From dea4444c4a8d615c68bd6d2b05124cc8d66bd6d7 Mon Sep 17 00:00:00 2001
From: Simon Paul St James <kdedevel@etotheipiplusone.com>
Date: Fri, 31 Oct 2008 21:45:51 +0000
Subject: Be better behaved in the presence of scroll events in the middle of
 an elastic band selection by storing the last selection elastic band in view
 (rather than viewport) coordinates.

svn path=/trunk/KDE/kdebase/apps/; revision=878316
---
 src/dolphindetailsview.cpp | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

(limited to 'src/dolphindetailsview.cpp')

diff --git a/src/dolphindetailsview.cpp b/src/dolphindetailsview.cpp
index 6d9038b46..b127aad49 100644
--- a/src/dolphindetailsview.cpp
+++ b/src/dolphindetailsview.cpp
@@ -654,6 +654,9 @@ void DolphinDetailsView::updateElasticBandSelection()
     QRect selRect = elasticBandRect().normalized();
     QRect nameColumnArea(nameColumnX, selRect.y(), nameColumnWidth, selRect.height());
     selRect = nameColumnArea.intersect(selRect).normalized();
+    // Get the last elastic band rectangle, expressed in viewpoint coordinates.
+    const QPoint scrollPos(horizontalScrollBar()->value(), verticalScrollBar()->value());
+    QRect oldSelRect = QRect(m_band.lastSelectionOrigin - scrollPos, m_band.lastSelectionDestination - scrollPos).normalized();
 
     if (selRect.isNull()) {
         selectionModel()->select(m_band.originalSelection, QItemSelectionModel::ClearAndSelect);
@@ -670,17 +673,16 @@ void DolphinDetailsView::updateElasticBandSelection()
             // No items in the model presumably.
             return;
         }
-        
+
         // If the elastic band does not cover the same rows as before, we'll
         // need to re-check, and also invalidate the old item distances.
         const int rowHeight = QTreeView::rowHeight(dummyIndex);
         const bool coveringSameRows =
-            (selRect.top()    / rowHeight == m_band.oldSelectionRect.top()    / rowHeight) &&
-            (selRect.bottom() / rowHeight == m_band.oldSelectionRect.bottom() / rowHeight);
+            (selRect.top()    / rowHeight == oldSelRect.top()    / rowHeight) &&
+            (selRect.bottom() / rowHeight == oldSelRect.bottom() / rowHeight);
         if (coveringSameRows) {
             // Covering the same rows, but have we moved far enough horizontally 
             // that we might have (de)selected some other items?
-            const QRect oldSelRect = m_band.oldSelectionRect;
             const bool itemSelectionChanged =
                 ((selRect.left() > oldSelRect.left()) &&
                  (selRect.left() > m_band.insideNearestLeftEdge)) ||
@@ -699,7 +701,9 @@ void DolphinDetailsView::updateElasticBandSelection()
     else {
         // This is the only piece of optimisation data that needs to be explicitly
         // discarded.
-        m_band.oldSelectionRect = selRect;
+        m_band.lastSelectionOrigin = QPoint();
+        m_band.lastSelectionDestination = QPoint();
+        oldSelRect = selRect;
     }
 
     // Do the selection from scratch. Force a update of the horizontal distances info.
@@ -710,7 +714,7 @@ void DolphinDetailsView::updateElasticBandSelection()
 
     // Include the old selection rect as well, so we can deselect
     // items that were inside it but not in the new selRect.
-    const QRect boundingRect = selRect.united(m_band.oldSelectionRect).normalized();
+    const QRect boundingRect = selRect.united(oldSelRect).normalized();
     if (boundingRect.isNull()) {
         return;
     }
@@ -735,7 +739,7 @@ void DolphinDetailsView::updateElasticBandSelection()
    QModelIndex currIndex = startIndex;
    QModelIndex lastIndex;
    bool allItemsInBoundDone = false;
-   
+
    // Calling selectionModel()->select(...) for each item that needs to be 
    // toggled is slow as each call emits selectionChanged(...) so store them
    // and do the selection toggle in one batch.
@@ -810,7 +814,8 @@ void DolphinDetailsView::updateElasticBandSelection()
 
     selectionModel()->select(itemsToToggle, QItemSelectionModel::Toggle);
 
-    m_band.oldSelectionRect = selRect;
+    m_band.lastSelectionOrigin = m_band.origin;
+    m_band.lastSelectionDestination = m_band.destination;
     m_band.ignoreOldInfo = false;
 }
 
@@ -915,7 +920,8 @@ DolphinDetailsView::ElasticBand::ElasticBand() :
     show(false),
     origin(),
     destination(),
-    oldSelectionRect(),
+    lastSelectionOrigin(),
+    lastSelectionDestination(),
     ignoreOldInfo(true),
     outsideNearestLeftEdge(0),
     outsideNearestRightEdge(0),
-- 
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