How can i replace big text in QLegendItem

**ruzik** · 28th December 2011, 16:59

Hellow!
How can i replace big text in the QLegendItem, for example:
I have this text "x^2+12325*x+14124", how can i do that program replace this on the "x^2...124"
In advance many thanks for your help!

**Uwe** · 2nd January 2012, 09:39

Well if your question is about this particular text you can simply set the shorter string as curve title.

A more general solution is to overload QwtPlotItem::updateLegend():

Qt Code:

Switch view

void YourCurve::updateLegend( QwtLegend *legend ) const
{
    if ( legend == NULL )
        return;
 
   QwtPlotCurve::updateLegend( legend );
 
   QwtLegendItem *label = qobject_cast<QwtLegendItem *>( legend->find( this ) );
   if ( label )
   {
       QwtText text = title();
       ...
       label->setText( ... );
    }
}

void YourCurve::updateLegend( QwtLegend *legend ) const
{
    if ( legend == NULL )
        return;

   QwtPlotCurve::updateLegend( legend );

   QwtLegendItem *label = qobject_cast<QwtLegendItem *>( legend->find( this ) );
   if ( label )
   {
       QwtText text = title();
       ...
       label->setText( ... );
    }
}

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Unfortunately there is no support for Qt::TextElideMode in the Qwt layout system yet,

Uwe

**ruzik** · 2nd January 2012, 15:17

It is question not about particular text, there are any text

**pkj** · 5th January 2012, 18:43

the solution Uwe suggested is not about particular text as well. Suppose you set your curve a title. That title is what you want to appear in the legend. In updateLegend function, title() gives that title you have set. Now suppose you want only 10 chars max in your title...then take out the first 4 chars of string, append with '...' then take out the last four chars of string and append, etc...