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

QScreen(3qt)									     QScreen(3qt)

NAME
       QScreen - And its descendants manage the framebuffer and palette

SYNOPSIS
       #include <qgfx_qws.h>

   Public Members
       QScreen ( int display_id )
       virtual ~QScreen ()
       virtual bool initDevice () = 0
       virtual bool connect ( const QString & displaySpec ) = 0
       virtual void disconnect () = 0
       virtual int initCursor ( void * end_of_location, bool init = FALSE )
       virtual void shutdownDevice ()
       virtual void setMode ( int, int, int ) = 0
       virtual bool supportsDepth ( int d ) const
       virtual QGfx * createGfx ( unsigned char * bytes, int w, int h, int d, int linestep )
       virtual QGfx * screenGfx ()
       virtual void save ()
       virtual void restore ()
       virtual void blank ( bool on )
       virtual int pixmapOffsetAlignment ()
       virtual int pixmapLinestepAlignment ()
       virtual bool onCard ( unsigned char * p ) const
       virtual bool onCard ( unsigned char * p, ulong & offset ) const
       virtual void set ( unsigned int, unsigned int, unsigned int, unsigned int )
       virtual int alloc ( unsigned int r, unsigned int g, unsigned int b )
       int width () const
       int height () const
       int depth () const
       virtual int pixmapDepth () const
       int pixelType () const
       int linestep () const
       int deviceWidth () const
       int deviceHeight () const
       uchar * base () const
       virtual uchar * cache ( int, int )
       virtual void uncache ( uchar * )
       int screenSize () const
       int totalSize () const
       QRgb * clut ()
       int numCols ()
       virtual QSize mapToDevice ( const QSize & s ) const
       virtual QSize mapFromDevice ( const QSize & s ) const
       virtual QPoint mapToDevice ( const QPoint &, const QSize & ) const
       virtual QPoint mapFromDevice ( const QPoint &, const QSize & ) const
       virtual QRect mapToDevice ( const QRect & r, const QSize & ) const
       virtual QRect mapFromDevice ( const QRect & r, const QSize & ) const
       virtual QImage mapToDevice ( const QImage & i ) const
       virtual QImage mapFromDevice ( const QImage & i ) const
       virtual QRegion mapToDevice ( const QRegion & r, const QSize & ) const
       virtual QRegion mapFromDevice ( const QRegion & r, const QSize & ) const
       virtual int transformOrientation () const
       virtual bool isTransformed () const
       virtual bool isInterlaced () const
       virtual void setDirty ( const QRect & )
       int * opType ()
       int * lastOp ()

DESCRIPTION
       The QScreen class and its descendants manage the framebuffer and palette.

       QScreens act as factories for the screen cursor and QGfx's. QLinuxFbScreen manages a Linux
       framebuffer; accelerated drivers subclass QLinuxFbScreen. There can only be one screen in
       a Qt/Embedded application.

       See also Qt/Embedded.

MEMBER FUNCTION DOCUMENTATION
QScreen::QScreen ( int display_id )
       Create a screen; the display_id is the number of the Qt/Embedded server to connect to.

QScreen::~QScreen () [virtual]
       Destroys a QScreen

int QScreen::alloc ( unsigned int r, unsigned int g, unsigned int b ) [virtual]
       Given an RGB value r g b, return an index which is the closest match to it in the screen's
       palette. Used in paletted modes only.

uchar * QScreen::base () const
       Returns a pointer to the start of the framebuffer.

void QScreen::blank ( bool on ) [virtual]
       If on is true, blank the screen. Otherwise unblank it.

uchar * QScreen::cache ( int, int ) [virtual]
       This function is used to store pixmaps in graphics memory for the use of the accelerated
       drivers. See QLinuxFbScreen (where the cacheing is implemented) for more information.

QRgb * QScreen::clut ()
       Returns the screen's color lookup table (color palette). This is only valid in paletted
       modes (8bpp and lower).

bool QScreen::connect ( const QString & displaySpec ) [pure virtual]
       This function is called by every Qt/Embedded application on startup. It maps in the
       framebuffer and in the accelerated drivers the graphics card control registers.
       displaySpec has the following syntax:

       [gfx driver][:driver specific options][:display number]

       for example if you want to use the mach64 driver on fb1 as display 2:

       Mach64:/dev/fb1:2

       displaySpec is passed in via the QWS_DISPLAY environment variable or the -display command
       line parameter.

QGfx * QScreen::createGfx ( unsigned char * bytes, int w, int h, int d, int linestep ) [virtual]
       Creates a gfx on an arbitrary buffer bytes, width w and height h in pixels, depth d and
       linestep (length in bytes of each line in the buffer). Accelerated drivers can check to
       see if bytes points into graphics memory and create an accelerated Gfx.

int QScreen::depth () const
       Gives the depth in bits per pixel of the framebuffer. This is the number of bits each
       pixel takes up rather than the number of significant bits, so 24bpp and 32bpp express the
       same range of colors (8 bits of red, green and blue)

int QScreen::deviceHeight () const
       Gives the full height of the framebuffer device, as opposed to the height which
       Qt/Embedded will actually use. These can differ if the display is centered within the
       framebuffer.

int QScreen::deviceWidth () const
       Gives the full width of the framebuffer device, as opposed to the width which Qt/Embedded
       will actually use. These can differ if the display is centered within the framebuffer.

void QScreen::disconnect () [pure virtual]
       This function is called by every Qt/Embedded application just before exitting; it's
       normally used to unmap the framebuffer.

int QScreen::height () const
       Gives the height in pixels of the framebuffer.

int QScreen::initCursor ( void * end_of_location, bool init = FALSE ) [virtual]
       This is used to initialize the software cursor - end_of_location points to the address
       after the area where the cursor image can be stored. init is true for the first
       application this method is called from (the Qt/Embedded server), false otherwise.

bool QScreen::initDevice () [pure virtual]
       This function is called by the Qt/Embedded server when initializing the framebuffer.
       Accelerated drivers use it to set up the graphics card.

bool QScreen::isInterlaced () const [virtual]
       Returns TRUE if the display is interlaced (for instance a television screen); otherwise
       returns FALSE. If TRUE, drawing is altered to look better on such displays.

bool QScreen::isTransformed () const [virtual]
       Returns TRUE if the screen is transformed (for instance, rotated 90 degrees); otherwise
       returns FALSE. QScreen's version always returns FALSE.

int * QScreen::lastOp ()
       Returns the screens last operation.

int QScreen::linestep () const
       Returns the length in bytes of each scanline of the framebuffer.

QSize QScreen::mapFromDevice ( const QSize & s ) const [virtual]
       Map a framebuffer coordinate to the coordinate space used by the application. Used by the
       rotated driver; the QScreen implementation simply returns s.

QPoint QScreen::mapFromDevice ( const QPoint &, const QSize & ) const [virtual]
       This is an overloaded member function, provided for convenience. It behaves essentially
       like the above function.

       Map a framebuffer coordinate to the coordinate space used by the application. Used by the
       rotated driver; the QScreen implementation simply returns the point.

QRect QScreen::mapFromDevice ( const QRect & r, const QSize & ) const [virtual]
       This is an overloaded member function, provided for convenience. It behaves essentially
       like the above function.

       Map a framebuffer coordinate to the coordinate space used by the application. Used by the
       rotated driver; the QScreen implementation simply returns r.

QImage QScreen::mapFromDevice ( const QImage & i ) const [virtual]
       This is an overloaded member function, provided for convenience. It behaves essentially
       like the above function.

       Transforms an image so that it matches the application coordinate space (e.g. rotating it
       90 degrees counter-clockwise). The QScreen implementation simply returns i.

QRegion QScreen::mapFromDevice ( const QRegion & r, const QSize & ) const [virtual]
       This is an overloaded member function, provided for convenience. It behaves essentially
       like the above function.

       Transforms a region so that it matches the application coordinate space (e.g. rotating it
       90 degrees counter-clockwise). The QScreen implementation simply returns r.

QSize QScreen::mapToDevice ( const QSize & s ) const [virtual]
       Map a user coordinate to the one to actually draw. Used by the rotated driver; the QScreen
       implementation simply returns s.

QPoint QScreen::mapToDevice ( const QPoint &, const QSize & ) const [virtual]
       This is an overloaded member function, provided for convenience. It behaves essentially
       like the above function.

       Map a user coordinate to the one to actually draw. Used by the rotated driver; the QScreen
       implementation simply returns the point passed in.

QRect QScreen::mapToDevice ( const QRect & r, const QSize & ) const [virtual]
       This is an overloaded member function, provided for convenience. It behaves essentially
       like the above function.

       Map a user coordinate to the one to actually draw. Used by the rotated driver; the QScreen
       implementation simply returns r.

QImage QScreen::mapToDevice ( const QImage & i ) const [virtual]
       This is an overloaded member function, provided for convenience. It behaves essentially
       like the above function.

       Transforms an image so that it fits the device coordinate space (e.g. rotating it 90
       degrees clockwise). The QScreen implementation simply returns i.

QRegion QScreen::mapToDevice ( const QRegion & r, const QSize & ) const [virtual]
       This is an overloaded member function, provided for convenience. It behaves essentially
       like the above function.

       Transforms a region so that it fits the device coordinate space (e.g. rotating it 90
       degrees clockwise). The QScreen implementation simply returns r.

int QScreen::numCols ()
       Returns the number of entries in the color table returned by clut().

bool QScreen::onCard ( unsigned char * p ) const [virtual]
       Returns true if the buffer pointed to by p is within graphics card memory, false if it's
       in main RAM.

bool QScreen::onCard ( unsigned char * p, ulong & offset ) const [virtual]
       This is an overloaded member function, provided for convenience. It behaves essentially
       like the above function.

       This checks whether the buffer specified by p is on the card (as per the other version of
       onCard) and returns an offset in bytes from the start of graphics card memory in offset if
       it is.

int * QScreen::opType ()
       Returns the screen's operation type.

int QScreen::pixelType () const
       Returns an integer (taking the same values as QGfx::PixelType) that specifies the pixel
       storage format of the screen.

int QScreen::pixmapDepth () const [virtual]
       Gives the preferred depth for pixmaps. By default this is the same as the screen depth,
       but for the VGA16 driver it's 8bpp.

int QScreen::pixmapLinestepAlignment () [virtual]
       Returns the value in bytes to which individual scanlines of pixmaps held in graphics card
       memory should be aligned. This is only useful for accelerated drivers. By default the
       value returned is 64 but it can be overridden by individual accelerated drivers.

int QScreen::pixmapOffsetAlignment () [virtual]
       Returns the value in bytes to which the start address of pixmaps held in graphics card
       memory should be aligned. This is only useful for accelerated drivers. By default the
       value returned is 64 but it can be overridden by individual accelerated drivers.

void QScreen::restore () [virtual]
       Restores the state of the graphics card from a previous save()

void QScreen::save () [virtual]
       Saves the state of the graphics card - used so that, for instance, the palette can be
       restored when switching between linux virtual consoles. Hardware QScreen descendants
       should save register state here if necessary if switching between virtual consoles (for
       example to/from X) is to be permitted.

QGfx * QScreen::screenGfx () [virtual]
       Returns a QGfx (normally a QGfxRaster) initialized to point to the screen, with an origin
       at 0,0 and a clip region covering the whole screen.

int QScreen::screenSize () const
       Returns the size in bytes of the screen. This is always located at the beginning of
       framebuffer memory (i.e. at base()).

void QScreen::set ( unsigned int, unsigned int, unsigned int, unsigned int ) [virtual]
       Sets an entry in the color palette.

void QScreen::setDirty ( const QRect & ) [virtual]
       Indicates which section of the screen has been altered. Used by the VNC and VFB displays;
       the QScreen version does nothing.

void QScreen::setMode ( int, int, int ) [pure virtual]
       This function can be used to set the framebuffer width, height and depth. It's currently
       unused.

void QScreen::shutdownDevice () [virtual]
       Called by the Qt/Embedded server on shutdown; never called by a Qt/Embedded client. This
       is intended to support graphics card specific shutdown; the unaccelerated implementation
       simply hides the mouse cursor.

bool QScreen::supportsDepth ( int d ) const [virtual]
       Returns true if the screen supports a particular color depth d. Possible values are
       1,4,8,16 and 32.

int QScreen::totalSize () const
       Returns the size in bytes of available graphics card memory, including the screen.
       Offscreen memory is only used by the accelerated drivers.

int QScreen::transformOrientation () const [virtual]
       Used by the rotated server. The QScreeen implementation returns 0.

void QScreen::uncache ( uchar * ) [virtual]
       This function is called on pixmap destruction to remove them from graphics card memory.

int QScreen::width () const
       Gives the width in pixels of the framebuffer.

SEE ALSO
       http://doc.trolltech.com/qscreen.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 (qscreen.3qt) and the Qt version (3.1.1).

Trolltech AS				 9 December 2002			     QScreen(3qt)


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