mirror of https://github.com/ppy/osu
79 lines
2.8 KiB
C#
79 lines
2.8 KiB
C#
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// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
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// See the LICENCE file in the repository root for full licence text.
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using osu.Framework.Graphics;
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using osu.Framework.Utils;
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using osu.Game.Graphics.Containers;
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namespace osu.Game.Overlays.Chat
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{
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/// <summary>
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/// An <see cref="OsuScrollContainer"/> with functionality to automatically scroll whenever the maximum scrollable distance increases.
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/// </summary>
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public class ChannelScrollContainer : OsuScrollContainer
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{
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/// <summary>
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/// The chat will be automatically scrolled to end if and only if
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/// the distance between the current scroll position and the end of the scroll
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/// is less than this value.
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/// </summary>
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private const float auto_scroll_leniency = 10f;
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private bool trackNewContent = true;
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protected override void Update()
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{
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base.Update();
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// If our behaviour hasn't been overriden and there has been new content added to the container, we should update our scroll position to track it.
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bool requiresScrollUpdate = trackNewContent && !IsScrolledToEnd();
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if (requiresScrollUpdate)
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{
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// Schedule required to allow FillFlow to be the correct size.
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Schedule(() =>
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{
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if (trackNewContent)
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{
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if (Current < ScrollableExtent)
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ScrollToEnd();
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}
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});
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}
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}
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private void updateTrackState() => trackNewContent = IsScrolledToEnd(auto_scroll_leniency);
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// todo: we may eventually want this encapsulated in a "OnScrollChange" event handler method provided by ScrollContainer.
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// important to note that this intentionally doesn't consider OffsetScrollPosition, but could make it do so with side changes.
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#region Scroll handling
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protected override void OnUserScroll(float value, bool animated = true, double? distanceDecay = null)
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{
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base.OnUserScroll(value, animated, distanceDecay);
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updateTrackState();
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}
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public new void ScrollIntoView(Drawable d, bool animated = true)
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{
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base.ScrollIntoView(d, animated);
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updateTrackState();
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}
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public new void ScrollToStart(bool animated = true, bool allowDuringDrag = false)
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{
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base.ScrollToStart(animated, allowDuringDrag);
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updateTrackState();
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}
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public new void ScrollToEnd(bool animated = true, bool allowDuringDrag = false)
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{
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base.ScrollToEnd(animated, allowDuringDrag);
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updateTrackState();
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}
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#endregion
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}
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}
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