From bd0f3345a938b35ce6a12f6150373b0955b8dd12 Mon Sep 17 00:00:00 2001 From: Timothy Pearson Date: Sun, 10 Jul 2011 15:24:15 -0500 Subject: Add Qt3 development HEAD version --- doc/html/qdirectpainter.html | 201 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 201 insertions(+) create mode 100644 doc/html/qdirectpainter.html (limited to 'doc/html/qdirectpainter.html') diff --git a/doc/html/qdirectpainter.html b/doc/html/qdirectpainter.html new file mode 100644 index 0000000..c4eea9d --- /dev/null +++ b/doc/html/qdirectpainter.html @@ -0,0 +1,201 @@ + + + + + +QDirectPainter Class + + + + + + + +

QDirectPainter Class Reference

+ +

The QDirectPainter class provides direct access to the video hardware. +More... +

#include <qdirectpainter_qws.h> +

Inherits QPainter. +

List of all member functions. +

Public Members

QDirectPainter ( const QWidget * w )
~QDirectPainter ()
uchar * frameBuffer ()
int lineStep ()
int transformOrientation ()
int numRects () const
const QRect & rect ( int i ) const
QRegion region () const
int depth () const
int width () const
int height () const
int xOffset () const
int yOffset () const
QPoint offset () const
QSize size () const
void setAreaChanged ( const QRect & r )

Detailed Description

+ + +The QDirectPainter class provides direct access to the video hardware. +

Only available in Qt/Embedded. +

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. +

QDirectPainter provides this functionality. +

In the simplest case, you make a QDirectPainter on a widget and +then, observing the clip region, perform some platform-specific +operation. For example: +

+        void MyWidget::updatePlatformGraphics()
+        {
+            QDirectPainter dp( this );
+            for ( int i = 0; i < dp.numRects; i++ ) {
+                const QRect& clip = dp.rect(i);
+                ... // platform specific operation
+            }
+        }
+

+ +

The platform-specific code has access to the display, but should +only modify graphics in the rectangles specified by numRects() and +rect(). Note that these rectangles are relative to the entire +display. +

The offset() function returns the position of the widget relative +to the entire display, allowing you to offset platform-specific +operations appropriately. The xOffset() and yOffset() functions +merely return the component values of offset(). +

For simple frame-buffer hardware, the frameBuffer(), lineStep(), +and depth() functions provide basic access, though some hardware +configurations are insufficiently specified by such simple +parameters. +

Note that while a QDirectPainter exists, the entire Qt/Embedded +window system is locked from use by other applications. Always +construct the QDirectPainter as an auto (stack) variable, and be +very careful to write robust and stable code within its scope. +

Member Function Documentation

QDirectPainter::QDirectPainter ( const QWidget * w ) +

+Construct a direct painter on w. The display is locked and the +mouse cursor is hidden if it is above w. + +

QDirectPainter::~QDirectPainter () +

+Destroys the direct painter. The mouse cursor is revealed if +necessary and the display is unlocked. + +

int QDirectPainter::depth () const +

+Returns the bit-depth of the display. + +

uchar * QDirectPainter::frameBuffer () +

+Returns a pointer to the framebuffer memory if available. + +

int QDirectPainter::height () const +

+Returns the height of the widget drawn upon. + +

int QDirectPainter::lineStep () +

+Returns the spacing in bytes from one framebuffer line to the +next. + +

int QDirectPainter::numRects () const +

+Returns the number of rectangles in the drawable region. +

QPoint QDirectPainter::offset () const +

+Returns the position of the widget relative to the entire display. + +

const QRect & QDirectPainter::rect ( int i ) const +

+Returns a reference to rectangle i of the drawable region. +Valid values for i are 0..numRects()-1. +

QRegion QDirectPainter::region () const +

+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. +

void QDirectPainter::setAreaChanged ( const QRect & r ) +

+Sets the area changed by the transaction to r. 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. + +

QSize QDirectPainter::size () const +

+Returns the size of the widget drawn upon. +

int QDirectPainter::transformOrientation () +

+Returns a number that signifies the orientation of the +framebuffer. + +

0	no rotation +
1	90 degrees rotation +
2	180 degrees rotation +
3	270 degrees rotation +

+ +

int QDirectPainter::width () const +

+Returns the width of the widget drawn upon. + +

int QDirectPainter::xOffset () const +

+Returns the X-position of the widget relative to the entire +display. + +

int QDirectPainter::yOffset () const +

+Returns the Y-position of the widget relative to the entire +display. + + +

+ +

Trademarks +

Qt 3.3.8

+ -- cgit v1.2.1