qimageio man page on aLinux

Man page or keyword search:  
man Server   7435 pages
apropos Keyword Search (all sections)
Output format
aLinux logo
[printable version]

QImageIO(3qt)							 QImageIO(3qt)

NAME
       QImageIO - Parameters for loading and saving images

SYNOPSIS
       #include <qimage.h>

   Public Members
       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 & image )
       void setStatus ( int status )
       void setFormat ( const char * format )
       void setIODevice ( QIODevice * ioDevice )
       void setFileName ( const QString & fileName )
       void setQuality ( int q )
       void setDescription ( const QString & description )
       void setParameters ( const char * parameters )
       void setGamma ( float gamma )
       bool read ()
       bool write ()

   Static Public Members
       const char * imageFormat ( const QString & fileName )
       const char * imageFormat ( QIODevice * d )
       QStrList inputFormats ()
       QStrList outputFormats ()
       void defineIOHandler ( const char * format, const char * header, const
	   char * flags, image_io_handler readImage, image_io_handler
	   writeImage )

DESCRIPTION
       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.

       Warning: 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.

       See also QImage, QPixmap, QFile, QMovie, Graphics Classes, Image
       Processing Classes, and Input/Output and Networking.

MEMBER FUNCTION DOCUMENTATION
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.

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.

QString QImageIO::description () const
       Returns the image description string.

       See also setDescription().

QString QImageIO::fileName () const
       Returns the file name currently set.

       See also setFileName().

const char * QImageIO::format () const
       Returns the image format string or 0 if no format has been explicitly
       set.

float QImageIO::gamma () const
       Returns the gamma value at which the image will be viewed.

       See also setGamma().

const QImage & QImageIO::image () const
       Returns the image currently set.

       See also 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]
       This is an overloaded member function, provided for convenience. It
       behaves essentially like the above function.

       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).

       See also QIODevice::at().

QStrList QImageIO::inputFormats () [static]
       Returns a sorted list of image formats that are supported for image
       input.

QIODevice * QImageIO::ioDevice () const
       Returns the IO device currently set.

       See also setIODevice().

QStrList QImageIO::outputFormats () [static]
       Returns a sorted list of image formats that are supported for image
       output.

       Example: scribble/scribble.cpp.

const char * QImageIO::parameters () const
       Returns the image's parameters string.

       See also setParameters().

int QImageIO::quality () const
       Returns the quality of the written image, related to the compression
       ratio.

       See also setQuality() and QImage::save().

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

       See also setIODevice(), setFileName(), setFormat(), write(), and
       QPixmap::load().

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::setFileName ( const QString & fileName )
       Sets the name of the file to read or write an image from to fileName.

       See also setIODevice().

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.

       See also read(), write(), and format().

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.

       See also gamma().

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.

       See also setFileName().

void QImageIO::setImage ( const QImage & image )
       Sets the image to image.

       See also image().

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).

       See also 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.)

       See also quality() and QImage::save().

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.

       See also status().

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

       See also setStatus().

bool QImageIO::write ()
       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

       See also setIODevice(), setFileName(), setFormat(), read(), and
       QPixmap::save().

SEE ALSO
       http://doc.trolltech.com/qimageio.html
       http://www.trolltech.com/faq/tech.html

COPYRIGHT
       Copyright 1992-2007 Trolltech ASA, http://www.trolltech.com.  See the
       license file included in the distribution for a complete license
       statement.

AUTHOR
       Generated automatically from the source code.

BUGS
       If you find a bug in Qt, please report it as described in
       http://doc.trolltech.com/bughowto.html.	Good bug reports help us to
       help you. Thank you.

       The definitive Qt documentation is provided in HTML format; it is
       located at $QTDIR/doc/html and can be read using Qt Assistant or with a
       web browser. This man page is provided as a convenience for those users
       who prefer man pages, although this format is not officially supported
       by Trolltech.

       If you find errors in this manual page, please report them to qt-
       bugs@trolltech.com.  Please include the name of the manual page
       (qimageio.3qt) and the Qt version (3.3.8).

Trolltech AS			2 February 2007			 QImageIO(3qt)
[top]

List of man pages available for aLinux

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.

[legal] [privacy] [GNU] [policy] [cookies] [netiquette] [sponsors] [FAQ]
Tweet
Polarhome, production since 1999.
Member of Polarhome portal.
Based on Fawad Halim's script.
....................................................................
Vote for polarhome
Free Shell Accounts :: the biggest list on the net