qquickstyleitemscrollbar.cpp

// Copyright (C) 2020 The Qt Company Ltd.

// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only

// Qt-Security score:significant reason:default

#include "qquickstyleitemscrollbar_p.h"

QT_BEGIN_NAMESPACE

QQuickStyleItemScrollBar::QQuickStyleItemScrollBar(QQuickItem *parent)

    : QQuickStyleItem(parent)

#ifdef QT_DEBUG

    setObjectName("styleItemScrollBar");

#endif

QFont QQuickStyleItemScrollBar::styleFont(QQuickItem *control) const

    return style()->font(QStyle::CE_ProgressBarLabel, controlSize(control));

void QQuickStyleItemScrollBar::connectToControl() const

    QQuickStyleItem::connectToControl();

    auto scrollBar = control<QQuickScrollBar>();

    connect(scrollBar, &QQuickScrollBar::orientationChanged, this, &QQuickStyleItem::markImageDirty);

    connect(scrollBar, &QQuickScrollBar::pressedChanged, this, &QQuickStyleItem::markImageDirty);

StyleItemGeometry QQuickStyleItemScrollBar::calculateGeometry()

    QStyleOptionSlider styleOption;

    initStyleOption(styleOption);

    StyleItemGeometry geometry;

    geometry.minimumSize = style()->sizeFromContents(QStyle::CT_ScrollBar, &styleOption, QSize(0, 0));

    if (m_subControl == SubLine || m_subControl == AddLine) {

        // So far, we know that only the windows style uses these subcontrols,

        // so we can use hardcoded sizes...

        QSize sz(16, 17);

        if (styleOption.orientation == Qt::Vertical)

            sz.transpose();

        geometry.minimumSize = sz;

    geometry.implicitSize = geometry.minimumSize;

    styleOption.rect = QRect(QPoint(0, 0), geometry.implicitSize);

    geometry.layoutRect = style()->subElementRect(QStyle::SE_ScrollBarLayoutItem, &styleOption);

    geometry.ninePatchMargins = style()->ninePatchMargins(QStyle::CC_ScrollBar, &styleOption, geometry.minimumSize);

    return geometry;

void QQuickStyleItemScrollBar::paintEvent(QPainter *painter) const

    QStyleOptionSlider styleOption;

    initStyleOption(styleOption);

    if (m_subControl == SubLine || m_subControl == AddLine) {

        QStyle::SubControl sc = m_subControl == SubLine ? QStyle::SC_ScrollBarSubLine : QStyle::SC_ScrollBarAddLine;

        QStyleOptionSlider opt = styleOption;

        opt.subControls = QStyle::SC_ScrollBarAddLine

                        | QStyle::SC_ScrollBarSubLine

                        | QStyle::SC_ScrollBarGroove;

        const qreal scale = window()->effectiveDevicePixelRatio();

        const QSize scrollBarMinSize = style()->sizeFromContents(QStyle::CT_ScrollBar, &opt, QSize(0, 0));

        const QSize sz = scrollBarMinSize * scale;

        QImage scrollBarImage(sz, QImage::Format_ARGB32_Premultiplied);

        scrollBarImage.setDevicePixelRatio(scale);

        QPainter p(&scrollBarImage);

        opt.rect = QRect(QPoint(0, 0), scrollBarMinSize);

        style()->drawComplexControl(QStyle::CC_ScrollBar, &opt, &p);

        QRect sourceImageRect = style()->subControlRect(QStyle::CC_ScrollBar, &opt, sc);

        sourceImageRect = QRect(sourceImageRect.topLeft() * scale, sourceImageRect.size() * scale);

        painter->drawImage(QPoint(0, 0), scrollBarImage, sourceImageRect);

    } else {

        style()->drawComplexControl(QStyle::CC_ScrollBar, &styleOption, painter);

void QQuickStyleItemScrollBar::initStyleOption(QStyleOptionSlider &styleOption) const

    initStyleOptionBase(styleOption);

    auto scrollBar = control<QQuickScrollBar>();

    switch (m_subControl) {

    case Groove:

        styleOption.subControls = QStyle::SC_ScrollBarGroove | QStyle::SC_ScrollBarAddLine | QStyle::SC_ScrollBarSubLine;

        break;

    case Handle:

        styleOption.subControls = QStyle::SC_ScrollBarSlider;

        break;

    case AddLine:

        styleOption.subControls = QStyle::SC_ScrollBarAddLine;

        break;

    case SubLine:

        styleOption.subControls = QStyle::SC_ScrollBarSubLine;

        break;

    styleOption.activeSubControls = QStyle::SC_None;

    styleOption.orientation = scrollBar->orientation();

    if (styleOption.orientation == Qt::Horizontal)

        styleOption.state |= QStyle::State_Horizontal;

    if (scrollBar->isPressed())

        styleOption.state |= QStyle::State_Sunken;

    if (m_overrideState != None) {

        // In ScrollBar.qml we fade between two versions of

        // the handle, depending on if it's hovered or not

        if (m_overrideState == AlwaysHovered) {

            styleOption.state &= ~QStyle::State_Sunken;

            styleOption.activeSubControls = (styleOption.subControls & (QStyle::SC_ScrollBarSlider | QStyle::SC_ScrollBarGroove | QStyle::SC_ScrollBarAddLine | QStyle::SC_ScrollBarSubLine));

        } else if (m_overrideState == NeverHovered) {

            styleOption.state &= ~QStyle::State_Sunken;

            styleOption.activeSubControls &= ~(styleOption.subControls & (QStyle::SC_ScrollBarSlider | QStyle::SC_ScrollBarGroove | QStyle::SC_ScrollBarAddLine | QStyle::SC_ScrollBarSubLine));

        } else if (m_overrideState  == AlwaysSunken) {

            styleOption.state |= QStyle::State_Sunken;

            styleOption.activeSubControls = (styleOption.subControls & (QStyle::SC_ScrollBarSlider | QStyle::SC_ScrollBarGroove | QStyle::SC_ScrollBarAddLine | QStyle::SC_ScrollBarSubLine));

    // The following values will let the handle fill 100% of the

    // groove / imageSize. But when the handle is resized by

    // QQuickScrollBar, it will end up with the correct size visually.

    styleOption.pageStep = 1000;

    styleOption.minimum = 0;

    styleOption.maximum = 1;

    styleOption.sliderValue = 0;

QT_END_NAMESPACE

#include "moc_qquickstyleitemscrollbar_p.cpp"

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