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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 > TQDirectPainter Class Reference< / h1 >
< p > The TQDirectPainter class provides direct access to the video hardware.
< a href = "#details" > More...< / a >
< p > < tt > #include < < a href = "qdirectpainter_qws-h.html" > qdirectpainter_qws.h< / a > > < / tt >
< p > Inherits < a href = "ntqpainter.html" > TQPainter< / a > .
< p > < a href = "qdirectpainter-members.html" > List of all member functions.< / a >
< h2 > Public Members< / h2 >
< ul >
< li class = fn > < a href = "#TQDirectPainter" > < b > TQDirectPainter< / b > < / a > ( const TQWidget * w )< / li >
< li class = fn > < a href = "#~TQDirectPainter" > < b > ~TQDirectPainter< / b > < / a > ()< / li >
< li class = fn > uchar * < a href = "#frameBuffer" > < b > frameBuffer< / b > < / a > ()< / li >
< li class = fn > int < a href = "#lineStep" > < b > lineStep< / b > < / a > ()< / li >
< li class = fn > int < a href = "#transformOrientation" > < b > transformOrientation< / b > < / a > ()< / li >
< li class = fn > int < a href = "#numRects" > < b > numRects< / b > < / a > () const< / li >
< li class = fn > const TQRect & < a href = "#rect" > < b > rect< / b > < / a > ( int i ) const< / li >
< li class = fn > TQRegion < a href = "#region" > < b > region< / b > < / a > () const< / li >
< li class = fn > int < a href = "#depth" > < b > depth< / b > < / a > () const< / li >
< li class = fn > int < a href = "#width" > < b > width< / b > < / a > () const< / li >
< li class = fn > int < a href = "#height" > < b > height< / b > < / a > () const< / li >
< li class = fn > int < a href = "#xOffset" > < b > xOffset< / b > < / a > () const< / li >
< li class = fn > int < a href = "#yOffset" > < b > yOffset< / b > < / a > () const< / li >
< li class = fn > TQPoint < a href = "#offset" > < b > offset< / b > < / a > () const< / li >
< li class = fn > TQSize < a href = "#size" > < b > size< / b > < / a > () const< / li >
< li class = fn > void < a href = "#setAreaChanged" > < b > setAreaChanged< / b > < / a > ( const TQRect & r )< / li >
< / ul >
< hr > < a name = "details" > < / a > < h2 > Detailed Description< / h2 >
The TQDirectPainter class provides direct access to the video hardware.
< p >
< p > Only available in TQt/Embedded.
< p > When the hardware is known and well defined, as is often the case
with software for embedded devices, it may be useful to manipulate
the underlying video hardware directly. In order to do this in a
way that is co-operative with other applications, you must lock
the video hardware for exclusive use for a small time while you
write to it, and you must know the clipping region which is
allocated to a widget.
< p > TQDirectPainter provides this functionality.
< p > In the simplest case, you make a TQDirectPainter on a widget and
then, observing the clip region, perform some platform-specific
operation. For example:
< pre >
void MyWidget::updatePlatformGraphics()
{
TQDirectPainter dp( this );
for ( int i = 0; i < dp.numRects; i++ ) {
const < a href = "ntqrect.html" > TQRect< / a > & clip = dp.< a href = "#rect" > rect< / a > (i);
... // platform specific operation
}
}
< / pre >
< p > The platform-specific code has access to the display, but should
only modify graphics in the rectangles specified by < a href = "#numRects" > numRects< / a > () and
< a href = "#rect" > rect< / a > (). Note that these rectangles are relative to the entire
display.
< p > The < a href = "#offset" > offset< / a > () function returns the position of the widget relative
to the entire display, allowing you to offset platform-specific
operations appropriately. The < a href = "#xOffset" > xOffset< / a > () and < a href = "#yOffset" > yOffset< / a > () functions
merely return the component values of offset().
< p > For simple frame-buffer hardware, the < a href = "#frameBuffer" > frameBuffer< / a > (), < a href = "#lineStep" > lineStep< / a > (),
and < a href = "#depth" > depth< / a > () functions provide basic access, though some hardware
configurations are insufficiently specified by such simple
parameters.
< p > Note that while a TQDirectPainter exists, the entire TQt/Embedded
window system is locked from use by other applications. Always
construct the TQDirectPainter as an auto (stack) variable, and be
very careful to write robust and stable code within its scope.
< p > See also < a href = "graphics.html" > Graphics Classes< / a > .
< hr > < h2 > Member Function Documentation< / h2 >
< h3 class = fn > < a name = "TQDirectPainter" > < / a > TQDirectPainter::TQDirectPainter ( const < a href = "ntqwidget.html" > TQWidget< / a > * w )
< / h3 >
Construct a direct painter on < em > w< / em > . The display is locked and the
mouse cursor is hidden if it is above < em > w< / em > .
< h3 class = fn > < a name = "~TQDirectPainter" > < / a > TQDirectPainter::~TQDirectPainter ()
< / h3 >
Destroys the direct painter. The mouse cursor is revealed if
necessary and the display is unlocked.
< h3 class = fn > int < a name = "depth" > < / a > TQDirectPainter::depth () const
< / h3 >
Returns the bit-depth of the display.
< h3 class = fn > uchar * < a name = "frameBuffer" > < / a > TQDirectPainter::frameBuffer ()
< / h3 >
Returns a pointer to the framebuffer memory if available.
< h3 class = fn > int < a name = "height" > < / a > TQDirectPainter::height () const
< / h3 >
Returns the height of the widget drawn upon.
< h3 class = fn > int < a name = "lineStep" > < / a > TQDirectPainter::lineStep ()
< / h3 >
Returns the spacing in bytes from one framebuffer line to the
next.
< h3 class = fn > int < a name = "numRects" > < / a > TQDirectPainter::numRects () const
< / h3 >
Returns the number of rectangles in the drawable region.
< p > < p > See also < a href = "#rect" > rect< / a > () and < a href = "#region" > region< / a > ().
< h3 class = fn > < a href = "ntqpoint.html" > TQPoint< / a > < a name = "offset" > < / a > TQDirectPainter::offset () const
< / h3 >
Returns the position of the widget relative to the entire display.
< h3 class = fn > const < a href = "ntqrect.html" > TQRect< / a > & < a name = "rect" > < / a > TQDirectPainter::rect ( int i ) const
< / h3 >
Returns a reference to rectangle < em > i< / em > of the drawable region.
Valid values for < em > i< / em > are 0..< a href = "#numRects" > numRects< / a > ()-1.
< p > < p > See also < a href = "#region" > region< / a > ().
< h3 class = fn > < a href = "ntqregion.html" > TQRegion< / a > < a name = "region" > < / a > TQDirectPainter::region () const
< / h3 >
Returns the region of the framebuffer which represents the exposed
area of the widget being painted on. Note that this may be a sub-area of
the clip region, because of child widgets and overlapping cousin widgets.
< p > < p > See also < a href = "#numRects" > numRects< / a > () and < a href = "#rect" > rect< / a > ().
< h3 class = fn > void < a name = "setAreaChanged" > < / a > TQDirectPainter::setAreaChanged ( const < a href = "ntqrect.html" > TQRect< / a > & r )
< / h3 >
Sets the area changed by the transaction to < em > r< / em > . By default, the
entire widget is assumed to have changed. The area changed is only
used by some graphics drivers, so often calling this function for
a smaller area will make no difference to performance.
< h3 class = fn > < a href = "ntqsize.html" > TQSize< / a > < a name = "size" > < / a > TQDirectPainter::size () const
< / h3 >
Returns the size of the widget drawn upon.
< p > < p > See also < a href = "#width" > width< / a > () and < a href = "#height" > height< / a > ().
< h3 class = fn > int < a name = "transformOrientation" > < / a > TQDirectPainter::transformOrientation ()
< / h3 >
Returns a number that signifies the orientation of the
framebuffer.
< center > < table cellpadding = "4" cellspacing = "2" border = "0" >
< tr bgcolor = "#f0f0f0" > < td valign = "top" colspan = "1" rowspan = "1" > 0 < td valign = "top" colspan = "1" rowspan = "1" > no rotation
< tr bgcolor = "#d0d0d0" > < td valign = "top" colspan = "1" rowspan = "1" > 1 < td valign = "top" colspan = "1" rowspan = "1" > 90 degrees rotation
< tr bgcolor = "#f0f0f0" > < td valign = "top" colspan = "1" rowspan = "1" > 2 < td valign = "top" colspan = "1" rowspan = "1" > 180 degrees rotation
< tr bgcolor = "#d0d0d0" > < td valign = "top" colspan = "1" rowspan = "1" > 3 < td valign = "top" colspan = "1" rowspan = "1" > 270 degrees rotation
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< h3 class = fn > int < a name = "width" > < / a > TQDirectPainter::width () const
< / h3 >
Returns the width of the widget drawn upon.
< h3 class = fn > int < a name = "xOffset" > < / a > TQDirectPainter::xOffset () const
< / h3 >
Returns the X-position of the widget relative to the entire
display.
< h3 class = fn > int < a name = "yOffset" > < / a > TQDirectPainter::yOffset () const
< / h3 >
Returns the Y-position of the widget relative to the entire
display.
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