Allow to specify whether an upscaling of images should be done

The option is currently hidden as up to now only Nuno requested it,
but it seems to be urgent: "my icon making productivity has drop subtantialy"
((c) 2012 Nuno)

As I don't want to get blamed for an outdated Oxygen-icon-set I have
no other choice ;-)

CCMAIL: nuno.pinheiro@kdab.com

dolphin/src/kitemviews/kfileitemlistview.cpp

@@ -82,13 +82,25 @@ KFileItemListView::~KFileItemListView()
 void KFileItemListView::setPreviewsShown(bool show)
 {
     if (m_modelRolesUpdater) {
-        m_modelRolesUpdater->setPreviewShown(show);
+        m_modelRolesUpdater->setPreviewsShown(show);
     }
 }
 
 bool KFileItemListView::previewsShown() const
 {
-    return m_modelRolesUpdater->isPreviewShown();
+    return m_modelRolesUpdater ? m_modelRolesUpdater->previewsShown() : false;
+}
+
+void KFileItemListView::setEnlargeSmallPreviews(bool enlarge)
+{
+    if (m_modelRolesUpdater) {
+        m_modelRolesUpdater->setEnlargeSmallPreviews(enlarge);
+    }
+}
+
+bool KFileItemListView::enlargeSmallPreviews() const
+{
+    return m_modelRolesUpdater ? m_modelRolesUpdater->enlargeSmallPreviews() : false;
 }
 
 void KFileItemListView::setItemLayout(Layout layout)

dolphin/src/kitemviews/kfileitemlistview.h

@@ -54,6 +54,14 @@ public:
     void setPreviewsShown(bool show);
     bool previewsShown() const;
 
+    /**
+     * If enabled a small preview gets upscaled to the icon size in case where
+     * the icon size is larger than the preview. Per default enlarging is
+     * enabled.
+     */
+    void setEnlargeSmallPreviews(bool enlarge);
+    bool enlargeSmallPreviews() const;
+
     void setItemLayout(Layout layout);
     Layout itemLayout() const;
 

dolphin/src/kitemviews/kfileitemmodelrolesupdater.cpp

@@ -67,6 +67,7 @@ KFileItemModelRolesUpdater::KFileItemModelRolesUpdater(KFileItemModel* model, QO
     m_iconSizeChangedDuringPausing(false),
     m_rolesChangedDuringPausing(false),
     m_previewShown(false),
+    m_enlargeSmallPreviews(true),
     m_clearPreviews(false),
     m_model(model),
     m_iconSize(),
@@ -155,7 +156,7 @@ void KFileItemModelRolesUpdater::setVisibleIndexRange(int index, int count)
     }
 }
 
-void KFileItemModelRolesUpdater::setPreviewShown(bool show)
+void KFileItemModelRolesUpdater::setPreviewsShown(bool show)
 {
     if (show == m_previewShown) {
         return;
@@ -166,30 +167,35 @@ void KFileItemModelRolesUpdater::setPreviewShown(bool show)
         m_clearPreviews = true;
     }
 
-    if (m_paused) {
-        m_previewChangedDuringPausing = true;
-    } else {
-        sortAndResolveAllRoles();
+    updateAllPreviews();
+}
+
+bool KFileItemModelRolesUpdater::previewsShown() const
+{
+    return m_previewShown;
+}
+
+void KFileItemModelRolesUpdater::setEnlargeSmallPreviews(bool enlarge)
+{
+    if (enlarge != m_enlargeSmallPreviews) {
+        m_enlargeSmallPreviews = enlarge;
+        if (m_previewShown) {
+            updateAllPreviews();
+        }
     }
 }
 
-bool KFileItemModelRolesUpdater::isPreviewShown() const
+bool KFileItemModelRolesUpdater::enlargeSmallPreviews() const
 {
-    return m_previewShown;
+    return m_enlargeSmallPreviews;
 }
 
 void KFileItemModelRolesUpdater::setEnabledPlugins(const QStringList& list)
 {
     if (m_enabledPlugins == list) {
-        return;
-    }
-
-    m_enabledPlugins = list;
-    if (m_previewShown) {
-        if (m_paused) {
-            m_previewChangedDuringPausing = true;
-        } else {
-            sortAndResolveAllRoles();
+        m_enabledPlugins = list;
+        if (m_previewShown) {
+            updateAllPreviews();
         }
     }
 }
@@ -390,7 +396,34 @@ void KFileItemModelRolesUpdater::slotGotPreview(const KFileItem& item, const QPi
     const int slashIndex = mimeType.indexOf(QLatin1Char('/'));
     const QString mimeTypeGroup = mimeType.left(slashIndex);
     if (mimeTypeGroup == QLatin1String("image")) {
-        KPixmapModifier::applyFrame(scaledPixmap, m_iconSize);
+        if (m_enlargeSmallPreviews) {
+            KPixmapModifier::applyFrame(scaledPixmap, m_iconSize);
+        } else {
+            // Assure that small previews don't get enlarged. Instead they
+            // should be shown centered within the frame.
+            const QSize contentSize = KPixmapModifier::sizeInsideFrame(m_iconSize);
+            const bool enlargingRequired = scaledPixmap.width()  < contentSize.width() &&
+                                           scaledPixmap.height() < contentSize.height();
+            if (enlargingRequired) {
+                QSize frameSize = scaledPixmap.size();
+                frameSize.scale(m_iconSize, Qt::KeepAspectRatio);
+
+                QPixmap largeFrame(frameSize);
+                largeFrame.fill(Qt::transparent);
+
+                KPixmapModifier::applyFrame(largeFrame, frameSize);
+
+                QPainter painter(&largeFrame);
+                painter.drawPixmap((largeFrame.width()  - scaledPixmap.width()) / 2,
+                                   (largeFrame.height() - scaledPixmap.height()) / 2,
+                                   scaledPixmap);
+                scaledPixmap = largeFrame;
+            } else {
+                // The image must be shrinked as it is too large to fit into
+                // the available icon size
+                KPixmapModifier::applyFrame(scaledPixmap, m_iconSize);
+            }
+        }
     } else {
         KPixmapModifier::scale(scaledPixmap, m_iconSize);
     }
@@ -968,4 +1001,13 @@ int KFileItemModelRolesUpdater::subItemsCount(const QString& path) const
 #endif
 }
 
+void KFileItemModelRolesUpdater::updateAllPreviews()
+{
+    if (m_paused) {
+        m_previewChangedDuringPausing = true;
+    } else {
+        sortAndResolveAllRoles();
+    }
+}
+
 #include "kfileitemmodelrolesupdater.moc"

dolphin/src/kitemviews/kfileitemmodelrolesupdater.h

@@ -81,8 +81,16 @@ public:
      * of the file. If \a show is false the MIME type icon will be used for the "iconPixmap"
      * role.
      */
-    void setPreviewShown(bool show);
-    bool isPreviewShown() const;
+    void setPreviewsShown(bool show);
+    bool previewsShown() const;
+
+    /**
+     * If enabled a small preview gets upscaled to the icon size in case where
+     * the icon size is larger than the preview. Per default enlarging is
+     * enabled.
+     */
+    void setEnlargeSmallPreviews(bool enlarge);
+    bool enlargeSmallPreviews() const;
 
     /**
      * If \a paused is set to true the asynchronous resolving of roles will be paused.
@@ -187,6 +195,12 @@ private:
      */
     int subItemsCount(const QString& path) const;
 
+    /**
+     * Must be invoked if a property has been changed that affects
+     * the look of the preview. Takes care to update all previews.
+     */
+    void updateAllPreviews();
+
 private:
     // Property for setPaused()/isPaused().
     bool m_paused;
@@ -197,9 +211,12 @@ private:
     bool m_iconSizeChangedDuringPausing;
     bool m_rolesChangedDuringPausing;
 
-    // Property for setPreviewShown()/previewShown().
+    // Property for setPreviewsShown()/previewsShown().
     bool m_previewShown;
 
+    // Property for setEnlargeSmallPreviews()/enlargeSmallPreviews()
+    bool m_enlargeSmallPreviews;
+
     // True if the role "iconPixmap" should be cleared when resolving the next
     // role with resolveRole(). Is necessary if the preview gets disabled
     // during the roles-updater has been paused by setPaused().

dolphin/src/kitemviews/kpixmapmodifier.cpp

@@ -392,3 +392,9 @@ void KPixmapModifier::applyFrame(QPixmap& icon, const QSize& scaledSize)
     icon = framedIcon;
 }
 
+QSize KPixmapModifier::sizeInsideFrame(const QSize& frameSize)
+{
+    return QSize(frameSize.width() - TileSet::LeftMargin - TileSet::RightMargin,
+                 frameSize.height() - TileSet::TopMargin - TileSet::BottomMargin);
+}
+

dolphin/src/kitemviews/kpixmapmodifier_p.h

@@ -30,6 +30,7 @@ class LIBDOLPHINPRIVATE_EXPORT KPixmapModifier
 public:
     static void scale(QPixmap& pixmap, const QSize& scaledSize);
     static void applyFrame(QPixmap& icon, const QSize& scaledSize);
+    static QSize sizeInsideFrame(const QSize& frameSize);
 };
 
 #endif

dolphin/src/settings/dolphin_generalsettings.kcfg

@@ -83,5 +83,9 @@
             <label>Lock the layout of the panels</label>
             <default>true</default>
         </entry>
+        <entry name="EnlargeSmallPreviews" type="Bool">
+            <label>Enlarge Small Previews</label>
+            <default>true</default>
+        </entry>
     </group>
 </kcfg>

dolphin/src/views/dolphinitemlistcontainer.cpp

@@ -48,9 +48,11 @@ DolphinItemListContainer::DolphinItemListContainer(KDirLister* dirLister,
     controller()->setModel(new KFileItemModel(dirLister, this));
 
     m_fileItemListView = new KFileItemListView();
+    controller()->setView(m_fileItemListView);
+
     m_fileItemListView->setWidgetCreator(new KItemListWidgetCreator<DolphinFileItemListWidget>());
     m_fileItemListView->setEnabledSelectionToggles(GeneralSettings::showSelectionToggle());
-    controller()->setView(m_fileItemListView);
+    m_fileItemListView->setEnlargeSmallPreviews(GeneralSettings::enlargeSmallPreviews());
 
     updateAutoActivationDelay();
     updateFont();