BlueBrain · rdumusc · Jun 23, 2016 · Jun 22, 2016 · Jun 22, 2016 · Jun 22, 2016
diff --git a/apps/Launcher/qml/FileBrowser.qml b/apps/Launcher/qml/FileBrowser.qml
@@ -60,12 +60,14 @@ Rectangle {
                     GradientStop { position: 0.0; color: Style.placeholderTopColor }
                     GradientStop { position: 1.0; color: Style.placeholderBottomColor }
                 }
-                Image {
-                    id: thumbnail
-                    anchors.fill: parent
-                    source: "image://thumbnail/" + filePath
-                    fillMode: Image.PreserveAspectFit
-                }
+                visible: thumbnail.status !== Image.Ready
+            }
+            Image {
+                id: thumbnail
+                anchors.fill: placeholder
+                fillMode: Image.PreserveAspectFit
+                cache: false
+                source: "image://thumbnail/" + filePath
             }
 
             Text {

diff --git a/doc/Changelog.md b/doc/Changelog.md
@@ -3,6 +3,11 @@ Changelog {#Changelog}
 
 # git master (1.1.0)
 
+* [46](https://github.com/BlueBrain/Tide/pull/46):
+  Improved Launcher:
+  - The creation and caching of file thumbnails is more efficient.
+  - File thumbnails are displayed with their correct aspect ratio.
+  Session preview images are of better quality (no longer pixelated).
 * [38](https://github.com/BlueBrain/Tide/pull/38):
   Fix a segfault that occured when opening grayscale images.
 * [36](https://github.com/BlueBrain/Tide/pull/36):

diff --git a/tests/cpp/core/StateSerializationTests.cpp b/tests/cpp/core/StateSerializationTests.cpp
@@ -414,16 +414,17 @@ BOOST_AUTO_TEST_CASE( testStateSerializationToFile )
     BOOST_CHECK_LT( previewError, 0.02f );
 
     // 4) Test restoring
-    DisplayGroupPtr loadedDisplayGroup = boost::make_shared<DisplayGroup>( wallSize );
-    StateSerializationHelper loader( loadedDisplayGroup );
+    DisplayGroupPtr loadedGroup = boost::make_shared<DisplayGroup>( wallSize );
+    StateSerializationHelper loader( loadedGroup );
     BOOST_CHECK( loader.load( TEST_DIR + "/test.dcx" ));
 
-    BOOST_REQUIRE_EQUAL( loadedDisplayGroup->getContentWindows().size(),
+    BOOST_REQUIRE_EQUAL( loadedGroup->getContentWindows().size(),
                          displayGroup->getContentWindows().size( ));
-    BOOST_REQUIRE_EQUAL( loadedDisplayGroup->getShowWindowTitles(),
+    BOOST_REQUIRE_EQUAL( loadedGroup->getShowWindowTitles(),
                          displayGroup->getShowWindowTitles());
-    BOOST_REQUIRE_EQUAL( loadedDisplayGroup->getCoordinates(), QRectF( QPointF( 0, 0 ), wallSize ));
-    checkWindow( loadedDisplayGroup->getContentWindows()[0] );
+    BOOST_REQUIRE_EQUAL( loadedGroup->getCoordinates(),
+                         QRectF( QPointF( 0, 0 ), wallSize ));
+    checkWindow( loadedGroup->getContentWindows()[0] );
 
     // 4) Cleanup
     cleanupTestDir();

diff --git a/tests/resources/state_v0.dcxpreview b/tests/resources/state_v0.dcxpreview
diff --git a/tide/core/StatePreview.cpp b/tide/core/StatePreview.cpp
@@ -1,5 +1,5 @@
 /*********************************************************************/
-/* Copyright (c) 2013, EPFL/Blue Brain Project                       */
+/* Copyright (c) 2013-2016, EPFL/Blue Brain Project                  */
 /*                     Raphael Dumusc <raphael.dumusc@epfl.ch>       */
 /* All rights reserved.                                              */
 /*                                                                   */
@@ -55,12 +55,11 @@
 
 namespace
 {
-static const QSize PREVIEW_IMAGE_SIZE( 512, 512 );
-static const QSize THUMBNAIL_SIZE( 128, 128 );
+const QSize PREVIEW_IMAGE_SIZE( 512, 512 );
 }
 
 StatePreview::StatePreview( const QString &dcxFileName )
-    : dcxFileName_( dcxFileName )
+    : _dcxFileName( dcxFileName )
 {
 }
 
@@ -71,20 +70,20 @@ QString StatePreview::getFileExtension()
 
 QImage StatePreview::getImage() const
 {
-    return previewImage_;
+    return _previewImage;
 }
 
 QString StatePreview::previewFilename() const
 {
-    QFileInfo fileinfo( dcxFileName_ );
+    QFileInfo fileinfo( _dcxFileName );
 
     const QString extension = fileinfo.suffix().toLower();
     if( extension != "dcx" )
     {
         put_flog( LOG_WARN, "wrong state file extension: '%s' for session: '%s'"
                             "(expected: .dcx)",
                   extension.toLocal8Bit().constData( ),
-                  dcxFileName_.toLocal8Bit().constData( ));
+                  _dcxFileName.toLocal8Bit().constData( ));
         return QString();
     }
     return fileinfo.path() + "/" + fileinfo.completeBaseName() + getFileExtension();
@@ -117,20 +116,21 @@ void StatePreview::generateImage( const QSize& wallDimensions,
 
         const QString& filename = window->getContent()->getURI();
         ThumbnailGeneratorPtr generator =
-            ThumbnailGeneratorFactory::getGenerator( filename, THUMBNAIL_SIZE );
+            ThumbnailGeneratorFactory::getGenerator( filename,
+                                                     area.size().toSize( ));
         const QImage image = generator->generate( filename );
 
         painter.drawImage( area, image );
     }
 
     painter.end();
 
-    previewImage_ = preview;
+    _previewImage = preview;
 }
 
 bool StatePreview::saveToFile() const
 {
-    const bool success = previewImage_.save( previewFilename(), "PNG" );
+    const bool success = _previewImage.save( previewFilename(), "PNG" );
 
     if( !success )
         put_flog( LOG_ERROR, "Saving StatePreview image failed: '%s'",
@@ -142,9 +142,5 @@ bool StatePreview::saveToFile() const
 bool StatePreview::loadFromFile()
 {
     QImageReader reader( previewFilename( ));
-    if ( reader.canRead( ))
-    {
-        return reader.read( &previewImage_ );
-    }
-    return false;
+    return reader.canRead() && reader.read( &_previewImage );
 }
diff --git a/tide/core/StatePreview.h b/tide/core/StatePreview.h
@@ -1,5 +1,5 @@
 /*********************************************************************/
-/* Copyright (c) 2013, EPFL/Blue Brain Project                       */
+/* Copyright (c) 2013-2016, EPFL/Blue Brain Project                  */
 /*                     Raphael Dumusc <raphael.dumusc@epfl.ch>       */
 /* All rights reserved.                                              */
 /*                                                                   */
@@ -96,8 +96,8 @@ class StatePreview
 protected:
     QString previewFilename() const;
 
-    QString dcxFileName_;
-    QImage previewImage_;
+    QString _dcxFileName;
+    QImage _previewImage;
 };
 
 #endif // STATEPREVIEW_H
diff --git a/tide/core/thumbnail/DefaultThumbnailGenerator.cpp b/tide/core/thumbnail/DefaultThumbnailGenerator.cpp
@@ -1,5 +1,5 @@
 /*********************************************************************/
-/* Copyright (c) 2013, EPFL/Blue Brain Project                       */
+/* Copyright (c) 2013-2016, EPFL/Blue Brain Project                  */
 /*                     Raphael Dumusc <raphael.dumusc@epfl.ch>       */
 /* All rights reserved.                                              */
 /*                                                                   */
@@ -39,15 +39,14 @@
 
 #include "DefaultThumbnailGenerator.h"
 
-DefaultThumbnailGenerator::DefaultThumbnailGenerator(const QSize &size)
-    : ThumbnailGenerator(size)
+DefaultThumbnailGenerator::DefaultThumbnailGenerator( const QSize& size )
+    : ThumbnailGenerator( size )
 {
 }
 
-QImage DefaultThumbnailGenerator::generate(const QString& filename) const
+QImage DefaultThumbnailGenerator::generate( const QString& ) const
 {
-    QImage img = createGradientImage( QColor(Qt::black), QColor(Qt::white) );
-    paintText(img, "FILE");
-    addMetadataToImage(img, filename);
+    QImage img = createGradientImage( QColor( Qt::black ), QColor( Qt::white ));
+    paintText( img, "FILE" );
     return img;
 }
diff --git a/tide/core/thumbnail/DefaultThumbnailGenerator.h b/tide/core/thumbnail/DefaultThumbnailGenerator.h
@@ -1,5 +1,5 @@
 /*********************************************************************/
-/* Copyright (c) 2013, EPFL/Blue Brain Project                       */
+/* Copyright (c) 2013-2016, EPFL/Blue Brain Project                  */
 /*                     Raphael Dumusc <raphael.dumusc@epfl.ch>       */
 /* All rights reserved.                                              */
 /*                                                                   */
@@ -45,9 +45,9 @@
 class DefaultThumbnailGenerator : public ThumbnailGenerator
 {
 public:
-    DefaultThumbnailGenerator(const QSize& size);
+    DefaultThumbnailGenerator( const QSize& size );
 
-    QImage generate(const QString& filename) const override;
+    QImage generate( const QString& filename ) const final;
 };
 
-#endif // DEFAULTTHUMBNAILGENERATOR_H
+#endif
diff --git a/tide/core/thumbnail/FolderThumbnailGenerator.cpp b/tide/core/thumbnail/FolderThumbnailGenerator.cpp
@@ -39,14 +39,14 @@
 
 #include "FolderThumbnailGenerator.h"
 
-#include <QDir>
-#include <QPainter>
-
+#include "ContentFactory.h"
 #include "ThumbnailGeneratorFactory.h"
 #include "ThumbnailGenerator.h"
-#include "ContentFactory.h"
 #include "log.h"
 
+#include <QDir>
+#include <QPainter>
+
 namespace
 {
 const int FOLDER_THUMBNAILS_X = 2;
@@ -57,75 +57,49 @@ const QString FOLDER_TEXT( "folder" );
 
 FolderThumbnailGenerator::FolderThumbnailGenerator( const QSize& size )
     : ThumbnailGenerator( size )
-{
-}
+{}
 
 QImage FolderThumbnailGenerator::generate( const QString& filename ) const
 {
     const QDir dir( filename );
     if( dir.exists( ))
-        return createFolderImage( dir, true );
+        return _createFolderImage( dir, true );
 
     put_flog( LOG_ERROR, "invalid directory: %s",
               filename.toLocal8Bit().constData( ));
     return createErrorImage( "folder" );
 }
 
 QImage
-FolderThumbnailGenerator::generatePlaceholderImage( const QDir& dir ) const
+FolderThumbnailGenerator::_createFolderImage( const QDir& dir,
+                                              const bool generateThumbnails ) const
 {
     QImage img = createGradientImage( Qt::black, Qt::white );
-    addMetadataToImage( img, dir.path( ));
-    return img;
-}
 
-void FolderThumbnailGenerator::addMetadataToImage( QImage& img,
-                                                   const QString& url ) const
-{
-    img.setText( "dir", "true" );
-    ThumbnailGenerator::addMetadataToImage( img, url );
-}
-
-QVector<QRectF>
-FolderThumbnailGenerator::calculatePlacement( int nX, int nY, float padding,
-                                              float totalWidth,
-                                              float totalHeight ) const
-{
-    const float totalPaddingWidth = padding*(nX+1);
-    const float imageWidth = (1.0f-totalPaddingWidth)/(float)nX;
+    const QFileInfoList& fileList = _getSupportedFilesInDir( dir );
 
-    const float totalPaddingHeight = padding*(nY+1);
-    const float imageHeight = (1.0f-totalPaddingHeight)/(float)nY;
+    if( generateThumbnails && fileList.size() > 0 )
+        _paintThumbnailsMosaic( img, fileList );
+    else
+        paintText( img, FOLDER_TEXT );
 
-    QVector<QRectF> rect;
-    for( int j = 0; j < nY; ++j )
-    {
-        const float y = padding + j*(imageHeight+padding);
-        for( int i = 0; i < nX; ++i )
-        {
-            const float x = padding + i*(imageWidth+padding);
-            rect.append( QRect( x*totalWidth, y*totalHeight,
-                                imageWidth*totalWidth,
-                                imageHeight*totalHeight ));
-        }
-    }
-    return rect;
+    return img;
 }
 
-void FolderThumbnailGenerator::paintThumbnailsMosaic( QImage& img,
-                                                      const QFileInfoList&
-                                                      fileList) const
+void FolderThumbnailGenerator::_paintThumbnailsMosaic( QImage& img,
+                                                       const QFileInfoList&
+                                                       fileList ) const
 {
     const int numPreviews = std::min( FOLDER_THUMBNAILS_X*FOLDER_THUMBNAILS_Y,
                                       fileList.size( ));
     if( numPreviews == 0 )
         return;
 
-    QVector<QRectF> rect = calculatePlacement( FOLDER_THUMBNAILS_X,
-                                               FOLDER_THUMBNAILS_Y,
-                                               FOLDER_THUMBNAILS_PADDING,
-                                               img.size().width(),
-                                               img.size().height( ));
+    QVector<QRectF> rect = _calculatePlacement( FOLDER_THUMBNAILS_X,
+                                                FOLDER_THUMBNAILS_Y,
+                                                FOLDER_THUMBNAILS_PADDING,
+                                                img.size().width(),
+                                                img.size().height( ));
     QPainter painter( &img );
     for( int i = 0; i < numPreviews; ++i )
     {
@@ -135,33 +109,53 @@ void FolderThumbnailGenerator::paintThumbnailsMosaic( QImage& img,
         QImage thumbnail;
         // Avoid recursion into subfolders
         if( QDir( filename ).exists( ))
-            thumbnail = createFolderImage( QDir( filename ), false );
+            thumbnail = _createFolderImage( QDir( filename ), false );
         else
-            thumbnail = ThumbnailGeneratorFactory::getGenerator( filename, size_ )->generate( filename );
+        {
+            const auto size = rect[i].size().toSize();
+            auto generator =
+                    ThumbnailGeneratorFactory::getGenerator( filename, size );
+            thumbnail = generator->generate( filename );
+        }
 
-        painter.drawImage( rect[i], thumbnail );
+        // Draw the thumbnail centered in its rectangle, preserving aspect ratio
+        QSizeF paintedSize( thumbnail.size( ));
+        paintedSize.scale( rect[i].size(), Qt::KeepAspectRatio );
+        QRectF paintRect( QPointF(), paintedSize );
+        paintRect.moveCenter( rect[i].center( ));
+        painter.drawImage( paintRect, thumbnail );
     }
     painter.end();
 }
 
-QImage
-FolderThumbnailGenerator::createFolderImage( const QDir& dir,
-                                             const bool generateThumbnails ) const
+QVector<QRectF>
+FolderThumbnailGenerator::_calculatePlacement( int nX, int nY, float padding,
+                                               float totalWidth,
+                                               float totalHeight ) const
 {
-    QImage img = generatePlaceholderImage( dir );
-
-    const QFileInfoList& fileList = getSupportedFilesInDir( dir );
+    const float totalPaddingWidth = padding*(nX+1);
+    const float imageWidth = (1.0f-totalPaddingWidth)/(float)nX;
 
-    if( generateThumbnails && fileList.size() > 0 )
-        paintThumbnailsMosaic(img, fileList);
-    else
-        paintText( img, FOLDER_TEXT );
+    const float totalPaddingHeight = padding*(nY+1);
+    const float imageHeight = (1.0f-totalPaddingHeight)/(float)nY;
 
-    return img;
+    QVector<QRectF> rect;
+    for( int j = 0; j < nY; ++j )
+    {
+        const float y = padding + j*(imageHeight+padding);
+        for( int i = 0; i < nX; ++i )
+        {
+            const float x = padding + i*(imageWidth+padding);
+            rect.append( QRect( x*totalWidth, y*totalHeight,
+                                imageWidth*totalWidth,
+                                imageHeight*totalHeight ));
+        }
+    }
+    return rect;
 }
 
 QFileInfoList
-FolderThumbnailGenerator::getSupportedFilesInDir( QDir dir ) const
+FolderThumbnailGenerator::_getSupportedFilesInDir( QDir dir ) const
 {
     dir.setFilter( QDir::Files | QDir::NoDotAndDotDot );
     QStringList filters = ContentFactory::getSupportedFilesFilter();