Differential D15755 Diff 43013 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", true);
30​ bool hideScrollBars = config.readEntry("KineticScrollingHideScrollbar", false);
31​ float resistanceCoefficient = config.readEntry("KineticScrollingResistanceCoefficient", 10.0f);
32​ float dragVelocitySmoothFactor = config.readEntry("KineticScrollingDragVelocitySmoothingFactor", 1.0f);
33​ float minimumVelocity = config.readEntry("KineticScrollingMinimumVelocity", 0.0f);
34​ float axisLockThresh = config.readEntry("KineticScrollingAxisLockThreshold", 1.0f);
35​ float maximumClickThroughVelocity = config.readEntry("KineticScrollingMaxClickThroughVelocity", 0.0f);
36​ float flickAccelerationFactor = config.readEntry("KineticScrollingFlickAccelerationFactor", 1.5f);
37​ float overshootDragResistanceFactor = config.readEntry("KineticScrollingOvershotDragResistanceFactor", 0.1f);
38​ float overshootDragDistanceFactor = config.readEntry("KineticScrollingOvershootDragDistanceFactor", 0.3f);
39​ float overshootScrollDistanceFactor = config.readEntry("KineticScrollingOvershootScrollDistanceFactor", 0.1f);
40​ float overshootScrollTime = config.readEntry("KineticScrollingOvershootScrollTime", 0.4f);
41​ QScroller::ScrollerGestureType gestureType = getConfiguredGestureType();
42​
43​ if (enabled && scrollArea) {
44​ if (hideScrollBars) {
45​ scrollArea->setVerticalScrollBarPolicy(Qt::ScrollBarPolicy::ScrollBarAlwaysOff);
46​ scrollArea->setHorizontalScrollBarPolicy(Qt::ScrollBarPolicy::ScrollBarAlwaysOff);
47​ }
48​
49​ QAbstractItemView *itemView = qobject_cast<QAbstractItemView *>(scrollArea);
50​ if (itemView) {
51​ itemView->setVerticalScrollMode(QAbstractItemView::ScrollPerPixel);
52​ }
53​
54​ QScroller *scroller = QScroller::scroller(scrollArea);
55​ scroller->grabGesture(scrollArea, gestureType);
56​
57​ QScrollerProperties properties;
58​
59​ // DragStartDistance seems to be based on meter per second; though it's
60​ // not explicitly documented, other QScroller values are in that metric.
61​ // To start kinetic scrolling, with minimal sensitity, we expect a drag
62​ // of 10 mm, with minimum sensitity any > 0 mm.
63​ const float mm = 0.001f;
64​ const float resistance = 1.0f - (sensitivity / 100.0f);
65​ const float mousePressEventDelay = config.readEntry("KineticScrollingMousePressDelay", 1.0f - 0.75f * resistance);
66​
67​ properties.setScrollMetric(QScrollerProperties::DragStartDistance, resistance * resistanceCoefficient * mm);
68​ properties.setScrollMetric(QScrollerProperties::DragVelocitySmoothingFactor, dragVelocitySmoothFactor);
69​ properties.setScrollMetric(QScrollerProperties::MinimumVelocity, minimumVelocity);
70​ properties.setScrollMetric(QScrollerProperties::AxisLockThreshold, axisLockThresh);
71​ properties.setScrollMetric(QScrollerProperties::MaximumClickThroughVelocity, maximumClickThroughVelocity);
72​ properties.setScrollMetric(QScrollerProperties::MousePressEventDelay, mousePressEventDelay);
73​ properties.setScrollMetric(QScrollerProperties::AcceleratingFlickSpeedupFactor, flickAccelerationFactor);
74​
75​ properties.setScrollMetric(QScrollerProperties::VerticalOvershootPolicy, QScrollerProperties::OvershootAlwaysOn);
76​ properties.setScrollMetric(QScrollerProperties::OvershootDragResistanceFactor, overshootDragResistanceFactor);
77​ properties.setScrollMetric(QScrollerProperties::OvershootDragDistanceFactor, overshootDragDistanceFactor);
78​ properties.setScrollMetric(QScrollerProperties::OvershootScrollDistanceFactor, overshootScrollDistanceFactor);
79​ properties.setScrollMetric(QScrollerProperties::OvershootScrollTime, overshootScrollTime);
80​
81​ scroller->setScrollerProperties(properties);
82​
83​ return scroller;
84​ }
85​
86​ return nullptr;
87​}
88​
89​QScroller::ScrollerGestureType KisKineticScroller::getConfiguredGestureType() {
90​ KConfigGroup config = KSharedConfig::openConfig()->group("");
91​ int gesture = config.readEntry("KineticScrollingGesture", 0);
92​
93​ switch (gesture) {
94​ case 0: {
95​ return QScroller::TouchGesture;
96​ }
97​ case 1: {
98​ return QScroller::LeftMouseButtonGesture;
99​ }
100​ case 2: {
101​ return QScroller::MiddleMouseButtonGesture;
102​ }
103​ case 3: {
104​ return QScroller::RightMouseButtonGesture;
105​ }
106​ default:
107​ return QScroller::MiddleMouseButtonGesture;
108​ }
109​}
110​
111​void KisKineticScroller::updateCursor(QWidget *source, QScroller::State state) {
112​ if( state == QScroller::State::Pressed ) {
113​ source->setCursor(Qt::OpenHandCursor);
114​ } else if (state == QScroller::State::Dragging) {
115​ source->setCursor(Qt::ClosedHandCursor);
116​ } else {
117​ source->setCursor(Qt::ArrowCursor);
118​ }
119​}