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RedHat 9 (Linux i386) - man page for qpixmap (redhat section 3qt)

QPixmap(3qt)									     QPixmap(3qt)

NAME
       QPixmap - Off-screen, pixel-based paint device

SYNOPSIS
       #include <qpixmap.h>

       Inherits QPaintDevice and Qt.

       Inherited by QBitmap and QCanvasPixmap.

   Public Members
       enum ColorMode { Auto, Color, Mono }
       enum Optimization { DefaultOptim, NoOptim, MemoryOptim = NoOptim, NormalOptim, BestOptim }
       QPixmap ()
       QPixmap ( const QImage & image )
       QPixmap ( int w, int h, int depth = -1, Optimization optimization = DefaultOptim )
       QPixmap ( const QSize & size, int depth = -1, Optimization optimization = DefaultOptim )
       QPixmap ( const QString & fileName, const char * format = 0, ColorMode mode = Auto )
       QPixmap ( const QString & fileName, const char * format, int conversion_flags )
       QPixmap ( const char * xpm[] )
       QPixmap ( const QByteArray & img_data )
       QPixmap ( const QPixmap & pixmap )
       ~QPixmap ()
       QPixmap & operator= ( const QPixmap & pixmap )
       QPixmap & operator= ( const QImage & image )
       bool isNull () const
       int width () const
       int height () const
       QSize size () const
       QRect rect () const
       int depth () const
       void fill ( const QColor & fillColor = Qt::white )
       void fill ( const QWidget * widget, int xofs, int yofs )
       void fill ( const QWidget * widget, const QPoint & ofs )
       void resize ( int w, int h )
       void resize ( const QSize & size )
       const QBitmap * mask () const
       void setMask ( const QBitmap & newmask )
       bool selfMask () const
       bool hasAlpha () const
       QBitmap createHeuristicMask ( bool clipTight = TRUE ) const
       QPixmap xForm ( const QWMatrix & matrix ) const
       QImage convertToImage () const
       bool convertFromImage ( const QImage & image, ColorMode mode = Auto )
       bool convertFromImage ( const QImage & img, int conversion_flags )
       bool load ( const QString & fileName, const char * format = 0, ColorMode mode = Auto )
       bool load ( const QString & fileName, const char * format, int conversion_flags )
       bool loadFromData ( const uchar * buf, uint len, const char * format = 0, ColorMode mode =
	   Auto )
       bool loadFromData ( const uchar * buf, uint len, const char * format, int conversion_flags
	   )
       bool loadFromData ( const QByteArray & buf, const char * format = 0, int conversion_flags
	   = 0 )
       bool save ( const QString & fileName, const char * format, int quality = -1 ) const
       int serialNumber () const
       Optimization optimization () const
       void setOptimization ( Optimization optimization )
       virtual void detach ()
       bool isQBitmap () const
       Q_DUMMY_COMPARISON_OPERATOR ( QPixmap )
       virtual int metric ( int m ) const

   Static Public Members
       int defaultDepth ()
       QPixmap fromMimeSource ( const QString & abs_name )
       QPixmap grabWindow ( WId window, int x = 0, int y = 0, int w = -1, int h = -1 )
       QPixmap grabWidget ( QWidget * widget, int x = 0, int y = 0, int w = -1, int h = -1 )
       QWMatrix trueMatrix ( const QWMatrix & matrix, int w, int h )
       const char * imageFormat ( const QString & fileName )
       Optimization defaultOptimization ()
       void setDefaultOptimization ( Optimization optimization )

RELATED FUNCTION DOCUMENTATION
       QDataStream & operator<< ( QDataStream & s, const QPixmap & pixmap )
       QDataStream & operator>> ( QDataStream & s, QPixmap & pixmap )

DESCRIPTION
       The QPixmap class is an off-screen, pixel-based paint device.

       QPixmap is one of the two classes Qt provides for dealing with images; the other is
       QImage. QPixmap is designed and optimized for drawing; QImage is designed and optimized
       for I/O and for direct pixel access/manipulation. There are (slow) functions to convert
       between QImage and QPixmap: convertToImage() and convertFromImage().

       One common use of the QPixmap class is to enable smooth updating of widgets. Whenever
       something complex needs to be drawn, you can use a pixmap to obtain flicker-free drawing,
       like this:

       <ol type=1>

       1      Create a pixmap with the same size as the widget.

       2      Fill the pixmap with the widget background color.

       3      Paint the pixmap.

       4      bitBlt() the pixmap contents onto the widget.

       Pixel data in a pixmap is internal and is managed by the underlying window system. Pixels
       can be accessed only through QPainter functions, through bitBlt(), and by converting the
       QPixmap to a QImage.

       You can easily display a QPixmap on the screen using QLabel::setPixmap(). For example, all
       the QButton subclasses support pixmap use.

       The QPixmap class uses copy-on-write, so it is practical to pass QPixmap objects by value.

       You can retrieve the width(), height(), depth() and size() of a pixmap. The enclosing
       rectangle is given by rect(). Pixmaps can be filled with fill() and resized with resize().
       You can create and set a mask with createHeuristicMask() and setMask(). Use selfMask() to
       see if the pixmap is identical to its mask.

       In addition to loading a pixmap from file using load() you can also loadFromData(). You
       can control optimization with setOptimization() and obtain a transformed version of the
       pixmap using xForm()

       Note regarding Windows 95 and 98: on Windows 9x the system crashes if you create more than
       about 1000 pixmaps, independent of the size of the pixmaps or installed RAM. Windows NT
       and 2000 do not have this limitation.

       Qt tries to work around the resource limitation. If you set the pixmap optimization to
       QPixmap::MemoryOptim and the width of your pixmap is less than or equal to 128 pixels, Qt
       stores the pixmap in a way that is very memory-efficient when there are many pixmaps.

       If your application uses dozens or hundreds of pixmaps (for example on tool bar buttons
       and in popup menus), and you plan to run it on Windows 95 or Windows 98, we recommend
       using code like this:

	       QPixmap::setDefaultOptimization( QPixmap::MemoryOptim );
	       while ( ... ) {
		   // load tool bar pixmaps etc.
		   QPixmap *pixmap = new QPixmap(fileName);
	       }
	       QPixmap::setDefaultOptimization( QPixmap::NormalOptim );

       See also QBitmap, QImage, QImageIO, Shared Classes, Graphics Classes, Image Processing
       Classes, and Implicitly and Explicitly Shared Classes.

   Member Type Documentation
QPixmap::ColorMode
       This enum type defines the color modes that exist for converting QImage objects to
       QPixmap.

       QPixmap::Auto - Select Color or Mono on a case-by-case basis.

       QPixmap::Color - Always create colored pixmaps.

       QPixmap::Mono - Always create bitmaps.

QPixmap::Optimization
       QPixmap has the choice of optimizing for speed or memory in a few places; the best choice
       varies from pixmap to pixmap but can generally be derived heuristically. This enum type
       defines a number of optimization modes that you can set for any pixmap to tweak the
       speed/memory tradeoffs:

       QPixmap::DefaultOptim - Whatever QPixmap::defaultOptimization() returns. A pixmap with
       this optimization will have whatever the current default optimization is. If the default
       optimization is changed using setDefaultOptimization(), then this will not effect any
       pixmaps that have already been created.

       QPixmap::NoOptim - No optimization (currently the same as MemoryOptim).

       QPixmap::MemoryOptim - Optimize for minimal memory use.

       QPixmap::NormalOptim - Optimize for typical usage. Often uses more memory than
       MemoryOptim, and is often faster.

       QPixmap::BestOptim - Optimize for pixmaps that are drawn very often and where performance
       is critical. Generally uses more memory than NormalOptim and may provide a little more
       speed.

       We recommend using DefaultOptim.

MEMBER FUNCTION DOCUMENTATION
QPixmap::QPixmap ()
       Constructs a null pixmap.

       See also isNull().

QPixmap::QPixmap ( const QImage & image )
       Constructs a pixmap from the QImage image.

       See also convertFromImage().

QPixmap::QPixmap ( int w, int h, int depth = -1, Optimization optimization = DefaultOptim )
       Constructs a pixmap with w width, h height and depth bits per pixel. The pixmap is
       optimized in accordance with the optimization value.

       The contents of the pixmap is uninitialized.

       The depth can be either 1 (monochrome) or the depth of the current video mode. If depth is
       negative, then the hardware depth of the current video mode will be used.

       If either w or h is zero, a null pixmap is constructed.

       See also isNull() and QPixmap::Optimization.

QPixmap::QPixmap ( const QSize & size, int depth = -1, Optimization optimization = DefaultOptim )

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

       Constructs a pixmap of size size, depth bits per pixel, optimized in accordance with the
       optimization value.

QPixmap::QPixmap ( const QString & fileName, const char * format = 0, ColorMode mode = Auto )
       Constructs a pixmap from the file fileName. If the file does not exist or is of an unknown
       format, the pixmap becomes a null pixmap.

       The fileName, format and mode parameters are passed on to load(). This means that the data
       in fileName is not compiled into the binary. If fileName contains a relative path (e.g.
       the filename only) the relevant file must be found relative to the runtime working
       directory.

       See also QPixmap::ColorMode, isNull(), load(), loadFromData(), save(), and imageFormat().

QPixmap::QPixmap ( const QString & fileName, const char * format, int conversion_flags )
       Constructs a pixmap from the file fileName. If the file does not exist or is of an unknown
       format, the pixmap becomes a null pixmap.

       The fileName, format and conversion_flags parameters are passed on to load(). This means
       that the data in fileName is not compiled into the binary. If fileName contains a relative
       path (e.g. the filename only) the relevant file must be found relative to the runtime
       working directory.

       If the image needs to be modified to fit in a lower-resolution result (e.g. converting
       from 32-bit to 8-bit), use the conversion_flags to specify how you'd prefer this to
       happen.

       See also Qt::ImageConversionFlags, isNull(), load(), loadFromData(), save(), and
       imageFormat().

QPixmap::QPixmap ( const char * xpm[] )
       Constructs a pixmap from xpm, which must be a valid XPM image.

       Errors are silently ignored.

       Note that it's possible to squeeze the XPM variable a little bit by using an unusual
       declaration:

	       static const char * const start_xpm[]={
		   "16 15 8 1",
		   "a c #cec6bd",
	       ....

       The extra const makes the entire definition read-only, which is slightly more efficient
       (for example, when the code is in a shared library) and ROMable when the application is to
       be stored in ROM.

       In order to use that sort of declaration you must cast the variable back to const char **
       when you create the QPixmap.

QPixmap::QPixmap ( const QByteArray & img_data )
       Constructs a pixmaps by loading from img_data. The data can be in any image format
       supported by Qt.

       See also loadFromData().

QPixmap::QPixmap ( const QPixmap & pixmap )
       Constructs a pixmap that is a copy of pixmap.

QPixmap::~QPixmap ()
       Destroys the pixmap.

bool QPixmap::convertFromImage ( const QImage & img, int conversion_flags )
       Converts image img and sets this pixmap. Returns TRUE if successful; otherwise returns
       FALSE.

       The conversion_flags argument is a bitwise-OR of the Qt::ImageConversionFlags. Passing 0
       for conversion_flags sets all the default options.

       Note that even though a QPixmap with depth 1 behaves much like a QBitmap, isQBitmap()
       returns FALSE.

       If a pixmap with depth 1 is painted with color0 and color1 and converted to an image, the
       pixels painted with color0 will produce pixel index 0 in the image and those painted with
       color1 will produce pixel index 1.

       See also convertToImage(), isQBitmap(), QImage::convertDepth(), defaultDepth(), and
       QImage::hasAlphaBuffer().

       Examples:

bool QPixmap::convertFromImage ( const QImage & image, ColorMode mode = Auto )
       This is an overloaded member function, provided for convenience. It behaves essentially
       like the above function.

       Converts image and sets this pixmap using color mode mode. Returns TRUE if successful;
       otherwise returns FALSE.

       See also QPixmap::ColorMode.

QImage QPixmap::convertToImage () const
       Converts the pixmap to a QImage. Returns a null image if it fails.

       If the pixmap has 1-bit depth, the returned image will also be 1 bit deep. If the pixmap
       has 2- to 8-bit depth, the returned image has 8-bit depth. If the pixmap has greater than
       8-bit depth, the returned image has 32-bit depth.

       Note that for the moment, alpha masks on monochrome images are ignored.

       See also convertFromImage().

       Example: qmag/qmag.cpp.

QBitmap QPixmap::createHeuristicMask ( bool clipTight = TRUE ) const
       Creates and returns a heuristic mask 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 mask may not be perfect but it should be reasonable, so you can do things such as the
       following:

	   pm->setMask( pm->createHeuristicMask() );

       This function is slow because it involves transformation to a QImage, non-trivial
       computations and a transformation back to a QBitmap.

       If clipTight is TRUE the mask is just large enough to cover the pixels; otherwise, the
       mask is larger than the data pixels.

       See also QImage::createHeuristicMask().

int QPixmap::defaultDepth () [static]
       Returns the default pixmap depth, i.e. the depth a pixmap gets if -1 is specified.

       See also depth().

Optimization QPixmap::defaultOptimization () [static]
       Returns the default pixmap optimization setting.

       See also setDefaultOptimization(), setOptimization(), and optimization().

int QPixmap::depth () const
       Returns the depth of the pixmap.

       The pixmap depth is also called bits per pixel (bpp) or bit planes of a pixmap. A null
       pixmap has depth 0.

       See also defaultDepth(), isNull(), and QImage::convertDepth().

void QPixmap::detach () [virtual]
       This is a special-purpose function that detaches the pixmap from shared pixmap data.

       A pixmap is automatically detached by Qt whenever its contents is about to change. This is
       done in all QPixmap member functions that modify the pixmap (fill(), resize(),
       convertFromImage(), load(), etc.), in bitBlt() for the destination pixmap and in
       QPainter::begin() on a pixmap.

       It is possible to modify a pixmap without letting Qt know. You can first obtain the
       system-dependent handle() and then call system-specific functions (for instance, BitBlt
       under Windows) that modify the pixmap contents. In such cases, you can call detach() to
       cut the pixmap loose from other pixmaps that share data with this one.

       detach() returns immediately if there is just a single reference or if the pixmap has not
       been initialized yet.

void QPixmap::fill ( const QColor & fillColor = Qt::white )
       Fills the pixmap with the color fillColor.

       Examples:

void QPixmap::fill ( const QWidget * widget, int xofs, int yofs )
       This is an overloaded member function, provided for convenience. It behaves essentially
       like the above function.

       Fills the pixmap with the widget's background color or pixmap. If the background is empty,
       nothing is done. xofs, yofs is an offset in the widget.

void QPixmap::fill ( const QWidget * widget, const QPoint & ofs )
       This is an overloaded member function, provided for convenience. It behaves essentially
       like the above function.

       Fills the pixmap with the widget's background color or pixmap. If the background is empty,
       nothing is done.

       The ofs point is an offset in the widget.

       The point ofs is a point in the widget's coordinate system. The pixmap's top-left pixel
       will be mapped to the point ofs in the widget. This is significant if the widget has a
       background pixmap; otherwise the pixmap will simply be filled with the background color of
       the widget.

       Example:

	   void CuteWidget::paintEvent( QPaintEvent *e )
	   {
	       QRect ur = e->rect();		// rectangle to update
	       QPixmap pix( ur.size() );	// Pixmap for double-buffering
	       pix.fill( this, ur.topLeft() );	// fill with widget background
	       QPainter p( &pix );
	       p.translate( -ur.x(), -ur.y() ); // use widget coordinate system
						// when drawing on pixmap
	       //    ... draw on pixmap ...
	       p.end();
	       bitBlt( this, ur.topLeft(), &pix );
	   }

QPixmap QPixmap::fromMimeSource ( const QString & abs_name ) [static]
       Convenience function. Gets the data associated with the absolute name abs_name from the
       default mime source factory and decodes it to a pixmap.

       See also QMimeSourceFactory, QImage::fromMimeSource(), and QImageDrag::decode().

QPixmap QPixmap::grabWidget ( QWidget * widget, int x = 0, int y = 0, int w = -1, int h = -1 )
       [static]
       Creates a pixmap and paints widget in it.

       If the widget has any children, then they are also painted in the appropriate positions.

       If you specify x, y, w or h, only the rectangle you specify is painted. The defaults are
       0, 0 (top-left corner) and -1,-1 (which means the entire widget).

       (If w is negative, the function copies everything to the right border of the window. If h
       is negative, the function copies everything to the bottom of the window.)

       If widget is 0, or if the rectangle defined by x, y, the modified w and the modified h
       does not overlap the widget->rect(), this function will return a null QPixmap.

       This function actually asks widget to paint itself (and its children to paint themselves).
       QPixmap::grabWindow() grabs pixels off the screen, which is a bit faster and picks up
       exactly what's on-screen. This function works by calling paintEvent() with painter
       redirection turned on. If there are overlaying windows, grabWindow() will see them, but
       not this function.

       If there is overlap, it returns a pixmap of the size you want, containing a rendering of
       widget. If the rectangle you ask for is a superset of widget, the areas outside widget are
       covered with the widget's background.

       See also grabWindow(), QPainter::redirect(), and QWidget::paintEvent().

QPixmap QPixmap::grabWindow ( WId window, int x = 0, int y = 0, int w = -1, int h = -1 ) [static]

       Grabs the contents of the window window and makes a pixmap out of it. Returns the pixmap.

       The arguments (x, y) specify the offset in the window, whereas (w, h) specify the width
       and height of the area to be copied.

       If w is negative, the function copies everything to the right border of the window. If h
       is negative, the function copies everything to the bottom of the window.

       Note that grabWindow() grabs pixels from the screen, not from the window. If there is
       another window partially or entirely over the one you grab, you get pixels from the
       overlying window, too.

       Note also that the mouse cursor is generally not grabbed.

       The reason we use a window identifier and not a QWidget is to enable grabbing of windows
       that are not part of the application, window system frames, and so on.

       Warning: Grabbing an area outside the screen is not safe in general. This depends on the
       underlying window system.

       See also grabWidget().

       Example: qmag/qmag.cpp.

bool QPixmap::hasAlpha () const
       Returns TRUE if painting with this pixmap might not necessarily paint all pixels in its
       rectangular area.

int QPixmap::height () const
       Returns the height of the pixmap.

       See also width(), size(), and rect().

       Examples:

const char * QPixmap::imageFormat ( const QString & fileName ) [static]
       Returns a string that specifies the image format of the file fileName, or 0 if the file
       cannot be read or if the format cannot be recognized.

       The QImageIO documentation lists the supported image formats.

       See also load() and save().

bool QPixmap::isNull () const
       Returns TRUE if this is a null pixmap; otherwise returns FALSE.

       A null pixmap has zero width, zero height and no contents. You cannot draw in a null
       pixmap or bitBlt() anything to it.

       Resizing an existing pixmap to (0, 0) makes a pixmap into a null pixmap.

       See also resize().

       Examples:

bool QPixmap::isQBitmap () const
       Returns TRUE if this is a QBitmap; otherwise returns FALSE.

bool QPixmap::load ( const QString & fileName, const char * format, int conversion_flags )
       Loads a pixmap from the file fileName at runtime. Returns TRUE if successful; otherwise
       returns FALSE.

       If format is specified, the loader attempts to read the pixmap using the specified format.
       If format is not specified (default), the loader reads a few bytes from the header to
       guess the file's format.

       See the convertFromImage() documentation for a description of the conversion_flags
       argument.

       The QImageIO documentation lists the supported image formats and explains how to add extra
       formats.

       See also loadFromData(), save(), imageFormat(), QImage::load(), and QImageIO.

       Examples:

bool QPixmap::load ( const QString & fileName, const char * format = 0, ColorMode mode = Auto )
       This is an overloaded member function, provided for convenience. It behaves essentially
       like the above function.

       Loads a pixmap from the file fileName at runtime.

       If format is specified, the loader attempts to read the pixmap using the specified format.
       If format is not specified (default), the loader reads a few bytes from the header to
       guess the file's format.

       The mode is used to specify the color mode of the pixmap.

       See also QPixmap::ColorMode.

bool QPixmap::loadFromData ( const uchar * buf, uint len, const char * format, int
       conversion_flags )
       Loads a pixmap from the binary data in buf (len bytes). Returns TRUE if successful;
       otherwise returns FALSE.

       If format is specified, the loader attempts to read the pixmap using the specified format.
       If format is not specified (default), the loader reads a few bytes from the header to
       guess the file's format.

       See the convertFromImage() documentation for a description of the conversion_flags
       argument.

       The QImageIO documentation lists the supported image formats and explains how to add extra
       formats.

       See also load(), save(), imageFormat(), QImage::loadFromData(), and QImageIO.

bool QPixmap::loadFromData ( const uchar * buf, uint len, const char * format = 0, ColorMode mode
       = Auto )
       This is an overloaded member function, provided for convenience. It behaves essentially
       like the above function.

       Loads a pixmap from the binary data in buf (len bytes) using color mode mode. Returns TRUE
       if successful; otherwise returns FALSE.

       If format is specified, the loader attempts to read the pixmap using the specified format.
       If format is not specified (default), the loader reads a few bytes from the header to
       guess the file's format.

       See also QPixmap::ColorMode.

bool QPixmap::loadFromData ( const QByteArray & buf, const char * format = 0, int
       conversion_flags = 0 )
       This is an overloaded member function, provided for convenience. It behaves essentially
       like the above function.

const QBitmap * QPixmap::mask () const
       Returns the mask bitmap, or 0 if no mask has been set.

       See also setMask() and QBitmap.

int QPixmap::metric ( int m ) const [virtual]
       Internal implementation of the virtual QPaintDevice::metric() function.

       Use the QPaintDeviceMetrics class instead.

       m is the metric to get.

QPixmap &; QPixmap::operator= ( const QPixmap & pixmap )
       Assigns the pixmap pixmap to this pixmap and returns a reference to this pixmap.

QPixmap &; QPixmap::operator= ( const QImage & image )
       This is an overloaded member function, provided for convenience. It behaves essentially
       like the above function.

       Converts the image image to a pixmap that is assigned to this pixmap. Returns a reference
       to the pixmap.

       See also convertFromImage().

Optimization QPixmap::optimization () const
       Returns the optimization setting for this pixmap.

       The default optimization setting is QPixmap::NormalOptim. You can change this setting in
       two ways:

       Call setDefaultOptimization() to set the default optimization for all new pixmaps.

       Call setOptimization() to set the optimization for individual pixmaps.

       See also setOptimization(), setDefaultOptimization(), and defaultOptimization().

QRect QPixmap::rect () const
       Returns the enclosing rectangle (0,0,width(),height()) of the pixmap.

       See also width(), height(), and size().

       Example: xform/xform.cpp.

void QPixmap::resize ( int w, int h )
       Resizes the pixmap to w width and h height. If either w or h is 0, the pixmap becomes a
       null pixmap.

       If both w and h are greater than 0, a valid pixmap is created. New pixels will be
       uninitialized (random) if the pixmap is expanded.

       Example: desktop/desktop.cpp.

void QPixmap::resize ( const QSize & size )
       This is an overloaded member function, provided for convenience. It behaves essentially
       like the above function.

       Resizes the pixmap to size size.

bool QPixmap::save ( const QString & fileName, const char * format, int quality = -1 ) const
       Saves the pixmap to the file fileName using the image file format format and a quality
       factor quality. quality must be in the range [0,100] or -1. Specify 0 to obtain small
       compressed files, 100 for large uncompressed files, and -1 to use the default settings.
       Returns TRUE if successful; otherwise returns FALSE.

       See also load(), loadFromData(), imageFormat(), QImage::save(), and QImageIO.

       Example: qmag/qmag.cpp.

bool QPixmap::selfMask () const
       Returns TRUE if the pixmap's mask is identical to the pixmap itself; otherwise returns
       FALSE.

       See also mask().

int QPixmap::serialNumber () const
       Returns a number that uniquely identifies the contents of this QPixmap object. This means
       that multiple QPixmap objects can have the same serial number as long as they refer to the
       same contents.

       An example of where this is useful is for caching QPixmaps.

       See also QPixmapCache.

void QPixmap::setDefaultOptimization ( Optimization optimization ) [static]
       Sets the default pixmap optimization.

       All new pixmaps that are created will use this default optimization. You may also set
       optimization for individual pixmaps using the setOptimization() function.

       The initial default optimization setting is QPixmap::Normal.

       See also defaultOptimization(), setOptimization(), and optimization().

void QPixmap::setMask ( const QBitmap & newmask )
       Sets a mask bitmap.

       The newmask bitmap defines the clip mask for this pixmap. Every pixel in newmask
       corresponds to a pixel in this pixmap. Pixel value 1 means opaque and pixel value 0 means
       transparent. The mask must have the same size as this pixmap.

       Warning: Setting the mask on a pixmap will cause any alpha channel data to be cleared. For
       example:

	       QPixmap alpha( "image-with-alpha.png" );
	       QPixmap alphacopy = alpha;
	       alphacopy.setMask( alphacopy.mask() );
       Now, alpha and alphacopy are visually different.

       Setting a null mask resets the mask.

       See also mask(), createHeuristicMask(), and QBitmap.

void QPixmap::setOptimization ( Optimization optimization )
       Sets pixmap drawing optimization for this pixmap.

       The optimization setting affects pixmap operations, in particular drawing of transparent
       pixmaps (bitBlt() a pixmap with a mask set) and pixmap transformations (the xForm()
       function).

       Pixmap optimization involves keeping intermediate results in a cache buffer and using the
       cache to speed up bitBlt() and xForm(). The cost is more memory consumption, up to twice
       as much as an unoptimized pixmap.

       Use the setDefaultOptimization() to change the default optimization for all new pixmaps.

       See also optimization(), setDefaultOptimization(), and defaultOptimization().

       Example: desktop/desktop.cpp.

QSize QPixmap::size () const
       Returns the size of the pixmap.

       See also width(), height(), and rect().

       Example: movies/main.cpp.

QWMatrix QPixmap::trueMatrix ( const QWMatrix & matrix, int w, int h ) [static]
       Returns the actual matrix used for transforming a pixmap with w width and h height and
       matrix matrix.

       When transforming a pixmap with xForm(), the transformation matrix is internally adjusted
       to compensate for unwanted translation, i.e. xForm() returns the smallest pixmap
       containing all transformed points of the original pixmap.

       This function returns the modified matrix, which maps points correctly from the original
       pixmap into the new pixmap.

       See also xForm() and QWMatrix.

int QPixmap::width () const
       Returns the width of the pixmap.

       See also height(), size(), and rect().

       Examples:

QPixmap QPixmap::xForm ( const QWMatrix & matrix ) const
       Returns a copy of the pixmap that is transformed using matrix. The original pixmap is not
       changed.

       The transformation matrix is internally adjusted to compensate for unwanted translation,
       i.e. xForm() returns the smallest image that contains all the transformed points of the
       original image.

       This function is slow because it involves transformation to a QImage, non-trivial
       computations and a transformation back to a QPixmap.

       See also trueMatrix(), QWMatrix, QPainter::setWorldMatrix(), and QImage::xForm().

       Examples:

RELATED FUNCTION DOCUMENTATION
QDataStream &; operator<< ( QDataStream & s, const QPixmap & pixmap )
       Writes the pixmap pixmap to the stream s as a PNG image.

       See also QPixmap::save() and Format of the QDataStream operators.

QDataStream &; operator>> ( QDataStream & s, QPixmap & pixmap )
       Reads a pixmap from the stream s into the pixmap pixmap.

       See also QPixmap::load() and Format of the QDataStream operators.

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

COPYRIGHT
       Copyright 1992-2001 Trolltech AS, 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 (qpixmap.3qt) and the Qt version (3.1.1).

Trolltech AS				 9 December 2002			     QPixmap(3qt)


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