qquickpalettecolorprovider.cpp

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// 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
#include "qquickpalettecolorprovider_p.h"
 
#include <QtQuick/private/qquickabstractpaletteprovider_p.h>
 
QT_BEGIN_NAMESPACE
 
static bool notEq(const QPalette &p1, const QPalette &p2)
{
    return p1.resolveMask() != p2.resolveMask() || p1 != p2;
}
 
static QPalette::ColorGroup adjustCg(QPalette::ColorGroup group)
{
    return group == QPalette::All ? QPalette::Active : group;
}
 
// Begin copy from qpalette.cpp
static constexpr QPalette::ResolveMask colorRoleOffset(QPalette::ColorGroup colorGroup)
{
    Q_ASSERT(colorGroup < QPalette::NColorGroups);
    // Exclude NoRole; that bit is used for AccentColor
    return (qToUnderlying(QPalette::NColorRoles) - 1) * qToUnderlying(colorGroup);
}
 
// TODO: Share the function by private interface in qtbase
static constexpr QPalette::ResolveMask bitPosition(QPalette::ColorGroup colorGroup,
                                                   QPalette::ColorRole colorRole)
{
    // Map AccentColor into NoRole for resolving purposes
    if (colorRole == QPalette::AccentColor)
        colorRole = QPalette::NoRole;
 
    return colorRole + colorRoleOffset(colorGroup);
}
 
static_assert(bitPosition(QPalette::ColorGroup(QPalette::NColorGroups - 1),
                          QPalette::ColorRole(QPalette::NColorRoles - 1))
                  < sizeof(QPalette::ResolveMask) * CHAR_BIT,
              "The resolve mask type is not wide enough to fit the entire bit mask.");
// End copy from qpalette.cpp
 
class DefaultPalettesProvider : public QQuickAbstractPaletteProvider
{
public:
    QPalette defaultPalette() const override { static QPalette p; return p; }
};
 
static std::default_delete<const QQuickAbstractPaletteProvider> defaultDeleter() { return {}; }
 
QQuickPaletteColorProvider::QQuickPaletteColorProvider()
    : m_paletteProvider(ProviderPtr(new DefaultPalettesProvider, defaultDeleter()))
{
}
 
const QColor &QQuickPaletteColorProvider::color(QPalette::ColorGroup group, QPalette::ColorRole role) const
{
    return m_resolvedPalette.color(adjustCg(group), role);
}
 
bool QQuickPaletteColorProvider::setColor(QPalette::ColorGroup g, QPalette::ColorRole r, QColor c)
{
    ensureRequestedPalette();
    m_requestedPalette->setColor(g, r, c);
 
    return updateInheritedPalette();
}
 
bool QQuickPaletteColorProvider::resetColor(QPalette::ColorGroup group, QPalette::ColorRole role)
{
    if (!m_requestedPalette.isAllocated())
        return false;
 
    QPalette::ResolveMask unsetResolveMask = 0;
 
    if (group == QPalette::Current)
        group = m_requestedPalette->currentColorGroup();
 
    if (group == QPalette::All) {
        for (int g = QPalette::Active; g < QPalette::NColorGroups; ++g)
            unsetResolveMask |= (QPalette::ResolveMask(1) << bitPosition(QPalette::ColorGroup(g), role));
    } else {
        unsetResolveMask = (QPalette::ResolveMask(1) << bitPosition(group, role));
    }
 
    m_requestedPalette->setResolveMask(m_requestedPalette->resolveMask() & ~unsetResolveMask);
 
    return updateInheritedPalette();
}
 
bool QQuickPaletteColorProvider::resetColor(QPalette::ColorGroup group)
{
    if (!m_requestedPalette.isAllocated())
        return false;
 
    QPalette::ResolveMask unsetResolveMask = 0;
 
    auto getResolveMask = [] (QPalette::ColorGroup group) {
        QPalette::ResolveMask mask = 0;
        for (int roleIndex = QPalette::WindowText; roleIndex < QPalette::NColorRoles; ++roleIndex) {
            const auto cr = QPalette::ColorRole(roleIndex);
            mask |= (QPalette::ResolveMask(1) << bitPosition(group, cr));
        }
        return mask;
    };
 
    if (group == QPalette::Current)
        group = m_requestedPalette->currentColorGroup();
 
    if (group == QPalette::All) {
        for (int g = QPalette::Active; g < QPalette::NColorGroups; ++g)
            unsetResolveMask |= getResolveMask(QPalette::ColorGroup(g));
    } else {
        unsetResolveMask = getResolveMask(group);
    }
 
    m_requestedPalette->setResolveMask(m_requestedPalette->resolveMask() & ~unsetResolveMask);
 
    return updateInheritedPalette();
}
 
bool QQuickPaletteColorProvider::fromQPalette(QPalette p)
{
    m_requestedPalette.value() = std::move(p);
    return updateInheritedPalette();
}
 
QPalette QQuickPaletteColorProvider::palette() const
{
    return m_resolvedPalette;
}
 
const QQuickAbstractPaletteProvider *QQuickPaletteColorProvider::paletteProvider() const
{
    Q_ASSERT(m_paletteProvider);
    return m_paletteProvider.get();
}
 
void QQuickPaletteColorProvider::setPaletteProvider(const QQuickAbstractPaletteProvider *paletteProvider)
{
    static const auto emptyDeleter = [](auto &&){};
    m_paletteProvider = ProviderPtr(paletteProvider, emptyDeleter);
}
 
bool QQuickPaletteColorProvider::copyColorGroup(QPalette::ColorGroup cg,
                                                const QQuickPaletteColorProvider &p)
{
    ensureRequestedPalette();
 
    auto srcPalette = p.palette();
    for (int roleIndex = QPalette::WindowText; roleIndex < QPalette::NColorRoles; ++roleIndex) {
        const auto cr = QPalette::ColorRole(roleIndex);
        if (srcPalette.isBrushSet(cg, cr)) {
            m_requestedPalette->setBrush(cg, cr, srcPalette.brush(cg, cr));
        }
    }
 
    return updateInheritedPalette();
}
 
bool QQuickPaletteColorProvider::reset()
{
    return fromQPalette(QPalette());
}
 
bool QQuickPaletteColorProvider::inheritPalette(const QPalette &palette)
{
    m_lastInheritedPalette.value() = palette;
    return doInheritPalette(palette);
}
 
bool QQuickPaletteColorProvider::doInheritPalette(const QPalette &palette)
{
    auto inheritedMask = m_requestedPalette.isAllocated() ? m_requestedPalette->resolveMask() | palette.resolveMask()
                                                          : palette.resolveMask();
    QPalette parentPalette = m_requestedPalette.isAllocated() ? m_requestedPalette->resolve(palette) : palette;
    parentPalette.setResolveMask(inheritedMask);
 
    auto tmpResolvedPalette = parentPalette.resolve(paletteProvider()->defaultPalette());
    tmpResolvedPalette.setResolveMask(tmpResolvedPalette.resolveMask() | inheritedMask);
 
    bool changed = notEq(tmpResolvedPalette, m_resolvedPalette);
    if (changed)
        std::swap(tmpResolvedPalette, m_resolvedPalette);
 
    return changed;
}
 
bool QQuickPaletteColorProvider::updateInheritedPalette()
{
    // Use last inherited palette as parentPalette's fallbackPalette: it's useful when parentPalette doesn't exist.
    const QPalette &p = m_lastInheritedPalette.isAllocated() ? m_lastInheritedPalette.value()
                                                             : paletteProvider()->defaultPalette();
    return doInheritPalette(paletteProvider()->parentPalette(p));
}
 
void QQuickPaletteColorProvider::ensureRequestedPalette()
{
    if (m_requestedPalette.isAllocated())
        return;
 
    m_requestedPalette.value() = QPalette();
}
 
QT_END_NAMESPACE