qimage.cpp

奇趣公司比较新的qt/emd版本

    Sets the color at the given \a index in the color table, to the
    given to \a colorValue.

    The color value is an ARGB quadruplet.

    \sa color(), setColorTable(), {QImage#Pixel Manipulation}{Pixel
    Manipulation}
*/
void QImage::setColor(int i, QRgb c)
{
    if (i < 0 || i >= numColors()) {
        qWarning("QImage::setColor: Index out of bound %d", i);
        return;
    }
    detach();
    d->colortable[i] = c;
    d->has_alpha_clut |= (qAlpha(c) != 255);
}

/*!
    Returns a pointer to the pixel data at the scanline with index \a
    i. The first scanline is at index 0.

    The scanline data is aligned on a 32-bit boundary.

    \warning If you are accessing 32-bpp image data, cast the returned
    pointer to \c{QRgb*} (QRgb has a 32-bit size) and use it to
    read/write the pixel value. You cannot use the \c{uchar*} pointer
    directly, because the pixel format depends on the byte order on
    the underlying platform. Use qRed(), qGreen(), qBlue(), and
    qAlpha() to access the pixels.

    \sa bytesPerLine(), bits(), {QImage#Pixel Manipulation}{Pixel
    Manipulation}
*/
uchar *QImage::scanLine(int i)
{
    detach();
    Q_ASSERT(i >= 0 && i < height());
    return d->data + i * d->bytes_per_line;
}

/*!
    \overload
*/
const uchar *QImage::scanLine(int i) const
{
    Q_ASSERT(i >= 0 && i < height());
    return d->data + i * d->bytes_per_line;
}


/*!
    Returns a pointer to the first pixel data. This is equivalent to
    scanLine(0).

    Note that QImage uses \l{Implicit Data Sharing} {implicit data
    sharing}. This function performs a deep copy of the shared pixel
    data, thus ensuring that this QImage is the only one using the
    current return value.

    \sa scanLine(), numBytes()
*/
uchar *QImage::bits()
{
    if (!d)
        return 0;
    detach();
    return d->data;
}

/*!
    \overload

    Note that QImage uses \l{Implicit Data Sharing} {implicit data
    sharing}, but this function does \e not perform a deep copy of the
    shared pixel data, because the returned data is const.
*/
const uchar *QImage::bits() const
{
    return d ? d->data : 0;
}



/*!
    \fn void QImage::reset()

    Resets all image parameters and deallocates the image data.

    Assign a null image instead.

    \oldcode
        QImage image;
        image.reset();
    \newcode
        QImage image;
        image = QImage();
    \endcode
*/

/*!
    \fn void QImage::fill(uint pixelValue)

    Fills the entire image with the given \a pixelValue.

    If the depth of this image is 1, only the lowest bit is used. If
    you say fill(0), fill(2), etc., the image is filled with 0s. If
    you say fill(1), fill(3), etc., the image is filled with 1s. If
    the depth is 8, the lowest 8 bits are used and if the depth is 16
    the lowest 16 bits are used.

    Note: QImage::pixel() returns the color of the pixel at the given
    coordinates while QColor::pixel() returns the pixel value of the
    underlying window system (essentially an index value), so normally
    you will want to use QImage::pixel() to use a color from an
    existing image or QColor::rgb() to use a specific color.

    \sa depth(), {QImage#Image Transformations}{Image Transformations}
*/

void QImage::fill(uint pixel)
{
    if (!d)
        return;

    detach();
    if (d->depth == 1 || d->depth == 8) {
        int w = d->width;
        if (d->depth == 1) {
            if (pixel & 1)
                pixel = 0xffffffff;
            else
                pixel = 0;
            w = (w + 7) / 8;
        } else {
            pixel &= 0xff;
        }
        qt_rectfill<quint8>(d->data, pixel, 0, 0,
                            w, d->height, d->bytes_per_line);
        return;
    } else if (d->depth == 16) {
        qt_rectfill<quint16>(reinterpret_cast<quint16*>(d->data), pixel,
                             0, 0, d->width, d->height, d->bytes_per_line);
        return;
    }

    if (d->format == Format_RGB32)
        pixel |= 0xff000000;

    qt_rectfill<uint>(reinterpret_cast<uint*>(d->data), pixel,
                      0, 0, d->width, d->height, d->bytes_per_line);
}

/*!
    Inverts all pixel values in the image.

    The given invert \a mode only have a meaning when the image's
    depth is 32. The default \a mode is InvertRgb, which leaves the
    alpha channel unchanged. If the \a mode is InvertRgba, the alpha
    bits are also inverted.

    Inverting an 8-bit image means to replace all pixels using color
    index \e i with a pixel using color index 255 minus \e i. The same
    is the case for a 1-bit image. Note that the color table is \e not
    changed.

    \sa {QImage#Image Transformations}{Image Transformations}
*/

void QImage::invertPixels(InvertMode mode)
{
    if (!d)
        return;

    detach();
    if (depth() != 32) {
        // number of used bytes pr line
        int bpl = (d->width * d->depth + 7) / 8;
        int pad = d->bytes_per_line - bpl;
        uchar *sl = d->data;
        for (int y=0; y<d->height; ++y) {
            for (int x=0; x<bpl; ++x)
                *sl++ ^= 0xff;
            sl += pad;
        }
    } else {
        quint32 *p = (quint32*)d->data;
        quint32 *end = (quint32*)(d->data + d->nbytes);
        uint xorbits = (mode == InvertRgba) ? 0xffffffff : 0x00ffffff;
        while (p < end)
            *p++ ^= xorbits;
    }
}

/*!
    \fn void QImage::invertPixels(bool invertAlpha)

    Use the invertPixels() function that takes a QImage::InvertMode
    parameter instead.
*/

/*! \fn QImage::Endian QImage::systemByteOrder()

    Determines the host computer byte order. Returns
    QImage::LittleEndian (LSB first) or QImage::BigEndian (MSB first).

    This function is no longer relevant for QImage. Use QSysInfo
    instead.
*/

// Windows defines these
#if defined(write)
# undef write
#endif
#if defined(close)
# undef close
#endif
#if defined(read)
# undef read
#endif

/*!
    Resizes the color table to contain \a numColors entries.

    If the color table is expanded, all the extra colors will be set to
    transparent (i.e qRgba(0, 0, 0, 0)).

    \sa numColors(), colorTable(), {QImage#Image
    Transformations}{Image Transformations}
*/

void QImage::setNumColors(int numColors)
{
    if (!d) {
        qWarning("QImage::setNumColors: null image");
        return;
    }

    detach();
    if (numColors == d->colortable.size())
        return;
    if (numColors <= 0) {                        // use no color table
        d->colortable = QVector<QRgb>();
        return;
    }
    int nc = d->colortable.size();
    d->colortable.resize(numColors);
    for (int i = nc; i < numColors; ++i)
        d->colortable[i] = 0;
}

/*!
    Returns the format of the image.

    \sa {QImage#Image Formats}{Image Formats}
*/
QImage::Format QImage::format() const
{
    return d ? d->format : Format_Invalid;
}


#ifdef QT3_SUPPORT
/*!
    Returns true if alpha buffer mode is enabled; otherwise returns
    false.

    Use the hasAlphaChannel() function instead.

*/
bool QImage::hasAlphaBuffer() const
{
    return d && (d->format != Format_RGB32)
        && (d->format != Format_RGB16);
}

/*!
    Enables alpha buffer mode if \a enable is true, otherwise disables
    it. The alpha buffer is used to set a mask when a QImage is
    translated to a QPixmap.

    If a monochrome or indexed 8-bit image has alpha channels in their
    color tables they will automatically detect that they have an
    alpha channel, so this function is not required.  To force alpha
    channels on 32-bit images, use the convertToFormat() function.
*/

void QImage::setAlphaBuffer(bool enable)
{
    if (!d
        || d->format == Format_Mono
        || d->format == Format_MonoLSB
        || d->format == Format_Indexed8)
        return;
    if (enable && (d->format == Format_ARGB32 || d->format == Format_ARGB32_Premultiplied))
        return;
    if (!enable && d->format == Format_RGB32)
        return;
    detach();
    d->format = (enable ? Format_ARGB32 : Format_RGB32);
}


/*!
  \fn bool QImage::create(int width, int height, int depth, int numColors, Endian bitOrder)

    Sets the image \a width, \a height, \a depth, its number of colors
    (in \a numColors), and bit order. Returns true if successful, or
    false if the parameters are incorrect or if memory cannot be
    allocated.

    The \a width and \a height is limited to 32767. \a depth must be
    1, 8, or 32. If \a depth is 1, \a bitOrder must be set to
    either QImage::LittleEndian or QImage::BigEndian. For other depths
    \a bitOrder must be QImage::IgnoreEndian.

    This function allocates a color table and a buffer for the image
    data. The image data is not initialized. The image buffer is
    allocated as a single block that consists of a table of scanLine()
    pointers (jumpTable()) and the image data (bits()).

    Use a QImage constructor instead.
*/
bool QImage::create(int width, int height, int depth, int numColors, Endian bitOrder)
{
    if (d && !d->ref.deref())
        delete d;
    d = QImageData::create(QSize(width, height), formatFor(depth, bitOrder), numColors);
    return true;
}

/*!
    \fn bool QImage::create(const QSize& size, int depth, int numColors, Endian bitOrder)
    \overload

    The width and height are specified in the \a size argument.

    Use a QImage constructor instead.
*/
bool QImage::create(const QSize& size, int depth, int numColors, QImage::Endian bitOrder)
{
    if (d && !d->ref.deref())
        delete d;
    d = QImageData::create(size, formatFor(depth, bitOrder), numColors);
    return true;
}
#endif // QT3_SUPPORT

/*****************************************************************************
  Internal routines for converting image depth.
 *****************************************************************************/

typedef void (*Image_Converter)(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags);

static void convert_ARGB_to_ARGB_PM(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(src->format == QImage::Format_ARGB32);
    Q_ASSERT(dest->format == QImage::Format_ARGB32_Premultiplied);
    Q_ASSERT(src->width == dest->width);
    Q_ASSERT(src->height == dest->height);

    const int src_pad = (src->bytes_per_line >> 2) - src->width;
    const int dest_pad = (dest->bytes_per_line >> 2) - dest->width;
    const QRgb *src_data = (QRgb *) src->data;
    QRgb *dest_data = (QRgb *) dest->data;

    for (int i = 0; i < src->height; ++i) {
        const QRgb *end = src_data + src->width;
        while (src_data < end) {
            *dest_data = PREMUL(*src_data);
            ++src_data;
            ++dest_data;
        }
        src_data += src_pad;
        dest_data += dest_pad;
    }
}

static void convert_ARGB_PM_to_ARGB(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(src->format == QImage::Format_ARGB32_Premultiplied);
    Q_ASSERT(dest->format == QImage::Format_ARGB32);
    Q_ASSERT(src->width == dest->width);
    Q_ASSERT(src->height == dest->height);

    const int src_pad = (src->bytes_per_line >> 2) - src->width;
    const int dest_pad = (dest->bytes_per_line >> 2) - dest->width;
    const QRgb *src_data = (QRgb *) src->data;
    QRgb *dest_data = (QRgb *) dest->data;

    for (int i = 0; i < src->height; ++i) {
        const QRgb *end = src_data + src->width;
        while (src_data < end) {
            *dest_data = INV_PREMUL(*src_data);
            ++src_data;
            ++dest_data;
        }
        src_data += src_pad;
        dest_data += dest_pad;
    }
}

static void convert_ARGB_PM_to_RGB(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(src->format == QImage::Format_ARGB32_Premultiplied);
    Q_ASSERT(dest->format == QImage::Format_RGB32);
    Q_ASSERT(src->width == dest->width);
    Q_ASSERT(src->height == dest->height);

    const int src_pad = (src->bytes_per_line >> 2) - src->width;
    const int dest_pad = (dest->bytes_per_line >> 2) - dest->width;
    const QRgb *src_data = (QRgb *) src->data;
    QRgb *dest_data = (QRgb *) dest->data;

    for (int i =