qpnghandler.cpp

奇趣公司比较新的qt/emd版本

    QMap<QString, QString>::ConstIterator it = text.constBegin();
    int i = 0;
    while (it != text.constEnd()) {
        QString t = it.value();
        if (t.length() < 40)
            text_ptr[i].compression = PNG_TEXT_COMPRESSION_NONE;
        else
            text_ptr[i].compression = PNG_TEXT_COMPRESSION_zTXt;
        text_ptr[i].key = qstrdup(it.key().left(79).toLatin1().constData());

#ifndef PNG_iTXt_SUPPORTED
        QByteArray value = it.value().toLatin1();
        text_ptr[i].text = qstrdup(value.constData());
        text_ptr[i].text_length = value.size();
#else
        QByteArray value = it.value().toUtf8();
        text_ptr[i].text = qstrdup(value.constData());
        text_ptr[i].text_length = 0;
        text_ptr[i].itxt_length = value.size();
        text_ptr[i].lang = "UTF-8";
        text_ptr[i].lang_key = qstrdup(it.key().toUtf8().constData());
#endif
        ++i;
        ++it;
    }

    png_set_text(png_ptr, info_ptr, text_ptr, i);
    for (i = 0; i < text.size(); ++i) {
        delete [] text_ptr[i].key;
        delete [] text_ptr[i].text;
#ifdef PNG_iTXt_SUPPORTED
        delete [] text_ptr[i].lang_key;
#endif
    }
    delete [] text_ptr;
}
#endif

bool QPNGImageWriter::writeImage(const QImage& image, int off_x, int off_y)
{
    return writeImage(image, -1, QString(), off_x, off_y);
}

bool QPNGImageWriter::writeImage(const QImage& image_in, int quality_in, const QString &description,
                                 int off_x_in, int off_y_in)
{
#ifdef QT_NO_IMAGE_TEXT
    Q_UNUSED(description);
#endif

    QImage image = image_in;
    if(image.format() == QImage::Format_ARGB32_Premultiplied)
        image = image.convertToFormat(QImage::Format_ARGB32);
    else if (image.format() == QImage::Format_RGB16)
        image = image.convertToFormat(QImage::Format_RGB32);

    QPoint offset = image.offset();
    int off_x = off_x_in + offset.x();
    int off_y = off_y_in + offset.y();

    png_structp png_ptr;
    png_infop info_ptr;
    png_bytep* row_pointers;

    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,0,0,0);
    if (!png_ptr) {
        return false;
    }

    png_set_error_fn(png_ptr, 0, 0, qt_png_warning);

    info_ptr = png_create_info_struct(png_ptr);
    if (!info_ptr) {
        png_destroy_write_struct(&png_ptr, 0);
        return false;
    }

    if (setjmp(png_jmpbuf(png_ptr))) {
        png_destroy_write_struct(&png_ptr, &info_ptr);
        return false;
    }

    int quality = quality_in;
    if (quality >= 0) {
        if (quality > 9) {
            qWarning("PNG: Quality %d out of range", quality);
            quality = 9;
        }
        png_set_compression_level(png_ptr, quality);
    }

    if (gamma != 0.0) {
        png_set_gAMA(png_ptr, info_ptr, 1.0/gamma);
    }

    png_set_write_fn(png_ptr, (void*)this, qpiw_write_fn, qpiw_flush_fn);

    info_ptr->channels =
        (image.depth() == 32)
        ? (image.format() == QImage::Format_RGB32 ? 3 : 4)
        : 1;

    png_set_IHDR(png_ptr, info_ptr, image.width(), image.height(),
        image.depth() == 1 ? 1 : 8 /* per channel */,
        image.depth() == 32
            ? image.format() == QImage::Format_RGB32
                ? PNG_COLOR_TYPE_RGB
                : PNG_COLOR_TYPE_RGB_ALPHA
            : PNG_COLOR_TYPE_PALETTE, 0, 0, 0);


    //png_set_sBIT(png_ptr, info_ptr, 8);
    info_ptr->sig_bit.red = 8;
    info_ptr->sig_bit.green = 8;
    info_ptr->sig_bit.blue = 8;

    if (image.format() == QImage::Format_MonoLSB)
       png_set_packswap(png_ptr);

    png_colorp palette = 0;
    png_bytep copy_trans = 0;
    if (image.numColors()) {
        // Paletted
        int num_palette = image.numColors();
        palette = new png_color[num_palette];
        png_set_PLTE(png_ptr, info_ptr, palette, num_palette);
        int* trans = new int[num_palette];
        int num_trans = 0;
        for (int i=0; i<num_palette; i++) {
            QRgb rgb=image.color(i);
            info_ptr->palette[i].red = qRed(rgb);
            info_ptr->palette[i].green = qGreen(rgb);
            info_ptr->palette[i].blue = qBlue(rgb);
            trans[i] = rgb >> 24;
            if (trans[i] < 255) {
                num_trans = i+1;
            }
        }
        if (num_trans) {
            copy_trans = new png_byte[num_trans];
            for (int i=0; i<num_trans; i++)
                copy_trans[i] = trans[i];
            png_set_tRNS(png_ptr, info_ptr, copy_trans, num_trans, 0);
        }
        delete [] trans;
    }

    if (image.format() != QImage::Format_RGB32) {
        info_ptr->sig_bit.alpha = 8;
    }

    // Swap ARGB to RGBA (normal PNG format) before saving on
    // BigEndian machines
    if (QSysInfo::ByteOrder == QSysInfo::BigEndian) {
        png_set_swap_alpha(png_ptr);
    }

    // Qt==ARGB==Big(ARGB)==Little(BGRA)
    if (QSysInfo::ByteOrder == QSysInfo::LittleEndian) {
        png_set_bgr(png_ptr);
    }

    if (off_x || off_y) {
        png_set_oFFs(png_ptr, info_ptr, off_x, off_y, PNG_OFFSET_PIXEL);
    }

    if (frames_written > 0)
        png_set_sig_bytes(png_ptr, 8);

    if (image.dotsPerMeterX() > 0 || image.dotsPerMeterY() > 0) {
        png_set_pHYs(png_ptr, info_ptr,
                image.dotsPerMeterX(), image.dotsPerMeterY(),
                PNG_RESOLUTION_METER);
    }

#ifndef QT_NO_IMAGE_TEXT
    set_text(image, png_ptr, info_ptr, description);
#endif
    png_write_info(png_ptr, info_ptr);

    if (image.depth() != 1)
        png_set_packing(png_ptr);

    if (image.format() == QImage::Format_RGB32)
        png_set_filler(png_ptr, 0,
            QSysInfo::ByteOrder == QSysInfo::BigEndian ?
                PNG_FILLER_BEFORE : PNG_FILLER_AFTER);

    if (looping >= 0 && frames_written == 0) {
        uchar data[13] = "NETSCAPE2.0";
        //                0123456789aBC
        data[0xB] = looping%0x100;
        data[0xC] = looping/0x100;
        png_write_chunk(png_ptr, (png_byte*)"gIFx", data, 13);
    }
    if (ms_delay >= 0 || disposal!=Unspecified) {
        uchar data[4];
        data[0] = disposal;
        data[1] = 0;
        data[2] = (ms_delay/10)/0x100; // hundredths
        data[3] = (ms_delay/10)%0x100;
        png_write_chunk(png_ptr, (png_byte*)"gIFg", data, 4);
    }

    png_uint_32 width;
    png_uint_32 height;
    int bit_depth;
    int color_type;
    png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
        0, 0, 0);

    const uchar *data = image.bits();
    int bpl = image.bytesPerLine();
    row_pointers = new png_bytep[height];
    uint y;
    for (y=0; y<height; y++) {
        row_pointers[y] = (png_bytep)(data + y * bpl);
    }
    png_write_image(png_ptr, row_pointers);
    delete [] row_pointers;

    png_write_end(png_ptr, info_ptr);
    frames_written++;

    if (palette)
        delete [] palette;
    if (copy_trans)
        delete [] copy_trans;

    png_destroy_write_struct(&png_ptr, &info_ptr);

    return true;
}

static bool write_png_image(const QImage &image, QIODevice *device,
                            int quality, float gamma, const QString &description)
{
    QPNGImageWriter writer(device);
    if (quality >= 0) {
        quality = qMin(quality, 100);
        quality = (100-quality) * 9 / 91; // map [0,100] -> [9,0]
    }
    writer.setGamma(gamma);
    return writer.writeImage(image, quality, description);
}

QPngHandler::QPngHandler()
    : d(new QPngHandlerPrivate(this))
{
}

QPngHandler::~QPngHandler()
{
    if (d->png_ptr)
        png_destroy_read_struct(&d->png_ptr, &d->info_ptr, &d->end_info);
    delete d;
}

bool QPngHandler::canRead() const
{
    if (d->state == QPngHandlerPrivate::Ready) {
        if (!canRead(device()))
            return false;
        setFormat("png");
        return true;
    }
    return d->state != QPngHandlerPrivate::Error;
}

bool QPngHandler::canRead(QIODevice *device)
{
    if (!device) {
        qWarning("QPngHandler::canRead() called with no device");
        return false;
    }

    return device->peek(8) == "\x89\x50\x4E\x47\x0D\x0A\x1A\x0A";
}

bool QPngHandler::read(QImage *image)
{
    if (!canRead())
        return false;
    return d->readPngImage(image);
}

bool QPngHandler::write(const QImage &image)
{
    return write_png_image(image, device(), d->quality, d->gamma, d->description);
}

bool QPngHandler::supportsOption(ImageOption option) const
{
    return option == Gamma
        || option == Description
        || option == Quality
        || option == Size;
}

QVariant QPngHandler::option(ImageOption option) const
{
    if (d->state == QPngHandlerPrivate::Error)
        return QVariant();
    if (d->state == QPngHandlerPrivate::Ready && !d->readPngHeader())
        return QVariant();

    if (option == Gamma)
        return d->gamma;
    else if (option == Quality)
        return d->quality;
    else if (option == Description)
        return d->description;
    else if (option == Size)
        return QSize(d->info_ptr->width, d->info_ptr->height);
    return 0;
}

void QPngHandler::setOption(ImageOption option, const QVariant &value)
{
    if (option == Gamma)
        d->gamma = value.toDouble();
    else if (option == Quality)
        d->quality = value.toInt();
    else if (option == Description)
        d->description = value.toString();
}

QByteArray QPngHandler::name() const
{
    return "png";
}

#endif // QT_NO_IMAGEFORMAT_PNG