KItemListView: add view position in scrollToItem()

An item, on being scrolled to, is always located at the nearest edge of
the view. This is not always convenient. Allow specifying where the item
should be positioned with respect to the view in scrollToItem().

BUG: 423884

1 files changed, 48 insertions, 12 deletions

diff --git a/src/kitemviews/kitemlistview.cpp b/src/kitemviews/kitemlistview.cpp
index 457c02ec5..be22b91cc 100644
--- a/src/kitemviews/kitemlistview.cpp
+++ b/src/kitemviews/kitemlistview.cpp
@@ -537,7 +537,7 @@ bool KItemListView::isElided(int index) const
     return m_sizeHintResolver->isElided(index);
 }
 
-void KItemListView::scrollToItem(int index)
+void KItemListView::scrollToItem(int index, ViewItemPosition viewItemPosition)
 {
     QRectF viewGeometry = geometry();
     if (m_headerWidget->isVisible()) {
@@ -546,29 +546,65 @@ void KItemListView::scrollToItem(int index)
     }
     QRectF currentRect = itemRect(index);
 
-    // Fix for Bug 311099 - View the underscore when using Ctrl + PagDown
+    // Fix for Bug 311099 - View the underscore when using Ctrl + PageDown
     currentRect.adjust(-m_styleOption.horizontalMargin, -m_styleOption.verticalMargin, m_styleOption.horizontalMargin, m_styleOption.verticalMargin);
 
-    if (!viewGeometry.contains(currentRect)) {
-        qreal newOffset = scrollOffset();
-        if (scrollOrientation() == Qt::Vertical) {
+    qreal newOffset = scrollOffset();
+    if (scrollOrientation() == Qt::Vertical && (currentRect.top() < viewGeometry.top() || currentRect.bottom() > viewGeometry.bottom())) {
+        switch (viewItemPosition) {
+        case Beginning:
+            newOffset += currentRect.top() - viewGeometry.top();
+            break;
+        case Middle:
+            newOffset += 0.5 * (currentRect.top() + currentRect.bottom() - (viewGeometry.top() + viewGeometry.bottom()));
+            break;
+        case End:
+            newOffset += currentRect.bottom() - viewGeometry.bottom();
+            break;
+        case Nearest:
             if (currentRect.top() < viewGeometry.top()) {
                 newOffset += currentRect.top() - viewGeometry.top();
-            } else if (currentRect.bottom() > viewGeometry.bottom()) {
+            } else {
                 newOffset += currentRect.bottom() - viewGeometry.bottom();
             }
-        } else {
+            break;
+        default:
+            Q_UNREACHABLE();
+        }
+    } else if (scrollOrientation() == Qt::Horizontal && (currentRect.left() < viewGeometry.left() || currentRect.right() > viewGeometry.right())) {
+        switch (viewItemPosition) {
+        case Beginning:
+            if (layoutDirection() == Qt::RightToLeft) {
+                newOffset += currentRect.right() - viewGeometry.right();
+            } else {
+                newOffset += currentRect.left() - viewGeometry.left();
+            }
+            break;
+        case Middle:
+            newOffset += 0.5 * (currentRect.left() + currentRect.right() - (viewGeometry.left() + viewGeometry.right()));
+            break;
+        case End:
+            if (layoutDirection() == Qt::RightToLeft) {
+                newOffset += currentRect.left() - viewGeometry.left();
+            } else {
+                newOffset += currentRect.right() - viewGeometry.right();
+            }
+            break;
+        case Nearest:
             if (currentRect.left() < viewGeometry.left()) {
                 newOffset += currentRect.left() - viewGeometry.left();
-            } else if (currentRect.right() > viewGeometry.right()) {
+            } else {
                 newOffset += currentRect.right() - viewGeometry.right();
             }
+            break;
+        default:
+            Q_UNREACHABLE();
         }
+    }
 
-        if (newOffset != scrollOffset()) {
-            Q_EMIT scrollTo(newOffset);
-            return;
-        }
+    if (newOffset != scrollOffset()) {
+        Q_EMIT scrollTo(newOffset);
+        return;
     }
 
     Q_EMIT scrollingStopped();