Qwt User's Guide: qwt_paint_buffer.cpp Source File

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# qwt_paint_buffer.cpp

    00001 /* -*- mode: C++ ; c-file-style: "stroustrup" -*- *****************************
    00002  * Qwt Widget Library
    00003  * Copyright (C) 1997   Josef Wilgen
    00004  * Copyright (C) 2002   Uwe Rathmann
    00005  *
    00006  * This library is free software; you can redistribute it and/or
    00007  * modify it under the terms of the Qwt License, Version 1.0
    00008  *****************************************************************************/
    00009
    00010
    00011 #include <qglobal.h>
    00012 #if QT_VERSION < 0x040000
    00013
    00014 #include <qwidget.h>
    00015 #include <qpainter.h>
    00016 #include "qwt_paint_buffer.h"
    00017
    00018 bool QwtPaintBuffer::d_enabled = true;
    00019
    00021 QwtPaintBuffer::QwtPaintBuffer():
    00022     d_device(0),
    00023     d_painter(0),
    00024     d_devicePainter(0)
    00025 {
    00026 }
    00027
    00038 QwtPaintBuffer::QwtPaintBuffer(QPaintDevice *device,
    00039         const QRect &rect, QPainter *painter):
    00040     d_device(0),
    00041     d_painter(0),
    00042     d_devicePainter(0)
    00043 {
    00044     open(device, rect, painter);
    00045 }
    00046
    00051 QwtPaintBuffer::~QwtPaintBuffer()
    00052 {
    00053     close();
    00054 }
    00055
    00062 QPainter *QwtPaintBuffer::painter()
    00063 {
    00064     return d_painter;
    00065 }
    00066
    00070 const QPaintDevice *QwtPaintBuffer::device()
    00071 {
    00072     return d_device;
    00073 }
    00074
    00080 void QwtPaintBuffer::setEnabled(bool enable)
    00081 {
    00082     d_enabled = enable;
    00083 }
    00084
    00088 bool QwtPaintBuffer::isEnabled()
    00089 {
    00090     return d_enabled;
    00091 }
    00092
    00101 void QwtPaintBuffer::open(QPaintDevice *device,
    00102         const QRect &rect, QPainter *painter)
    00103 {
    00104     close();
    00105
    00106     if ( device == 0 || !rect.isValid() )
    00107         return;
    00108
    00109     d_device = device;
    00110     d_devicePainter = painter;
    00111     d_rect = rect;
    00112
    00113     if ( isEnabled() )
    00114     {
    00115 #ifdef Q_WS_X11
    00116         if ( d_pixBuffer.x11Screen() != d_device->x11Screen() )
    00117             d_pixBuffer.x11SetScreen(d_device->x11Screen());
    00118 #endif
    00119         d_pixBuffer.resize(d_rect.size());
    00120
    00121         d_painter = new QPainter();
    00122         if ( d_device->devType() == QInternal::Widget )
    00123         {
    00124             QWidget *w = (QWidget *)d_device;
    00125             d_pixBuffer.fill(w, d_rect.topLeft());
    00126             d_painter->begin(&d_pixBuffer, w);
    00127             d_painter->translate(-d_rect.x(), -d_rect.y());
    00128         }
    00129         else
    00130         {
    00131             d_painter->begin(&d_pixBuffer);
    00132         }
    00133     }
    00134     else
    00135     {
    00136         if ( d_devicePainter )
    00137             d_painter = d_devicePainter;
    00138         else
    00139             d_painter = new QPainter(d_device);
    00140
    00141         if ( d_device->devType() == QInternal::Widget )
    00142         {
    00143             QWidget *w = (QWidget *)d_device;
    00144             if ( w->testWFlags( Qt::WNoAutoErase ) )
    00145                 d_painter->eraseRect(d_rect);
    00146         }
    00147     }
    00148 }
    00149
    00153 void QwtPaintBuffer::flush()
    00154 {
    00155     if ( d_enabled && d_device != 0 && d_rect.isValid())
    00156     {
    00157         // We need a painter to find out if
    00158         // there is a painter redirection for d_device.
    00159
    00160         QPainter *p;
    00161         if ( d_devicePainter == 0 )
    00162             p = new QPainter(d_device);
    00163         else
    00164             p = d_devicePainter;
    00165
    00166         QPaintDevice *device = p->device();
    00167         if ( device->isExtDev() )
    00168             d_devicePainter->drawPixmap(d_rect.topLeft(), d_pixBuffer);
    00169         else
    00170             bitBlt(device, d_rect.topLeft(), &d_pixBuffer );
    00171
    00172         if ( d_devicePainter == 0 )
    00173             delete p;
    00174     }
    00175 }
    00176
    00180 void QwtPaintBuffer::close()
    00181 {
    00182     flush();
    00183
    00184     if ( d_painter )
    00185     {
    00186         if ( d_painter->isActive() )
    00187             d_painter->end();
    00188
    00189         if ( d_painter != d_devicePainter )
    00190             delete d_painter;
    00191     }
    00192
    00193     if ( !d_pixBuffer.isNull() )
    00194         d_pixBuffer = QPixmap();
    00195
    00196     d_device = 0;
    00197     d_painter = 0;
    00198     d_devicePainter = 0;
    00199 }
    00200
    00201 #endif // QT_VERSION < 0x040000