qpixmap.cpp

奇趣公司比较新的qt/emd版本

{
    if (data->type == BitmapType)
        *this = QBitmap::fromImage(image);
    else
        *this = fromImage(image);
    return *this;
}

/*!
    Use the load() function that takes a Qt::ImageConversionFlag instead.
*/

bool QPixmap::load(const QString &fileName, const char *format, ColorMode mode)
{
    return load(fileName, format, colorModeToFlags(mode));
}

/*!
    Use the loadFromData() function that takes a Qt::ImageConversionFlag instead.
*/

bool QPixmap::loadFromData(const uchar *buf, uint len, const char *format, ColorMode mode)
{
    return loadFromData(buf, len, format, colorModeToFlags(mode));
}

/*!
    Use the static fromImage() function instead.
*/
bool QPixmap::convertFromImage(const QImage &image, ColorMode mode)
{
    if (data->type == BitmapType)
        *this = QBitmap::fromImage(image, colorModeToFlags(mode));
    else
        *this = fromImage(image, colorModeToFlags(mode));
    return !isNull();
}

#endif

/*****************************************************************************
  QPixmap stream functions
 *****************************************************************************/
#if !defined(QT_NO_DATASTREAM)
/*!
    \relates QPixmap

    Writes the given \a pixmap to the the given \a stream as a PNG
    image. Note that writing the stream to a file will not produce a
    valid image file.

    \sa QPixmap::save(), {Format of the QDataStream Operators}
*/

QDataStream &operator<<(QDataStream &stream, const QPixmap &pixmap)
{
    return stream << pixmap.toImage();
}

/*!
    \relates QPixmap

    Reads an image from the given \a stream into the given \a pixmap.

    \sa QPixmap::load(), {Format of the QDataStream Operators}
*/

QDataStream &operator>>(QDataStream &stream, QPixmap &pixmap)
{
    QImage image;
    stream >> image;

    if (image.isNull()) {
        pixmap = QPixmap();
    } else if (image.depth() == 1) {
        pixmap = QBitmap::fromImage(image);
    } else {
        pixmap = QPixmap::fromImage(image);
    }
    return stream;
}

#endif //QT_NO_DATASTREAM

#ifdef QT3_SUPPORT
Q_GUI_EXPORT void copyBlt(QPixmap *dst, int dx, int dy,
                          const QPixmap *src, int sx, int sy, int sw, int sh)
{
    Q_ASSERT_X(dst, "::copyBlt", "Destination pixmap must be non-null");
    Q_ASSERT_X(src, "::copyBlt", "Source pixmap must be non-null");

    if (src->hasAlphaChannel()) {
        if (dst->paintEngine()->hasFeature(QPaintEngine::PorterDuff)) {
            QPainter p(dst);
            p.setCompositionMode(QPainter::CompositionMode_Source);
            p.drawPixmap(dx, dy, *src, sx, sy, sw, sh);
        } else {
            QImage image = dst->toImage().convertToFormat(QImage::Format_ARGB32_Premultiplied);
            QPainter p(&image);
            p.setCompositionMode(QPainter::CompositionMode_Source);
            p.drawPixmap(dx, dy, *src, sx, sy, sw, sh);
            p.end();
            *dst = QPixmap::fromImage(image);
        }
    } else {
        QPainter p(dst);
        p.drawPixmap(dx, dy, *src, sx, sy, sw, sh);
    }

}
#endif

/*!
    \internal
*/

bool QPixmap::isDetached() const
{
    return data->count == 1;
}

void QPixmap::deref()
{
    if(data && data->deref()) { // Destroy image if last ref
        if (qt_pixmap_cleanup_hook_64)
            qt_pixmap_cleanup_hook_64(cacheKey());
        delete data;
        data = 0;
    }
}

/*!
    \fn QImage QPixmap::convertToImage() const

    Use the toImage() function instead.
*/

/*!
    \fn bool QPixmap::convertFromImage(const QImage &image, Qt::ImageConversionFlags flags)

    Use the static fromImage() function instead.
*/

/*!
    \fn QPixmap QPixmap::xForm(const QMatrix &matrix) const

    Use transformed() instead.
*/

/*!
    \fn QPixmap QPixmap::scaled(int width, int height,
    Qt::AspectRatioMode aspectRatioMode, Qt::TransformationMode
    transformMode) const

    \overload

    Returns a copy of the pixmap scaled to a rectangle with the given
    \a width and \a height according to the given \a aspectRatioMode and
    \a transformMode.

    If either the \a width or the \a height is zero or negative, this
    function returns a null pixmap.
*/

/*!
    \fn QPixmap QPixmap::scaled(const QSize &size, Qt::AspectRatioMode
    aspectRatioMode, Qt::TransformationMode transformMode) const

    Scales the pixmap to the given \a size, using the aspect ratio and
    transformation modes specified by \a aspectRatioMode and \a
    transformMode.

    \image qimage-scaling.png

    \list
    \i If \a aspectRatioMode is Qt::IgnoreAspectRatio, the pixmap
       is scaled to \a size.
    \i If \a aspectRatioMode is Qt::KeepAspectRatio, the pixmap is
       scaled to a rectangle as large as possible inside \a size, preserving the aspect ratio.
    \i If \a aspectRatioMode is Qt::KeepAspectRatioByExpanding,
       the pixmap is scaled to a rectangle as small as possible
       outside \a size, preserving the aspect ratio.
    \endlist

    If the given \a size is empty, this function returns a null
    pixmap.

    \sa isNull(), {QPixmap#Pixmap Transformations}{Pixmap
    Transformations}

*/
QPixmap QPixmap::scaled(const QSize& s, Qt::AspectRatioMode aspectMode, Qt::TransformationMode mode) const
{
    if (isNull()) {
        qWarning("QPixmap::scaled: Pixmap is a null pixmap");
        return QPixmap();
    }
    if (s.isEmpty())
        return QPixmap();

    QSize newSize = size();
    newSize.scale(s, aspectMode);
    if (newSize == size())
        return copy();

    QPixmap pix;
    QTransform wm;
    wm.scale((double)newSize.width() / width(), (double)newSize.height() / height());
    pix = transformed(wm, mode);
    return pix;
}

/*!
    \fn QPixmap QPixmap::scaledToWidth(int width, Qt::TransformationMode
    mode) const

    Returns a scaled copy of the image. The returned image is scaled
    to the given \a width using the specified transformation \a mode.
    The height of the pixmap is automatically calculated so that the
    aspect ratio of the pixmap is preserved.

    If \a width is 0 or negative, a null pixmap is returned.

    \sa isNull(), {QPixmap#Pixmap Transformations}{Pixmap
    Transformations}
*/
QPixmap QPixmap::scaledToWidth(int w, Qt::TransformationMode mode) const
{
    if (isNull()) {
        qWarning("QPixmap::scaleWidth: Pixmap is a null pixmap");
        return copy();
    }
    if (w <= 0)
        return QPixmap();

    QTransform wm;
    double factor = (double) w / width();
    wm.scale(factor, factor);
    return transformed(wm, mode);
}

/*!
    \fn QPixmap QPixmap::scaledToHeight(int height,
    Qt::TransformationMode mode) const

    Returns a scaled copy of the image. The returned image is scaled
    to the given \a height using the specified transformation \a mode.
    The width of the pixmap is automatically calculated so that the
    aspect ratio of the pixmap is preserved.

    If \a height is 0 or negative, a null pixmap is returned.

    \sa isNull(), {QPixmap#Pixmap Transformations}{Pixmap
    Transformations}
*/
QPixmap QPixmap::scaledToHeight(int h, Qt::TransformationMode mode) const
{
    if (isNull()) {
        qWarning("QPixmap::scaleHeight: Pixmap is a null pixmap");
        return copy();
    }
    if (h <= 0)
        return QPixmap();

    QTransform wm;
    double factor = (double) h / height();
    wm.scale(factor, factor);
    return transformed(wm, mode);
}

/*!
    \class QPixmap

    \brief The QPixmap class is an off-screen image representation
    that can be used as a paint device.

    \ingroup multimedia
    \ingroup shared
    \mainclass

    Qt provides four classes for handling image data: QImage, QPixmap,
    QBitmap and QPicture. QImage is designed and optimized for I/O,
    and for direct pixel access and manipulation, while QPixmap is
    designed and optimized for showing images on screen. QBitmap is
    only a convenience class that inherits QPixmap, ensuring a depth
    of 1. The isQBitmap() function returns true if a QPixmap object is
    really a bitmap, otherwise returns false. Finally, the QPicture class is a
    paint device that records and replays QPainter commands.

    A QPixmap can easily be displayed on the screen using QLabel or
    one of QAbstractButton's subclasses (such as QPushButton and
    QToolButton). QLabel has a pixmap property, whereas
    QAbstractButton has an icon property. And because QPixmap is a
    QPaintDevice subclass, QPainter can be used to draw directly onto
    pixmaps.

    In addition to the ordinary constructors, a QPixmap can be
    constructed using the static grabWidget() and grabWindow()
    functions which creates a QPixmap and paints the given widget, or
    window, in it.

    Note that the pixel data in a pixmap is internal and is managed by
    the underlying window system. Pixels can only be accessed through
    QPainter functions or by converting the QPixmap to a QImage.
    Depending on the system, QPixmap is stored using a RGB32 or a
    premultiplied alpha format. If the image has an alpha channel, and
    if the system allows, the preferred format is premultiplied alpha.
    Note also that QPixmap, unlike QImage, may be hardware dependent.
    On X11 and Mac, a QPixmap is stored on the server side while a
    QImage is stored on the client side (on Windows, these two classes
    have an equivalent internal representation, i.e. both QImage and
    QPixmap are stored on the client side and don't use any GDI
    resources).

    There are functions to convert between QImage and
    QPixmap. Typically, the QImage class is used to load an image
    file, optionally manipulating the image data, before the QImage
    object is converted into a QPixmap to be shown on
    screen. Alternatively, if no manipulation is desired, the image
    file can be loaded directly into a QPixmap. On Windows, the
    QPixmap class also supports conversion between \c HBITMAP and
    QPixmap.

    QPixmap provides a collection of functions that can be used to
    obtain a variety of information about the pixmap. In addition,
    there are several functions that enables transformation of the
    pixmap.

    QPixmap objects can be passed around by value since the QPixmap
    class uses implicit data sharing. For more information, see the \l
    {Implicit Data Sharing} documentation. QPixmap objects can also be
    streamed.

    \tableofcontents

    \section1 Reading and Writing Image Files

    QPixmap provides several ways of reading an image file: The file
    can be loaded when constructing the QPixmap object, or by using
    the load() or loadFromData() functions later on. When loading an
    image, the file name can either refer to an actual file on disk or
    to one of the application's embedded resources. See \l{The Qt
    Resource System} overview for details on how to embed images and
    other resource files in the application's executable.

    Simply call the save() function to save a QPixmap object.

    The complete list of supported file formats are available through
    the QImageReader::supportedImageFormats() and
    QImageWriter::supportedImageFormats() functions. New file formats
    can be added as plugins. By default, Qt supports the following
    formats:

    \table
    \header \o Format \o Description                      \o Qt's support
    \row    \o BMP    \o Windows Bitmap                   \o Read/write
    \row    \o GIF    \o Graphic Interchange Format (optional) \o Read
    \row    \o JPG    \o Joint Photographic Experts Group \o Read/write
    \row    \o JPEG   \o Joint Photographic Experts Group \o Read/write
    \row    \o PNG    \o Portable Network Graphics        \o Read/write
    \row    \o PBM    \o Portable Bitmap                  \o Read
    \row    \o PGM    \o Portable Graymap                 \o Read
    \row    \o PPM    \o Portable Pixmap                  \o Read/write
    \row    \o XBM    \o X11 Bitmap                       \o Read/write
    \row    \o XPM    \o X11 Pixmap                       \o Read/write
    \endtable

    (To configure Qt with GIF support, pass \c -qt-gif to the \c
    configure script or check the appropriate option in the graphical
    installer.)

    \section1 Pixmap Information

    QPixmap provides a collection of functions that can be used to
    obtain a variety of information about the pixmap:

    \table
    \header
    \o \o Available Functions
    \row
    \o Geometry
    \o
    The size(), width() and height() functions provide information
    about the pixmap's size. The rect() function returns the image's
    enclosing rectangle.

    \row
    \o Alpha component
    \o

    The hasAlphaChannel() returns true if the pixmap has a format that
    respects the alpha channel, otherwise returns false, while the
    hasAlpha() function returns true if the pixmap has an alpha
    channel \e or a mask (otherwise false).

    The alphaChannel() function returns the alpha channel as a new
    QPixmap object, while the mask() function returns the mask as a
    QBitmap object. The alpha channel and mask can be set using the
    setAlphaChannel() and setMask() functions, respectively.

    \row
    \o Low-level information
    \o

    The depth() function returns the depth of the pixmap. The
    defaultDepth() function returns the default depth, i.e. the depth
    used by the application on the given screen.

    The cacheKey() function returns a number that uniquely
    identifies the contents of the QPixmap object.

    The x11Info() function returns information about the configuration
    of the X display used to display the widget.  The
    x11PictureHandle() function returns the X11 Picture handle of the
    pixmap for XRender support. Note that the two latter functions are
    only available on x11.

    \endtable

    \section1 Pixmap Conversion

    A QPixmap object can be converted into a QImage using the
    toImage() function. Likewise, a QImage can be converted into a
    QPixmap using the fromImage(). If this is too expensive an
    operation, you can use QBitmap::fromImage() instead.

    In addition, on Windows, the QPixmap class supports conversion to
    and from HBitmap: the toWinHBITMAP() function creates a HBITMAP
    equivalent to the QPixmap, based on the given HBitmapFormat, and
    returns the HBITMAP handle. The fromWinHBITMAP() function returns
    a QPixmap that is equivalent to the given bitmap which has the
    specified format.

    \section1 Pixmap Transformations

    QPixmap supports a number of functions for creating a new pixmap
    that is a transformed version of the original: The
    createHeuristicMask() function creates and returns a 1-bpp
    heuristic mask (i.e. a QBitmap) for this pixmap. It works by
    selecting a color from one of the corners and then chipping away
    pixels of that color, starting at all the edges. The
    createMaskFromColor() function creates and returns a mask (i.e. a
    QBitmap) for the pixmap based on a given color.


    The scaled(), scaledToWidth() and scaledToHeight() functions
    return scaled copies of the pixmap, while the copy() function
    creates a QPixmap that is a plain copy of the original one.

    The transformed() function returns a copy of the pixmap that is
    transformed with the given transformation matrix and
    transformation mode: Internally, the transformation matrix is
    adjusted to compensate for unwanted translation,
    i.e. transformed() returns the smallest pixmap containing all
    transformed points of the original pixmap. The static trueMatrix()
    function returns the actual matrix used for transforming the
    pixmap.

    There are also functions for changing attributes of a pixmap.
    in-place: The fill() function fills the entire image with the
    given color, the setMask() function sets a mask bitmap, and the
    setAlphaChannel() function sets the pixmap's alpha channel.

    \sa QBitmap, QImage, QImageReader, QImageWriter
*/


/*!
    \typedef QPixmap::DataPtr
    \internal
*/

/*!
    \fn DataPtr &QPixmap::data_ptr()
    \internal
*/