tdegraphics/kolourpaint/pixmapfx/kppixmapfx.cpp

/*
   Copyright (c) 2003,2004,2005 Clarence Dang <dang@kde.org>
   All rights reserved.

   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions
   are met:

   1. Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.
   2. Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in the
      documentation and/or other materials provided with the distribution.

   THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/


#define DEBUG_KP_PIXMAP_FX 0


#include <kppixmapfx.h>

#include <math.h>

#include <tqapplication.h>
#include <tqbitmap.h>
#include <tqdatetime.h>
#include <tqimage.h>
#include <tqpainter.h>
#include <tqpixmap.h>
#include <tqpoint.h>
#include <tqpointarray.h>
#include <tqrect.h>

#include <tdeconfig.h>
#include <kdebug.h>
#include <tdelocale.h>
#include <tdemessagebox.h>

#include <kpcolor.h>
#include <kpdefs.h>
#include <kpselection.h>
#include <kptool.h>


//
// Overflow Resistant Arithmetic:
//

// public static
int kpPixmapFX::addDimensions (int lhs, int rhs)
{
    if (lhs < 0 || rhs < 0 ||
        lhs > INT_MAX - rhs)
    {
        return INT_MAX;
    }

    return lhs + rhs;
}

// public static
int kpPixmapFX::multiplyDimensions (int lhs, int rhs)
{
    if (rhs == 0)
        return 0;

    if (lhs < 0 || rhs < 0 ||
        lhs > INT_MAX / rhs)
    {
        return INT_MAX;
    }

    return lhs * rhs;
}


//
// TQPixmap Statistics
//

// public static
int kpPixmapFX::pixmapArea (const TQPixmap &pixmap)
{
    return kpPixmapFX::pixmapArea (pixmap.width (), pixmap.height ());
}

// public static
int kpPixmapFX::pixmapArea (const TQPixmap *pixmap)
{
    return (pixmap ? kpPixmapFX::pixmapArea (*pixmap) : 0);
}

// public static
int kpPixmapFX::pixmapArea (int width, int height)
{
    return multiplyDimensions (width, height);
}


// public static
int kpPixmapFX::pixmapSize (const TQPixmap &pixmap)
{
    return kpPixmapFX::pixmapSize (pixmap.width (), pixmap.height (),
                                   pixmap.depth ());
}

// public static
int kpPixmapFX::pixmapSize (const TQPixmap *pixmap)
{
    return (pixmap ? kpPixmapFX::pixmapSize (*pixmap) : 0);
}

// public static
int kpPixmapFX::pixmapSize (int width, int height, int depth)
{
    // handle 15bpp
    int roundedDepth = (depth > 8 ? (depth + 7) / 8 * 8 : depth);

#if DEBUG_KP_PIXMAP_FX && 0
    kdDebug () << "kpPixmapFX::pixmapSize() w=" << width
               << " h=" << height
               << " d=" << depth
               << " roundedDepth=" << roundedDepth
               << " ret="
               << multiplyDimensions (kpPixmapFX::pixmapArea (width, height), roundedDepth) / 8
               << endl;
#endif
    return multiplyDimensions (kpPixmapFX::pixmapArea (width, height), roundedDepth) / 8;
}


// public static
int kpPixmapFX::imageSize (const TQImage &image)
{
    return kpPixmapFX::imageSize (image.width (), image.height (), image.depth ());
}

// public static
int kpPixmapFX::imageSize (const TQImage *image)
{
    return (image ? kpPixmapFX::imageSize (*image) : 0);
}

// public static
int kpPixmapFX::imageSize (int width, int height, int depth)
{
    // handle 15bpp
    int roundedDepth = (depth > 8 ? (depth + 7) / 8 * 8 : depth);

#if DEBUG_KP_PIXMAP_FX && 0
    kdDebug () << "kpPixmapFX::imageSize() w=" << width
               << " h=" << height
               << " d=" << depth
               << " roundedDepth=" << roundedDepth
               << " ret="
               << multiplyDimensions (multiplyDimensions (width, height), roundedDepth) / 8
               << endl;
#endif

    return multiplyDimensions (multiplyDimensions (width, height), roundedDepth) / 8;
}


// public static
int kpPixmapFX::selectionSize (const kpSelection &sel)
{
    return sel.size ();
}

// public static
int kpPixmapFX::selectionSize (const kpSelection *sel)
{
    return (sel ? sel->size () : 0);
}


// public static
int kpPixmapFX::stringSize (const TQString &string)
{
#if DEBUG_KP_PIXMAP_FX && 1
    kdDebug () << "kpPixmapFX::stringSize(" << string << ")"
               << " len=" << string.length ()
               << " sizeof(TQChar)=" << sizeof (TQChar)
               << endl;
#endif
    return string.length () * sizeof (TQChar);
}


// public static
int kpPixmapFX::pointArraySize (const TQPointArray &points)
{
#if DEBUG_KP_PIXMAP_FX && 1
    kdDebug () << "kpPixmapFX::pointArraySize() points.size="
               << points.size ()
               << " sizeof(TQPoint)=" << sizeof (TQPoint)
               << endl;
#endif

    return (points.size () * sizeof (TQPoint));
}


//
// TQPixmap/TQImage Conversion Functions
//

// public static
TQImage kpPixmapFX::convertToImage (const TQPixmap &pixmap)
{
    if (pixmap.isNull ())
        return TQImage ();

    return pixmap.convertToImage ();
}


// Returns true if <image> contains translucency (rather than just transparency)
// TQPixmap::hasAlphaChannel() appears to give incorrect results
static bool imageHasAlphaChannel (const TQImage &image)
{
    if (image.depth () < 32)
        return false;

    for (int y = 0; y < image.height (); y++)
    {
        for (int x = 0; x < image.width (); x++)
        {
            const TQRgb rgb = image.pixel (x, y);

            if (tqAlpha (rgb) > 0 && tqAlpha (rgb) < 255)
                return true;
        }
    }

    return false;
}

static int imageNumColorsUpTo (const TQImage &image, int max)
{
    TQMap <TQRgb, bool> rgbMap;

    if (image.depth () <= 8)
    {
        for (int i = 0; i < image.numColors () && (int) rgbMap.size () < max; i++)
        {
            rgbMap.insert (image.color (i), true);
        }
    }
    else
    {
        for (int y = 0; y < image.height () && (int) rgbMap.size () < max; y++)
        {
            for (int x = 0; x < image.width () && (int) rgbMap.size () < max; x++)
            {
                rgbMap.insert (image.pixel (x, y), true);
            }
        }
    }

    return rgbMap.size ();
}

static void convertToPixmapWarnAboutLoss (const TQImage &image,
                                          const kpPixmapFX::WarnAboutLossInfo &wali)
{
    if (!wali.isValid ())
        return;


    const TQString colorDepthTranslucencyDontAskAgain =
        wali.m_dontAskAgainPrefix + "_ColorDepthTranslucency";
    const TQString colorDepthDontAskAgain =
        wali.m_dontAskAgainPrefix + "_ColorDepth";
    const TQString translucencyDontAskAgain =
        wali.m_dontAskAgainPrefix + "_Translucency";

#if DEBUG_KP_PIXMAP_FX && 1
    TQTime timer;
    timer.start ();
#endif

    bool hasAlphaChannel =
        (KMessageBox::shouldBeShownContinue (translucencyDontAskAgain) &&
         imageHasAlphaChannel (image));

#if DEBUG_KP_PIXMAP_FX && 1
    kdDebug () << "\twarnAboutLoss - check hasAlphaChannel took "
               << timer.restart () << "msec" << endl;
#endif

    bool moreColorsThanDisplay =
        (KMessageBox::shouldBeShownContinue (colorDepthDontAskAgain) &&
         image.depth () > TQColor::numBitPlanes () &&
         TQColor::numBitPlanes () < 24);  // 32 indicates alpha channel

    int screenDepthNeeded = 0;

    if (moreColorsThanDisplay)
        screenDepthNeeded = TQMIN (24, image.depth ());

#if DEBUG_KP_PIXMAP_FX && 1
    kdDebug () << "\ttranslucencyShouldBeShown="
                << KMessageBox::shouldBeShownContinue (translucencyDontAskAgain)
                << endl
                << "\thasAlphaChannel=" << hasAlphaChannel
                << endl
                << "\tcolorDepthShownBeShown="
                << KMessageBox::shouldBeShownContinue (colorDepthDontAskAgain)
                << endl
                << "\timage.depth()=" << image.depth ()
                << endl
                << "\tscreenDepth=" << TQColor::numBitPlanes ()
                << endl
                << "\tmoreColorsThanDisplay=" << moreColorsThanDisplay
                << endl
                << "\tneedDepth=" << screenDepthNeeded
                << endl;
#endif


    TQApplication::setOverrideCursor (TQt::arrowCursor);

    if (moreColorsThanDisplay && hasAlphaChannel)
    {
        KMessageBox::information (wali.m_parent,
            wali.m_moreColorsThanDisplayAndHasAlphaChannelMessage
                .arg (screenDepthNeeded),
            TQString(),  // or would you prefer "Low Screen Depth and Image Contains Transparency"? :)
            colorDepthTranslucencyDontAskAgain);

        if (!KMessageBox::shouldBeShownContinue (colorDepthTranslucencyDontAskAgain))
        {
            KMessageBox::saveDontShowAgainContinue (colorDepthDontAskAgain);
            KMessageBox::saveDontShowAgainContinue (translucencyDontAskAgain);
        }
    }
    else if (moreColorsThanDisplay)
    {
        KMessageBox::information (wali.m_parent,
            wali.m_moreColorsThanDisplayMessage
                .arg (screenDepthNeeded),
            i18n ("Low Screen Depth"),
            colorDepthDontAskAgain);
    }
    else if (hasAlphaChannel)
    {
        KMessageBox::information (wali.m_parent,
            wali.m_hasAlphaChannelMessage,
            i18n ("Image Contains Translucency"),
            translucencyDontAskAgain);
    }

    TQApplication::restoreOverrideCursor ();
}

// public static
TQPixmap kpPixmapFX::convertToPixmap (const TQImage &image, bool pretty,
                                     const WarnAboutLossInfo &wali)
{
#if DEBUG_KP_PIXMAP_FX && 1
    kdDebug () << "kpPixmapFX::convertToPixmap(image,pretty=" << pretty
               << ",warnAboutLossInfo.isValid=" << wali.isValid ()
               << ")" << endl;
    TQTime timer;
    timer.start ();
#endif

    if (image.isNull ())
        return TQPixmap ();


    TQPixmap destPixmap;

    if (!pretty)
    {
        destPixmap.convertFromImage (image,
                                     TQt::ColorOnly/*always display depth*/ |
                                     TQt::ThresholdDither/*no dither*/ |
                                     TQt::ThresholdAlphaDither/*no dither alpha*/|
                                     TQt::AvoidDither);
    }
    else
    {
        destPixmap.convertFromImage (image,
                                     TQt::ColorOnly/*always display depth*/ |
                                     TQt::DiffuseDither/*hi quality dither*/ |
                                     TQt::ThresholdAlphaDither/*no dither alpha*/ |
                                     TQt::PreferDither/*(dither even if <256 colours)*/);
    }

#if DEBUG_KP_PIXMAP_FX && 1
    kdDebug () << "\tconversion took " << timer.elapsed () << "msec" << endl;
#endif

    kpPixmapFX::ensureNoAlphaChannel (&destPixmap);


    if (wali.isValid ())
        convertToPixmapWarnAboutLoss (image, wali);


    return destPixmap;
}

// TODO: don't dup convertToPixmap() code
// public static
TQPixmap kpPixmapFX::convertToPixmapAsLosslessAsPossible (const TQImage &image,
    const WarnAboutLossInfo &wali)
{
#if DEBUG_KP_PIXMAP_FX && 1
    kdDebug () << "kpPixmapFX::convertToPixmapAsLosslessAsPossible(image depth="
               << image.depth ()
               << ",warnAboutLossInfo.isValid=" << wali.isValid ()
               << ") screenDepth=" << TQPixmap::defaultDepth ()
               << " imageNumColorsUpTo257=" << imageNumColorsUpTo (image, 257)
               << endl;
    TQTime timer;
    timer.start ();
#endif

    if (image.isNull ())
        return TQPixmap ();


    const int screenDepth = (TQPixmap::defaultDepth () >= 24 ?
                                 32 :
                                 TQPixmap::defaultDepth ());

    TQPixmap destPixmap;
    int ditherFlags = 0;

    if (image.depth () <= screenDepth)
    {
    #if DEBUG_KP_PIXMAP_FX && 1
        kdDebug () << "\timage depth <= screen depth - don't dither"
                   << " (AvoidDither | ThresholdDither)" << endl;
    #endif

        ditherFlags = (TQt::AvoidDither | TQt::ThresholdDither);
    }
    // PRE: image.depth() > screenDepth
    // ASSERT: screenDepth < 32
    else if (screenDepth <= 8)
    {
        const int screenNumColors = (1 << screenDepth);

    #if DEBUG_KP_PIXMAP_FX && 1
        kdDebug () << "\tscreen depth <= 8; imageNumColorsUpTo"
                   << (screenNumColors + 1)
                   << "=" << imageNumColorsUpTo (image, screenNumColors + 1)
                   << endl;
    #endif

        if (imageNumColorsUpTo (image, screenNumColors + 1) <= screenNumColors)
        {
        #if DEBUG_KP_PIXMAP_FX && 1
            kdDebug () << "\t\tcolors fit on screen - don't dither"
                       << " (AvoidDither | ThresholdDither)" << endl;
        #endif
            ditherFlags = (TQt::AvoidDither | TQt::ThresholdDither);
        }
        else
        {
        #if DEBUG_KP_PIXMAP_FX && 1
            kdDebug () << "\t\tcolors don't fit on screen - dither"
                       << " (PreferDither | DiffuseDither)" << endl;
        #endif
            ditherFlags = (TQt::PreferDither | TQt::DiffuseDither);
        }
    }
    // PRE: image.depth() > screenDepth &&
    //      screenDepth > 8
    // ASSERT: screenDepth < 32
    else
    {
    #if DEBUG_KP_PIXMAP_FX && 1
        kdDebug () << "\tscreen depth > 8 - read config" << endl;
    #endif

        int configDitherIfNumColorsGreaterThan = 323;

        TDEConfigGroupSaver cfgGroupSaver (TDEGlobal::config (),
                                         kpSettingsGroupGeneral);
        TDEConfigBase *cfg = cfgGroupSaver.config ();

        if (cfg->hasKey (kpSettingDitherOnOpen))
        {
            configDitherIfNumColorsGreaterThan = cfg->readNumEntry (kpSettingDitherOnOpen);
        }
        else
        {
            cfg->writeEntry (kpSettingDitherOnOpen, configDitherIfNumColorsGreaterThan);
            cfg->sync ();
        }

    #if DEBUG_KP_PIXMAP_FX && 1
        kdDebug () << "\t\tcfg=" << configDitherIfNumColorsGreaterThan
                   << " image=" << imageNumColorsUpTo (image, configDitherIfNumColorsGreaterThan + 1)
                   << endl;
    #endif

        if (imageNumColorsUpTo (image, configDitherIfNumColorsGreaterThan + 1) >
            configDitherIfNumColorsGreaterThan)
        {
        #if DEBUG_KP_PIXMAP_FX && 1
            kdDebug () << "\t\t\talways dither (PreferDither | DiffuseDither)"
                        << endl;
        #endif
            ditherFlags = (TQt::PreferDither | TQt::DiffuseDither);
        }
        else
        {
        #if DEBUG_KP_PIXMAP_FX && 1
            kdDebug () << "\t\t\tdon't dither (AvoidDither | ThresholdDither)"
                       << endl;
        #endif
            ditherFlags = (TQt::AvoidDither | TQt::ThresholdDither);
        }
    }


    destPixmap.convertFromImage (image,
                                 TQt::ColorOnly/*always display depth*/ |
                                 TQt::ThresholdAlphaDither/*no dither alpha*/ |
                                 ditherFlags);

#if DEBUG_KP_PIXMAP_FX && 1
    kdDebug () << "\tconversion took " << timer.elapsed () << "msec" << endl;
#endif

    kpPixmapFX::ensureNoAlphaChannel (&destPixmap);


    if (wali.isValid ())
        convertToPixmapWarnAboutLoss (image, wali);


    return destPixmap;
}


// public static
TQPixmap kpPixmapFX::pixmapWithDefinedTransparentPixels (const TQPixmap &pixmap,
                                                        const TQColor &transparentColor)
{
    if (!pixmap.mask ())
        return pixmap;

    TQPixmap retPixmap (pixmap.width (), pixmap.height ());
    retPixmap.fill (transparentColor);

    TQPainter p (&retPixmap);
    p.drawPixmap (TQPoint (0, 0), pixmap);
    p.end ();

    retPixmap.setMask (*pixmap.mask ());
    return retPixmap;
}


//
// Get/Set Parts of Pixmap
//


// public static
TQPixmap kpPixmapFX::getPixmapAt (const TQPixmap &pm, const TQRect &rect)
{
    TQPixmap retPixmap (rect.width (), rect.height ());

#if DEBUG_KP_PIXMAP_FX && 0
    kdDebug () << "kpPixmapFX::getPixmapAt(pm.hasMask="
               << (pm.mask () ? 1 : 0)
               << ",rect="
               << rect
               << ")"
               << endl;
#endif

    const TQRect validSrcRect = pm.rect ().intersect (rect);
    const bool wouldHaveUndefinedPixels = (validSrcRect != rect);

    if (wouldHaveUndefinedPixels)
    {
    #if DEBUG_KP_PIXMAP_FX && 0
        kdDebug () << "\tret would contain undefined pixels - setting them to transparent" << endl;
    #endif
        TQBitmap transparentMask (rect.width (), rect.height ());
        transparentMask.fill (TQt::color0/*transparent*/);
        retPixmap.setMask (transparentMask);
    }

    if (validSrcRect.isEmpty ())
    {
    #if DEBUG_KP_PIXMAP_FX && 0
        kdDebug () << "\tsilly case - completely invalid rect - ret transparent pixmap" << endl;
    #endif
        return retPixmap;
    }


    const TQPoint destTopLeft = validSrcRect.topLeft () - rect.topLeft ();

    // copy data _and_ mask (if avail)
    copyBlt (&retPixmap, /* dest */
             destTopLeft.x (), destTopLeft.y (), /* dest pt */
             &pm, /* src */
             validSrcRect.x (), validSrcRect.y (), /* src pt */
             validSrcRect.width (), validSrcRect.height ());

    if (wouldHaveUndefinedPixels && retPixmap.mask () && !pm.mask ())
    {
    #if DEBUG_KP_PIXMAP_FX && 0
        kdDebug () << "\tensure opaque in valid region" << endl;
    #endif
        kpPixmapFX::ensureOpaqueAt (&retPixmap,
                                    TQRect (destTopLeft.x (), destTopLeft.y (),
                                           validSrcRect.width (), validSrcRect.height ()));
    }

#if DEBUG_KP_PIXMAP_FX && 0
    kdDebug () << "\tretPixmap.hasMask="
               << (retPixmap.mask () ? 1 : 0)
               << endl;
#endif

    return retPixmap;
}


// public static
void kpPixmapFX::setPixmapAt (TQPixmap *destPixmapPtr, const TQRect &destRect,
                              const TQPixmap &srcPixmap)
{
    if (!destPixmapPtr)
        return;

#if DEBUG_KP_PIXMAP_FX && 0
    kdDebug () << "kpPixmapFX::setPixmapAt(destPixmap->rect="
               << destPixmapPtr->rect ()
               << ",destPixmap->hasMask="
               << (destPixmapPtr->mask () ? 1 : 0)
               << ",destRect="
               << destRect
               << ",srcPixmap.rect="
               << srcPixmap.rect ()
               << ",srcPixmap.hasMask="
               << (srcPixmap.mask () ? 1 : 0)
               << ")"
               << endl;
#endif

#if DEBUG_KP_PIXMAP_FX && 0
    if (destPixmapPtr->mask ())
    {
        TQImage image = kpPixmapFX::convertToImage (*destPixmapPtr);
        int numTrans = 0;

        for (int y = 0; y < image.height (); y++)
        {
            for (int x = 0; x < image.width (); x++)
            {
                if (tqAlpha (image.pixel (x, y)) == 0)
                    numTrans++;
            }
        }

        kdDebug () << "\tdestPixmapPtr numTrans=" << numTrans << endl;
    }
#endif

#if 0
    // TODO: why does undo'ing a single pen dot on a transparent pixel,
    //       result in a opaque image, except for that single transparent pixel???
    //       TQt bug on boundary case?

    // copy data _and_ mask
    copyBlt (destPixmapPtr,
             destAt.x (), destAt.y (),
             &srcPixmap,
             0, 0,
             destRect.width (), destRect.height ());
#else
    bitBlt (TQT_TQPAINTDEVICE(destPixmapPtr),
            destRect.x (), destRect.y (),
            TQT_TQPAINTDEVICE(const_cast<TQPixmap*>(&srcPixmap)),
            0, 0,
            destRect.width (), destRect.height (),
            TQt::CopyROP,
            true/*ignore mask*/);

    if (srcPixmap.mask ())
    {
        TQBitmap mask = getNonNullMask (*destPixmapPtr);
        bitBlt (TQT_TQPAINTDEVICE(&mask),
                destRect.x (), destRect.y (),
                TQT_TQPAINTDEVICE(const_cast<TQBitmap*>(srcPixmap.mask ())),
                0, 0,
                destRect.width (), destRect.height (),
                TQt::CopyROP,
                true/*ignore mask*/);
        destPixmapPtr->setMask (mask);
    }
#endif

    if (destPixmapPtr->mask () && !srcPixmap.mask ())
    {
    #if DEBUG_KP_PIXMAP_FX && 0
        kdDebug () << "\t\topaque'ing dest rect" << endl;
    #endif
        kpPixmapFX::ensureOpaqueAt (destPixmapPtr, destRect);
    }

#if DEBUG_KP_PIXMAP_FX && 0
    kdDebug () << "\tdestPixmap->hasMask="
               << (destPixmapPtr->mask () ? 1 : 0)
               << endl;
    if (destPixmapPtr->mask ())
    {
        TQImage image = kpPixmapFX::convertToImage (*destPixmapPtr);
        int numTrans = 0;

        for (int y = 0; y < image.height (); y++)
        {
            for (int x = 0; x < image.width (); x++)
            {
                if (tqAlpha (image.pixel (x, y)) == 0)
                    numTrans++;
            }
        }

        kdDebug () << "\tdestPixmapPtr numTrans=" << numTrans << endl;
    }
#endif
}

// public static
void kpPixmapFX::setPixmapAt (TQPixmap *destPixmapPtr, const TQPoint &destAt,
                              const TQPixmap &srcPixmap)
{
    kpPixmapFX::setPixmapAt (destPixmapPtr,
                             TQRect (destAt.x (), destAt.y (),
                                    srcPixmap.width (), srcPixmap.height ()),
                             srcPixmap);
}

// public static
void kpPixmapFX::setPixmapAt (TQPixmap *destPixmapPtr, int destX, int destY,
                              const TQPixmap &srcPixmap)
{
    kpPixmapFX::setPixmapAt (destPixmapPtr, TQPoint (destX, destY), srcPixmap);
}


// public static
void kpPixmapFX::paintPixmapAt (TQPixmap *destPixmapPtr, const TQPoint &destAt,
                                const TQPixmap &srcPixmap)
{
    if (!destPixmapPtr)
        return;

    // Copy src (masked by src's mask) on top of dest.
    bitBlt (destPixmapPtr, /* dest */
            destAt.x (), destAt.y (), /* dest pt */
            &srcPixmap, /* src */
            0, 0 /* src pt */);

    kpPixmapFX::ensureOpaqueAt (destPixmapPtr, destAt, srcPixmap);
}

// public static
void kpPixmapFX::paintPixmapAt (TQPixmap *destPixmapPtr, int destX, int destY,
                                const TQPixmap &srcPixmap)
{
    kpPixmapFX::paintPixmapAt (destPixmapPtr, TQPoint (destX, destY), srcPixmap);
}


// public static
kpColor kpPixmapFX::getColorAtPixel (const TQPixmap &pm, const TQPoint &at)
{
#if DEBUG_KP_PIXMAP_FX && 0
    kdDebug () << "kpToolColorPicker::colorAtPixel" << p << endl;
#endif

    if (at.x () < 0 || at.x () >= pm.width () ||
        at.y () < 0 || at.y () >= pm.height ())
    {
        return kpColor::invalid;
    }

    TQPixmap pixmap = getPixmapAt (pm, TQRect (at, at));
    TQImage image = kpPixmapFX::convertToImage (pixmap);
    if (image.isNull ())
    {
        kdError () << "kpPixmapFX::getColorAtPixel(TQPixmap) could not convert to TQImage" << endl;
        return kpColor::invalid;
    }

    return getColorAtPixel (image, TQPoint (0, 0));
}

// public static
kpColor kpPixmapFX::getColorAtPixel (const TQPixmap &pm, int x, int y)
{
    return kpPixmapFX::getColorAtPixel (pm, TQPoint (x, y));
}

// public static
kpColor kpPixmapFX::getColorAtPixel (const TQImage &img, const TQPoint &at)
{
    if (!img.valid (at.x (), at.y ()))
        return kpColor::invalid;

    TQRgb rgba = img.pixel (at.x (), at.y ());
    return kpColor (rgba);
}

// public static
kpColor kpPixmapFX::getColorAtPixel (const TQImage &img, int x, int y)
{
    return kpPixmapFX::getColorAtPixel (img, TQPoint (x, y));
}


//
// Mask Operations
//


// public static
void kpPixmapFX::ensureNoAlphaChannel (TQPixmap *destPixmapPtr)
{
    if (destPixmapPtr->hasAlphaChannel ())
        destPixmapPtr->setMask (kpPixmapFX::getNonNullMask/*just in case*/ (*destPixmapPtr));
}


// public static
TQBitmap kpPixmapFX::getNonNullMask (const TQPixmap &pm)
{
    if (pm.mask ())
        return *pm.mask ();
    else
    {
        TQBitmap maskBitmap (pm.width (), pm.height ());
        maskBitmap.fill (TQt::color1/*opaque*/);

        return maskBitmap;
    }
}


// public static
void kpPixmapFX::ensureTransparentAt (TQPixmap *destPixmapPtr, const TQRect &destRect)
{
    if (!destPixmapPtr)
        return;

    TQBitmap maskBitmap = getNonNullMask (*destPixmapPtr);

    TQPainter p (&maskBitmap);

    p.setPen (TQt::color0/*transparent*/);
    p.setBrush (TQt::color0/*transparent*/);

    p.drawRect (destRect);

    p.end ();

    destPixmapPtr->setMask (maskBitmap);
}


// public static
void kpPixmapFX::paintMaskTransparentWithBrush (TQPixmap *destPixmapPtr, const TQPoint &destAt,
                                                const TQPixmap &brushBitmap)
{
    if (!destPixmapPtr)
        return;

    if (brushBitmap.depth () > 1)
    {
        kdError () << "kpPixmapFX::paintMaskTransparentWidthBrush() passed brushPixmap with depth > 1" << endl;
        return;
    }

    TQBitmap destMaskBitmap = kpPixmapFX::getNonNullMask (*destPixmapPtr);

    //                  Src
    //  Dest Mask   Brush Bitmap   =   Result
    //  -------------------------------------
    //      0            0               0
    //      0            1               0
    //      1            0               1
    //      1            1               0
    //
    // Brush Bitmap value of 1 means "make transparent"
    //                       0 means "leave it as it is"

    bitBlt (&destMaskBitmap,
            destAt.x (), destAt.y (),
            &brushBitmap,
            0, 0,
            brushBitmap.width (), brushBitmap.height (),
            TQt::NotAndROP);

    destPixmapPtr->setMask (destMaskBitmap);
}

// public static
void kpPixmapFX::paintMaskTransparentWithBrush (TQPixmap *destPixmapPtr, int destX, int destY,
                                                const TQPixmap &brushBitmap)
{
    kpPixmapFX::paintMaskTransparentWithBrush (destPixmapPtr,
                                               TQPoint (destX, destY),
                                               brushBitmap);
}


// public static
void kpPixmapFX::ensureOpaqueAt (TQPixmap *destPixmapPtr, const TQRect &destRect)
{
    if (!destPixmapPtr || !destPixmapPtr->mask ()/*already opaque*/)
        return;

    TQBitmap maskBitmap = *destPixmapPtr->mask ();

    TQPainter p (&maskBitmap);

    p.setPen (TQt::color1/*opaque*/);
    p.setBrush (TQt::color1/*opaque*/);

    p.drawRect (destRect);

    p.end ();

    destPixmapPtr->setMask (maskBitmap);
}

// public static
void kpPixmapFX::ensureOpaqueAt (TQPixmap *destPixmapPtr, const TQPoint &destAt,
                                 const TQPixmap &srcPixmap)
{
    if (!destPixmapPtr || !destPixmapPtr->mask ()/*already opaque*/)
        return;

    TQBitmap destMask = *destPixmapPtr->mask ();

    if (srcPixmap.mask ())
    {
        bitBlt (&destMask, /* dest */
                destAt, /* dest pt */
                srcPixmap.mask (), /* src */
                TQRect (0, 0, srcPixmap.width (), srcPixmap.height ()), /* src rect */
                TQt::OrROP/*if either is opaque, it's opaque*/);
    }
    else
    {
        TQPainter p (&destMask);

        p.setPen (TQt::color1/*opaque*/);
        p.setBrush (TQt::color1/*opaque*/);

        p.drawRect (destAt.x (), destAt.y (),
                    srcPixmap.width (), srcPixmap.height ());

        p.end ();
    }

    destPixmapPtr->setMask (destMask);
}

// public static
void kpPixmapFX::ensureOpaqueAt (TQPixmap *destPixmapPtr, int destX, int destY,
                                 const TQPixmap &srcPixmap)
{
    kpPixmapFX::ensureOpaqueAt (destPixmapPtr, TQPoint (destX, destY), srcPixmap);
}


//
// Effects
//

// public static
void kpPixmapFX::convertToGrayscale (TQPixmap *destPixmapPtr)
{
    TQImage image = kpPixmapFX::convertToImage (*destPixmapPtr);
    kpPixmapFX::convertToGrayscale (&image);
    *destPixmapPtr = kpPixmapFX::convertToPixmap (image);
}

// public static
TQPixmap kpPixmapFX::convertToGrayscale (const TQPixmap &pm)
{
    TQImage image = kpPixmapFX::convertToImage (pm);
    kpPixmapFX::convertToGrayscale (&image);
    return kpPixmapFX::convertToPixmap (image);
}

static TQRgb toGray (TQRgb rgb)
{
    // naive way that doesn't preserve brightness
    // int gray = (tqRed (rgb) + tqGreen (rgb) + tqBlue (rgb)) / 3;

    // over-exaggerates red & blue
    // int gray = tqGray (rgb);

    int gray = (212671 * tqRed (rgb) + 715160 * tqGreen (rgb) + 72169 * tqBlue (rgb)) / 1000000;
    return tqRgba (gray, gray, gray, tqAlpha (rgb));
}

// public static
void kpPixmapFX::convertToGrayscale (TQImage *destImagePtr)
{
    if (destImagePtr->depth () > 8)
    {
        // hmm, why not just write to the pixmap directly???

        for (int y = 0; y < destImagePtr->height (); y++)
        {
            for (int x = 0; x < destImagePtr->width (); x++)
            {
                destImagePtr->setPixel (x, y, toGray (destImagePtr->pixel (x, y)));
            }
        }
    }
    else
    {
        // 1- & 8- bit images use a color table
        for (int i = 0; i < destImagePtr->numColors (); i++)
            destImagePtr->setColor (i, toGray (destImagePtr->color (i)));
    }
}

// public static
TQImage kpPixmapFX::convertToGrayscale (const TQImage &img)
{
    TQImage retImage = img;
    kpPixmapFX::convertToGrayscale (&retImage);
    return retImage;
}


// public static
void kpPixmapFX::fill (TQPixmap *destPixmapPtr, const kpColor &color)
{
    if (!destPixmapPtr)
        return;

    if (color.isOpaque ())
    {
        destPixmapPtr->setMask (TQBitmap ());  // no mask = opaque
        destPixmapPtr->fill (color.toTQColor ());
    }
    else
    {
        kpPixmapFX::ensureTransparentAt (destPixmapPtr, destPixmapPtr->rect ());
    }
}

// public static
TQPixmap kpPixmapFX::fill (const TQPixmap &pm, const kpColor &color)
{
    TQPixmap ret = pm;
    kpPixmapFX::fill (&ret, color);
    return ret;
}


// public static
void kpPixmapFX::resize (TQPixmap *destPixmapPtr, int w, int h,
                         const kpColor &backgroundColor, bool fillNewAreas)
{
#if DEBUG_KP_PIXMAP_FX && 1
    kdDebug () << "kpPixmapFX::resize()" << endl;
#endif

    if (!destPixmapPtr)
        return;

    int oldWidth = destPixmapPtr->width ();
    int oldHeight = destPixmapPtr->height ();

    if (w == oldWidth && h == oldHeight)
        return;


    destPixmapPtr->resize (w, h);

    if (fillNewAreas && (w > oldWidth || h > oldHeight))
    {
    #if DEBUG_KP_PIXMAP_FX && 1
        kdDebug () << "\tfilling in new areas" << endl;
    #endif
        TQBitmap maskBitmap;
        TQPainter painter, maskPainter;

        if (backgroundColor.isOpaque ())
        {
            painter.begin (destPixmapPtr);
            painter.setPen (backgroundColor.toTQColor ());
            painter.setBrush (backgroundColor.toTQColor ());
        }

        if (backgroundColor.isTransparent () || destPixmapPtr->mask ())
        {
            maskBitmap = kpPixmapFX::getNonNullMask (*destPixmapPtr);
            maskPainter.begin (&maskBitmap);
            maskPainter.setPen (backgroundColor.maskColor ());
            maskPainter.setBrush (backgroundColor.maskColor ());
        }

    #define PAINTER_CALL(cmd)         \
    {                                 \
        if (painter.isActive ())      \
            painter . cmd ;           \
                                      \
        if (maskPainter.isActive ())  \
            maskPainter . cmd ;       \
    }
        if (w > oldWidth)
            PAINTER_CALL (drawRect (oldWidth, 0, w - oldWidth, oldHeight));

        if (h > oldHeight)
            PAINTER_CALL (drawRect (0, oldHeight, w, h - oldHeight));
    #undef PAINTER_CALL

        if (maskPainter.isActive ())
            maskPainter.end ();

        if (painter.isActive ())
            painter.end ();

        if (!maskBitmap.isNull ())
            destPixmapPtr->setMask (maskBitmap);
    }
}

// public static
TQPixmap kpPixmapFX::resize (const TQPixmap &pm, int w, int h,
                            const kpColor &backgroundColor, bool fillNewAreas)
{
    TQPixmap ret = pm;
    kpPixmapFX::resize (&ret, w, h, backgroundColor, fillNewAreas);
    return ret;
}


// public static
void kpPixmapFX::scale (TQPixmap *destPixmapPtr, int w, int h, bool pretty)
{
    if (!destPixmapPtr)
        return;

    *destPixmapPtr = kpPixmapFX::scale (*destPixmapPtr, w, h, pretty);
}

// public static
TQPixmap kpPixmapFX::scale (const TQPixmap &pm, int w, int h, bool pretty)
{
#if DEBUG_KP_PIXMAP_FX && 0
    kdDebug () << "kpPixmapFX::scale(oldRect=" << pm.rect ()
               << ",w=" << w
               << ",h=" << h
               << ",pretty=" << pretty
               << ")"
               << endl;
#endif

    if (w == pm.width () && h == pm.height ())
        return pm;

    if (pretty)
    {
        TQImage image = kpPixmapFX::convertToImage (pm);

    #if DEBUG_KP_PIXMAP_FX && 0
        kdDebug () << "\tBefore smooth scale:" << endl;
        for (int y = 0; y < image.height (); y++)
        {
            for (int x = 0; x < image.width (); x++)
            {
                fprintf (stderr, " %08X", image.pixel (x, y));
            }
            fprintf (stderr, "\n");
        }
    #endif

        image = image.smoothScale (w, h);

    #if DEBUG_KP_PIXMAP_FX && 0
        kdDebug () << "\tAfter smooth scale:" << endl;
        for (int y = 0; y < image.height (); y++)
        {
            for (int x = 0; x < image.width (); x++)
            {
                fprintf (stderr, " %08X", image.pixel (x, y));
            }
            fprintf (stderr, "\n");
        }
    #endif

        return kpPixmapFX::convertToPixmap (image, false/*let's not smooth it again*/);
    }
    else
    {
        TQWMatrix matrix;

        matrix.scale (double (w) / double (pm.width ()),
                      double (h) / double (pm.height ()));

        return pm.xForm (matrix);
    }
}


// public static
double kpPixmapFX::AngleInDegreesEpsilon =
    KP_RADIANS_TO_DEGREES (atan (1.0 / 10000.0))
        / (2.0/*max error allowed*/ * 2.0/*for good measure*/);


static TQWMatrix matrixWithZeroOrigin (const TQWMatrix &matrix, int width, int height)
{
#if DEBUG_KP_PIXMAP_FX
    kdDebug () << "matrixWithZeroOrigin(w=" << width << ",h=" << height << ")" << endl;
    kdDebug () << "\tmatrix: m11=" << matrix.m11 ()
               << " m12=" << matrix.m12 ()
               << " m21=" << matrix.m21 ()
               << " m22=" << matrix.m22 ()
               << " dx=" << matrix.dx ()
               << " dy=" << matrix.dy ()
               << endl;
#endif
    // TODO: Should we be using TQWMatrix::Areas?
    TQRect newRect = matrix.mapRect (TQRect (0, 0, width, height));
#if DEBUG_KP_PIXMAP_FX
    kdDebug () << "\tnewRect=" << newRect << endl;
#endif

    TQWMatrix translatedMatrix (matrix.m11 (), matrix.m12 (), matrix.m21 (), matrix.m22 (),
                               matrix.dx () - newRect.left (), matrix.dy () - newRect.top ());

    return translatedMatrix;
}

static TQPixmap xForm (const TQPixmap &pm, const TQWMatrix &transformMatrix_,
                      const kpColor &backgroundColor,
                      int targetWidth, int targetHeight)
{
    TQWMatrix transformMatrix = transformMatrix_;

#if DEBUG_KP_PIXMAP_FX && 1
    kdDebug () << "kppixmapfx.cpp: xForm(pm.size=" << pm.size ()
               << ",targetWidth=" << targetWidth
               << ",targetHeight=" << targetHeight
               << ")"
               << endl;
#endif
    // TODO: Should we be using TQWMatrix::Areas?
    TQRect newRect = transformMatrix.map (pm.rect ());
#if DEBUG_KP_PIXMAP_FX && 1
    kdDebug () << "\tmappedRect=" << newRect << endl;

#endif

    TQWMatrix scaleMatrix;
    if (targetWidth > 0 && targetWidth != newRect.width ())
    {
    #if DEBUG_KP_PIXMAP_FX && 1
        kdDebug () << "\tadjusting for targetWidth" << endl;
    #endif
        scaleMatrix.scale (double (targetWidth) / double (newRect.width ()), 1);
    }

    if (targetHeight > 0 && targetHeight != newRect.height ())
    {
    #if DEBUG_KP_PIXMAP_FX && 1
        kdDebug () << "\tadjusting for targetHeight" << endl;
    #endif
        scaleMatrix.scale (1, double (targetHeight) / double (newRect.height ()));
    }

    if (!scaleMatrix.isIdentity ())
    {
    #if DEBUG_KP_PIXMAP_FX && 1
        // TODO: What is going on here???  Why isn't matrix * working properly?
        TQWMatrix wrongMatrix = transformMatrix * scaleMatrix;
        TQWMatrix oldHat = transformMatrix;
        if (targetWidth > 0 && targetWidth != newRect.width ())
            oldHat.scale (double (targetWidth) / double (newRect.width ()), 1);
        if (targetHeight > 0 && targetHeight != newRect.height ())
            oldHat.scale (1, double (targetHeight) / double (newRect.height ()));
        TQWMatrix altHat = transformMatrix;
        altHat.scale ((targetWidth > 0 && targetWidth != newRect.width ()) ? double (targetWidth) / double (newRect.width ()) : 1,
                      (targetHeight > 0 && targetHeight != newRect.height ()) ? double (targetHeight) / double (newRect.height ()) : 1);
        TQWMatrix correctMatrix = scaleMatrix * transformMatrix;

        kdDebug () << "\tsupposedlyWrongMatrix: m11=" << wrongMatrix.m11 ()  // <<<---- this is the correct matrix???
                   << " m12=" << wrongMatrix.m12 ()
                   << " m21=" << wrongMatrix.m21 ()
                   << " m22=" << wrongMatrix.m22 ()
                   << " dx=" << wrongMatrix.dx ()
                   << " dy=" << wrongMatrix.dy ()
                   << " rect=" << wrongMatrix.map (pm.rect ())
                   << endl
                   << "\ti_used_to_use_thisMatrix: m11=" << oldHat.m11 ()
                   << " m12=" << oldHat.m12 ()
                   << " m21=" << oldHat.m21 ()
                   << " m22=" << oldHat.m22 ()
                   << " dx=" << oldHat.dx ()
                   << " dy=" << oldHat.dy ()
                   << " rect=" << oldHat.map (pm.rect ())
                   << endl
                   << "\tabove but scaled at the same time: m11=" << altHat.m11 ()
                   << " m12=" << altHat.m12 ()
                   << " m21=" << altHat.m21 ()
                   << " m22=" << altHat.m22 ()
                   << " dx=" << altHat.dx ()
                   << " dy=" << altHat.dy ()
                   << " rect=" << altHat.map (pm.rect ())
                   << endl
                   << "\tsupposedlyCorrectMatrix: m11=" << correctMatrix.m11 ()
                   << " m12=" << correctMatrix.m12 ()
                   << " m21=" << correctMatrix.m21 ()
                   << " m22=" << correctMatrix.m22 ()
                   << " dx=" << correctMatrix.dx ()
                   << " dy=" << correctMatrix.dy ()
                   << " rect=" << correctMatrix.map (pm.rect ())
                   << endl;
    #endif

        transformMatrix = transformMatrix * scaleMatrix;

        // TODO: Should we be using TQWMatrix::Areas?
        newRect = transformMatrix.map (pm.rect ());
    #if DEBUG_KP_PIXMAP_FX && 1
        kdDebug () << "\tnewRect after targetWidth,targetHeight adjust=" << newRect << endl;
    #endif
    }


    TQPixmap newPixmap (targetWidth > 0 ? targetWidth : newRect.width (),
                       targetHeight > 0 ? targetHeight : newRect.height ());
    if ((targetWidth > 0 && targetWidth != newRect.width ()) ||
        (targetHeight > 0 && targetHeight != newRect.height ()))
    {
    #if DEBUG_KP_PIXMAP_FX && 1
        kdDebug () << "kppixmapfx.cpp: xForm(pm.size=" << pm.size ()
                   << ",targetWidth=" << targetWidth
                   << ",targetHeight=" << targetHeight
                   << ") newRect=" << newRect
                   << " (you are a victim of rounding error)"
                   << endl;
    #endif
    }

    TQBitmap newBitmapMask;

    if (backgroundColor.isOpaque ())
        newPixmap.fill (backgroundColor.toTQColor ());

    if (backgroundColor.isTransparent () || pm.mask ())
    {
        newBitmapMask.resize (newPixmap.width (), newPixmap.height ());
        newBitmapMask.fill (backgroundColor.maskColor ());
    }

    TQPainter painter (&newPixmap);
#if DEBUG_KP_PIXMAP_FX && 1
    kdDebug () << "\tmatrix: m11=" << transformMatrix.m11 ()
            << " m12=" << transformMatrix.m12 ()
            << " m21=" << transformMatrix.m21 ()
            << " m22=" << transformMatrix.m22 ()
            << " dx=" << transformMatrix.dx ()
            << " dy=" << transformMatrix.dy ()
            << endl;
    const TQWMatrix trueMatrix = TQPixmap::trueMatrix (transformMatrix,
        pm.width (), pm.height ());
    kdDebug () << "\ttrue matrix: m11=" << trueMatrix.m11 ()
            << " m12=" << trueMatrix.m12 ()
            << " m21=" << trueMatrix.m21 ()
            << " m22=" << trueMatrix.m22 ()
            << " dx=" << trueMatrix.dx ()
            << " dy=" << trueMatrix.dy ()
            << endl;
#endif
    painter.setWorldMatrix (transformMatrix);
#if DEBUG_KP_PIXMAP_FX && 0
    kdDebug () << "\ttranslate top=" << painter.xForm (TQPoint (0, 0)) << endl;
    kdDebug () << "\tmatrix: m11=" << painter.worldMatrix ().m11 ()
               << " m12=" << painter.worldMatrix ().m12 ()
               << " m21=" << painter.worldMatrix ().m21 ()
               << " m22=" << painter.worldMatrix ().m22 ()
               << " dx=" << painter.worldMatrix ().dx ()
               << " dy=" << painter.worldMatrix ().dy ()
               << endl;
#endif
    painter.drawPixmap (TQPoint (0, 0), pm);
    painter.end ();

    if (!newBitmapMask.isNull ())
    {
        TQPainter maskPainter (&newBitmapMask);
        maskPainter.setWorldMatrix (transformMatrix);
        maskPainter.drawPixmap (TQPoint (0, 0), kpPixmapFX::getNonNullMask (pm));
        maskPainter.end ();
        newPixmap.setMask (newBitmapMask);
    }

    return newPixmap;
}

// public static
TQWMatrix kpPixmapFX::skewMatrix (int width, int height, double hangle, double vangle)
{
    if (fabs (hangle - 0) < kpPixmapFX::AngleInDegreesEpsilon &&
        fabs (vangle - 0) < kpPixmapFX::AngleInDegreesEpsilon)
    {
        return TQWMatrix ();
    }


    /* Diagram for completeness :)
     *
     *       |---------- w ----------|
     *     (0,0)
     *  _     _______________________ (w,0)
     *  |    |\~_ va                 |
     *  |    | \ ~_                  |
     *  |    |ha\  ~__               |
     *       |   \    ~__            | dy
     *  h    |    \      ~___        |
     *       |     \         ~___    |
     *  |    |      \            ~___| (w,w*tan(va)=dy)
     *  |    |       \         *     \
     *  _    |________\________|_____|\                                     vertical shear factor
     *     (0,h) dx   ^~_      |       \                                             |
     *                |  ~_    \________\________ General Point (x,y)                V
     *                |    ~__           \        Skewed Point (x + y*tan(ha),y + x*tan(va))
     *      (h*tan(ha)=dx,h)  ~__         \                             ^
     *                           ~___      \                            |
     *                               ~___   \                   horizontal shear factor
     *   Key:                            ~___\
     *    ha = hangle                         (w + h*tan(ha)=w+dx,h + w*tan(va)=w+dy)
     *    va = vangle
     *
     * Skewing really just twists a rectangle into a parallelogram.
     *
     */

    //TQWMatrix matrix (1, tan (KP_DEGREES_TO_RADIANS (vangle)), tan (KP_DEGREES_TO_RADIANS (hangle)), 1, 0, 0);
    // I think this is clearer than above :)
    TQWMatrix matrix;
    matrix.shear (tan (KP_DEGREES_TO_RADIANS (hangle)),
                  tan (KP_DEGREES_TO_RADIANS (vangle)));

    return matrixWithZeroOrigin (matrix, width, height);
}

// public static
TQWMatrix kpPixmapFX::skewMatrix (const TQPixmap &pixmap, double hangle, double vangle)
{
    return kpPixmapFX::skewMatrix (pixmap.width (), pixmap.height (), hangle, vangle);
}


// public static
void kpPixmapFX::skew (TQPixmap *destPixmapPtr, double hangle, double vangle,
                       const kpColor &backgroundColor,
                       int targetWidth, int targetHeight)
{
    if (!destPixmapPtr)
        return;

    *destPixmapPtr = kpPixmapFX::skew (*destPixmapPtr, hangle, vangle,
                                       backgroundColor,
                                       targetWidth, targetHeight);
}

// public static
TQPixmap kpPixmapFX::skew (const TQPixmap &pm, double hangle, double vangle,
                          const kpColor &backgroundColor,
                          int targetWidth, int targetHeight)
{
#if DEBUG_KP_PIXMAP_FX
    kdDebug () << "kpPixmapFX::skew() pm.width=" << pm.width ()
               << " pm.height=" << pm.height ()
               << " hangle=" << hangle
               << " vangle=" << vangle
               << " targetWidth=" << targetWidth
               << " targetHeight=" << targetHeight
               << endl;
#endif

    if (fabs (hangle - 0) < kpPixmapFX::AngleInDegreesEpsilon &&
        fabs (vangle - 0) < kpPixmapFX::AngleInDegreesEpsilon &&
        (targetWidth <= 0 && targetHeight <= 0)/*don't want to scale?*/)
    {
        return pm;
    }

    if (fabs (hangle) > 90 - kpPixmapFX::AngleInDegreesEpsilon ||
        fabs (vangle) > 90 - kpPixmapFX::AngleInDegreesEpsilon)
    {
        kdError () << "kpPixmapFX::skew() passed hangle and/or vangle out of range (-90 < x < 90)" << endl;
        return pm;
    }


    TQWMatrix matrix = skewMatrix (pm, hangle, vangle);

    return ::xForm (pm, matrix, backgroundColor, targetWidth, targetHeight);
}


// public static
TQWMatrix kpPixmapFX::rotateMatrix (int width, int height, double angle)
{
    if (fabs (angle - 0) < kpPixmapFX::AngleInDegreesEpsilon)
    {
        return TQWMatrix ();
    }

    TQWMatrix matrix;
    matrix.translate (width / 2, height / 2);
    matrix.rotate (angle);

    return matrixWithZeroOrigin (matrix, width, height);
}

// public static
TQWMatrix kpPixmapFX::rotateMatrix (const TQPixmap &pixmap, double angle)
{
    return kpPixmapFX::rotateMatrix (pixmap.width (), pixmap.height (), angle);
}


// public static
bool kpPixmapFX::isLosslessRotation (double angle)
{
    const double angleIn = angle;

    // Reflect angle into positive if negative
    if (angle < 0)
        angle = -angle;

    // Remove multiples of 90 to make sure 0 <= angle <= 90
    angle -= ((int) angle) / 90 * 90;

    // "Impossible" situation?
    if (angle < 0 || angle > 90)
    {
        kdError () << "kpPixmapFX::isLosslessRotation(" << angleIn
                   << ") result=" << angle
                   << endl;
        return false;  // better safe than sorry
    }

    const bool ret = (angle < kpPixmapFX::AngleInDegreesEpsilon ||
                      90 - angle < kpPixmapFX::AngleInDegreesEpsilon);
#if DEBUG_KP_PIXMAP_FX
    kdDebug () << "kpPixmapFX::isLosslessRotation(" << angleIn << ")"
               << "  residual angle=" << angle
               << "  returning " << ret
               << endl;
#endif
    return ret;
}


// public static
void kpPixmapFX::rotate (TQPixmap *destPixmapPtr, double angle,
                         const kpColor &backgroundColor,
                         int targetWidth, int targetHeight)
{
    if (!destPixmapPtr)
        return;

    *destPixmapPtr = kpPixmapFX::rotate (*destPixmapPtr, angle,
                                         backgroundColor,
                                         targetWidth, targetHeight);
}

// public static
TQPixmap kpPixmapFX::rotate (const TQPixmap &pm, double angle,
                            const kpColor &backgroundColor,
                            int targetWidth, int targetHeight)
{
    if (fabs (angle - 0) < kpPixmapFX::AngleInDegreesEpsilon &&
        (targetWidth <= 0 && targetHeight <= 0)/*don't want to scale?*/)
    {
        return pm;
    }


    TQWMatrix matrix = rotateMatrix (pm, angle);

    return ::xForm (pm, matrix, backgroundColor, targetWidth, targetHeight);
}


// public static
TQWMatrix kpPixmapFX::flipMatrix (int width, int height, bool horz, bool vert)
{
    if (width <= 0 || height <= 0)
    {
        kdError () << "kpPixmapFX::flipMatrix() passed invalid dimensions" << endl;
        return TQWMatrix ();
    }

    return TQWMatrix (horz ? -1 : +1,  // m11
                     0,  // m12
                     0,  // m21
                     vert ? -1 : +1,  // m22
                     horz ? (width - 1) : 0,  // dx
                     vert ? (height - 1) : 0);  // dy
}

// public static
TQWMatrix kpPixmapFX::flipMatrix (const TQPixmap &pixmap, bool horz, bool vert)
{
    return kpPixmapFX::flipMatrix (pixmap.width (), pixmap.height (),
                                   horz, vert);
}


// public static
void kpPixmapFX::flip (TQPixmap *destPixmapPtr, bool horz, bool vert)
{
    if (!horz && !vert)
        return;

    *destPixmapPtr = kpPixmapFX::flip (*destPixmapPtr, horz, vert);
}

// public static
TQPixmap kpPixmapFX::flip (const TQPixmap &pm, bool horz, bool vert)
{
    if (!horz && !vert)
        return pm;

    return pm.xForm (flipMatrix (pm, horz, vert));
}

// public static
void kpPixmapFX::flip (TQImage *destImagePtr, bool horz, bool vert)
{
    if (!horz && !vert)
        return;

    *destImagePtr = kpPixmapFX::flip (*destImagePtr, horz, vert);
}

// public static
TQImage kpPixmapFX::flip (const TQImage &img, bool horz, bool vert)
{
    if (!horz && !vert)
        return img;

    return img.mirror (horz, vert);
}