/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
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** Copyright (C) 2009 netlabs.org. OS/2 parts.
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#include "qbitmap.h"
#include "qbuffer.h"
#include "qimage.h"
#include "qpolygon.h"
#include "qregion.h"

#include "qt_os2.h"

QT_BEGIN_NAMESPACE

//  To compensate the difference between Qt (where y axis goes downwards) and
//  GPI (where y axis goes upwards) coordinate spaces when dealing with regions
//  we use the following technique: when a GPI resource is allocated for a Qt
//  region, we simply change the sign of all y coordinates to quickly flip it
//  top to bottom in a manner that doesn't depend on the target device height.
//  All we have to do to apply the created GPI region to a particular GPI device
//  is to align its y axis to the top of the device (i.e. offset the region
//  up by the height of the device), and unalign it afterwards to bring it back
//  to the coordinate space of other device-independent (unaligned) regions.
//  To optimize this, we remember (in data->hgt) the last height value used to
//  align the region, and align it again only if the target device height
//  changes. Zero height indicates a device-independent target (such as other
//  unaligned Qt region).
//
//  The handle() function, used for external access to the region, takes an
//  argument that must be always set to the height of the target device to
//  guarantee the correct coordinate space alignment.

#if defined(__GNUC__) && defined(__INNOTEK_LIBC__)

// Innotek GCC lacks some API functions in its version of OS/2 Toolkit headers

extern "C" HRGN APIENTRY GpiCreateEllipticRegion(HPS hps,
                                                 PRECTL prclRect);

extern "C" HRGN APIENTRY GpiCreatePolygonRegion(HPS hps,
                                                ULONG ulCount,
                                                PPOLYGON paplgn,
                                                ULONG flOptions);
#endif

QRegion::QRegionData QRegion::shared_empty = { Q_BASIC_ATOMIC_INITIALIZER(1),
                                               NULLHANDLE, 0 };

QRegion::QRegion()
    : d(&shared_empty)
{
    d->ref.ref();
}

QRegion::QRegion(const QRect &r, RegionType t)
{
    if (r.isEmpty()) {
        d = &shared_empty;
        d->ref.ref();
    } else {
        d = new QRegionData;
        d->ref = 1;
        d->height = 0;
        HPS hps = qt_display_ps();
        if (t == Rectangle) {
            RECTL rcl = { r.left(), -(r.bottom()+1), r.right()+1, -r.top() };
            d->rgn = GpiCreateRegion(hps, 1, &rcl);
        } else if (t == Ellipse) {
            // if the width or height of the ellipse is odd, GPI always
            // converts it to a nearest even value, which is obviously stupid
            // So, we don't use GpiCreateEllipticRegion(), but create an array
            // of points to call GpiCreatePolygonRegion() instead.
            QPainterPath p(QPointF(r.x(), r.y()));
            p.arcTo(r.x(), r.y(), r.width(), r.height(), 0, 360);
            QPolygon a = p.toFillPolygon().toPolygon();
            for (int i = 0; i < a.size(); ++ i)
                a[i].ry() = -(a[i].y() + 1);
            // GpiCreatePolygonRegion() is bogus and always starts a poligon from
            // the current position. Make the last point the current one and reduce
            // the number of points by one.
            GpiMove(hps, reinterpret_cast<PPOINTL>(&a[a.size() - 1]));
            POLYGON poly = { a.size() - 1, reinterpret_cast<PPOINTL>(a.data()) };
            d->rgn = GpiCreatePolygonRegion(hps, 1, &poly, POLYGON_ALTERNATE);
        }
    }
}

QRegion::QRegion(const QPolygon &a, Qt::FillRule fillRule)
{
    if (a.size() < 3) {
        d = &shared_empty;
        d->ref.ref();
    } else {
        d = new QRegionData;
        d->ref = 1;
        d->height = 0;
        HPS hps = qt_display_ps();
        POINTL *pts = new POINTL[a.size()];
        for (int i = 0; i < a.size(); ++ i) {
            pts[i].x = a[i].x();
            pts[i].y = - (a[i].y() + 1);
        }
        // GpiCreatePolygonRegion() is bogus and always starts a poligon from
        // the current position. Make the last point the current one and reduce
        // the number of points by one.
        GpiMove(hps, &pts[a.size() - 1]);
        POLYGON poly = { a.size() - 1, pts };
        ULONG opts = Qt::OddEvenFill ? POLYGON_ALTERNATE : POLYGON_WINDING;
        d->rgn = GpiCreatePolygonRegion(hps, 1, &poly, opts);
        delete[] pts;
    }
}

QRegion::QRegion(const QRegion &r)
{
    d = r.d;
    d->ref.ref();
}

static HRGN bitmapToRegion(const QBitmap& bitmap)
{
    HRGN region = 0;
    QImage image = bitmap.toImage();
    const int maxrect = 256;
    RECTL rects[maxrect];
    HPS hps = qt_display_ps();

#define FlushSpans \
    { \
        HRGN r = GpiCreateRegion(hps, n, rects); \
	    if (region) { \
	        GpiCombineRegion(hps, region, region, r, CRGN_OR); \
	        GpiDestroyRegion(hps, r); \
    	} else { \
    	    region = r; \
    	} \
    }

#define AddSpan \
    { \
        rects[n].xLeft = prev1; \
        rects[n].yBottom = -(y+1); \
        rects[n].xRight = x-1+1; \
        rects[n].yTop = -y; \
        n++; \
        if (n == maxrect) { \
            FlushSpans \
            n = 0; \
        } \
    }

    int n = 0;
    int zero = 0x00;

    int x, y;
    for (y = 0; y < image.height(); y++) {
    	uchar *line = image.scanLine(y);
    	int w = image.width();
    	uchar all = zero;
    	int prev1 = -1;
    	for (x = 0; x < w;) {
    	    uchar byte = line[x/8];
    	    if (x > w-8 || byte != all) {
    		for (int b = 8; b > 0 && x < w; b--) {
    		    if (!(byte & 0x80) == !all) {
                    // More of the same
    		    } else {
        			// A change.
        			if (all != zero) {
        			    AddSpan;
        			    all = zero;
        			} else {
        			    prev1 = x;
        			    all = ~zero;
        			}
    		    }
    		    byte <<= 1;
    		    x++;
    		}
    	    } else {
                x += 8;
    	    }
    	}
    	if (all != zero) {
    	    AddSpan;
    	}
    }
    if (n) {
        FlushSpans;
    }

    if (!region)
        region = GpiCreateRegion(hps, 0, NULL);

    return region;
}

QRegion::QRegion(const QBitmap &bm)
{
    if (bm.isNull()) {
        d = &shared_empty;
        d->ref.ref();
    } else {
        d = new QRegionData;
        d->ref = 1;
        d->height = 0;
        d->rgn = bitmapToRegion(bm);
    }
}

void QRegion::cleanUp(QRegion::QRegionData *x)
{
    if (x->rgn != NULLHANDLE)
        GpiDestroyRegion(qt_display_ps(), x->rgn);
    delete x;
}

QRegion::~QRegion()
{
    if (!d->ref.deref())
        cleanUp(d);
}

QRegion &QRegion::operator=(const QRegion &r)
{
    r.d->ref.ref();
    if (!d->ref.deref())
        cleanUp(d);
    d = r.d;
    return *this;
}


QRegion QRegion::copy() const
{
    QRegion r;
    QRegionData *x = new QRegionData;
    x->ref = 1;
    if (d->rgn != NULLHANDLE) {
        x->height = d->height;
        HPS hps = qt_display_ps();
        x->rgn = GpiCreateRegion(hps, 0, NULL);
        GpiCombineRegion(hps, x->rgn, d->rgn, NULL, CRGN_COPY);
    } else {
        x->height = 0;
        x->rgn = NULLHANDLE;
    }
    if (!r.d->ref.deref())
        cleanUp(r.d);
    r.d = x;
    return r;
}

bool QRegion::isEmpty() const
{
    return (d == &shared_empty || boundingRect().isEmpty());
}

bool QRegion::contains(const QPoint &p) const
{
    LONG rc = PRGN_OUTSIDE;
    if (d->rgn != NULLHANDLE) {
        POINTL ptl = { p.x(), d->height - (p.y() + 1) };
        rc = GpiPtInRegion(qt_display_ps(), d->rgn, &ptl);
    }
    return rc == PRGN_INSIDE;
}

bool QRegion::contains(const QRect &r) const
{
    LONG rc = PRGN_OUTSIDE;
    if (d->rgn != NULLHANDLE) {
        RECTL rcl = { r.left(), d->height - (r.bottom() + 1),
                      r.right() + 1, d->height - r.top() };
        rc = GpiRectInRegion(qt_display_ps(), d->rgn, &rcl);
    }
    return rc == RRGN_INSIDE || rc == RRGN_PARTIAL;
}

void QRegion::translate(int dx, int dy)
{
    if (d->rgn == NULLHANDLE || (dx == 0 && dy == 0))
        return;
    detach();
    POINTL ptl = { dx, -dy };
    GpiOffsetRegion(qt_display_ps(), d->rgn, &ptl);
}

#define CRGN_NOP -1

// Duplicates of those in qregion.cpp
#define QRGN_OR               6
#define QRGN_AND              7
#define QRGN_SUB              8
#define QRGN_XOR              9

/*
  Performs the actual OR, AND, SUB and XOR operation between regions.
  Sets the resulting region handle to 0 to indicate an empty region.
*/

QRegion QRegion::pmCombine(const QRegion &r, int op) const
{
    LONG both = CRGN_NOP, left = CRGN_NOP, right = CRGN_NOP;
    switch (op) {
    case QRGN_OR:
        both = CRGN_OR;
        left = right = CRGN_COPY;
        break;
    case QRGN_AND:
        both = CRGN_AND;
        break;
    case QRGN_SUB:
        both = CRGN_DIFF;
        left = CRGN_COPY;
        break;
    case QRGN_XOR:
        both = CRGN_XOR;
        left = right = CRGN_COPY;
        break;
    default:
        qWarning( "QRegion: Internal error in pmCombine" );
    }

    QRegion result;
    if (d->rgn == NULLHANDLE && r.d->rgn == NULLHANDLE)
        return result;
    HPS hps = qt_display_ps();
    result.detach();
    result.d->rgn = GpiCreateRegion(hps, 0, NULL);
    LONG rc = RGN_NULL;
    if (d->rgn != NULLHANDLE && r.d->rgn != NULLHANDLE) {
        updateHandle(r.d->height); // bring to the same coordinate space
        rc = GpiCombineRegion(hps, result.d->rgn, d->rgn, r.d->rgn, both);
        result.d->height = r.d->height;
    } else if (d->rgn && left != CRGN_NOP) {
        rc = GpiCombineRegion(hps, result.d->rgn, d->rgn, 0, left);
        result.d->height = d->height;
    } else if (r.d->rgn != NULLHANDLE && right != CRGN_NOP) {
        rc = GpiCombineRegion(hps, result.d->rgn, r.d->rgn, 0, right);
        result.d->height = r.d->height;
    }
    if (rc == RGN_NULL || rc == RGN_ERROR) {
        result = QRegion(); // shared_empty
    }
    return result;
}

QRegion QRegion::unite(const QRegion &r) const
{
    if (d->rgn == NULLHANDLE)
        return r;
    if (r.d->rgn == NULLHANDLE)
        return *this;
    return pmCombine(r, QRGN_OR);
}

QRegion QRegion::unite(const QRect &r) const
{
    return unite(QRegion(r));
}

QRegion QRegion::intersect(const QRegion &r) const
{
    if (r.d->rgn == NULLHANDLE || d->rgn == NULLHANDLE)
        return QRegion();
     return pmCombine(r, QRGN_AND);
}

QRegion QRegion::subtract(const QRegion &r) const
{
    if (r.d->rgn == NULLHANDLE || d->rgn == NULLHANDLE)
        return *this;
    return pmCombine(r, QRGN_SUB);
}

QRegion QRegion::eor(const QRegion &r) const
{
    if (d->rgn == NULLHANDLE)
        return r;
    if (r.d->rgn == NULLHANDLE)
        return *this;
    return pmCombine(r, QRGN_XOR);
}

QRect QRegion::boundingRect() const
{
    if (!d->rgn)
        return QRect();

    RECTL rcl;
    LONG rc = RGN_NULL;
    if (d->rgn != NULLHANDLE)
        rc = GpiQueryRegionBox(qt_display_ps(), d->rgn, &rcl);
    if (rc == RGN_NULL || rc == RGN_ERROR)
        return QRect();
    else
        return QRect(rcl.xLeft, d->height - rcl.yTop,
                     rcl.xRight - rcl.xLeft, rcl.yTop - rcl.yBottom);
}

QVector<QRect> QRegion::rects() const
{
    QVector<QRect> a;

    if (d->rgn == NULLHANDLE)
        return a;

    HPS hps = qt_display_ps();
    RGNRECT ctl = {1, 0, 0, RECTDIR_LFRT_TOPBOT};
    if (!GpiQueryRegionRects(hps, d->rgn, NULL, &ctl, NULL))
        return a;

    ctl.crc = ctl.crcReturned;
    PRECTL rcls = new RECTL[ctl.crcReturned];
    if (rcls == 0)
        return a;
    if (!GpiQueryRegionRects(hps, d->rgn, NULL, &ctl, rcls)) {
        delete [] rcls;
        return a;
    }

    a = QVector<QRect>(ctl.crcReturned);
    PRECTL r = rcls;
    for (int i = 0; i < a.size(); ++i) {
        a[i].setRect(r->xLeft, d->height - r->yTop,
                     r->xRight - r->xLeft, r->yTop - r->yBottom);
        ++r;
    }

    delete [] rcls;
    return a;
 }

void QRegion::setRects(const QRect *rects, int num)
{
    *this = QRegion();
    if (!rects || num == 0 || (num == 1 && rects->isEmpty()))
        return;
    for (int i = 0; i < num; ++i)
        *this |= rects[i];
}

int QRegion::numRects() const
{
    if (d->rgn == NULLHANDLE)
        return 0;

    RGNRECT ctl = {1, 0, 0, RECTDIR_LFRT_TOPBOT};
    if (!GpiQueryRegionRects(qt_display_ps(), d->rgn, NULL, &ctl, NULL))
        return 0;

    return ctl.crcReturned;
}

bool QRegion::operator==(const QRegion &r) const
{
    if (d == r.d)
        return true;
    if ((d->rgn == NULLHANDLE) ^ (r.d->rgn == NULLHANDLE)) // one is empty, not both
        return false;
    if (d->rgn == NULLHANDLE) // both empty
        return true;
    updateHandle(r.d->height); // bring to the same coordinate space
    return // both not empty
        GpiEqualRegion(qt_display_ps(), d->rgn, r.d->rgn) == EQRGN_EQUAL;
}

QRegion& QRegion::operator+=(const QRegion &r)
{
    if (r.d->rgn == NULLHANDLE)
        return *this;

    if (d->rgn == NULLHANDLE) {
        *this = r;
        return *this;
    }

    *this = unite(r);
    return *this;
}

QRegion& QRegion::operator-=(const QRegion &r)
{
    if (r.d->rgn == NULLHANDLE || d->rgn == NULLHANDLE)
        return *this;

    *this = subtract(r);
    return *this;
}

QRegion& QRegion::operator&=(const QRegion &r)
{
    if (d->rgn == NULLHANDLE)
        return *this;

    if (r.d->rgn == NULLHANDLE) {
        *this = QRegion();
        return *this;
    }

    *this = intersect(r);
    return *this;
}

bool qt_region_strictContains(const QRegion &region, const QRect &rect)
{
    Q_UNUSED(region);
    Q_UNUSED(rect);
    return false;
}

/*!
    \internal

    Updates the region handle so that it is suitable for selection to
    a device with the given \a height.
 */
void QRegion::updateHandle(int targetHeight) const
{
    QRegion *that = const_cast<QRegion*>(this); // we're const here
    if (d->rgn == NULLHANDLE) {
        // a handle of a null region is requested, allocate an empty region
        that->detach();
        that->d->rgn = GpiCreateRegion(qt_display_ps(), 0, NULL);
        that->d->height = targetHeight;
    } else if (d->height != targetHeight) {
        // align region y axis to the top of the device
        that->detach();
        POINTL ptl = { 0, targetHeight - d->height };
        GpiOffsetRegion(qt_display_ps(), d->rgn, &ptl);
        that->d->height = targetHeight;
    }
}

QT_END_NAMESPACE