Re: After resizing Widget with table, table contents not properly displayed

Richard Dale <[email protected]> Sun, 11 Jul 2004 10:41:39 +0100

Newsgroups	gmane.comp.kde.devel.perl
Organization	Lost Highway
Message-ID	<[email protected]>

On Saturday 10 July 2004 13:10, Richard Dale wrote:
> On Friday 09 July 2004 09:49, Oliver Kreuer wrote:
> > I appended two example scripts. The first shows the strange update
> > behaviour. In the second script I reimplemented method resizeEvent. So
> > the second one works.
> > I also tried the Qt::debug qw(virtual) statement but unfortunately the
> > output doesn't give me a clue.
>
> I've been looking at the source in qtable.cpp, and I noticed that QTimers
> are being used:
>
> baldhead duke 1456% grep -i timer qtable.cpp
> ..
>     widgetStretchTimer->stop();
>     stretchTimer->start( 0, TRUE );
>     widgetStretchTimer->start( 100, TRUE );
>     autoScrollTimer->start( 100, TRUE );
>
> So it looks to me that the problem is that perlqt and qtruby are too slow
> to get something done in 100ms, and the timer times out before anything is
> drawn. Everytime a virtual method is called the PerlQt runtime checks to
> see whether on not you have overriden the method in your perl code:
>
> 	const char *methodName = smoke->methodNames[smoke->methods[method].name];
> 	GV *gv = gv_fetchmethod_autoload(stash, methodName, 0);
> 	if(!gv) return false;
>
> The only way I can think to speed this up is to have some sort of 'virtual
> method callbacks' cache which was only updated when you created a new
> instance of your perl object.
I tried increasing the timeout interval to 1 second, and that had no effect. 
Then I commented out the code above that looks for the perl method via 
autoload, and just made it always return false. Apart from stopping signals 
and slots working, so I had to call tableTwoRows() directly, that didn't have 
any effect.

I just couldn't see what the problem was, so I translated the example to C++. 
Guess what? I doesn't work either! So it does look like some sort of Qt bug, 
or maybe the code is using the QTable api wrongly in some way.

-- Richard

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tabletest.cpp (text/x-c++src, 4.5 KB)

/****************************************************************************
** Form implementation generated from reading ui file 'tabletest.ui'
**
** Created: Sun Jul 11 10:01:57 2004
**      by: The User Interface Compiler ($Id: qt/main.cpp   3.1.1   edited Nov 21 17:40 $)
**
** WARNING! All changes made in this file will be lost!
****************************************************************************/

#include "tabletest.h"

#include <qvariant.h>
#include <qpushbutton.h>
#include <qtable.h>
#include <qlayout.h>
#include <qtooltip.h>
#include <qwhatsthis.h>
#include <qimage.h>
#include <qpixmap.h>
#include <qapplication.h>

/* 
 *  Constructs a TableExample as a child of 'parent', with the 
 *  name 'name' and widget flags set to 'f'.
 */
TableExample::TableExample( QWidget* parent, const char* name, WFlags fl )
    : QWidget( parent, name, fl )
{
    if ( !name )
	setName( "TableExample" );
	
    QGridLayout * table_exampleLayout = new QGridLayout(this, 1, 1, 11, 6, "$table_exampleLayout");

    QFrame * frame6 = new QFrame(this, "frame6");
    frame6->setFrameShape( QFrame::StyledPanel);
    frame6->setFrameShadow( QFrame::Raised );
    QGridLayout * frame6Layout = new QGridLayout(frame6, 1, 1, 11, 6, "$frame6Layout");
    QSpacerItem * spacer = new QSpacerItem(190, 20, QSizePolicy::Expanding, QSizePolicy::Minimum);
    frame6Layout->addItem(spacer, 1, 3);

    One_Row = new QPushButton( frame6, "One_Row" );
    frame6Layout->addWidget(One_Row, 1, 1);

    table = new QTable( this, "table1" );
    table->setNumRows( 8 );
    table->setNumCols( 2 );
    table->setReadOnly( true );
    table->setSelectionMode( QTable::NoSelection );
    table->setLeftMargin(0);                               // don't show left vertical header
    
	frame6Layout->addMultiCellWidget(table, 0, 0, 0, 3);
    
	Two_Rows = new QPushButton( frame6, "Two_Rows" );
    
	frame6Layout->addWidget(Two_Rows, 1, 2);
    QSpacerItem * spacer_2 = new QSpacerItem(190, 20, QSizePolicy::Expanding, QSizePolicy::Minimum);
    frame6Layout->addItem(spacer_2, 1, 0);
    
   table_exampleLayout->addWidget(frame6, 0, 0);
	
	languageChange();
	
    QSize res(586, 482);
    res.expandedTo(minimumSizeHint());
    resize( res );
    clearWState( WState_Polished );

    QObject::connect(One_Row, SIGNAL(clicked()), this, SLOT(tableOneRow()));
    QObject::connect(Two_Rows, SIGNAL(clicked()), this, SLOT(tableTwoRows()));
}

/*
 *  Destroys the object and frees any allocated resources
 */
TableExample::~TableExample()
{
    // no need to delete child widgets, Qt does it all for us
}

void
TableExample::tableOneRow()
{
}

void
TableExample::tableTwoRows()
{
        table->setNumCols(2);
        table->horizontalHeader()->setStretchEnabled(true);
        table->horizontalHeader()->setLabel(0,"Erste Spalte",-1);
        table->horizontalHeader()->setLabel(1,"Zweite Spalte",-1);
        table->horizontalHeader()->setClickEnabled(0,-1);
        table->setNumRows(8);
		table->setFocusPolicy( QTable::NoFocus );
		
        table->setItem(0,0,new QTableItem(table,QTableItem::Never,"One"));
        table->setItem(0,1,new QTableItem(table,QTableItem::Never,""));
        
		table->setItem(1,0,new QTableItem(table,QTableItem::Never,"Two"));
        table->setItem(1,1,new QTableItem(table,QTableItem::Never,""));
		
		table->setItem(2,0,new QTableItem(table,QTableItem::Never,"Three"));
        table->setItem(2,1,new QTableItem(table,QTableItem::Never,""));
		
		table->setItem(3,0,new QTableItem(table,QTableItem::Never,"Four"));
        table->setItem(3,1,new QTableItem(table,QTableItem::Never,""));
		
		table->setItem(4,0,new QTableItem(table,QTableItem::Never,"1_1"));
        table->setItem(4,1,new QTableItem(table,QTableItem::Never,"1_2"));
		
		table->setItem(5,0,new QTableItem(table,QTableItem::Never,"2_1"));
        table->setItem(5,1,new QTableItem(table,QTableItem::Never,"2_2"));
		
		table->setItem(6,0,new QTableItem(table,QTableItem::Never,"3_1"));
        table->setItem(6,1,new QTableItem(table,QTableItem::Never,"3_2"));
		
		table->setItem(7,0,new QTableItem(table,QTableItem::Never,"4_1"));
        table->setItem(7,1,new QTableItem(table,QTableItem::Never,"4_2"));
}

/*
 *  Sets the strings of the subwidgets using the current
 *  language.
 */
void TableExample::languageChange()
{
    setCaption( tr( "TableExample" ) );
    One_Row->setText( trUtf8("One Row") );
    Two_Rows->setText( trUtf8("Two Rows") );
}

int main(int argc, char * argv[]) {
	QApplication app(argc, argv);
	TableExample * w = new TableExample();
	app.setMainWidget(w);
	w->show();
	app.exec();
	return 0;
}

tabletest.h (text/x-chdr, 957 B)

/****************************************************************************
** Form interface generated from reading ui file 'tabletest.ui'
**
** Created: Sun Jul 11 09:24:21 2004
**      by: The User Interface Compiler ($Id: qt/main.cpp   3.1.1   edited Nov 21 17:40 $)
**
** WARNING! All changes made in this file will be lost!
****************************************************************************/

#ifndef FORM1_H
#define FORM1_H

#include <qvariant.h>
#include <qwidget.h>

class QVBoxLayout;
class QHBoxLayout;
class QGridLayout;
class QPushButton;
class QTable;

class TableExample : public QWidget
{
    Q_OBJECT

public:
    TableExample( QWidget* parent = 0, const char* name = 0, WFlags fl = 0 );
    ~TableExample();

    QPushButton* One_Row;
    QPushButton* Two_Rows;
    QTable* table;

public slots:
	void tableOneRow();
	void tableTwoRows();


protected:

protected slots:
    virtual void languageChange();
};

#endif // FORM1_H