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373 lines
19 KiB
373 lines
19 KiB
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<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>TQImageIO Class Reference</h1>
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<p>The TQImageIO class contains parameters for loading and
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saving images.
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<a href="#details">More...</a>
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<p><tt>#include <<a href="qimage-h.html">ntqimage.h</a>></tt>
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<p><a href="qimageio-members.html">List of all member functions.</a>
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<h2>Public Members</h2>
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<ul>
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<li class=fn><a href="#TQImageIO"><b>TQImageIO</b></a> ()</li>
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<li class=fn><a href="#TQImageIO-2"><b>TQImageIO</b></a> ( TQIODevice * ioDevice, const char * format )</li>
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<li class=fn><a href="#TQImageIO-3"><b>TQImageIO</b></a> ( const TQString & fileName, const char * format )</li>
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<li class=fn><a href="#~TQImageIO"><b>~TQImageIO</b></a> ()</li>
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<li class=fn>const TQImage & <a href="#image"><b>image</b></a> () const</li>
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<li class=fn>int <a href="#status"><b>status</b></a> () const</li>
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<li class=fn>const char * <a href="#format"><b>format</b></a> () const</li>
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<li class=fn>TQIODevice * <a href="#ioDevice"><b>ioDevice</b></a> () const</li>
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<li class=fn>TQString <a href="#fileName"><b>fileName</b></a> () const</li>
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<li class=fn>int <a href="#quality"><b>quality</b></a> () const</li>
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<li class=fn>TQString <a href="#description"><b>description</b></a> () const</li>
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<li class=fn>const char * <a href="#parameters"><b>parameters</b></a> () const</li>
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<li class=fn>float <a href="#gamma"><b>gamma</b></a> () const</li>
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<li class=fn>void <a href="#setImage"><b>setImage</b></a> ( const TQImage & image )</li>
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<li class=fn>void <a href="#setStatus"><b>setStatus</b></a> ( int status )</li>
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<li class=fn>void <a href="#setFormat"><b>setFormat</b></a> ( const char * format )</li>
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<li class=fn>void <a href="#setIODevice"><b>setIODevice</b></a> ( TQIODevice * ioDevice )</li>
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<li class=fn>void <a href="#setFileName"><b>setFileName</b></a> ( const TQString & fileName )</li>
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<li class=fn>void <a href="#setQuality"><b>setQuality</b></a> ( int q )</li>
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<li class=fn>void <a href="#setDescription"><b>setDescription</b></a> ( const TQString & description )</li>
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<li class=fn>void <a href="#setParameters"><b>setParameters</b></a> ( const char * parameters )</li>
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<li class=fn>void <a href="#setGamma"><b>setGamma</b></a> ( float gamma )</li>
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<li class=fn>bool <a href="#read"><b>read</b></a> ()</li>
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<li class=fn>bool <a href="#write"><b>write</b></a> ()</li>
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</ul>
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<h2>Static Public Members</h2>
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<ul>
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<li class=fn>const char * <a href="#imageFormat"><b>imageFormat</b></a> ( const TQString & fileName )</li>
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<li class=fn>const char * <a href="#imageFormat-2"><b>imageFormat</b></a> ( TQIODevice * d )</li>
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<li class=fn>TQStrList <a href="#inputFormats"><b>inputFormats</b></a> ()</li>
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<li class=fn>TQStrList <a href="#outputFormats"><b>outputFormats</b></a> ()</li>
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<li class=fn>void <a href="#defineIOHandler"><b>defineIOHandler</b></a> ( const char * format, const char * header, const char * flags, image_io_handler readImage, image_io_handler writeImage )</li>
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</ul>
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<hr><a name="details"></a><h2>Detailed Description</h2>
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<p> The TQImageIO class contains parameters for loading and
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saving images.
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<p>
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<p> TQImageIO contains a <a href="ntqiodevice.html">TQIODevice</a> object that is used for image data
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I/O. The programmer can install new image file formats in addition
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to those that TQt provides.
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<p> TQt currently supports the following image file formats: PNG, BMP,
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XBM, XPM and PNM. It may also support JPEG, MNG and GIF, if
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specially configured during compilation. The different PNM formats
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are: PBM (P1 or P4), PGM (P2 or P5), and PPM (P3 or P6).
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<p> You don't normally need to use this class; <a href="ntqpixmap.html#load">TQPixmap::load</a>(),
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<a href="ntqpixmap.html#save">TQPixmap::save</a>(), and <a href="ntqimage.html">TQImage</a> contain sufficient functionality.
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<p> For image files that contain sequences of images, only the first
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is read. See <a href="ntqmovie.html">TQMovie</a> for loading multiple images.
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<p> PBM, PGM, and PPM format <em>output</em> is always in the more condensed
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raw format. PPM and PGM files with more than 256 levels of
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intensity are scaled down when reading.
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<p> <b>Warning:</b> If you are in a country which recognizes software patents
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and in which Unisys holds a patent on LZW compression and/or
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decompression and you want to use GIF, Unisys may require you to
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license the technology. Such countries include Canada, Japan, the
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USA, France, Germany, Italy and the UK.
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<p> GIF support may be removed completely in a future version of TQt.
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We recommend using the PNG format.
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<p> <p>See also <a href="ntqimage.html">TQImage</a>, <a href="ntqpixmap.html">TQPixmap</a>, <a href="ntqfile.html">TQFile</a>, <a href="ntqmovie.html">TQMovie</a>, <a href="graphics.html">Graphics Classes</a>, <a href="images.html">Image Processing Classes</a>, and <a href="io.html">Input/Output and Networking</a>.
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<hr><h2>Member Function Documentation</h2>
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<h3 class=fn><a name="TQImageIO"></a>TQImageIO::TQImageIO ()
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</h3>
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Constructs a TQImageIO object with all parameters set to zero.
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<h3 class=fn><a name="TQImageIO-2"></a>TQImageIO::TQImageIO ( <a href="ntqiodevice.html">TQIODevice</a> * ioDevice, const char * format )
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</h3>
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Constructs a TQImageIO object with the I/O device <em>ioDevice</em> and a
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<em>format</em> tag.
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<h3 class=fn><a name="TQImageIO-3"></a>TQImageIO::TQImageIO ( const <a href="ntqstring.html">TQString</a> & fileName, const char * format )
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</h3>
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Constructs a TQImageIO object with the file name <em>fileName</em> and a
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<em>format</em> tag.
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<h3 class=fn><a name="~TQImageIO"></a>TQImageIO::~TQImageIO ()
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</h3>
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Destroys the object and all related data.
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<h3 class=fn>void <a name="defineIOHandler"></a>TQImageIO::defineIOHandler ( const char * format, const char * header, const char * flags, image_io_handler readImage, image_io_handler writeImage )<tt> [static]</tt>
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</h3>
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Defines an image I/O handler for the image format called <em>format</em>, which is recognized using the <a href="ntqregexp.html#details">regular expression</a> <em>header</em>, read using <em>readImage</em> and
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written using <em>writeImage</em>.
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<p> <em>flags</em> is a string of single-character flags for this format.
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The only flag defined currently is T (upper case), so the only
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legal value for <em>flags</em> are "T" and the empty string. The "T"
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flag means that the image file is a text file, and TQt should treat
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all newline conventions as equivalent. (XPM files and some PPM
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files are text files for example.)
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<p> <em>format</em> is used to select a handler to write a <a href="ntqimage.html">TQImage</a>; <em>header</em>
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is used to select a handler to read an image file.
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<p> If <em>readImage</em> is a null pointer, the TQImageIO will not be able
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to read images in <em>format</em>. If <em>writeImage</em> is a null pointer,
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the TQImageIO will not be able to write images in <em>format</em>. If
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both are null, the TQImageIO object is valid but useless.
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<p> Example:
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<pre>
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void readGIF( TQImageIO *image )
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{
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// read the image using the image-><a href="#ioDevice">ioDevice</a>()
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}
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void writeGIF( TQImageIO *image )
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{
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// write the image using the image-><a href="#ioDevice">ioDevice</a>()
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}
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// add the GIF image handler
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TQImageIO::<a href="#defineIOHandler">defineIOHandler</a>( "GIF",
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"^GIF[0-9][0-9][a-z]",
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0,
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readGIF,
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writeGIF );
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</pre>
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<p> Before the regex test, all the 0 bytes in the file header are
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converted to 1 bytes. This is done because when TQt was
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ASCII-based, <a href="ntqregexp.html">TQRegExp</a> could not handle 0 bytes in strings.
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<p> The regexp is only applied on the first 14 bytes of the file.
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<p> Note that TQt assumes that there is only one handler per format; if
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two handlers support the same format, TQt will choose one
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arbitrarily. It is not possible to have one handler support
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reading, and another support writing.
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<h3 class=fn><a href="ntqstring.html">TQString</a> <a name="description"></a>TQImageIO::description () const
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</h3>
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<p> Returns the image description string.
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<p> <p>See also <a href="#setDescription">setDescription</a>().
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<h3 class=fn><a href="ntqstring.html">TQString</a> <a name="fileName"></a>TQImageIO::fileName () const
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</h3>
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<p> Returns the file name currently set.
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<p> <p>See also <a href="#setFileName">setFileName</a>().
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<h3 class=fn>const char * <a name="format"></a>TQImageIO::format () const
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</h3>
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<p> Returns the image format string or 0 if no format has been
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explicitly set.
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<h3 class=fn>float <a name="gamma"></a>TQImageIO::gamma () const
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</h3>
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Returns the gamma value at which the image will be viewed.
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<p> <p>See also <a href="#setGamma">setGamma</a>().
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<h3 class=fn>const <a href="ntqimage.html">TQImage</a> & <a name="image"></a>TQImageIO::image () const
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</h3>
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<p> Returns the image currently set.
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<p> <p>See also <a href="#setImage">setImage</a>().
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<h3 class=fn>const char * <a name="imageFormat"></a>TQImageIO::imageFormat ( const <a href="ntqstring.html">TQString</a> & fileName )<tt> [static]</tt>
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</h3>
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Returns a string that specifies the image format of the file <em>fileName</em>, or null if the file cannot be read or if the format is
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not recognized.
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<h3 class=fn>const char * <a name="imageFormat-2"></a>TQImageIO::imageFormat ( <a href="ntqiodevice.html">TQIODevice</a> * d )<tt> [static]</tt>
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</h3>
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This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
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<p> Returns a string that specifies the image format of the image read
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from IO device <em>d</em>, or 0 if the device cannot be read or if the
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format is not recognized.
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<p> Make sure that <em>d</em> is at the right position in the device (for
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example, at the beginning of the file).
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<p> <p>See also <a href="ntqiodevice.html#at">TQIODevice::at</a>().
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<h3 class=fn><a href="ntqstrlist.html">TQStrList</a> <a name="inputFormats"></a>TQImageIO::inputFormats ()<tt> [static]</tt>
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</h3>
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Returns a sorted list of image formats that are supported for
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image input.
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<h3 class=fn><a href="ntqiodevice.html">TQIODevice</a> * <a name="ioDevice"></a>TQImageIO::ioDevice () const
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</h3>
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<p> Returns the IO device currently set.
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<p> <p>See also <a href="#setIODevice">setIODevice</a>().
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<h3 class=fn><a href="ntqstrlist.html">TQStrList</a> <a name="outputFormats"></a>TQImageIO::outputFormats ()<tt> [static]</tt>
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</h3>
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Returns a sorted list of image formats that are supported for
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image output.
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<p>Example: <a href="scribble-example.html#x911">scribble/scribble.cpp</a>.
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<h3 class=fn>const char * <a name="parameters"></a>TQImageIO::parameters () const
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</h3>
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Returns the image's parameters string.
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<p> <p>See also <a href="#setParameters">setParameters</a>().
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<h3 class=fn>int <a name="quality"></a>TQImageIO::quality () const
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</h3>
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Returns the quality of the written image, related to the
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compression ratio.
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<p> <p>See also <a href="#setQuality">setQuality</a>() and <a href="ntqimage.html#save">TQImage::save</a>().
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<h3 class=fn>bool <a name="read"></a>TQImageIO::read ()
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</h3>
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Reads an image into memory and returns TRUE if the image was
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successfully read; otherwise returns FALSE.
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<p> Before reading an image you must set an IO device or a file name.
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If both an IO device and a file name have been set, the IO device
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will be used.
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<p> Setting the image file format string is optional.
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<p> Note that this function does <em>not</em> set the <a href="#format">format</a> used to read the image. If you need that
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information, use the <a href="#imageFormat">imageFormat</a>() static functions.
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<p> Example:
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<p> <pre>
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TQImageIO iio;
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<a href="ntqpixmap.html">TQPixmap</a> pixmap;
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iio.<a href="#setFileName">setFileName</a>( "vegeburger.bmp" );
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if ( image.read() ) // ok
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pixmap = iio.<a href="#image">image</a>(); // convert to pixmap
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</pre>
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<p> <p>See also <a href="#setIODevice">setIODevice</a>(), <a href="#setFileName">setFileName</a>(), <a href="#setFormat">setFormat</a>(), <a href="#write">write</a>(), and <a href="ntqpixmap.html#load">TQPixmap::load</a>().
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<h3 class=fn>void <a name="setDescription"></a>TQImageIO::setDescription ( const <a href="ntqstring.html">TQString</a> & description )
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</h3>
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Sets the image description string for image handlers that support
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image descriptions to <em>description</em>.
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<p> Currently, no image format supported by TQt uses the description
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string.
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<h3 class=fn>void <a name="setFileName"></a>TQImageIO::setFileName ( const <a href="ntqstring.html">TQString</a> & fileName )
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</h3>
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Sets the name of the file to read or write an image from to <em>fileName</em>.
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<p> <p>See also <a href="#setIODevice">setIODevice</a>().
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<h3 class=fn>void <a name="setFormat"></a>TQImageIO::setFormat ( const char * format )
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</h3>
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Sets the image format to <em>format</em> for the image to be read or
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written.
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<p> It is necessary to specify a format before writing an image, but
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it is not necessary to specify a format before reading an image.
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<p> If no format has been set, TQt guesses the image format before
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reading it. If a format is set the image will only be read if it
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has that format.
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<p> <p>See also <a href="#read">read</a>(), <a href="#write">write</a>(), and <a href="#format">format</a>().
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<h3 class=fn>void <a name="setGamma"></a>TQImageIO::setGamma ( float gamma )
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</h3>
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Sets the gamma value at which the image will be viewed to <em>gamma</em>. If the image format stores a gamma value for which the
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image is intended to be used, then this setting will be used to
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modify the image. Setting to 0.0 will disable gamma correction
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(i.e. any specification in the file will be ignored).
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<p> The default value is 0.0.
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<p> <p>See also <a href="#gamma">gamma</a>().
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<h3 class=fn>void <a name="setIODevice"></a>TQImageIO::setIODevice ( <a href="ntqiodevice.html">TQIODevice</a> * ioDevice )
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</h3>
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Sets the IO device to be used for reading or writing an image.
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<p> Setting the IO device allows images to be read/written to any
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block-oriented <a href="ntqiodevice.html">TQIODevice</a>.
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<p> If <em>ioDevice</em> is not null, this IO device will override file name
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settings.
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<p> <p>See also <a href="#setFileName">setFileName</a>().
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<h3 class=fn>void <a name="setImage"></a>TQImageIO::setImage ( const <a href="ntqimage.html">TQImage</a> & image )
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</h3>
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Sets the image to <em>image</em>.
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<p> <p>See also <a href="#image">image</a>().
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<h3 class=fn>void <a name="setParameters"></a>TQImageIO::setParameters ( const char * parameters )
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</h3>
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Sets the image's parameter string to <em>parameters</em>. This is for
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image handlers that require special parameters.
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<p> Although the current image formats supported by TQt ignore the
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parameters string, it may be used in future extensions or by
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contributions (for example, JPEG).
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<p> <p>See also <a href="#parameters">parameters</a>().
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<h3 class=fn>void <a name="setQuality"></a>TQImageIO::setQuality ( int q )
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</h3>
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Sets the quality of the written image to <em>q</em>, related to the
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compression ratio.
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<p> <em>q</em> must be in the range -1..100. Specify 0 to obtain small
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compressed files, 100 for large uncompressed files. (-1 signifies
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the default compression.)
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<p> <p>See also <a href="#quality">quality</a>() and <a href="ntqimage.html#save">TQImage::save</a>().
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<h3 class=fn>void <a name="setStatus"></a>TQImageIO::setStatus ( int status )
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</h3>
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Sets the image IO status to <em>status</em>. A non-zero value indicates
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an error, whereas 0 means that the IO operation was successful.
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<p> <p>See also <a href="#status">status</a>().
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<h3 class=fn>int <a name="status"></a>TQImageIO::status () const
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</h3>
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<p> Returns the image's IO status. A non-zero value indicates an
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error, whereas 0 means that the IO operation was successful.
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<p> <p>See also <a href="#setStatus">setStatus</a>().
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<h3 class=fn>bool <a name="write"></a>TQImageIO::write ()
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</h3>
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Writes an image to an IO device and returns TRUE if the image was
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|
successfully written; otherwise returns FALSE.
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<p> Before writing an image you must set an IO device or a file name.
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If both an IO device and a file name have been set, the IO device
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will be used.
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<p> The image will be written using the specified image format.
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<p> Example:
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<pre>
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TQImageIO iio;
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<a href="ntqimage.html">TQImage</a> im;
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im = pixmap; // convert to image
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iio.<a href="#setImage">setImage</a>( im );
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iio.<a href="#setFileName">setFileName</a>( "vegeburger.bmp" );
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iio.<a href="#setFormat">setFormat</a>( "BMP" );
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if ( iio.<a href="#write">write</a>() )
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// returned TRUE if written successfully
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</pre>
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<p> <p>See also <a href="#setIODevice">setIODevice</a>(), <a href="#setFileName">setFileName</a>(), <a href="#setFormat">setFormat</a>(), <a href="#read">read</a>(), and <a href="ntqpixmap.html#save">TQPixmap::save</a>().
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This file is part of the <a href="index.html">TQt toolkit</a>.
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Copyright © 1995-2007
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|
<a href="http://www.trolltech.com/">Trolltech</a>. All Rights Reserved.<p><address><hr><div align=center>
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<table width=100% cellspacing=0 border=0><tr>
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<td>Copyright © 2007
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|
<a href="troll.html">Trolltech</a><td align=center><a href="trademarks.html">Trademarks</a>
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<td align=right><div align=right>TQt 3.3.8</div>
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</table></div></address></body>
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</html>
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