Differential D15755 Diff 42334 libs/widgets/KisKineticScroller.cpp

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libs/widgets/KisKineticScroller.cpp

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1​/* This file is part of the KDE project
2​ * Copyright (C) 2018 Emmet O'Neill <emmetoneill.pdx@gmail.com>
3​ * Copyright (C) 2018 Eoin O'Neill <eoinoneill1991@gmail.com>
4​ *
5​ * This library is free software; you can redistribute it and/or
6​ * modify it under the terms of the GNU Library General Public
7​ * License as published by the Free Software Foundation; either
8​ * version 2 of the License, or (at your option) any later version.
9​ *
10​ * This library is distributed in the hope that it will be useful,
11​ * but WITHOUT ANY WARRANTY; without even the implied warranty of
12​ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13​ * Library General Public License for more details.
14​ *
15​ * You should have received a copy of the GNU Library General Public License
16​ * along with this library; see the file COPYING.LIB. If not, write to
17​ * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
18​ * Boston, MA 02110-1301, USA.
19​ */
20​
21​#include <KisKineticScroller.h>
22​#include <QAbstractItemView>
23​#include <ksharedconfig.h>
24​#include <kconfiggroup.h>
25​
26​QScroller* KisKineticScroller::createPreconfiguredScroller(QAbstractScrollArea *scrollArea) {
27​ KConfigGroup config = KSharedConfig::openConfig()->group("");
28​ int sensitivity = config.readEntry("KineticScrollingSensitivity", 75);
29​ bool enabled = config.readEntry("KineticScrollingEnabled", false);
30​ bool hideScrollBars = config.readEntry("KineticScrollingHideScrollbar", false);
31​ QScroller::ScrollerGestureType gestureType = getConfiguredGestureType();
32​
33​ if(enabled && scrollArea){
34​ if(hideScrollBars){
35​ scrollArea->setVerticalScrollBarPolicy(Qt::ScrollBarPolicy::ScrollBarAlwaysOff);
36​ scrollArea->setHorizontalScrollBarPolicy(Qt::ScrollBarPolicy::ScrollBarAlwaysOff);
37​ }
38​
39​ QAbstractItemView *itemView = qobject_cast<QAbstractItemView *>(scrollArea);
40​ if(itemView){
41​ itemView->setVerticalScrollMode(QAbstractItemView::ScrollPerPixel);
42​ }
43​
44​ QScroller *scroller = QScroller::scroller(scrollArea);
45​ scroller->grabGesture(scrollArea, gestureType);
46​
47​ QScrollerProperties properties;
48​
49​ // DragStartDistance seems to be based on meter per second; though it's
50​ // not explicitly documented, other QScroller values are in that metric.
51​ // To start kinetic scrolling, with minimal sensitity, we expect a drag
52​ // of 10 mm, with minimum sensitity any > 0 mm.
53​ const float mm = 0.001f;
54​ const float resistance = 1.0f - (sensitivity / 100.0f);
55​
56​ properties.setScrollMetric(QScrollerProperties::DragStartDistance, resistance * 10.0f * mm);
57​ properties.setScrollMetric(QScrollerProperties::DragVelocitySmoothingFactor, 1.0f);
58​ properties.setScrollMetric(QScrollerProperties::MinimumVelocity, 0.0f);
59​ properties.setScrollMetric(QScrollerProperties::AxisLockThreshold, 1.0f);
60​ properties.setScrollMetric(QScrollerProperties::MaximumClickThroughVelocity, 0.0f);
61​ properties.setScrollMetric(QScrollerProperties::MousePressEventDelay, 1.0f - 0.75f * resistance);
62​ properties.setScrollMetric(QScrollerProperties::AcceleratingFlickSpeedupFactor, 1.5f);
63​
64​ properties.setScrollMetric(QScrollerProperties::VerticalOvershootPolicy, QScrollerProperties::OvershootAlwaysOn);
65​ properties.setScrollMetric(QScrollerProperties::OvershootDragResistanceFactor, 0.1);
66​ properties.setScrollMetric(QScrollerProperties::OvershootDragDistanceFactor, 0.3);
67​ properties.setScrollMetric(QScrollerProperties::OvershootScrollDistanceFactor, 0.1);
68​ properties.setScrollMetric(QScrollerProperties::OvershootScrollTime, 0.4);
69​
70​ scroller->setScrollerProperties(properties);
71​
72​ return scroller;
73​ }
74​
75​ return nullptr;
76​}
77​
78​QScroller::ScrollerGestureType KisKineticScroller::getConfiguredGestureType() {
79​ KConfigGroup config = KSharedConfig::openConfig()->group("");
80​ int gesture = config.readEntry("KineticScrollingGesture", 0);
81​
82​ switch (gesture) {
83​ case 0: {
84​ return QScroller::TouchGesture;
85​ }
86​ case 1: {
87​ return QScroller::LeftMouseButtonGesture;
88​ }
89​ case 2: {
90​ return QScroller::MiddleMouseButtonGesture;
91​ }
92​ case 3: {
93​ return QScroller::RightMouseButtonGesture;
94​ }
95​ default:
96​ return QScroller::MiddleMouseButtonGesture;
97​ }
98​}
99​
100​void KisKineticScroller::updateCursor(QWidget *source, QScroller::State state) {
101​ if( state == QScroller::State::Pressed ) {
102​ source->setCursor(Qt::OpenHandCursor);
103​ } else if (state == QScroller::State::Dragging) {
104​ source->setCursor(Qt::ClosedHandCursor);
105​ } else {
106​ source->setCursor(Qt::ArrowCursor);
107​ }
108​}