i))->culled) {
            item = items.at(i);
            break;
        }
    }
    return item;
}

void QQuickVisualTestUtil::dumpTree(QQuickItem *parent, int depth)
{
    static QString padding("                       ");
    for (int i = 0; i < parent->childItems().count(); ++i) {
        QQuickItem *item = qobject_cast<QQuickItem*>(parent->childItems().at(i));
        if (!item)
            continue;
        qDebug() << padding.left(depth*2) << item;
        dumpTree(item, depth+1);
    }
}

// A custom compare function to avoid issues such as:
// When running on native Nvidia graphics cards on linux, the
// distance field glyph pixels have a measurable, but not visible
// pixel error. This was GT-216 with the ubuntu "nvidia-319" driver package.
// llvmpipe does not show the same issue.

bool QQuickVisualTestUtil::compareImages(const QImage &ia, const QImage &ib, QString *errorMessage)
{
    if (ia.size() != ib.size()) {
        QDebug(errorMessage) << "Images are of different size:" << ia.size() << ib.size()
            << "DPR:" << ia.devicePixelRatio() << ib.devicePixelRatio();
        return false;
    }
    if (ia.format() != ib.format()) {
        QDebug(errorMessage) << "Images are of different formats:" << ia.format() << ib.format();
        return false;
    }

    int w = ia.width();
    int h = ia.height();
    const int tolerance = 5;
    for (int y=0; y<h; ++y) {
        const uint *as= (const uint *) ia.constScanLine(y);
        const uint *bs= (const uint *) ib.constScanLine(y);
        for (int x=0; x<w; ++x) {
            uint a = as[x];
            uint b = bs[x];

            // No tolerance for error in the alpha.
            if ((a & 0xff000000) != (b & 0xff000000)
                || qAbs(qRed(a) - qRed(b)) > tolerance
                || qAbs(qRed(a) - qRed(b)) > tolerance
                || qAbs(qRed(a) - qRed(b)) > tolerance) {
                QDebug(errorMessage) << "Mismatch at:" << x << y << ':'
                    << hex << showbase << a << b;
                return false;
            }
        }
    }
    return true;
}