/* ============================================================
 *
 * This file is a part of digiKam project
 * https://www.digikam.org
 *
 * Date        : 2005-07-18
 * Description : Free rotation threaded image filter.
 *
 * SPDX-FileCopyrightText: 2004-2026 by Gilles Caulier <caulier dot gilles at gmail dot com>
 * SPDX-FileCopyrightText: 2009-2010 by Andi Clemens <andi dot clemens at gmail dot com>
 * SPDX-FileCopyrightText: 2010      by Martin Klapetek <martin dot klapetek at gmail dot com>
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 *
 * ============================================================ */

#include "freerotationfilter.h"

// C++ includes

#include <cmath>
#include <cstdlib>

// Local includes

#include "dimg.h"
#include "dpixelsaliasfilter.h"
#include "digikam_globals_p.h"      // For KF6::Ki18n deprecated

namespace Digikam
{

class Q_DECL_HIDDEN FreeRotationFilter::Private
{
public:

    Private() = default;

    FreeRotationContainer settings;
};

FreeRotationFilter::FreeRotationFilter(QObject* const parent)
    : DImgThreadedFilter(parent),
      d                 (new Private)
{
    initFilter();
}

FreeRotationFilter::FreeRotationFilter(DImg* const orgImage, QObject* const parent, const FreeRotationContainer& settings)
    : DImgThreadedFilter(orgImage, parent, QLatin1String("FreeRotation")),
      d                 (new Private)
{
    d->settings = settings;
    initFilter();
}

FreeRotationFilter::~FreeRotationFilter()
{
    cancelFilter();
    delete d;
}

QString FreeRotationFilter::DisplayableName()
{
    return QString::fromUtf8(I18N_NOOP("Free Rotation"));
}

QSize FreeRotationFilter::getNewSize() const
{
    return d->settings.newSize;
}

double FreeRotationFilter::calculateAngle(int x1, int y1, int x2, int y2)
{
    QPoint p1(x1, y1);
    QPoint p2(x2, y2);

    return calculateAngle(p1, p2);
}

double FreeRotationFilter::calculateAngle(const QPoint& p1, const QPoint& p2)
{
    // check for invalid points. This should have been handled by the calling method,
    // but we want to be really sure here

    if (
        (p1.x() < 0) ||
        (p1.y() < 0) ||
        (p2.x() < 0) ||
        (p2.y() < 0)
       )
    {
        return 0.0;
    }

    // check if points are equal

    if (p1 == p2)
    {
        return 0.0;
    }

    // if y() is equal, no angle needs to be calculated

    if (p1.y() == p2.y())
    {
        return 0.0;
    }

    // if x() is equal, angle equals 90°

    if (p1.x() == p2.x())
    {
        return 90.0;
    }

    // do we rotate to the left (counter clock wise)?

    bool ccw     = ((p1.x() < p2.x()) && (p2.y() > p1.y())) ||
                   ((p1.x() > p2.x()) && (p2.y() < p1.y()));

    // calculate the angle

    double ly    = fabs((double)p2.y() - p1.y());
    double lx    = fabs((double)p2.x() - p1.x());
    double angle = atan2(ly, lx) * 180.0 / M_PI;
    angle        = ccw ? -angle : angle;

    return angle;
}

void FreeRotationFilter::filterImage()
{
    int          progress;
    int w, h, nw, nh, j, i  = 0;
    int          nNewHeight, nNewWidth;
    int          nhdx, nhdy, nhsx, nhsy;
    double       lfSin, lfCos, lfx, lfy;

    int nWidth              = m_orgImage.width();
    int nHeight             = m_orgImage.height();

    uchar* pBits            = m_orgImage.bits();
    unsigned short* pBits16 = reinterpret_cast<unsigned short*>(m_orgImage.bits());

    // first of all, we need to calculate the sin and cos of the given angle

    lfSin                   = sin(d->settings.angle * -DEG2RAD);
    lfCos                   = cos(d->settings.angle * -DEG2RAD);

    // now, we have to calc the new size for the destination image

    if ((lfSin * lfCos) < 0)
    {
        nNewWidth  = lround(fabs(nWidth * lfCos - nHeight * lfSin));
        nNewHeight = lround(fabs(nWidth * lfSin - nHeight * lfCos));
    }
    else
    {
        nNewWidth  = lround(fabs(nWidth * lfCos + nHeight * lfSin));
        nNewHeight = lround(fabs(nWidth * lfSin + nHeight * lfCos));
    }

    // getting the destination's center position

    nhdx = nNewWidth  / 2;
    nhdy = nNewHeight / 2;

    // getting the source's center position

    nhsx = nWidth  / 2;
    nhsy = nHeight / 2;

    // now, we have to alloc a new image

    bool sixteenBit = m_orgImage.sixteenBit();
    m_destImage     = DImg(nNewWidth, nNewHeight, sixteenBit, m_orgImage.hasAlpha());

    if (m_destImage.isNull())
    {
        return;
    }

    m_destImage.fill(DColor(d->settings.backgroundColor.rgb(), sixteenBit));

    uchar* pResBits            = m_destImage.bits();
    unsigned short* pResBits16 = reinterpret_cast<unsigned short*>(m_destImage.bits());

    DPixelsAliasFilter alias;

    // main loop

    for (h = 0 ; runningFlag() && (h < nNewHeight) ; ++h)
    {
        nh = h - nhdy;

        for (w = 0 ; runningFlag() && (w < nNewWidth) ; ++w)
        {
            nw = w - nhdx;

            i = setPosition(nNewWidth, w, h);

            lfx = (double)nw * lfCos - (double)nh * lfSin + nhsx;
            lfy = (double)nw * lfSin + (double)nh * lfCos + nhsy;

            if (isInside(nWidth, nHeight, (int)lfx, (int)lfy))
            {
                if (d->settings.antiAlias)
                {
                    if (!sixteenBit)
                    {
                        alias.pixelAntiAliasing(pBits, nWidth, nHeight, lfx, lfy,
                                                &pResBits[i + 3], &pResBits[i + 2],
                                                &pResBits[i + 1], &pResBits[i]);
                    }
                    else
                    {
                        alias.pixelAntiAliasing16(pBits16, nWidth, nHeight, lfx, lfy,
                                                  &pResBits16[i + 3], &pResBits16[i + 2],
                                                  &pResBits16[i + 1], &pResBits16[i]);
                    }
                }
                else
                {
                    j = setPosition(nWidth, (int)lfx, (int)lfy);

                    for (int p = 0 ; p < 4 ; ++p)
                    {
                        if (!sixteenBit)
                        {
                            pResBits[i] = pBits[j];
                        }
                        else
                        {
                            pResBits16[i] = pBits16[j];
                        }

                        ++i;
                        ++j;
                    }
                }
            }
        }

        // Update the progress bar in dialog.

        progress = (int)(((double) h * 100.0) / nNewHeight);

        if ((progress % 5) == 0)
        {
            postProgress(progress);
        }
    }

    // Compute the rotated destination image size using original image dimensions.

    int    W, H;
    double absAngle = fabs(d->settings.angle);

    // stop here when no angle was set

    if (absAngle == 0.0)
    {
        return;
    }

    if (absAngle < 90.0)
    {
        W = (int)(d->settings.orgW * cos(absAngle * DEG2RAD) + d->settings.orgH * sin(absAngle * DEG2RAD));
        H = (int)(d->settings.orgH * cos(absAngle * DEG2RAD) + d->settings.orgW * sin(absAngle * DEG2RAD));
    }
    else
    {
        H = (int)(d->settings.orgW * cos((absAngle - 90.0) * DEG2RAD) + d->settings.orgH * sin((absAngle - 90.0) * DEG2RAD));
        W = (int)(d->settings.orgH * cos((absAngle - 90.0) * DEG2RAD) + d->settings.orgW * sin((absAngle - 90.0) * DEG2RAD));
    }

    // Auto-cropping destination image without black holes around.

    QRect autoCrop;

    switch (d->settings.autoCrop)
    {
        case FreeRotationContainer::WidestArea:
        {
            // 'Widest Area' method (by Renchi Raju).

            autoCrop.setX((int)(nHeight * sin(absAngle * DEG2RAD)));
            autoCrop.setY((int)(nWidth  * sin(absAngle * DEG2RAD)));
            autoCrop.setWidth((int)(nNewWidth  - 2 * nHeight * sin(absAngle * DEG2RAD)));
            autoCrop.setHeight((int)(nNewHeight - 2 * nWidth  * sin(absAngle * DEG2RAD)));

            if (!autoCrop.isValid())
            {
                m_destImage         = DImg(m_orgImage.width(), m_orgImage.height(), m_orgImage.sixteenBit(), m_orgImage.hasAlpha());
                m_destImage.fill(DColor(d->settings.backgroundColor.rgb(), sixteenBit));
                d->settings.newSize = QSize();
            }
            else
            {
                m_destImage = m_destImage.copy(autoCrop);
                d->settings.newSize.setWidth((int)(W - 2 * d->settings.orgH * sin(absAngle * DEG2RAD)));
                d->settings.newSize.setHeight((int)(H - 2 * d->settings.orgW * sin(absAngle * DEG2RAD)));
            }

            break;
        }

        case FreeRotationContainer::LargestArea:
        {
            // 'Largest Area' method (by Gerhard Kulzer).

            float gamma = 0.0f;

            if (nHeight > nWidth)
            {
                gamma = atan((float) nWidth / (float) nHeight);

                if (absAngle < 90.0)
                {
                    autoCrop.setHeight((int)((float) nWidth / cos(absAngle * DEG2RAD) / (tan(gamma) +
                                             tan(absAngle * DEG2RAD))));
                    autoCrop.setWidth((int)((float) autoCrop.height() * tan(gamma)));
                }
                else
                {
                    autoCrop.setWidth((int)((float) nWidth / cos((absAngle - 90.0) * DEG2RAD) / (tan(gamma) +
                                            tan((absAngle - 90.0) * DEG2RAD))));
                    autoCrop.setHeight((int)((float) autoCrop.width() * tan(gamma)));
                }
            }
            else
            {
                gamma = atan((float) nHeight / (float) nWidth);

                if (absAngle < 90.0)
                {
                    autoCrop.setWidth((int)((float) nHeight / cos(absAngle * DEG2RAD) / (tan(gamma) +
                                            tan(absAngle * DEG2RAD))));
                    autoCrop.setHeight((int)((float) autoCrop.width() * tan(gamma)));
                }
                else
                {
                    autoCrop.setHeight((int)((float) nHeight / cos((absAngle - 90.0) * DEG2RAD) /
                                             (tan(gamma) + tan((absAngle - 90.0) * DEG2RAD))));
                    autoCrop.setWidth((int)((float) autoCrop.height() * tan(gamma)));
                }
            }

            autoCrop.moveCenter(QPoint(nNewWidth / 2, nNewHeight / 2));

            if (!autoCrop.isValid())
            {
                m_destImage         = DImg(m_orgImage.width(), m_orgImage.height(), m_orgImage.sixteenBit(), m_orgImage.hasAlpha());
                m_destImage.fill(DColor(d->settings.backgroundColor.rgb(), sixteenBit));
                d->settings.newSize = QSize();
            }
            else
            {
                m_destImage = m_destImage.copy(autoCrop);
                gamma       = atan((float) d->settings.orgH / (float) d->settings.orgW);

                if (absAngle < 90.0)
                {
                    d->settings.newSize.setWidth((int)((float) d->settings.orgH / cos(absAngle * DEG2RAD) / (tan(gamma) +
                                                       tan(absAngle * DEG2RAD))));
                    d->settings.newSize.setHeight((int)((float) d->settings.newSize.width() * tan(gamma)));
                }
                else
                {
                    d->settings.newSize.setHeight((int)((float) d->settings.orgH / cos((absAngle - 90.0) * DEG2RAD) /
                                                        (tan(gamma) + tan((absAngle - 90.0) * DEG2RAD))));
                    d->settings.newSize.setWidth((int)((float) d->settings.newSize.height() * tan(gamma)));
                }
            }

            break;
        }

        default: // No auto cropping.
        {
            d->settings.newSize.setWidth(W);
            d->settings.newSize.setHeight(H);
            break;
        }
    }
}

int FreeRotationFilter::setPosition(int Width, int X, int Y)
{
    return (Y * Width * 4 + 4 * X);
}

bool FreeRotationFilter::isInside(int Width, int Height, int X, int Y)
{
    bool bIsWOk = ((X < 0) ? false : (X >= Width)  ? false : true);
    bool bIsHOk = ((Y < 0) ? false : (Y >= Height) ? false : true);

    return (bIsWOk && bIsHOk);
}

FilterAction FreeRotationFilter::filterAction()
{
    FilterAction action(FilterIdentifier(), CurrentVersion());
    action.setDisplayableName(DisplayableName());

    action.addParameter(QLatin1String("angle"),            d->settings.angle);
    action.addParameter(QLatin1String("antiAlias"),        d->settings.antiAlias);
    action.addParameter(QLatin1String("autoCrop"),         d->settings.autoCrop);
    action.addParameter(QLatin1String("newSize"),          d->settings.newSize);
    action.addParameter(QLatin1String("orgH"),             d->settings.orgH);
    action.addParameter(QLatin1String("orgW"),             d->settings.orgW);
    action.addParameter(QLatin1String("backgroundColorR"), d->settings.backgroundColor.red());
    action.addParameter(QLatin1String("backgroundColorG"), d->settings.backgroundColor.green());
    action.addParameter(QLatin1String("backgroundColorB"), d->settings.backgroundColor.blue());
    action.addParameter(QLatin1String("backgroundColorA"), d->settings.backgroundColor.alpha());

    return action;
}

void FreeRotationFilter::readParameters(const FilterAction& action)
{
    d->settings.angle     = action.parameter(QLatin1String("angle")).toDouble();
    d->settings.antiAlias = action.parameter(QLatin1String("antiAlias")).toBool();
    d->settings.autoCrop  = action.parameter(QLatin1String("autoCrop")).toInt();
    d->settings.newSize   = action.parameter(QLatin1String("newSize")).toSize();
    d->settings.orgH      = action.parameter(QLatin1String("orgH")).toInt();
    d->settings.orgW      = action.parameter(QLatin1String("orgW")).toInt();
    d->settings.backgroundColor.setRed(action.parameter(QLatin1String("backgroundColorR")).toInt());
    d->settings.backgroundColor.setGreen(action.parameter(QLatin1String("backgroundColorG")).toInt());
    d->settings.backgroundColor.setBlue(action.parameter(QLatin1String("backgroundColorB")).toInt());
    d->settings.backgroundColor.setAlpha(action.parameter(QLatin1String("backgroundColorA")).toInt());
}

} // namespace Digikam

#include "moc_freerotationfilter.cpp"
