qimage.cpp

奇趣公司比较新的qt/emd版本

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#include "qimage.h"
#include "qdatastream.h"
#include "qbuffer.h"
#include "qmap.h"
#include "qmatrix.h"
#include "qtransform.h"
#include "qimagereader.h"
#include "qimagewriter.h"
#include "qstringlist.h"
#include "qvariant.h"
#include <ctype.h>
#include <stdlib.h>
#include <limits.h>
#include <math.h>
#include <private/qdrawhelper_p.h>
#include <private/qpixmap_p.h>
#include <private/qimagescale_p.h>

#include <qhash.h>

#ifdef QT_RASTER_IMAGEENGINE
#include <private/qpaintengine_raster_p.h>
#else
#include <qpaintengine.h>
#endif

#include <private/qimage_p.h>

#ifdef Q_WS_QWS
#include <qscreen_qws.h> //### for qt_conv...
#else
static inline ushort qt_convRgbTo16(QRgb c)
{
    return ((c >> 8) & 0xf800)
        | ((c >> 5) & 0x07e0)
        | ((c >> 3) & 0x1f);
}

static inline QRgb qt_conv16ToRgb(ushort c)
{
    QRgb r = (((c) << 3) & 0xf8)
             | (((c) << 5) & 0xfc00)
             | (((c) << 8) & 0xf80000);
    r |= (r >> 5) & 0x70007;
    r |= (r >> 6) & 0x300;
    return r | 0xff000000;
}
#endif

#if defined(Q_CC_DEC) && defined(__alpha) && (__DECCXX_VER-0 >= 50190001)
#pragma message disable narrowptr
#endif


#define QIMAGE_SANITYCHECK_MEMORY(image) \
    if ((image).isNull()) { \
        qWarning("QImage: out of memory, returning null image"); \
        return QImage(); \
    }


// ### Qt 5: remove
typedef void (*_qt_image_cleanup_hook)(int);
Q_GUI_EXPORT _qt_image_cleanup_hook qt_image_cleanup_hook = 0;

// ### Qt 5: rename
typedef void (*_qt_image_cleanup_hook_64)(qint64);
Q_GUI_EXPORT _qt_image_cleanup_hook_64 qt_image_cleanup_hook_64 = 0;

static QImage rotated90(const QImage &src);
static QImage rotated180(const QImage &src);
static QImage rotated270(const QImage &src);

// ### Qt 5: remove
Q_GUI_EXPORT qint64 qt_image_id(const QImage &image)
{
    return image.cacheKey();
}

const QVector<QRgb> *qt_image_colortable(const QImage &image)
{
    return (image.d->format <= QImage::Format_Indexed8 && !image.d->colortable.isEmpty()) ? &image.d->colortable : 0;
}

extern int qt_defaultDpi();
extern int qt_defaultDpiX();
extern int qt_defaultDpiY();

QBasicAtomic qimage_serial_number = Q_ATOMIC_INIT(1);

QImageData::QImageData()
{
    ser_no = qimage_serial_number.fetchAndAdd(1);
    detach_no = 0;
    ref = 0;

    width = height = depth = 0;
    nbytes = 0;
    data = 0;
    own_data = true;
    ro_data = false;
    has_alpha_clut = false;
#ifdef QT3_SUPPORT
    jumptable = 0;
#endif
    bytes_per_line = 0;
    format = QImage::Format_ARGB32;

    // ### Qt 4.4: remove #ifdef
#ifdef Q_WS_QWS
    dpmx = qt_defaultDpiX()*100./2.54;
    dpmy = qt_defaultDpiY()*100./2.54;
#else
    dpmx = qt_defaultDpi()*100./2.54;
    dpmy = qt_defaultDpi()*100./2.54;
#endif
    offset = QPoint(0,0);

    paintEngine = 0;
}

static int depthForFormat(QImage::Format format)
{
    int depth = 0;
    switch(format) {
    case QImage::Format_Invalid:
    case QImage::NImageFormats:
        Q_ASSERT(false);
    case QImage::Format_Mono:
    case QImage::Format_MonoLSB:
        depth = 1;
        break;
    case QImage::Format_Indexed8:
        depth = 8;
        break;
    case QImage::Format_RGB32:
    case QImage::Format_ARGB32:
    case QImage::Format_ARGB32_Premultiplied:
        depth = 32;
        break;
    case QImage::Format_RGB16:
        depth = 16;
        break;
    }
    return depth;
}

QImageData * QImageData::create(const QSize &size, QImage::Format format, int numColors)
{
    if (!size.isValid() || numColors < 0 || format == QImage::Format_Invalid)
        return 0;                                // invalid parameter(s)
    uint width = size.width();
    uint height = size.height();

    uint depth = 0;
    switch(format) {
    case QImage::NImageFormats:
    case QImage::Format_Invalid:
        Q_ASSERT(false);
    case QImage::Format_Mono:
    case QImage::Format_MonoLSB:
        depth = 1;
        numColors = 2;
        break;
    case QImage::Format_Indexed8:
        depth = 8;
        numColors = qMin(numColors, 256);
        numColors = qMax(0, numColors);
        break;
    case QImage::Format_RGB32:
    case QImage::Format_ARGB32:
    case QImage::Format_ARGB32_Premultiplied:
        depth = 32;
        numColors = 0;
        break;
    case QImage::Format_RGB16:
        depth = 16;
        numColors = 0;
        break;
    }

    const int bytes_per_line = ((width * depth + 31) >> 5) << 2; // bytes per scanline (must be multiple of 8)

    // sanity check for potential overflows
    if (INT_MAX/depth < width
        || bytes_per_line <= 0
        || INT_MAX/uint(bytes_per_line) < height
        || INT_MAX/sizeof(uchar *) < uint(height))
        return 0;

    QImageData *d = new QImageData;
    d->colortable.resize(numColors);
    if (depth == 1) {
        d->colortable[0] = QColor(Qt::black).rgba();
        d->colortable[1] = QColor(Qt::white).rgba();
    } else {
        for (int i = 0; i < numColors; ++i)
            d->colortable[i] = 0;
    }

    d->width = width;
    d->height = height;
    d->depth = depth;
    d->format = format;
    d->has_alpha_clut = false;

    d->bytes_per_line = bytes_per_line;

    d->nbytes = d->bytes_per_line*height;
    d->data  = (uchar *)malloc(d->nbytes);

    if (!d->data) {
        delete d;
        return 0;
    }

    d->ref.ref();
    return d;

}

QImageData::~QImageData()
{
    if (qt_image_cleanup_hook_64)
        qt_image_cleanup_hook_64((((qint64) ser_no) << 32) | ((qint64) detach_no));
    delete paintEngine;
    if (data && own_data)
        free(data);
#ifdef QT3_SUPPORT
    if (jumptable)
        free(jumptable);
    jumptable = 0;
#endif
    data = 0;
}

/*!
    \class QImage

    \ingroup multimedia
    \ingroup shared
    \mainclass

    \brief The QImage class provides a hardware-independent image
    representation that allows direct access to the pixel data, and
    can be used as a paint device.

    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. Finally, the QPicture class is a paint device that
    records and replays QPainter commands.

    Because QImage is a QPaintDevice subclass, QPainter can be used to
    draw directly onto images.  When using QPainter on a QImage, the
    painting can be performed in another thread than the current GUI
    thread, that is except rendering text (because QFont is GUI
    dependent). To render text in another thread, the text must first
    be derived as a QPainterPath in the GUI thread.

    The QImage class supports several image formats described by the
    \l Format enum. These include monochrome, 8-bit, 32-bit and
    alpha-blended images which are available in all versions of Qt
    4.x. In addition, QImage supports several formats that are
    specific to \l {Qtopia Core}.

    QImage provides a collection of functions that can be used to
    obtain a variety of information about the image. There are also
    several functions that enables transformation of the image.

    QImage objects can be passed around by value since the QImage
    class uses \l{Implicit Data Sharing}{implicit data
    sharing}. QImage objects can also be streamed and compared.

    \tableofcontents

    \section1 Reading and Writing Image Files

    QImage provides several ways of loading an image file: The file
    can be loaded when constructing the QImage object, or by using the
    load() or loadFromData() functions later on. QImage also provides
    the static fromData() function, constructing a QImage from the
    given data.  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 QImage 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 TIFF   \o Tagged Image File Format         \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 Image Information

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

    \table
    \header
    \o \o Available Functions

    \row
    \o Geometry
    \o

    The size(), width(), height(), dotsPerMeterX(), and
    dotsPerMeterY() functions provide information about the image size
    and aspect ratio.

    The rect() function returns the image's enclosing rectangle. The
    valid() function tells if a given pair of coordinates is within
    this rectangle. The offset() function returns the number of pixels
    by which the image is intended to be offset by when positioned
    relative to other images, which also can be manipulated using the
    setOffset() function.

    \row
    \o Colors
    \o

    The color of a pixel can be retrieved by passing its coordinates
    to the pixel() function.  The pixel() function returns the color
    as a QRgb value indepedent of the image's format.

    In case of monochrome and 8-bit images, the numColors() and
    colorTable() functions provide information about the color
    components used to store the image data: The colorTable() function
    returns the image's entire color table. To obtain a single entry,
    use the pixelIndex() function to retrieve the pixel index for a
    given pair of coordinates, then use the color() function to
    retrieve the color. Note that if you create an 8-bit image
    manually, you have to set a valid color table on the image as
    well.

    The hasAlphaChannel() function tells if the image's format
    respects the alpha channel, or not. The allGray() and
    isGrayscale() functions tell whether an image's colors are all
    shades of gray.

    See also the \l {QImage#Pixel Manipulation}{Pixel Manipulation}
    and \l {QImage#Image Transformations}{Image Transformations}
    sections.

    \row
    \o Text
    \o

    The text() function returns the image text associated with the
    given text key. An image's text keys can be retrieved using the
    textKeys() function. Use the setText() function to alter an
    image's text.

    \row
    \o Low-level information
    \o
    The depth() function returns the depth of the image. The supported
    depths are 1 (monochrome), 8 and 32 (for more information see the