From 90beb4a5e37b887caad1e767046a42dad0af1ab3 Mon Sep 17 00:00:00 2001
From: Elvis Angelaccio <elvis.angelaccio@kde.org>
Date: Sun, 20 Nov 2016 12:21:29 +0100
Subject: Fix slow scrolling in dock panels

Commit f688bcd1f1 fixed slow scrolling with xf86-input-libinput on DolphinView.

However the commit also exposed a bug in the Dolphin scrolling
algorithm, which was previously hidden. This resulted in slow
scrolling in dock panels (Places and Folders), with both
xf86-input-evdev and xf86-input-libinput drivers, as well as libinput on
Wayland.

KItemListContainer::updateScrollOffsetScrollBar() relied on the view's
itemSize() method to compute the scrollbar's singleStep, but this QSize
was invalid for the dock panels' views.

We use a new itemSizeHint() method instead, which is always valid and
also adapts to the current icon size set in the view.

BUG: 365968
FIXED-IN: 16.12.0
REVIEW: 129409
---
 src/kitemviews/private/kitemlistsizehintresolver.h | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'src/kitemviews/private/kitemlistsizehintresolver.h')

diff --git a/src/kitemviews/private/kitemlistsizehintresolver.h b/src/kitemviews/private/kitemlistsizehintresolver.h
index ff17f2de2..841e9ca10 100644
--- a/src/kitemviews/private/kitemlistsizehintresolver.h
+++ b/src/kitemviews/private/kitemlistsizehintresolver.h
@@ -36,6 +36,7 @@ class DOLPHIN_EXPORT KItemListSizeHintResolver
 public:
     KItemListSizeHintResolver(const KItemListView* itemListView);
     virtual ~KItemListSizeHintResolver();
+    QSizeF maxSizeHint();
     QSizeF sizeHint(int index);
 
     void itemsInserted(const KItemRangeList& itemRanges);
@@ -50,6 +51,7 @@ private:
     const KItemListView* m_itemListView;
     mutable QVector<qreal> m_logicalHeightHintCache;
     mutable qreal m_logicalWidthHint;
+    mutable qreal m_logicalHeightHint;
     bool m_needsResolving;
 };
 
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