Build a less (unix http://linux.about.com/library/cmd/blcmdl1_less.htm ) similar function .... and limit him to 20-30 line....

and as slot a vertical slider...... tickintervall 30-20

and get line from file ..... chanche this code to get line start and end...

is very fast....

Qt Code:
  1. QString Sqlitedb::file_get_line(QString fullFileName,int linenr)
  2. {
  3. QString result;
  4. QFile file( fullFileName );
  5. if( file.open( QIODevice::ReadOnly | QIODevice::Text ) ) {
  6. QTextStream in( &file );
  7. int currentLineNr = 0; // or 1
  8. while( ! in.atEnd() ) {
  9. QString line( in.readLine() );
  10. if( currentLineNr == linenr ) { /* only rewrite here .. lineNr */
  11. result = line;
  12. break;
  13. }
  14. currentLineNr += 1;
  15. /*qDebug() << "### linerr " << currentLineNr; */
  16. }
  17. }
  18. return result;
  19. }
To copy to clipboard, switch view to plain text mode