106 lines
3.8 KiB
QML
106 lines
3.8 KiB
QML
/*
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* Copyright (C) 2016 Michael Bohlender, <michael.bohlender@kdemail.net>
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* Copyright (C) 2017 Christian Mollekopf, <mollekopf@kolabsystems.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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import QtQuick 2.12
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import QtQuick.Controls 2.12
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/*
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* The MouseArea + interactive: false + maximumFlickVelocity are required
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* to fix scrolling for desktop systems where we don't want flicking behaviour.
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*
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* See also:
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* ScrollView.qml in qtquickcontrols
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* qquickwheelarea.cpp in qtquickcontrols
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*/
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MouseArea {
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id: root
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propagateComposedEvents: true
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property Flickable flickable
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property alias enabled: root.enabled
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//Place the mouse area under the flickable
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z: -1
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onFlickableChanged: {
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if (enabled) {
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flickable.interactive = false
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flickable.maximumFlickVelocity = 100000
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flickable.boundsBehavior = Flickable.StopAtBounds
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root.parent = flickable
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}
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}
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function calculateNewPosition(flickableItem, wheel) {
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//Nothing to scroll
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if (flickableItem.contentHeight < flickableItem.height) {
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return flickableItem.contentY;
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}
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//Ignore 0 events (happens at least with Christians trackpad)
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if (wheel.pixelDelta.y == 0 && wheel.angleDelta.y == 0) {
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return flickableItem.contentY;
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}
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//pixelDelta seems to be the same as angleDelta/8
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var pixelDelta = 0
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//The pixelDelta is a smaller number if both are provided, so pixelDelta can be 0 while angleDelta is still something. So we check the angleDelta
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if (wheel.angleDelta.y) {
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var wheelScrollLines = 3 //Default value of QApplication wheelScrollLines property
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var pixelPerLine = 20 //Default value in Qt, originally comes from QTextEdit
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var ticks = (wheel.angleDelta.y / 8) / 15.0 //Divide by 8 gives us pixels typically come in 15pixel steps.
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pixelDelta = ticks * pixelPerLine * wheelScrollLines
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} else {
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pixelDelta = wheel.pixelDelta.y
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}
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if (!pixelDelta) {
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return flickableItem.contentY;
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}
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var minYExtent = flickableItem.originY + flickableItem.topMargin;
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var maxYExtent = (flickableItem.contentHeight + flickableItem.bottomMargin + flickableItem.originY) - flickableItem.height;
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if (typeof(flickableItem.headerItem) !== "undefined" && flickableItem.headerItem) {
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minYExtent += flickableItem.headerItem.height
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}
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//Avoid overscrolling
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return Math.max(minYExtent, Math.min(maxYExtent, flickableItem.contentY - pixelDelta));
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}
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onWheel: {
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var newPos = calculateNewPosition(flickable, wheel);
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// console.warn("Delta: ", wheel.pixelDelta.y);
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// console.warn("Old position: ", flickable.contentY);
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// console.warn("New position: ", newPos);
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// Show the scrollbars
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flickable.flick(0, 0);
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flickable.contentY = newPos;
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cancelFlickStateTimer.start()
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}
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Timer {
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id: cancelFlickStateTimer
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//How long the scrollbar will remain visible
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interval: 500
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// Hide the scrollbars
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onTriggered: flickable.cancelFlick();
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}
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}
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