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#include "algorithm.h"
#include "icon.h"
#include "qtcassert.h"
#include "theme/theme.h"
#include "stylehelper.h"

#include <QApplication>
#include <QIcon>
#include <QImage>
#include <QMetaEnum>
#include <QPainter>
#include <QPaintEngine>
#include <QWidget>
#include <QDebug>

namespace Utils {

static const qreal PunchEdgeWidth = 0.5;
static const qreal PunchEdgeIntensity = 0.6;

static QPixmap maskToColorAndAlpha(const QPixmap &mask, const QColor &color)
{
    QImage result(mask.toImage().convertToFormat(QImage::Format_ARGB32));
    result.setDevicePixelRatio(mask.devicePixelRatio());
    auto bitsStart = reinterpret_cast<QRgb*>(result.bits());
    const QRgb *bitsEnd = bitsStart + result.width() * result.height();
    const QRgb tint = color.rgb() & 0x00ffffff;
    const auto alpha = QRgb(color.alpha());
    for (QRgb *pixel = bitsStart; pixel < bitsEnd; ++pixel) {
        QRgb pixelAlpha = (((~*pixel) & 0xff) * alpha) >> 8;
        *pixel = (pixelAlpha << 24) | tint;
    }
    return QPixmap::fromImage(result);
}

using MaskAndColor = QPair<QPixmap, QColor>;
using MasksAndColors = QList<MaskAndColor>;
static MasksAndColors masksAndColors(const Icon &icon, int dpr)
{
    MasksAndColors result;
    for (const IconMaskAndColor &i: icon) {
        const QString &fileName = i.first;
        const QColor color = creatorTheme()->color(i.second);
        const QString dprFileName = StyleHelper::availableImageResolutions(i.first).contains(dpr) ?
                    StyleHelper::imageFileWithResolution(fileName, dpr) : fileName;
        QPixmap pixmap;
        if (!pixmap.load(dprFileName)) {
            pixmap = QPixmap(1, 1);
            qWarning() << "Could not load image: " << dprFileName;
        }
        result.append({pixmap, color});
    }
    return result;
}

static void smearPixmap(QPainter *painter, const QPixmap &pixmap, qreal radius)
{
    const qreal nagative = -radius - 0.01; // Workaround for QPainter rounding behavior
    const qreal positive = radius;
    painter->drawPixmap(QPointF(nagative, nagative), pixmap);
    painter->drawPixmap(QPointF(0, nagative), pixmap);
    painter->drawPixmap(QPointF(positive, nagative), pixmap);
    painter->drawPixmap(QPointF(positive, 0), pixmap);
    painter->drawPixmap(QPointF(positive, positive), pixmap);
    painter->drawPixmap(QPointF(0, positive), pixmap);
    painter->drawPixmap(QPointF(nagative, positive), pixmap);
    painter->drawPixmap(QPointF(nagative, 0), pixmap);
}

static QPixmap combinedMask(const MasksAndColors &masks, Icon::IconStyleOptions style)
{
    if (masks.count() == 1)
        return masks.first().first;

    QPixmap result(masks.first().first);
    QPainter p(&result);
    p.setCompositionMode(QPainter::CompositionMode_Darken);
    auto maskImage = masks.constBegin();
    maskImage++;
    for (;maskImage != masks.constEnd(); ++maskImage) {
        if (style & Icon::PunchEdges) {
            p.save();
            p.setOpacity(PunchEdgeIntensity);
            p.setCompositionMode(QPainter::CompositionMode_Lighten);
            smearPixmap(&p, maskToColorAndAlpha((*maskImage).first, Qt::white), PunchEdgeWidth);
            p.restore();
        }
        p.drawPixmap(0, 0, (*maskImage).first);
    }
    p.end();
    return result;
}

static QPixmap masksToIcon(const MasksAndColors &masks, const QPixmap &combinedMask, Icon::IconStyleOptions style)
{
    QPixmap result(combinedMask.size());
    result.setDevicePixelRatio(combinedMask.devicePixelRatio());
    result.fill(Qt::transparent);
    QPainter p(&result);

    for (MasksAndColors::const_iterator maskImage = masks.constBegin();
         maskImage != masks.constEnd(); ++maskImage) {
        if (style & Icon::PunchEdges && maskImage != masks.constBegin()) {
            // Punch a transparent outline around an overlay.
            p.save();
            p.setOpacity(PunchEdgeIntensity);
            p.setCompositionMode(QPainter::CompositionMode_DestinationOut);
            smearPixmap(&p, maskToColorAndAlpha((*maskImage).first, Qt::white), PunchEdgeWidth);
            p.restore();
        }
        p.drawPixmap(0, 0, maskToColorAndAlpha((*maskImage).first, (*maskImage).second));
    }

    if (style & Icon::DropShadow && creatorTheme()->flag(Theme::ToolBarIconShadow)) {
        const QPixmap shadowMask = maskToColorAndAlpha(combinedMask, Qt::black);
        p.setCompositionMode(QPainter::CompositionMode_DestinationOver);
        p.setOpacity(0.08);
        p.drawPixmap(QPointF(0, -0.501), shadowMask);
        p.drawPixmap(QPointF(-0.501, 0), shadowMask);
        p.drawPixmap(QPointF(0.5, 0), shadowMask);
        p.drawPixmap(QPointF(0.5, 0.5), shadowMask);
        p.drawPixmap(QPointF(-0.501, 0.5), shadowMask);
        p.setOpacity(0.3);
        p.drawPixmap(0, 1, shadowMask);
    }

    p.end();

    return result;
}

Icon::Icon() = default;

Icon::Icon(std::initializer_list<IconMaskAndColor> args, Icon::IconStyleOptions style)
    : QVector<IconMaskAndColor>(args)
    , m_style(style)
{
}

Icon::Icon(const QString &imageFileName)
    : m_style(None)
{
    append({imageFileName, Theme::Color(-1)});
}

QIcon Icon::icon() const
{
    if (isEmpty()) {
        return QIcon();
    } else if (m_style == None) {
        return QIcon(constFirst().first);
    } else {
        QIcon result;
        const int maxDpr = qRound(qApp->devicePixelRatio());
        for (int dpr = 1; dpr <= maxDpr; dpr++) {
            const MasksAndColors masks = masksAndColors(*this, dpr);
            const QPixmap combinedMask = Utils::combinedMask(masks, m_style);
            result.addPixmap(masksToIcon(masks, combinedMask, m_style));

            const QColor disabledColor = creatorTheme()->color(Theme::IconsDisabledColor);
            result.addPixmap(maskToColorAndAlpha(combinedMask, disabledColor), QIcon::Disabled);
        }
        return result;
    }
}

QPixmap Icon::pixmap(QIcon::Mode iconMode) const
{
    if (isEmpty()) {
        return QPixmap();
    } else if (m_style == None) {
        return QPixmap(StyleHelper::dpiSpecificImageFile(constFirst().first));
    } else {
        const MasksAndColors masks =
                masksAndColors(*this, qRound(qApp->devicePixelRatio()));
        const QPixmap combinedMask = Utils::combinedMask(masks, m_style);
        return iconMode == QIcon::Disabled
                ? maskToColorAndAlpha(combinedMask, creatorTheme()->color(Theme::IconsDisabledColor))
                : masksToIcon(masks, combinedMask, m_style);
    }
}

QString Icon::imageFileName() const
{
    QTC_ASSERT(length() == 1, return QString());
    return first().first;
}

QIcon Icon::sideBarIcon(const Icon &classic, const Icon &flat)
{
    QIcon result;
    if (creatorTheme()->flag(Theme::FlatSideBarIcons)) {
        result = flat.icon();
    } else {
        const QPixmap pixmap = classic.pixmap();
        result.addPixmap(pixmap);
        // Ensure that the icon contains a disabled state of that size, since
        // Since we have icons with mixed sizes (e.g. DEBUG_START), and want to
        // avoid that QIcon creates scaled versions of missing QIcon::Disabled
        // sizes.
        result.addPixmap(StyleHelper::disabledSideBarIcon(pixmap), QIcon::Disabled);
    }
    return result;
}

QIcon Icon::modeIcon(const Icon &classic, const Icon &flat, const Icon &flatActive)
{
    QIcon result = sideBarIcon(classic, flat);
    if (creatorTheme()->flag(Theme::FlatSideBarIcons))
        result.addPixmap(flatActive.pixmap(), QIcon::Active);
    return result;
}

QIcon Icon::combinedIcon(const QList<QIcon> &icons)
{
    QIcon result;
    QWindow *window = QApplication::allWidgets().constFirst()->windowHandle();
    for (const QIcon &icon: icons)
        for (const QIcon::Mode mode: {QIcon::Disabled, QIcon::Normal})
            for (const QSize &size: icon.availableSizes(mode))
                result.addPixmap(icon.pixmap(window, size, mode), mode);
    return result;
}

QIcon Icon::combinedIcon(const QList<Icon> &icons)
{
    const QList<QIcon> qIcons = transform(icons, &Icon::icon);
    return combinedIcon(qIcons);
}

} // namespace Utils