5 files changed, 26 insertions, 9 deletions

diff --git a/src/kitemviews/kitemlistcontainer.cpp b/src/kitemviews/kitemlistcontainer.cpp
index 128140e2e..3ec56e5f1 100644
--- a/src/kitemviews/kitemlistcontainer.cpp
+++ b/src/kitemviews/kitemlistcontainer.cpp
@@ -286,7 +286,6 @@ void KItemListContainer::updateScrollOffsetScrollBar()
 
     KItemListSmoothScroller *smoothScroller = nullptr;
     QScrollBar *scrollOffsetScrollBar = nullptr;
-    int singleStep = 0;
     int pageStep = 0;
     int maximum = 0;
     if (view->scrollOrientation() == Qt::Vertical) {
@@ -296,13 +295,6 @@ void KItemListContainer::updateScrollOffsetScrollBar()
         }
         scrollOffsetScrollBar = verticalScrollBar();
 
-        // Don't scroll super fast when using a wheel mouse:
-        // We want to consider one "line" to be the text label which has a
-        // roughly fixed height rather than using the height of the icon which
-        // may be very tall
-        const QFontMetrics metrics(font());
-        singleStep = metrics.height() * QApplication::wheelScrollLines();
-
         // We cannot use view->size().height() because this height might
         // include the header widget, which is not part of the scrolled area.
         pageStep = view->verticalPageStep();
@@ -318,11 +310,11 @@ void KItemListContainer::updateScrollOffsetScrollBar()
             return;
         }
         scrollOffsetScrollBar = horizontalScrollBar();
-        singleStep = view->itemSize().width();
         pageStep = view->size().width();
         maximum = qMax(0, int(view->maximumScrollOffset() - view->size().width()));
     }
 
+    const int singleStep = view->scrollSingleStep();
     const int value = view->scrollOffset();
     if (smoothScroller->requestScrollBarUpdate(maximum)) {
         const bool updatePolicy = (scrollOffsetScrollBar->maximum() > 0 && maximum == 0) || horizontalScrollBarPolicy() == Qt::ScrollBarAlwaysOn;
diff --git a/src/kitemviews/kitemlistview.cpp b/src/kitemviews/kitemlistview.cpp
index c56785c36..265e41e6c 100644
--- a/src/kitemviews/kitemlistview.cpp
+++ b/src/kitemviews/kitemlistview.cpp
@@ -398,6 +398,12 @@ void KItemListView::setGeometry(const QRectF &rect)
     doLayout(NoAnimation);
 }
 
+qreal KItemListView::scrollSingleStep() const
+{
+    const QFontMetrics metrics(font());
+    return metrics.height();
+}
+
 qreal KItemListView::verticalPageStep() const
 {
     qreal headerHeight = 0;
diff --git a/src/kitemviews/kitemlistview.h b/src/kitemviews/kitemlistview.h
index 7fb3344b4..1a4ff0df1 100644
--- a/src/kitemviews/kitemlistview.h
+++ b/src/kitemviews/kitemlistview.h
@@ -176,6 +176,11 @@ public:
     qreal verticalPageStep() const;
 
     /**
+     * @return The line step which should be used for the scroll by mouse wheel.
+     */
+    virtual qreal scrollSingleStep() const;
+
+    /**
      * @return Index of the item that is below the point \a pos.
      *         The position is relative to the upper right of
      *         the visible area. Only (at least partly) visible
diff --git a/src/kitemviews/kstandarditemlistview.cpp b/src/kitemviews/kstandarditemlistview.cpp
index a4e7c3edd..0d57388f3 100644
--- a/src/kitemviews/kstandarditemlistview.cpp
+++ b/src/kitemviews/kstandarditemlistview.cpp
@@ -4,6 +4,8 @@
  * SPDX-License-Identifier: GPL-2.0-or-later
  */
 
+#include <QApplication>
+
 #include "kstandarditemlistview.h"
 
 #include "kstandarditemlistwidget.h"
@@ -110,6 +112,17 @@ bool KStandardItemListView::itemLayoutSupportsItemExpanding(ItemLayout layout) c
     return layout == DetailsLayout;
 }
 
+qreal KStandardItemListView::scrollSingleStep() const
+{
+    if (itemLayout() == DetailsLayout) {
+        // We want each scroll in details view mode to move by some number of complete rows.
+        const int rowsPerFullScroll = qCeil((KItemListView::scrollSingleStep() * QApplication::wheelScrollLines()) / itemSize().height());
+        return (rowsPerFullScroll * itemSize().height()) / QApplication::wheelScrollLines();
+    }
+
+    return KItemListView::scrollSingleStep();
+}
+
 void KStandardItemListView::onItemLayoutChanged(ItemLayout current, ItemLayout previous)
 {
     Q_UNUSED(current)
diff --git a/src/kitemviews/kstandarditemlistview.h b/src/kitemviews/kstandarditemlistview.h
index 396383718..eb2f01d19 100644
--- a/src/kitemviews/kstandarditemlistview.h
+++ b/src/kitemviews/kstandarditemlistview.h
@@ -48,6 +48,7 @@ protected:
     /** To be overriden by sub-classes to specify when full row highlighting should be enabled. */
     virtual bool itemLayoutHighlightEntireRow(ItemLayout layout) const;
     virtual void onItemLayoutChanged(ItemLayout current, ItemLayout previous);
+    virtual qreal scrollSingleStep() const override;
     void onScrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous) override;
     void onSupportsItemExpandingChanged(bool supportsExpanding) override;
     void polishEvent() override;