qjp2handler.cpp

Go to the documentation of this file.

// Copyright (C) 2016 The Qt Company Ltd.
// Copyright (C) 2016 Petroules Corporation.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
#include "qjp2handler_p.h"
 
#include "qimage.h"
#include "qvariant.h"
#include "qcolor.h"
#include "qimagereader.h"
 
#include <jasper/jasper.h>
#include <math.h> // for pow
 
QT_BEGIN_NAMESPACE
 
class QJp2HandlerPrivate
{
    Q_DECLARE_PUBLIC(QJp2Handler)
    Q_DISABLE_COPY(QJp2HandlerPrivate)
public:
    int writeQuality;
    QByteArray subType;
    QJp2Handler *q_ptr;
    QJp2HandlerPrivate(QJp2Handler *q_ptr);
};
 
enum SubFormat { Jp2Format, J2kFormat };
 
/*
    \class Jpeg2000JasperReader
    \brief Jpeg2000JasperReader implements reading and writing of JPEG 2000
    image files.
 
    \internal
 
    This class is designed to be used together with the an QImageIO IOHandler,
    and it should probably not be necessary to instantiate it directly.
 
    Internally it used the Jasper library for coding the image data.
*/
class Jpeg2000JasperReader
{
public:
    Jpeg2000JasperReader(QIODevice *iod, const SubFormat format = Jp2Format);
 
    ~Jpeg2000JasperReader();
 
    bool read(QImage *pImage);
    bool write(const QImage &image, int quality);
private:
    typedef void (Jpeg2000JasperReader::*ScanlineFunc)(jas_seqent_t** const, uchar*);
    typedef void (Jpeg2000JasperReader::*ScanlineFuncWrite)(jas_matrix_t**, uchar*);
 
    void copyJasperQt(ScanlineFunc scanlinecopier);
    void copyJasperQtGeneric();
    void copyScanlineJasperQtRGB(jas_seqent_t ** const jasperRow, uchar *qtScanLine);
    void copyScanlineJasperQtRGBA(jas_seqent_t ** const jasperRow, uchar *qtScanLine);
    void copyScanlineJasperQtGray(jas_seqent_t ** const jasperRow, uchar *qtScanLine);
    void copyScanlineJasperQtGrayA(jas_seqent_t ** const jasperRow, uchar *qtScanLine);
 
    void copyQtJasper(const ScanlineFuncWrite scanlinecopier);
    void copyScanlineQtJasperRGB(jas_matrix_t ** jasperRow, uchar *qtScanLine);
    void copyScanlineQtJasperRGBA(jas_matrix_t ** jasperRow, uchar *qtScanLine);
    void copyScanlineQtJasperColormapRGB(jas_matrix_t ** jasperRow, uchar *qtScanLine);
    void copyScanlineQtJasperColormapRGBA(jas_matrix_t ** jasperRow, uchar *qtScanLine);
    void copyScanlineQtJasperColormapGrayscale(jas_matrix_t ** jasperRow, uchar *qtScanLine);
    void copyScanlineQtJasperColormapGrayscaleA(jas_matrix_t ** jasperRow, uchar *qtScanLine);
 
    bool attemptColorspaceChange(int wantedColorSpace);
    bool createJasperMatrix(jas_matrix_t **&matrix);
    bool freeJasperMatrix(jas_matrix_t **matrix);
    void printColorSpaceError();
    jas_image_cmptparm_t createComponentMetadata(const int width, const int height);
    jas_image_t *newRGBAImage(const int width, const int height, bool alpha);
    jas_image_t *newGrayscaleImage(const int width, const int height, bool alpha);
    bool decodeColorSpace(int clrspc, QString &family, QString &specific);
    void printMetadata(jas_image_t *image);
 
    bool jasperOk;
 
    QIODevice *ioDevice;
    QImage qtImage;
    SubFormat format;
 
    // Qt image properties
    int qtWidth;
    int qtHeight;
    int qtDepth;
    int qtNumComponents;
 
    jas_image_t *jasper_image;
    // jasper image properties
    int jasNumComponents;
    int jasComponentPrecicion[4];
    int computedComponentWidth ;
    int computedComponentHeight;
    int computedComponentHorizontalSubsampling;
    int computedComponentVerticalSubsampling;
    int jasperColorspaceFamily;
    // maps color to component (ex: colorComponentMapping[RED]
    // gives the component that contains the red color)
    int colorComponentMapping[4];
    bool hasAlpha;
};
 
QJp2HandlerPrivate::QJp2HandlerPrivate(QJp2Handler *q_ptr)
    : writeQuality(100), subType("jp2"), q_ptr(q_ptr)
{
}
 
QJp2Handler::QJp2Handler()
    : d_ptr(new QJp2HandlerPrivate(this))
{
}
 
QJp2Handler::~QJp2Handler()
{
 
}
 
bool QJp2Handler::canRead(QIODevice *iod, QByteArray *subType)
{
    bool bCanRead = false;
    if (iod) {
        const QByteArray header = iod->peek(12);
        if (header.startsWith(QByteArrayLiteral("\000\000\000\fjP  \r\n\207\n"))) {
            // Jp2 is the JPEG 2000 file format
            bCanRead = true;
            if (subType)
                *subType = QByteArray("jp2");
        } else if (header.startsWith(QByteArrayLiteral("\377\117\377\121\000"))) {
            // J2c is the JPEG 2000 code stream
            bCanRead = true;
            if (subType)
                *subType = QByteArray("j2k");
        }
    }
    return bCanRead;
}
 
bool QJp2Handler::canRead() const
{
    QByteArray subType;
    if (canRead(device(), &subType)) {
        setFormat(subType);
        return true;
    }
    return false;
}
 
bool QJp2Handler::read(QImage *image)
{
    Jpeg2000JasperReader reader(device());
    return reader.read(image);
}
 
bool QJp2Handler::write(const QImage &image)
{
    Q_D(const QJp2Handler);
    SubFormat subFormat;
    if (d->subType == QByteArray("jp2"))
        subFormat = Jp2Format;
    else
        subFormat = J2kFormat;
 
    Jpeg2000JasperReader writer(device(), subFormat);
    return writer.write(image, d->writeQuality);
}
 
QVariant QJp2Handler::option(ImageOption option) const
{
    Q_D(const QJp2Handler);
    if (option == Quality) {
        return QVariant(d->writeQuality);
    } else if (option == SubType) {
        return QVariant(d->subType);
    }
    return QVariant();
}
 
void QJp2Handler::setOption(ImageOption option, const QVariant &value)
{
    Q_D(QJp2Handler);
    if (option == Quality) {
        bool ok;
        const int quality = value.toInt(&ok);
        if (ok)
            d->writeQuality = quality;
    } else if (option == SubType) {
        const QByteArray subTypeCandidate = value.toByteArray();
        // Test for default Jpeg2000 file format (jp2), or stream format (j2k).
        if (subTypeCandidate == QByteArrayLiteral("jp2") ||
            subTypeCandidate == QByteArrayLiteral("j2k"))
            d->subType = subTypeCandidate;
    }
}
 
bool QJp2Handler::supportsOption(ImageOption option) const
{
    return (option == Quality || option == SubType);
}
 
class ScopedJasperImage
{
public:
    // Take reference to the pointer here, because the pointer
    // may change when we change color spaces.
    ScopedJasperImage(jas_image_t *&image):image(image) { }
    ~ScopedJasperImage() { jas_image_destroy(image); }
private:
    jas_image_t *&image;
};
 
Jpeg2000JasperReader::Jpeg2000JasperReader(QIODevice *iod, SubFormat format)
    : jasperOk(true), ioDevice(iod), format(format), hasAlpha(false)
{
#if JAS_VERSION_MAJOR < 3
    if (jas_init()) {
        jasperOk = false;
        qDebug("Jasper Library initialization failed");
    }
#else
    jas_conf_clear();
#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
    jas_conf_set_max_mem_usage(QImageReader::allocationLimit() * 1024 * 1024);
#else
    // 128MB seems to be enough.
    jas_conf_set_max_mem_usage(128 * 1024 * 1024);
#endif
    if (jas_init_library()) {
        jasperOk = false;
        qDebug("Jasper library initialization failed");
    }
    if (jas_init_thread()) {
        jas_cleanup_library();
        jasperOk = false;
        qDebug("Jasper thread initialization failed");
    }
#endif
}
 
Jpeg2000JasperReader::~Jpeg2000JasperReader()
{
#if JAS_VERSION_MAJOR < 3
    if (jasperOk)
        jas_cleanup();
#else
    if (jasperOk) {
        if (jas_cleanup_thread()) {
            qDebug("Jasper thread cleanup failed");
        }
        if (jas_cleanup_library()) {
            qDebug("Jasper library cleanup failed");
        }
    }
#endif
}
 
bool Jpeg2000JasperReader::read(QImage *pImage)
{
    if (!jasperOk)
        return false;
 
    /*
        Reading proceeds approximately as follows:
        1. Open stream and decode using Jasper
        2. Get image metadata
        3. Change colorspace if necessary
        4. Create a QImage of the appropriate type (32-bit for RGB,
           8-bit for grayscale)
        5. Copy image data from Jasper to the QImage
 
        When copying the image data from the Jasper data structures to the
        QImage, a generic copy function (copyJasperQt) iterates through the
        scanlines and calls the provided (via the scanlineCopier argument)
        scanline copy function for each scanline. The scanline copy function
        selected according to image metadata such as color space and the
        presence of an alpha channel.
    */
    QByteArray fileContents = ioDevice->readAll();
    jas_stream_t *imageData = jas_stream_memopen(fileContents.data(),
                                                 fileContents.size());
    jasper_image = jas_image_decode(imageData, jas_image_getfmt(imageData), 0);
    jas_stream_close(imageData);
    if (!jasper_image) {
        qDebug("Jasper library can't decode Jpeg2000 image data");
        return false;
    }
    ScopedJasperImage scopedImage(jasper_image);
    //printMetadata(jasper_image);
 
    qtWidth = jas_image_width(jasper_image);
    qtHeight = jas_image_height(jasper_image);
    jasNumComponents = jas_image_numcmpts(jasper_image);
    jasperColorspaceFamily = jas_clrspc_fam(jas_image_clrspc(jasper_image));
 
    bool needColorspaceChange = false;
    if (jasperColorspaceFamily != JAS_CLRSPC_FAM_RGB &&
        jasperColorspaceFamily != JAS_CLRSPC_FAM_GRAY)
        needColorspaceChange = true;
 
    // Get per-component data
    int c;
    for (c = 0; c < jasNumComponents; ++c) {
        jasComponentPrecicion[c] = jas_image_cmptprec(jasper_image, c);
 
        // Test for precision
        if (jasComponentPrecicion[c] > 8 || jasComponentPrecicion[c] < 8)
            needColorspaceChange = true;
 
        // Test for subsampling
        if (jas_image_cmpthstep(jasper_image, c) != 1 ||
            jas_image_cmptvstep(jasper_image, c) != 1)
            needColorspaceChange = true;
 
        // Test for signed components
        if (jas_image_cmptsgnd(jasper_image, c) != 0)
            needColorspaceChange = true;
    }
 
    /*
        If we encounter a different color space than RGB
        (such as XYZ or YCbCr) we change that to RGB.
        Also, if any component has "funny" metadata (such as precicion != 8 bits
        or subsampling != 1) we also do a colorspace
        change in order to convert it to something we can load.
    */
 
    bool decodeOk = true;
    if (needColorspaceChange)
        decodeOk = attemptColorspaceChange(JAS_CLRSPC_SRGB);
 
    if (!decodeOk) {
        printColorSpaceError();
        return false;
    }
 
    // Image metadata may have changed, get from Jasper.
    qtWidth = jas_image_width(jasper_image);
    qtHeight = jas_image_height(jasper_image);
    jasNumComponents = jas_image_numcmpts(jasper_image);
    jasperColorspaceFamily = jas_clrspc_fam(jas_image_clrspc(jasper_image));
    for (c = 0; c < jasNumComponents; ++c) {
        jasComponentPrecicion[c] = jas_image_cmptprec(jasper_image, c);
    }
 
    if (jasperColorspaceFamily != JAS_CLRSPC_FAM_RGB &&
        jasperColorspaceFamily != JAS_CLRSPC_FAM_GRAY) {
        qDebug("The Qt JPEG 2000 reader was unable to convert colorspace to RGB or grayscale");
        return false;
    }
 
    // If a component has a subsampling factor != 1, we can't trust
    // jas_image_height/width, so we need to figure it out ourselves
    bool oddComponentSubsampling = false;
    for (c = 0; c < jasNumComponents; ++c) {
        if (jas_image_cmpthstep(jasper_image, c) != 1 ||
            jas_image_cmptvstep(jasper_image, c) != 1) {
            oddComponentSubsampling = true;
        }
    }
 
    if (oddComponentSubsampling) {
        // Check if all components have the same vertical/horizontal dim and
        // subsampling
        computedComponentWidth = jas_image_cmptwidth(jasper_image, 0);
        computedComponentHeight = jas_image_cmptheight(jasper_image, 0);
        computedComponentHorizontalSubsampling = jas_image_cmpthstep(jasper_image, 0);
        computedComponentVerticalSubsampling = jas_image_cmptvstep(jasper_image, 0);
 
        for (c = 1; c < jasNumComponents; ++c) {
            if (computedComponentWidth != jas_image_cmptwidth(jasper_image, c) ||
                computedComponentWidth != jas_image_cmptwidth(jasper_image, c) ||
                computedComponentHorizontalSubsampling != jas_image_cmpthstep(jasper_image, c) ||
                computedComponentVerticalSubsampling != jas_image_cmptvstep(jasper_image, c)) {
                qDebug("The Qt JPEG 2000 reader does not support images where "
                       "component geometry differs from image geometry");
                return false;
            }
        }
        qtWidth = computedComponentWidth * computedComponentHorizontalSubsampling;
        qtHeight = computedComponentHeight * computedComponentVerticalSubsampling;
    }
 
    // Sanity check each component
    for (c = 0; c < jasNumComponents; ++c) {
        // Test for precision
        if (jasComponentPrecicion[c]>8 || jasComponentPrecicion[c]<8) {
            qDebug("The Qt JPEG 2000 reader does not support components with "
                   "precision != 8");
            decodeOk = false;
        }
#if 0
        // Test the subsampling factor (space between pixels on the image grid)
        if (oddComponentSubsampling) {
            qDebug("The Qt JPEG 2000 reader does not support components with "
                   "a subsampling factor != 1 (yet)");
            decodeOk = false;
        }
#endif
        // Test for signed components
        if (jas_image_cmptsgnd(jasper_image, c) != 0) {
            qDebug("Qt JPEG 2000 reader does not support signed components");
            decodeOk = false;
        }
 
        // Test for component/image geomoetry mismach.
        // If oddComponentSubsampling, then this is already taken care of above.
        if (!oddComponentSubsampling)
            if (jas_image_cmpttlx(jasper_image,c) != 0 ||
                jas_image_cmpttly(jasper_image,c) != 0 ||
                jas_image_cmptbrx(jasper_image,c) != jas_image_brx(jasper_image) ||
                jas_image_cmptbry(jasper_image,c) != jas_image_bry(jasper_image) ||
                jas_image_cmptwidth (jasper_image, c) != jas_image_width (jasper_image) ||
                jas_image_cmptheight(jasper_image, c) != jas_image_height(jasper_image )) {
                qDebug("The Qt JPEG 2000 reader does not support images where "
                       "component geometry differs from image geometry");
                printMetadata(jasper_image);
                decodeOk = false;
            }
    }
    if (!decodeOk)
        return false;
 
    // At this point, the colorspace should be either RGB or grayscale,
    // and each component should have eight bits of precision and
    // no unsupported geometry.
    //printMetadata(jasper_image);
 
    // Get color components
    jasperColorspaceFamily = jas_clrspc_fam(jas_image_clrspc(jasper_image));
    if (jasperColorspaceFamily == JAS_CLRSPC_FAM_RGB) {
        if (jasNumComponents > 4)
            qDebug("JPEG 2000 reader expected 3 or 4 components, got %d",
                   jasNumComponents);
 
        // Set up mapping from R,G,B -> component num.
        colorComponentMapping[0] = jas_image_getcmptbytype(jasper_image,
                                                           JAS_IMAGE_CT_RGB_R);
        colorComponentMapping[1] = jas_image_getcmptbytype(jasper_image,
                                                           JAS_IMAGE_CT_RGB_G);
        colorComponentMapping[2] = jas_image_getcmptbytype(jasper_image,
                                                           JAS_IMAGE_CT_RGB_B);
        qtNumComponents = 3;
    } else if (jasperColorspaceFamily == JAS_CLRSPC_FAM_GRAY) {
        if (jasNumComponents > 2)
            qDebug("JPEG 2000 reader expected 1 or 2 components, got %d",
                   jasNumComponents);
        colorComponentMapping[0] = jas_image_getcmptbytype(jasper_image,
                                    JAS_IMAGE_CT_COLOR(JAS_IMAGE_CT_GRAY_Y));
        qtNumComponents = 1;
    } else {
        printColorSpaceError();
        return false;
    }
 
    // Get alpha component if one exists. Due to the lack of test images,
    // loading images with alpha channels is a bit untested. It works
    // with images saved with this implementation though.
    const int posibleAlphaComponent1 = 3;
    const int posibleAlphaComponent2 = 48;
 
    if (jasNumComponents == qtNumComponents + 1) {
        colorComponentMapping[qtNumComponents] = jas_image_getcmptbytype(jasper_image, posibleAlphaComponent1);
        if (colorComponentMapping[qtNumComponents] < 0) {
            colorComponentMapping[qtNumComponents] = jas_image_getcmptbytype(jasper_image, posibleAlphaComponent2);
        }
        if (colorComponentMapping[qtNumComponents] > 0) {
            hasAlpha = true;
            qtNumComponents++;
        }
    }
 
    // Check for missing components
    for (c = 0; c < qtNumComponents; ++c) {
        if (colorComponentMapping[c] < 0) {
            qDebug("JPEG 2000 reader missing a color component");
            return false;
        }
    }
 
    // Create a QImage of the correct type
    QImage::Format qtFormat = QImage::Format_Invalid;
    if (jasperColorspaceFamily == JAS_CLRSPC_FAM_RGB)
        qtFormat = hasAlpha ? QImage::Format_ARGB32 : QImage::Format_RGB32;
    else if (jasperColorspaceFamily == JAS_CLRSPC_FAM_GRAY)
        qtFormat = hasAlpha ? QImage::Format_ARGB32 : QImage::Format_Grayscale8;
    if (!QImageIOHandler::allocateImage(QSize(qtWidth, qtHeight), qtFormat, &qtImage))
        return false;
 
    // Copy data
    if (oddComponentSubsampling) {
        // This is a hack really, copying of data with component subsampling
        // != 1 doesn't fit in with the rest of the scanline copying framework.
        copyJasperQtGeneric();
    } else if (jasperColorspaceFamily == JAS_CLRSPC_FAM_RGB) {
        if (hasAlpha)
            copyJasperQt(&Jpeg2000JasperReader::copyScanlineJasperQtRGBA);
        else
            copyJasperQt(&Jpeg2000JasperReader::copyScanlineJasperQtRGB);
    } else if (jasperColorspaceFamily == JAS_CLRSPC_FAM_GRAY) {
        if (hasAlpha)
            copyJasperQt(&Jpeg2000JasperReader::copyScanlineJasperQtGrayA);
        else
            copyJasperQt(&Jpeg2000JasperReader::copyScanlineJasperQtGray);
    }
    if (decodeOk)
        *pImage = qtImage;
 
    return decodeOk;
}
 
void Jpeg2000JasperReader::copyJasperQtGeneric()
{
    // Create scanline data poinetrs
    jas_matrix_t **jasperMatrix;
    jas_seqent_t **jasperRow;
    createJasperMatrix(jasperMatrix);
    jasperRow = (jas_seqent_t**)malloc(jasNumComponents * sizeof(jas_seqent_t *));
    Q_CHECK_PTR(jasperRow);
 
    int imageY = 0;
    for (int componentY = 0; componentY < computedComponentHeight; ++componentY) {
        for (int c = 0; c < jasNumComponents; ++c) {
            jas_image_readcmpt(jasper_image, colorComponentMapping[c], 0,
                               componentY, computedComponentWidth, 1,
                               jasperMatrix[c]);
            jasperRow[c] = jas_matrix_getref(jasperMatrix[c], 0, 0);
        }
        for (int verticalSubsample = 0;
                verticalSubsample < computedComponentVerticalSubsampling;
                ++verticalSubsample) {
            uchar *scanLineUchar = qtImage.scanLine(imageY);
            QRgb *scanLineQRgb = reinterpret_cast<QRgb *>(scanLineUchar);
            for (int componentX = 0; componentX < computedComponentWidth;
                    ++componentX) {
                for (int horizontalSubsample = 0;
                        horizontalSubsample <
                            computedComponentHorizontalSubsampling;
                        ++horizontalSubsample) {
                    if (jasperColorspaceFamily == JAS_CLRSPC_FAM_RGB) {
                        if (hasAlpha) {
                            *scanLineQRgb++ = (jasperRow[3][componentX] << 24) |
                                              (jasperRow[0][componentX] << 16) |
                                              (jasperRow[1][componentX] << 8) |
                                              jasperRow[2][componentX];
                        } else {
                            *scanLineQRgb++ = (jasperRow[0][componentX] << 16) |
                                              (jasperRow[1][componentX] << 8) |
                                              jasperRow[2][componentX];
                        }
                    } else if (jasperColorspaceFamily == JAS_CLRSPC_FAM_GRAY) {
                        if (hasAlpha) {
                            *scanLineQRgb++ = (jasperRow[1][componentX] << 24) |
                                              (jasperRow[0][componentX] << 16) |
                                              (jasperRow[0][componentX] << 8) |
                                              jasperRow[0][componentX];
                        } else {
                            *scanLineUchar++ = jasperRow[0][componentX];
                        }
                    }
                }
            }
            ++imageY;
        }
    }
}
 
void Jpeg2000JasperReader::copyJasperQt(const ScanlineFunc scanlineCopier)
{
    // Create scanline data poinetrs
    jas_matrix_t **jasperMatrix;
    jas_seqent_t **jasperRow;
 
    createJasperMatrix(jasperMatrix);
    jasperRow = (jas_seqent_t**)malloc(jasNumComponents * sizeof(jas_seqent_t *));
    Q_CHECK_PTR(jasperRow);
 
    for (int scanline = 0; scanline < qtHeight; ++scanline) {
        for (int c = 0; c < jasNumComponents; ++c) {
            jas_image_readcmpt(jasper_image, colorComponentMapping[c], 0,
                               scanline, qtWidth, 1, jasperMatrix[c]);
            jasperRow[c] = jas_matrix_getref(jasperMatrix[c], 0, 0);
        }
        (this->*scanlineCopier)(jasperRow, qtImage.scanLine(scanline));
    }
 
    freeJasperMatrix(jasperMatrix);
    free(jasperRow);
}
 
void Jpeg2000JasperReader::copyScanlineJasperQtRGB(
                            jas_seqent_t ** const jasperRow, uchar *qtScanLine)
{
    QRgb *scanLine = reinterpret_cast<QRgb *>(qtScanLine);
    for (int c = 0; c < qtWidth; ++c) {
        *scanLine++ = (0xFF << 24) |
                      (jasperRow[0][c] << 16) |
                      (jasperRow[1][c] << 8) |
                      jasperRow[2][c];
    }
}
 
void Jpeg2000JasperReader::copyScanlineJasperQtRGBA(jas_seqent_t ** const jasperRow,  uchar *qtScanLine)
{
    QRgb *scanLine = reinterpret_cast<QRgb *>(qtScanLine);
    for (int c = 0; c < qtWidth; ++c) {
        *scanLine++ = (jasperRow[3][c] << 24) |
                      (jasperRow[0][c] << 16) |
                      (jasperRow[1][c] << 8) |
                      jasperRow[2][c];
    }
}
 
void Jpeg2000JasperReader::copyScanlineJasperQtGray(jas_seqent_t ** const jasperRow,  uchar *qtScanLine)
{
    for (int c = 0; c < qtWidth; ++c) {
        // *qtScanLine++ = (jasperRow[0][c] >> (jasComponentPrecicion[0] - 8));
        *qtScanLine++ = jasperRow[0][c];
    }
}
 
void Jpeg2000JasperReader::copyScanlineJasperQtGrayA(jas_seqent_t ** const jasperRow,  uchar *qtScanLine)
{
    QRgb *scanLine = reinterpret_cast<QRgb *>(qtScanLine);
    for (int c = 0; c < qtWidth; ++c) {
        *scanLine++ = (jasperRow[1][c] << 24) |
                      (jasperRow[0][c] << 16) |
                      (jasperRow[0][c] << 8) |
                      jasperRow[0][c];
    }
}
 
bool Jpeg2000JasperReader::write(const QImage &image, int quality)
{
    if (!jasperOk)
        return false;
 
    qtImage = image;
 
    qtHeight = qtImage.height();
    qtWidth = qtImage.width();
    qtDepth = qtImage.depth();
 
    if (qtDepth == 32) { // RGB(A)
        jasper_image = newRGBAImage(qtWidth, qtHeight, qtImage.hasAlphaChannel());
        if (!jasper_image)
            return false;
 
        if (qtImage.hasAlphaChannel())
            copyQtJasper(&Jpeg2000JasperReader::copyScanlineQtJasperRGBA);
        else
            copyQtJasper(&Jpeg2000JasperReader::copyScanlineQtJasperRGB);
    } else if (qtDepth == 8) {
        // Color mapped grayscale
        if (qtImage.allGray()) {
            jasper_image = newGrayscaleImage(qtWidth, qtHeight, qtImage.hasAlphaChannel());
            if (!jasper_image)
                return false;
 
            if (qtImage.hasAlphaChannel())
                copyQtJasper(&Jpeg2000JasperReader::copyScanlineQtJasperColormapGrayscaleA);
            else
                copyQtJasper(&Jpeg2000JasperReader::copyScanlineQtJasperColormapGrayscale);
        } else {
            // Color mapped color
            jasper_image = newRGBAImage(qtWidth, qtHeight, qtImage.hasAlphaChannel());
            if (!jasper_image)
                return false;
 
            if (qtImage.hasAlphaChannel())
                copyQtJasper(&Jpeg2000JasperReader::copyScanlineQtJasperColormapRGBA);
            else
                copyQtJasper(&Jpeg2000JasperReader::copyScanlineQtJasperColormapRGB);
        }
    } else {
        qDebug("Unable to handle color depth %d", qtDepth);
        return false;
    }
 
    int fmtid;
    if (format == Jp2Format)
        fmtid = jas_image_strtofmt(const_cast<char*>("jp2"));
    else /* if (format == J2cFormat) */
        // JasPer refers to the code stream format as jpc
        fmtid = jas_image_strtofmt(const_cast<char*>("jpc"));
 
    const int minQuality = 0;
    const int maxQuality = 100;
 
    if (quality == -1)
        quality = 100;
    if (quality <= minQuality)
        quality = minQuality;
    if (quality > maxQuality)
        quality = maxQuality;
 
    // Qt specifies quality as an integer in the range 0..100. Jasper specifies
    // compression rate as an real in the range 0..1, where 1 corresponds to no
    // compression. Computing the rate from quality is difficult, large images
    // get better image quality than small images at the same rate. If the rate
    // is too low, Jasper will generate a completely black image.
    // minirate is the smallest safe rate value.
    const double minRate = 0.001;
 
    // maxRate specifies maximum target rate, which give the minimum amount
    // of compression. Tests show that maxRates higer than 0.3 give no
    // additional image quality for most images. Large images could use an even
    // smaller maxRate value.
    const double maxRate = 0.3;
 
    // Set jasperRate to a value in the range minRate..maxRate. Distribute the
    // quality steps more densely at the lower end if the rate scale.
    const double jasperRate = minRate + pow((double(quality) / double(maxQuality)), 2) * maxRate;
 
    // The Jasper format string contains two options:
    // rate: rate=x
    // lossy/lossless compression : mode=real/mode=int
    QString jasperFormatString;
 
    // If quality is not maxQuality, we set lossy encoding.
    // (lossless is default)
    if (quality != maxQuality) {
        jasperFormatString += QLatin1String("mode=real");
        jasperFormatString += QString(QLatin1String(" rate=%1")).arg(jasperRate);
    }
 
    // Open an empty jasper stream that grows automatically
    jas_stream_t * memory_stream = jas_stream_memopen(0, 0);
 
    // Jasper wants a non-const string.
    char *str = qstrdup(jasperFormatString.toLatin1().constData());
    jas_image_encode(jasper_image, memory_stream, fmtid, str);
    delete[] str;
    jas_stream_flush(memory_stream);
 
    // jas_stream_t::obj_ is a void* which points to the stream implementation,
    // e.g a file stream or a memory stream. But in our case we know that it is
    // a memory stream since we created the object, so we just reiterpret_cast
    // here..
    char *buffer = reinterpret_cast<char *>(reinterpret_cast<jas_stream_memobj_t*>(memory_stream->obj_)->buf_);
    qint64 length = jas_stream_length(memory_stream);
    ioDevice->write(buffer, length);
 
    jas_stream_close(memory_stream);
    jas_image_destroy(jasper_image);
 
    return true;
}
 
void Jpeg2000JasperReader::copyQtJasper(const ScanlineFuncWrite scanlinecopier)
{
    // Create jasper matrix for holding one scanline
    jas_matrix_t **jasperMatrix;
    createJasperMatrix(jasperMatrix);
 
    for (int scanline = 0; scanline < qtHeight; ++scanline) {
        (this->*scanlinecopier)(jasperMatrix, qtImage.scanLine(scanline));
 
        // Write a scanline of data to jasper_image
        for (int c = 0; c < jasNumComponents; ++c)
            jas_image_writecmpt(jasper_image, c, 0, scanline, qtWidth, 1,
                                jasperMatrix[c]);
    }
    freeJasperMatrix(jasperMatrix);
}
 
void Jpeg2000JasperReader::copyScanlineQtJasperRGB(jas_matrix_t ** jasperRow,
                                                   uchar *qtScanLine)
{
    QRgb *scanLineBuffer = reinterpret_cast<QRgb *>(qtScanLine);
    for (int col = 0; col < qtWidth; ++col) {
        jas_matrix_set(jasperRow[0], 0, col, (*scanLineBuffer & 0xFF0000) >> 16);
        jas_matrix_set(jasperRow[1], 0, col, (*scanLineBuffer & 0x00FF00) >> 8);
        jas_matrix_set(jasperRow[2], 0, col, *scanLineBuffer & 0x0000FF);
        ++scanLineBuffer;
    }
}
 
void Jpeg2000JasperReader::copyScanlineQtJasperRGBA(jas_matrix_t ** jasperRow,
                                                    uchar *qtScanLine)
{
    QRgb *scanLineBuffer = reinterpret_cast<QRgb *>(qtScanLine);
    for (int col = 0; col < qtWidth; ++col) {
        jas_matrix_set(jasperRow[3], 0, col, (*scanLineBuffer & 0xFF000000) >> 24);
        jas_matrix_set(jasperRow[0], 0, col, (*scanLineBuffer & 0x00FF0000) >> 16);
        jas_matrix_set(jasperRow[1], 0, col, (*scanLineBuffer & 0x0000FF00) >> 8);
        jas_matrix_set(jasperRow[2], 0, col, *scanLineBuffer & 0x000000FF);
        ++scanLineBuffer;
    }
}
 
void Jpeg2000JasperReader::copyScanlineQtJasperColormapRGB(jas_matrix_t ** jasperRow,
                                                           uchar *qtScanLine)
{
    for (int col = 0; col < qtWidth; ++col) {
        QRgb color = qtImage.color(*qtScanLine);
        jas_matrix_set(jasperRow[0], 0, col, qRed(color));
        jas_matrix_set(jasperRow[1], 0, col, qGreen(color));
        jas_matrix_set(jasperRow[2], 0, col, qBlue(color));
        ++qtScanLine;
    }
}
 
void Jpeg2000JasperReader::copyScanlineQtJasperColormapRGBA(jas_matrix_t ** jasperRow,
                                                            uchar *qtScanLine)
{
    for (int col = 0; col < qtWidth; ++col) {
        QRgb color = qtImage.color(*qtScanLine);
        jas_matrix_set(jasperRow[0], 0, col, qRed(color));
        jas_matrix_set(jasperRow[1], 0, col, qGreen(color));
        jas_matrix_set(jasperRow[2], 0, col, qBlue(color));
        jas_matrix_set(jasperRow[3], 0, col, qAlpha(color));
        ++qtScanLine;
    }
}
 
void Jpeg2000JasperReader::copyScanlineQtJasperColormapGrayscale(jas_matrix_t ** jasperRow,
                                                                 uchar *qtScanLine)
{
    for (int col = 0; col < qtWidth; ++col) {
        QRgb color = qtImage.color(*qtScanLine);
        jas_matrix_set(jasperRow[0], 0, col, qGray(color));
        ++qtScanLine;
    }
}
 
void Jpeg2000JasperReader::copyScanlineQtJasperColormapGrayscaleA(jas_matrix_t ** jasperRow,
                                                                  uchar *qtScanLine)
{
    for (int col = 0; col < qtWidth; ++col) {
        QRgb color = qtImage.color(*qtScanLine);
        jas_matrix_set(jasperRow[0], 0, col, qGray(color));
        jas_matrix_set(jasperRow[1], 0, col, qAlpha(color));
        ++qtScanLine;
    }
}
 
bool Jpeg2000JasperReader::attemptColorspaceChange(int wantedColorSpace)
{
    //qDebug("Attemting color space change");
    jas_cmprof_t *outprof;
    if (!(outprof = jas_cmprof_createfromclrspc(wantedColorSpace)))
        return false;
 
    jas_image_t *newimage;
    if (!(newimage = jas_image_chclrspc(jasper_image, outprof,
                                        JAS_CMXFORM_INTENT_PER))) {
        jas_cmprof_destroy(outprof);
        return false;
    }
    jas_image_destroy(jasper_image);
    jas_cmprof_destroy(outprof);
    jasper_image = newimage;
    return true;
}
 
jas_image_cmptparm_t Jpeg2000JasperReader::createComponentMetadata(
                                            const int width, const int height)
{
    jas_image_cmptparm_t param;
    param.tlx = 0;
    param.tly = 0;
    param.hstep = 1;
    param.vstep = 1;
    param.width = width;
    param.height = height;
    param.prec = 8;
    param.sgnd = 0;
    return param;
}
 
jas_image_t* Jpeg2000JasperReader::newRGBAImage(const int width,
                                                const int height, bool alpha)
{
    jasNumComponents = alpha ? 4 : 3;
    jas_image_cmptparm_t *params = new jas_image_cmptparm_t[jasNumComponents];
    jas_image_cmptparm_t param = createComponentMetadata(width, height);
    for (int c=0; c < jasNumComponents; c++)
        params[c] = param;
    jas_image_t *newImage = jas_image_create(jasNumComponents, params,
                                             JAS_CLRSPC_SRGB);
 
    if (!newImage) {
        delete[] params;
        return 0;
    }
 
    jas_image_setcmpttype(newImage, 0, JAS_IMAGE_CT_RGB_R);
    jas_image_setcmpttype(newImage, 1, JAS_IMAGE_CT_RGB_G);
    jas_image_setcmpttype(newImage, 2, JAS_IMAGE_CT_RGB_B);
 
    /*
        It is unclear how one stores opacity(alpha) components with JasPer,
        the following seems to have no effect. The opacity component gets
        type id 3 or 48 depending jp2 or j2c format no matter what one puts
        in here.
 
        The symbols are defined as follows:
        #define JAS_IMAGE_CT_RGB_R 0
        #define JAS_IMAGE_CT_RGB_G 1
        #define JAS_IMAGE_CT_RGB_B 2
        #define JAS_IMAGE_CT_OPACITY 0x7FFF
    */
    if (alpha)
        jas_image_setcmpttype(newImage, 3, JAS_IMAGE_CT_OPACITY);
    delete[] params;
    return newImage;
}
 
jas_image_t *Jpeg2000JasperReader::newGrayscaleImage(const int width,
                                                     const int height,
                                                     bool alpha)
{
    jasNumComponents = alpha ? 2 : 1;
    jas_image_cmptparm_t param = createComponentMetadata(width, height);
    jas_image_t *newImage = jas_image_create(1, &param, JAS_CLRSPC_SGRAY);
    if (!newImage)
        return 0;
 
    jas_image_setcmpttype(newImage, 0, JAS_IMAGE_CT_GRAY_Y);
 
    // See corresponding comment for newRGBAImage.
    if (alpha)
        jas_image_setcmpttype(newImage, 1, JAS_IMAGE_CT_OPACITY);
    return newImage;
}
 
bool Jpeg2000JasperReader::createJasperMatrix(jas_matrix_t **&matrix)
{
    matrix = (jas_matrix_t**)malloc(jasNumComponents * sizeof(jas_matrix_t *));
    for (int c = 0; c < jasNumComponents; ++c)
        matrix[c] = jas_matrix_create(1, qtWidth);
    return true;
}
 
bool Jpeg2000JasperReader::freeJasperMatrix(jas_matrix_t **matrix)
{
    for (int c = 0; c < jasNumComponents; ++c)
        jas_matrix_destroy(matrix[c]);
    free(matrix);
    return false;
}
 
void Jpeg2000JasperReader::printColorSpaceError()
{
    QString colorspaceFamily, colorspaceSpecific;
    decodeColorSpace(jas_image_clrspc(jasper_image), colorspaceFamily,
                     colorspaceSpecific);
    qDebug("Jpeg2000 decoder is not able to handle color space %s - %s",
           qPrintable(colorspaceFamily), qPrintable(colorspaceSpecific));
}
bool Jpeg2000JasperReader::decodeColorSpace(int clrspc, QString &family,
                                                        QString &specific)
{
    int fam = jas_clrspc_fam(clrspc);
    int mbr = jas_clrspc_mbr(clrspc);
 
    switch (fam) {
        case 0: family = QLatin1String("JAS_CLRSPC_FAM_UNKNOWN"); break;
        case 1: family = QLatin1String("JAS_CLRSPC_FAM_XYZ"); break;
        case 2: family = QLatin1String("JAS_CLRSPC_FAM_LAB"); break;
        case 3: family = QLatin1String("JAS_CLRSPC_FAM_GRAY"); break;
        case 4: family = QLatin1String("JAS_CLRSPC_FAM_RGB"); break;
        case 5: family = QLatin1String("JAS_CLRSPC_FAM_YCBCR"); break;
        default: family = QLatin1String("Unknown"); return false;
    }
 
    switch (mbr) {
        case 0:
            switch (fam) {
                case 1: specific = QLatin1String("JAS_CLRSPC_CIEXYZ"); break;
                case 2: specific = QLatin1String("JAS_CLRSPC_CIELAB"); break;
                case 3: specific = QLatin1String("JAS_CLRSPC_SGRAY"); break;
                case 4: specific = QLatin1String("JAS_CLRSPC_SRGB"); break;
                case 5: specific = QLatin1String("JAS_CLRSPC_SYCBCR"); break;
                default: specific = QLatin1String("Unknown"); return false;
            }
            break;
        case 1:
            switch (fam) {
                case 3: specific = QLatin1String("JAS_CLRSPC_GENGRAY"); break;
                case 4: specific = QLatin1String("JAS_CLRSPC_GENRGB"); break;
                case 5: specific = QLatin1String("JAS_CLRSPC_GENYCBCR"); break;
                default: specific = QLatin1String("Unknown"); return false;
            }
            break;
        default:
            return false;
    }
    return true;
}
void Jpeg2000JasperReader::printMetadata(jas_image_t *image)
{
#ifndef QT_NO_DEBUG
    // jas_image_cmptparm_t param
    qDebug("Image width: %ld", long(jas_image_width(image)));
    qDebug("Image height: %ld", long(jas_image_height(image)));
    qDebug("Coordinates on reference grid: (%ld,%ld) (%ld,%ld)",
           long(jas_image_tlx(image)), long(jas_image_tly(image)),
           long(jas_image_brx(image)), long(jas_image_bry(image)));
    qDebug("Number of image components: %d", jas_image_numcmpts(image));
 
    QString colorspaceFamily;
    QString colorspaceSpecific;
    decodeColorSpace(jas_image_clrspc(image), colorspaceFamily, colorspaceSpecific);
    qDebug("Color model (space): %d, %s - %s", jas_image_clrspc(image),
           qPrintable(colorspaceFamily), qPrintable(colorspaceSpecific));
 
    qDebug("Component metadata:");
 
    for (int c = 0; c < static_cast<int>(jas_image_numcmpts(image)); ++c) {
        qDebug("Component %d:", c);
        qDebug("    Component type: %ld", long(jas_image_cmpttype(image, c)));
        qDebug("    Width: %ld", long(jas_image_cmptwidth(image, c)));
        qDebug("    Height: %ld", long(jas_image_cmptheight(image, c)));
        qDebug("    Signedness: %d", jas_image_cmptsgnd(image, c));
        qDebug("    Precision: %d", jas_image_cmptprec(image, c));
        qDebug("    Horizontal subsampling factor: %ld",long(jas_image_cmpthstep(image, c)));
        qDebug("    Vertical subsampling factor: %ld",  long(jas_image_cmptvstep(image, c)));
        qDebug("    Coordinates on reference grid: (%ld,%ld) (%ld,%ld)",
               long(jas_image_cmpttlx(image, c)), long(jas_image_cmpttly(image, c)),
               long(jas_image_cmptbrx(image, c)), long(jas_image_cmptbry(image, c)));
    }
#else
    Q_UNUSED(image);
#endif
}
 
QT_END_NAMESPACE