Mirror details view mode for right-to-left languages

This commit implements mirroring of the details view mode for right-to-
left languages. This is the last of the Dolphin view modes which did
not adapt to right-to-left languages correctly.

Implementation-wise this is mostly about adapting the math so all the
information is placed correctly no matter the view mode or layout
direction. While most of the view actually changes the painting code
for right-to-left languages, for the column header I decided to keep
the logic left-to-right and instead reverse the order of the role
columns.

To implement this mirroring I needed to rework quite a bit of logic, so
I used the opportunity to fix some bugs/behaviur quirks:
- Left and right padding is now saved and restored separately instead
  of only saving the left padding
- Changing the right padding no longer disables "automatic column
  resizing".
- The grip handles for column resizing can now be grabbed when near the
  grip handle instead of only allowing grabbing when slightly to the
  left of the grip.
- Role column headers now only show a hover highlight effect when the
  mouse cursor is actually above that role and not above the grip
  handle or the padding.
- There is now a soft-boarder when shrinking the right padding so
  shrinking the padding "below zero width" will no longer immediately
  clear automatic resize behaviour. So now it is possible to simply
  remove the right padding by resizing it to zero width.

BUG: 449211
BUG: 495942

# Acknowledgement

This work is part of a my project funded through the NGI0 Entrust Fund,
a fund established by NLnet with financial support from the European
Commission's Next Generation Internet programme, under the aegis of DG
Communications Networks, Content and Technology.

1 files changed, 48 insertions, 25 deletions

diff --git a/src/kitemviews/kstandarditemlistwidget.cpp b/src/kitemviews/kstandarditemlistwidget.cpp
index bc7023e12..05628d391 100644
--- a/src/kitemviews/kstandarditemlistwidget.cpp
+++ b/src/kitemviews/kstandarditemlistwidget.cpp
@@ -409,15 +409,26 @@ void KStandardItemListWidget::paint(QPainter *painter, const QStyleOptionGraphic
     painter->drawStaticText(textInfo->pos, textInfo->staticText);
 
     bool clipAdditionalInfoBounds = false;
-    if (m_supportsItemExpanding) {
-        // Prevent a possible overlapping of the additional-information texts
-        // with the icon. This can happen if the user has minimized the width
-        // of the name-column to a very small value.
-        const qreal minX = m_pixmapPos.x() + m_pixmap.width() + 4 * itemListStyleOption.padding;
-        if (textInfo->pos.x() + columnWidth("text") > minX) {
-            clipAdditionalInfoBounds = true;
-            painter->save();
-            painter->setClipRect(minX, 0, size().width() - minX, size().height(), Qt::IntersectClip);
+    if (m_supportsItemExpanding && m_sortedVisibleRoles.count() > 1) {
+        // Prevent a possible overlapping of the additional-information-texts with the icon.
+        // This will happen if the user has resized the width of the name-column to be very narrow while having folders expanded.
+        // We only want to draw additional info text outside the area of the icon or expansion area, so we set a clip rect that does not contain the icon area.
+        // This needs to work both for left-to-right as well as right-to-left layout directions.
+        const TextInfo *potentiallyOverlappingRoleText = m_textInfo.value(m_sortedVisibleRoles[1]); // Only the first column after the name column can overlap.
+        if (layoutDirection() == Qt::LeftToRight) { // In left-to-right languages the left end of text would overlap. This is mirrored for right-to-left.
+            const qreal minX = m_iconRect.right() + 2 * itemListStyleOption.padding;
+            if (potentiallyOverlappingRoleText->pos.x() < minX) {
+                clipAdditionalInfoBounds = true;
+                painter->save();
+                painter->setClipRect(minX, 0, size().width() - minX, size().height(), Qt::IntersectClip);
+            }
+        } else {
+            const qreal maxX = m_iconRect.left() - 2 * itemListStyleOption.padding;
+            if (potentiallyOverlappingRoleText->pos.x() + m_customizedFontMetrics.horizontalAdvance(potentiallyOverlappingRoleText->staticText.text()) > maxX) {
+                clipAdditionalInfoBounds = true;
+                painter->save();
+                painter->setClipRect(0, 0, maxX, size().height(), Qt::IntersectClip);
+            }
         }
     }
 
@@ -524,7 +535,11 @@ QRectF KStandardItemListWidget::selectionRect() const
         QRectF adjustedIconRect = iconRect().adjusted(-padding, -padding, padding, padding);
         QRectF result = adjustedIconRect | m_textRect;
         if (m_highlightEntireRow) {
-            result.setRight(m_columnWidthSum + sidePadding());
+            if (layoutDirection() == Qt::LeftToRight) {
+                result.setRight(leftPadding() + m_columnWidthSum);
+            } else {
+                result.setLeft(size().width() - m_columnWidthSum - rightPadding());
+            }
         }
         return result;
     }
@@ -786,9 +801,10 @@ void KStandardItemListWidget::columnWidthChanged(const QByteArray &role, qreal c
     m_dirtyLayout = true;
 }
 
-void KStandardItemListWidget::sidePaddingChanged(qreal padding)
+void KStandardItemListWidget::sidePaddingChanged(qreal leftPaddingWidth, qreal rightPaddingWidth)
 {
-    Q_UNUSED(padding)
+    Q_UNUSED(leftPaddingWidth)
+    Q_UNUSED(rightPaddingWidth)
     m_dirtyLayout = true;
 }
 
@@ -1012,8 +1028,13 @@ void KStandardItemListWidget::updateExpansionArea()
             const qreal inc = (widgetHeight - widgetIconSize) / 2;
             const qreal x = expandedParentsCount * widgetHeight + inc;
             const qreal y = inc;
-            const qreal xPadding = m_highlightEntireRow ? sidePadding() : 0;
-            m_expansionArea = QRectF(xPadding + x, y, widgetIconSize, widgetIconSize);
+            if (layoutDirection() == Qt::LeftToRight) {
+                const qreal leftPaddingWidth = m_highlightEntireRow ? leftPadding() : 0;
+                m_expansionArea = QRectF(leftPaddingWidth + x, y, widgetIconSize, widgetIconSize);
+                return;
+            }
+            const qreal rightPaddingWidth = m_highlightEntireRow ? rightPadding() : 0;
+            m_expansionArea = QRectF(size().width() - rightPaddingWidth - x - widgetIconSize, y, widgetIconSize, widgetIconSize);
             return;
         }
     }
@@ -1155,8 +1176,8 @@ void KStandardItemListWidget::updatePixmapCache()
     } else {
         // Center horizontally and vertically within the icon-area
         const TextInfo *textInfo = m_textInfo.value("text");
-        if (QApplication::isRightToLeft() && m_layout == CompactLayout) {
-            m_pixmapPos.setX(size().width() - padding - (scaledIconSize + m_scaledPixmapSize.width()) / 2.0);
+        if (QApplication::isRightToLeft()) {
+            m_pixmapPos.setX(m_textRect.right() + 2.0 * padding);
         } else {
             m_pixmapPos.setX(textInfo->pos.x() - 2.0 * padding - (scaledIconSize + m_scaledPixmapSize.width()) / 2.0);
         }
@@ -1464,6 +1485,8 @@ void KStandardItemListWidget::updateDetailsLayoutTextCache()
     // +------+
     // | Icon |  Name role   Additional role 1   Additional role 2
     // +------+
+    // Mirror the above for right-to-left languages.
+    const bool isLeftToRight = QApplication::layoutDirection() == Qt::LeftToRight;
     m_textRect = QRectF();
 
     const KItemListStyleOption &option = styleOption();
@@ -1475,9 +1498,10 @@ void KStandardItemListWidget::updateDetailsLayoutTextCache()
     const qreal columnWidthInc = columnPadding(option);
     qreal firstColumnInc = iconSize();
     if (m_supportsItemExpanding) {
-        firstColumnInc += (m_expansionArea.left() + m_expansionArea.right() + widgetHeight) / 2;
+        firstColumnInc += isLeftToRight ? (m_expansionArea.left() + m_expansionArea.right() + widgetHeight) / 2
+                                        : ((size().width() - m_expansionArea.left()) + (size().width() - m_expansionArea.right()) + widgetHeight) / 2;
     } else {
-        firstColumnInc += option.padding + sidePadding();
+        firstColumnInc += option.padding + (isLeftToRight ? leftPadding() : rightPadding());
     }
 
     qreal x = firstColumnInc;
@@ -1494,7 +1518,7 @@ void KStandardItemListWidget::updateDetailsLayoutTextCache()
         const bool isTextRole = (role == "text");
         if (isTextRole) {
             text = escapeString(text);
-            availableTextWidth -= firstColumnInc - sidePadding();
+            availableTextWidth -= firstColumnInc - (isLeftToRight ? leftPadding() : rightPadding());
         }
 
         if (requiredWidth > availableTextWidth) {
@@ -1504,17 +1528,16 @@ void KStandardItemListWidget::updateDetailsLayoutTextCache()
 
         TextInfo *textInfo = m_textInfo.value(role);
         textInfo->staticText.setText(text);
-        textInfo->pos = QPointF(x + columnWidthInc / 2, y);
+        textInfo->pos = QPointF(isLeftToRight ? (x + columnWidthInc / 2) : (size().width() - (x + columnWidthInc / 2) - requiredWidth), y);
         x += roleWidth;
 
         if (isTextRole) {
-            const qreal textWidth = option.extendedSelectionRegion ? size().width() - textInfo->pos.x() : requiredWidth + 2 * option.padding;
-            m_textRect = QRectF(textInfo->pos.x() - option.padding, 0, textWidth, size().height());
+            m_textRect = QRectF(textInfo->pos.x() - option.padding, 0, requiredWidth + 2 * option.padding, size().height());
 
             // The column after the name should always be aligned on the same x-position independent
             // from the expansion-level shown in the name column
-            x -= firstColumnInc - sidePadding();
-        } else if (isRoleRightAligned(role)) {
+            x -= firstColumnInc - (isLeftToRight ? leftPadding() : rightPadding());
+        } else if (isRoleRightAligned(role) && isLeftToRight) {
             textInfo->pos.rx() += roleWidth - requiredWidth - columnWidthInc;
         }
     }
@@ -1594,7 +1617,7 @@ void KStandardItemListWidget::drawSiblingsInformation(QPainter *painter)
 
         style()->drawPrimitive(QStyle::PE_IndicatorBranch, &option, painter);
 
-        siblingRect.translate(-siblingRect.width(), 0);
+        siblingRect.translate(layoutDirection() == Qt::LeftToRight ? -siblingRect.width() : siblingRect.width(), 0);
     }
 }