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Métodos públicos | Métodos públicos estáticos
Referencia de la Clase QImageIO

The QImageIO class contains parameters for loading and saving images. Más...

#include <qimage.h>

Lista de todos los miembros.

Métodos públicos

 QImageIO ()
 QImageIO (QIODevice *ioDevice, const char *format)
 QImageIO (const QString &fileName, const char *format)
 ~QImageIO ()
const QImage & image () const
int status () const
const char * format () const
QIODevice * ioDevice () const
QString fileName () const
int quality () const
QString description () const
const char * parameters () const
float gamma () const
void setImage (const QImage &)
void setStatus (int)
void setFormat (const char *)
void setIODevice (QIODevice *)
void setFileName (const QString &)
void setQuality (int)
void setDescription (const QString &)
void setParameters (const char *)
void setGamma (float)
bool read ()
bool write ()
 QImageIO ()
 QImageIO (QIODevice *ioDevice, const char *format)
 QImageIO (const QString &fileName, const char *format)
 ~QImageIO ()
const QImage & image () const
int status () const
const char * format () const
QIODevice * ioDevice () const
QString fileName () const
int quality () const
QString description () const
const char * parameters () const
float gamma () const
void setImage (const QImage &)
void setStatus (int)
void setFormat (const char *)
void setIODevice (QIODevice *)
void setFileName (const QString &)
void setQuality (int)
void setDescription (const QString &)
void setParameters (const char *)
void setGamma (float)
bool read ()
bool write ()

Métodos públicos estáticos

static const char * imageFormat (const QString &fileName)
static const char * imageFormat (QIODevice *)
static QStrList inputFormats ()
static QStrList outputFormats ()
static void defineIOHandler (const char *format, const char *header, const char *flags, image_io_handler read_image, image_io_handler write_image)
static const char * imageFormat (const QString &fileName)
static const char * imageFormat (QIODevice *)
static QStrList inputFormats ()
static QStrList outputFormats ()
static void defineIOHandler (const char *format, const char *header, const char *flags, image_io_handler read_image, image_io_handler write_image)

Descripción detallada

The QImageIO class contains parameters for loading and saving images.

QImageIO contains a QIODevice object that is used for image data I/O. The programmer can install new image file formats in addition to those that Qt provides.

Qt currently supports the following image file formats: PNG, BMP, XBM, XPM and PNM. It may also support JPEG, MNG and GIF, if specially configured during compilation. The different PNM formats are: PBM (P1 or P4), PGM (P2 or P5), and PPM (P3 or P6).

You don't normally need to use this class; QPixmap::load(), QPixmap::save(), and QImage contain sufficient functionality.

For image files that contain sequences of images, only the first is read. See QMovie for loading multiple images.

PBM, PGM, and PPM format output is always in the more condensed raw format. PPM and PGM files with more than 256 levels of intensity are scaled down when reading.

Atención:
If you are in a country which recognizes software patents and in which Unisys holds a patent on LZW compression and/or decompression and you want to use GIF, Unisys may require you to license the technology. Such countries include Canada, Japan, the USA, France, Germany, Italy and the UK.

GIF support may be removed completely in a future version of Qt. We recommend using the PNG format.

Ver también:
QImage QPixmap QFile QMovie

Documentación del constructor y destructor

QImageIO::QImageIO ( )

Constructs a QImageIO object with all parameters set to zero.

QImageIO::QImageIO ( QIODevice *  ioDevice,
const char *  format 
)

Constructs a QImageIO object with the I/O device ioDevice and a format tag.

QImageIO::QImageIO ( const QString &  fileName,
const char *  format 
)

Constructs a QImageIO object with the file name fileName and a format tag.

QImageIO::~QImageIO ( )

Destroys the object and all related data.

QImageIO::QImageIO ( )
QImageIO::QImageIO ( QIODevice *  ioDevice,
const char *  format 
)
QImageIO::QImageIO ( const QString &  fileName,
const char *  format 
)
QImageIO::~QImageIO ( )

Documentación de las funciones miembro

void QImageIO::defineIOHandler ( const char *  format,
const char *  header,
const char *  flags,
image_io_handler  readImage,
image_io_handler  writeImage 
) [static]

Defines an image I/O handler for the image format called format, which is recognized using the regular expression header, read using readImage and written using writeImage.

flags is a string of single-character flags for this format. The only flag defined currently is T (upper case), so the only legal value for flags are "T" and the empty string. The "T" flag means that the image file is a text file, and Qt should treat all newline conventions as equivalent. (XPM files and some PPM files are text files for example.)

format is used to select a handler to write a QImage; header is used to select a handler to read an image file.

If readImage is a null pointer, the QImageIO will not be able to read images in format. If writeImage is a null pointer, the QImageIO will not be able to write images in format. If both are null, the QImageIO object is valid but useless.

Example: 

        void readGIF( QImageIO *image )
        {
        // read the image using the image->ioDevice()
        }

        void writeGIF( QImageIO *image )
        {
        // write the image using the image->ioDevice()
        }

        // add the GIF image handler

        QImageIO::defineIOHandler( "GIF",
                                   "^GIF[0-9][0-9][a-z]",
                                   0,
                                   readGIF,
                                   writeGIF );

Before the regex test, all the 0 bytes in the file header are converted to 1 bytes. This is done because when Qt was ASCII-based, QRegExp could not handle 0 bytes in strings.

The regexp is only applied on the first 14 bytes of the file.

Note that Qt assumes that there is only one handler per format; if two handlers support the same format, Qt will choose one arbitrarily. It is not possible to have one handler support reading, and another support writing.

static void QImageIO::defineIOHandler ( const char *  format,
const char *  header,
const char *  flags,
image_io_handler  read_image,
image_io_handler  write_image 
) [static]
QString QImageIO::description ( ) const [inline]
QString QImageIO::description ( ) const [inline]

Returns the image description string.

Ver también:
setDescription()
QString QImageIO::fileName ( ) const [inline]

Returns the file name currently set.

Ver también:
setFileName()
QString QImageIO::fileName ( ) const [inline]
const char * QImageIO::format ( ) const [inline]

Returns the image format string or 0 if no format has been explicitly set.

const char* QImageIO::format ( ) const [inline]
float QImageIO::gamma ( ) const

Returns the gamma value at which the image will be viewed.

Ver también:
setGamma()
float QImageIO::gamma ( ) const
const QImage& QImageIO::image ( ) const [inline]
const QImage & QImageIO::image ( ) const [inline]

Returns the image currently set.

Ver también:
setImage()
const char * QImageIO::imageFormat ( const QString &  fileName) [static]

Returns a string that specifies the image format of the file fileName, or null if the file cannot be read or if the format is not recognized.

const char * QImageIO::imageFormat ( QIODevice *  d) [static]

Esta es una función miembro sobrecargada que se suministra por conveniencia. Difiere de la anterior función solamente en los argumentos que acepta. Returns a string that specifies the image format of the image read from IO device d, or 0 if the device cannot be read or if the format is not recognized.

Make sure that d is at the right position in the device (for example, at the beginning of the file).

Ver también:
QIODevice::at()
static const char* QImageIO::imageFormat ( const QString &  fileName) [static]
static const char* QImageIO::imageFormat ( QIODevice *  ) [static]
static QStrList QImageIO::inputFormats ( ) [static]
QStrList QImageIO::inputFormats ( ) [static]

Returns a sorted list of image formats that are supported for image input.

QIODevice * QImageIO::ioDevice ( ) const [inline]

Returns the IO device currently set.

Ver también:
setIODevice()
QIODevice* QImageIO::ioDevice ( ) const [inline]
static QStrList QImageIO::outputFormats ( ) [static]
QStrList QImageIO::outputFormats ( ) [static]

Returns a sorted list of image formats that are supported for image output.

const char* QImageIO::parameters ( ) const
const char * QImageIO::parameters ( ) const

Returns the image's parameters string.

Ver también:
setParameters()
int QImageIO::quality ( ) const

Returns the quality of the written image, related to the compression ratio.

Ver también:
setQuality() QImage::save()
int QImageIO::quality ( ) const
bool QImageIO::read ( )

Reads an image into memory and returns TRUE if the image was successfully read; otherwise returns FALSE.

Before reading an image you must set an IO device or a file name. If both an IO device and a file name have been set, the IO device will be used.

Setting the image file format string is optional.

Note that this function does not set the format used to read the image. If you need that information, use the imageFormat() static functions.

Example:

        QImageIO iio;
        QPixmap  pixmap;
        iio.setFileName( "vegeburger.bmp" );
        if ( image.read() )        // ok
            pixmap = iio.image();  // convert to pixmap
Ver también:
setIODevice() setFileName() setFormat() write() QPixmap::load()
bool QImageIO::read ( )
void QImageIO::setDescription ( const QString &  description)

Sets the image description string for image handlers that support image descriptions to description.

Currently, no image format supported by Qt uses the description string.

void QImageIO::setDescription ( const QString &  )
void QImageIO::setFileName ( const QString &  )
void QImageIO::setFileName ( const QString &  fileName)

Sets the name of the file to read or write an image from to fileName.

Ver también:
setIODevice()
void QImageIO::setFormat ( const char *  )
void QImageIO::setFormat ( const char *  format)

Sets the image format to format for the image to be read or written.

It is necessary to specify a format before writing an image, but it is not necessary to specify a format before reading an image.

If no format has been set, Qt guesses the image format before reading it. If a format is set the image will only be read if it has that format.

Ver también:
read() write() format()
void QImageIO::setGamma ( float  )
void QImageIO::setGamma ( float  gamma)

Sets the gamma value at which the image will be viewed to gamma. If the image format stores a gamma value for which the image is intended to be used, then this setting will be used to modify the image. Setting to 0.0 will disable gamma correction (i.e. any specification in the file will be ignored).

The default value is 0.0.

Ver también:
gamma()
void QImageIO::setImage ( const QImage &  image)

Sets the image to image.

Ver también:
image()
void QImageIO::setImage ( const QImage &  )
void QImageIO::setIODevice ( QIODevice *  )
void QImageIO::setIODevice ( QIODevice *  ioDevice)

Sets the IO device to be used for reading or writing an image.

Setting the IO device allows images to be read/written to any block-oriented QIODevice.

If ioDevice is not null, this IO device will override file name settings.

Ver también:
setFileName()
void QImageIO::setParameters ( const char *  )
void QImageIO::setParameters ( const char *  parameters)

Sets the image's parameter string to parameters. This is for image handlers that require special parameters.

Although the current image formats supported by Qt ignore the parameters string, it may be used in future extensions or by contributions (for example, JPEG).

Ver también:
parameters()
void QImageIO::setQuality ( int  q)

Sets the quality of the written image to q, related to the compression ratio.

q must be in the range -1..100. Specify 0 to obtain small compressed files, 100 for large uncompressed files. (-1 signifies the default compression.)

Ver también:
quality() QImage::save()
void QImageIO::setQuality ( int  )
void QImageIO::setStatus ( int  )
void QImageIO::setStatus ( int  status)

Sets the image IO status to status. A non-zero value indicates an error, whereas 0 means that the IO operation was successful.

Ver también:
status()
int QImageIO::status ( ) const [inline]

Returns the image's IO status. A non-zero value indicates an error, whereas 0 means that the IO operation was successful.

Ver también:
setStatus()
int QImageIO::status ( ) const [inline]
bool QImageIO::write ( void  )

Writes an image to an IO device and returns TRUE if the image was successfully written; otherwise returns FALSE.

Before writing an image you must set an IO device or a file name. If both an IO device and a file name have been set, the IO device will be used.

The image will be written using the specified image format.

Example: 

        QImageIO iio;
        QImage   im;
        im = pixmap; // convert to image
        iio.setImage( im );
        iio.setFileName( "vegeburger.bmp" );
        iio.setFormat( "BMP" );
        if ( iio.write() )
            // returned TRUE if written successfully
Ver también:
setIODevice() setFileName() setFormat() read() QPixmap::save()
bool QImageIO::write ( )
La documentación para esta clase fue generada a partir de los siguientes ficheros:
 Todo Clases Namespaces Archivos Funciones Variables 'typedefs' Enumeraciones Valores de enumeraciones Propiedades Amigas 'defines'
Generado el Martes, 7 de Febrero de 2012 09:53:08 para Eneboo - Documentación para desarrolladores por  doxygen 1.7.4