[Qt-interest] Screen Getting White
Sujan Dasmahapatra
sdh at lmglasfiber.com
Tue Apr 21 14:29:27 CEST 2009
Dear Friends
I am into the development of an engineering software where I am loading
multiple geometries from the QFileDialog and displaying them on the
main window and at the same time the file names are being uploaded onto
the QTableWdiget one by one. I am using a QGraphicsScene and
QGraphicsView which is used for display, the default Scene color is
black..Everything is going fine but sometimes when I load a geometry the
screen is getting white and no geometries are found.But actually the
geometries are there and filename is nicely uploaded in my
QTableWidget. If I continue the operation and if I load another geometry
next then all the geometries are coming back on the screen and all are
visible.I am facing this problem severely.
I thought that I am not refreshing the screen during
and after loading the geometry so I am calling "qApp->processEvents()"
before and after loading the geometry as one of our friends suggested
but it's still happening and I am fade up with this bug.Please help me
somebody.
Some codes I am writing here for understanding.
////////////////////////////////////////////Scene and View
Management///////////////////////
scene = new GraphicsScene;
view = new QGraphicsView(scene);
view->setWindowTitle(QT_TRANSLATE_NOOP(QGraphicsView,"Geometry
View"));
view->setGeometry(250,70,1020,646);
view->setParent(this,Qt::SubWindow);
scene->setParent(view);
/////////////////////////loading
geometry/////////////////////////////////////////////////////////
void MainWindow::open()
{
qApp->processEvents();
int i;
xmax=0.0,xmin=0.0,ymax=0.0,ymin=0.0;
fileopendialog.setAcceptMode(QFileDialog::AcceptOpen);
if(fileopendialog.exec())
{
Filenames = fileopendialog.selectedFiles();
}
if(Filenames[0].isEmpty())
return;
if(fileopendialog.result()==QDialog::Rejected)
return;
if(!firstTime)
{
if(tableWidget->countTableWidget == 0)
{
countMainWindow = 0;
fileGeometry.clear();
geometry.clear();
}
}
if(fileopendialog.selectedNameFilter()=="*.dat")
{
fileGeometry.append(Filenames[0]);
QFile file(fileGeometry[countMainWindow]);
file.open(QIODevice::ReadOnly);
QTextStream stream(&file);
QString ch;
ch = stream.read(2);
stream >> numberOfPoints;
x =new double[numberOfPoints];
y = new double[numberOfPoints];
QPointF *dataPoints = new QPointF[numberOfPoints];
for(i = 0; i< numberOfPoints; i++)
{
stream >> x[i] >> y[i];
dataPoints[i].setX(x[i]);
dataPoints[i].setY(y[i]);
}
xmax = dataPoints[0].x();
for(i=1; i<=numberOfPoints; i++)
{
if(dataPoints[i].x() > xmax)
xmax = dataPoints[i].x();
}
xmin = dataPoints[0].x();
for(i=1; i<=numberOfPoints; i++)
{
if(dataPoints[i].x() < xmin )
xmin = dataPoints[i].x();
}
width = xmax-xmin;
if(width <0.0)
width = width * (-1.0);
ymax = dataPoints[0].y();
for(i=1; i<=numberOfPoints; i++)
{
if(dataPoints[i].y() > ymax)
ymax = dataPoints[i].y();
}
ymin = dataPoints[0].y();
for(i=1; i<=numberOfPoints; i++)
{
if(dataPoints[i].y() < ymin)
ymin = dataPoints[i].y();
}
height = ymax-ymin;
if(height < 0.0)
height = height * (-1.0);
geometry.append(new Geometry(numberOfPoints,dataPoints));
file.close();
delete x;
delete y;
}
else if(fileopendialog.selectedNameFilter()=="*.tyk")
{
fileGeometry.append(Filenames[0]);
QFile filetykread(fileGeometry[countMainWindow]);
filetykread.open(QIODevice::ReadOnly);
QTextStream stream(&filetykread);
stream >> numberOfPoints;
numberOfPoints = numberOfPoints;
double *xval = new double[numberOfPoints];
double *ytop = new double[numberOfPoints];
double *ybot = new double[numberOfPoints];
for(i=0; i<numberOfPoints; i++)
{
stream >> xval[i] >> ytop[i] >> ybot[i];
}
numberOfPoints = (2*numberOfPoints);
x = new double[numberOfPoints-1];
y = new double[numberOfPoints-1];
QPointF *dataPoints = new QPointF[numberOfPoints-1];
for(i=0; i<(numberOfPoints-1); i++)
{
if(i<=(numberOfPoints/2)-1)
{
x[i] = xval[(numberOfPoints/2)-1-i];
y[i] = ybot[(numberOfPoints/2)-1-i];
}
if(i>=numberOfPoints/2)
{
x[i] = xval[i-(numberOfPoints/2)+1];
y[i] = ytop[i-(numberOfPoints/2)+1];
}
}
for(i=0; i<(numberOfPoints-1);i++)
{
dataPoints[i].setX(x[i]);
dataPoints[i].setY(y[i]);
}
xmax = dataPoints[0].x();
for(i=1; i<=numberOfPoints; i++)
{
if(dataPoints[i].x() > xmax)
xmax = dataPoints[i].x();
}
xmin = dataPoints[0].x();
for(i=1; i<=numberOfPoints; i++)
{
if(dataPoints[i].x() < xmin )
xmin = dataPoints[i].x();
}
width = xmax-xmin;
if(width <0.0)
width = width * (-1.0);
ymax = dataPoints[0].y();
for(i=1; i<=numberOfPoints; i++)
{
if(dataPoints[i].y() > ymax)
ymax = dataPoints[i].y();
}
ymin = dataPoints[0].y();
for(i=1; i<=numberOfPoints; i++)
{
if(dataPoints[i].y() < ymin)
ymin = dataPoints[i].y();
}
height = ymax-ymin;
if(height < 0.0)
height = height * (-1.0);
geometry.append(new Geometry(numberOfPoints-1,dataPoints));
filetykread.close();
delete xval;
delete ytop;
delete ybot;
delete x;
delete y;
}
else
{
statusBar()->showMessage(tr("Unknown format"),2000);
}
qApp->processEvents();
scene->addItem(geometry[countMainWindow]);
tableWidget->fileNameUpdate(fileGeometry[countMainWindow],
geometry[countMainWindow]);
view->fitInView(geometry[countMainWindow],Qt::KeepAspectRatio);
//This two functions are fitting the geometry on the view
view->setSceneRect(xmin,-ymax,width,height);
view->show();
statusBar()->showMessage(tr("Part loaded"),2000);
consoleView->append(fileGeometry[countMainWindow] + " is loaded");
countMainWindow++;
firstTime = false;
qApp->processEvents();
}
////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////
Kind regards,
LM Glasfiber R&D (India) Pvt. Ltd.
Sujan Dasmahapatra
Project Engineer - CFD
Telephone: +91 80 66470248
Mobile:
E-mail: sdh at lmglasfiber.com <mailto:sdh at lmglasfiber.com>
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