[KPhotoAlbum] Performance issues

[Robert L Krawitz]

   From: "Jesper K. Pedersen" <blackie at blackie.dk>
   Date: Sat, 11 Feb 2006 14:02:45 -0500

   Thanks again for spotting this.  I changed the code so it doesn't
   use QStringList at all in the thumbnail view, but instead a
   QValueVector.

Since you never actually mutate the list, that also makes sense.  I
wanted to make a minimal change to the code for purposes of testing it.

   On Thursday 09 February 2006 21:46, Robert L Krawitz wrote:
   | This change -- which adds a vector in addition to the list for holding
   | the thumbnails -- makes the thumbnail view much more responsive.
   | Flipping between pages now takes about 2 seconds if the thumbnails
   | aren't loaded; if they're already loaded, it's almost instantaneous.
   |
   |
   | [2(rlk)||{!26}<rlk-mobile>/home/rlk/sandbox/kphotoalbum-2006-01-28-noi18n/s
   |rc/ThumbnailView] $ diff -u ThumbnailView.h{~,}
   | --- ThumbnailView.h~    2006-01-28 23:38:50.000000000 -0500
   | +++ ThumbnailView.h     2006-02-09 21:37:58.000000000 -0500
   | @@ -3,6 +3,7 @@
   |
   |  #include <qgridview.h>
   |  #include <qvaluelist.h>
   | +#include <qvaluevector.h>
   |  #include "imageclient.h"
   |  #include "set.h"
   |  #include "ThumbnailToolTip.h"
   | @@ -121,6 +122,12 @@
   |
   |  private:
   |      QStringList _imageList;
   | +    QValueVector<QString> _imageVector;
   | +
   | +    /**
   | +     * Reload the value vector
   | +     */
   | +    void reloadVector(void);
   |
   |      /**
   |       * When the user selects a date on the date bar the thumbnail view
   | will
   | [2(rlk)||{!27}<rlk-mobile>/home/rlk/sandbox/kphotoalbum-2006-01-28-noi18n/s
   |rc/ThumbnailView] $ diff -u ThumbnailView.cpp{~,}
   | --- ThumbnailView.cpp~  2006-01-28 23:38:50.000000000 -0500
   | +++ ThumbnailView.cpp   2006-02-09 21:40:36.000000000 -0500
   | @@ -126,7 +126,14 @@
   |      painter->drawText( rect, align, title );
   |  }
   |
   | -
   | +void ThumbnailView::ThumbnailView::reloadVector( void )
   | +{
   | +    _imageVector.clear();
   | +    _imageVector.reserve(_imageList.count());
   | +    for( QStringList::Iterator imageIt = _imageList.begin(); imageIt !=
   | _imageList.end(); ++imageIt ) +      _imageVector.append(*imageIt);
   | +}
   | +
   |
   |  void ThumbnailView::ThumbnailView::setImageList( const QStringList& list )
   |  {
   | @@ -135,6 +142,8 @@
   |      else
   |          _imageList = reverseList( list );
   |
   | +    reloadVector();
   | +
   |      if ( isVisible() ) {
   |          updateGridSize();
   |          repaintScreen();
   | @@ -148,10 +157,10 @@
   |  QString ThumbnailView::ThumbnailView::fileNameInCell( int row, int col )
   | const {
   |      uint index = row * numCols() + col;
   | -    if ( index >= _imageList.count() )
   | +    if ( index >= _imageVector.count() )
   |          return QString::null;
   |      else
   | -        return _imageList[index];
   | +        return _imageVector[index];
   |  }
   |
   |  /**
   | @@ -790,14 +799,14 @@
   |          _leftDrop = fileName;
   |          int index = _imageList.findIndex( fileName ) -1;
   |          if ( index != -1 )
   | -            _rightDrop = _imageList[index];
   | +            _rightDrop = _imageVector[index];
   |      }
   |
   |      else {
   |          _rightDrop = fileName;
   |          uint index = _imageList.findIndex( fileName ) +1;
   |          if ( index != _imageList.count() )
   | -            _leftDrop = _imageList[index];
   | +            _leftDrop = _imageVector[index];
   |      }
   |
   |      updateCell( _leftDrop );
   | @@ -893,6 +902,9 @@
   |
   |      Options::instance()->setShowNewestFirst( direction == NewestFirst );
   |      _imageList = reverseList( _imageList );
   | +
   | +    reloadVector();
   | +
   |      if ( !_currentItem.isNull() )
   |          setCurrentItem( _currentItem );
   |      repaintScreen();
   |
   | _______________________________________________
   | KPhotoAlbum mailing list
   | KPhotoAlbum at mail.kdab.net
   | http://mail.kdab.net/mailman/listinfo/kphotoalbum

   -- 
   Jesper K. Pedersen          |  Klarälvdalens Datakonsult
   Senior Software Engineer    |  www.klaralvdalens-datakonsult.se
   Prinsensgade 4a st.         |
   9800 Hjørring               |  Platform-independent
   Denmark                     |  software solutions