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Refactored again
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Tig
608
Terminal.Gui/Views/ScrollBar/ScrollBar.cs
Normal file
608
Terminal.Gui/Views/ScrollBar/ScrollBar.cs
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@@ -0,0 +1,608 @@
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#nullable enable
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using System.ComponentModel;
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using System.Drawing;
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namespace Terminal.Gui;
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/// <summary>
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/// Indicates the size of scrollable content and provides a visible element, referred to as the "ScrollSlider" that
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/// that is sized to
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/// show the proportion of the scrollable content to the size of the <see cref="View.Viewport"/>. The ScrollSlider
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/// can be dragged with the mouse. A Scroll can be oriented either vertically or horizontally and is used within a
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/// <see cref="ScrollBar"/>.
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/// </summary>
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/// <remarks>
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/// <para>
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/// By default, this view cannot be focused and does not support keyboard.
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/// </para>
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/// </remarks>
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public class ScrollBar : View, IOrientation, IDesignable
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{
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private readonly Button _decreaseButton;
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internal readonly ScrollSlider _slider;
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private readonly Button _increaseButton;
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/// <inheritdoc/>
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public ScrollBar ()
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{
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_decreaseButton = new ()
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{
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CanFocus = false,
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NoDecorations = true,
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NoPadding = true,
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ShadowStyle = ShadowStyle.None,
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WantContinuousButtonPressed = true
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};
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_decreaseButton.Accepting += OnDecreaseButtonOnAccept;
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_slider = new ()
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{
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ShrinkBy = 2, // For the buttons
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};
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_slider.Scrolled += SliderOnScroll;
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_slider.PositionChanged += SliderOnPositionChanged;
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_increaseButton = new ()
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{
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CanFocus = false,
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NoDecorations = true,
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NoPadding = true,
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ShadowStyle = ShadowStyle.None,
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WantContinuousButtonPressed = true
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};
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_increaseButton.Accepting += OnIncreaseButtonOnAccept;
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base.Add (_decreaseButton, _slider, _increaseButton);
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CanFocus = false;
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_orientationHelper = new (this); // Do not use object initializer!
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_orientationHelper.Orientation = Orientation.Vertical;
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_orientationHelper.OrientationChanging += (sender, e) => OrientationChanging?.Invoke (this, e);
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_orientationHelper.OrientationChanged += (sender, e) => OrientationChanged?.Invoke (this, e);
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// This sets the width/height etc...
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OnOrientationChanged (Orientation);
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void OnDecreaseButtonOnAccept (object? s, CommandEventArgs e)
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{
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ContentPosition -= Increment;
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e.Cancel = true;
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}
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void OnIncreaseButtonOnAccept (object? s, CommandEventArgs e)
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{
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ContentPosition += Increment;
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e.Cancel = true;
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}
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}
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/// <inheritdoc/>
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protected override void OnFrameChanged (in Rectangle frame)
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{
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ShowHide ();
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}
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private void ShowHide ()
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{
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if (!AutoHide || !IsInitialized)
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{
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return;
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}
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if (Orientation == Orientation.Vertical)
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{
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Visible = Frame.Height < Size;
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}
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else
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{
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Visible = Frame.Width < Size;
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}
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}
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/// <inheritdoc/>
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protected override void OnSubviewLayout (LayoutEventArgs args)
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{
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_slider.Size = CalculateSliderSize ();
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if (Orientation == Orientation.Vertical)
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{
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_slider.ViewportDimension = Viewport.Height - _slider.ShrinkBy;
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}
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else
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{
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_slider.ViewportDimension = Viewport.Width - _slider.ShrinkBy;
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}
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}
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private int CalculateSliderSize ()
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{
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if (Size == 0 || ViewportDimension == 0)
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{
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return 1;
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}
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int viewport = Orientation == Orientation.Vertical ? Viewport.Height : Viewport.Width;
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return (int)Math.Clamp (Math.Floor ((double)ViewportDimension / Size * (viewport - 2)), 1, ViewportDimension);
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}
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private void PositionSubviews ()
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{
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if (Orientation == Orientation.Vertical)
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{
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_decreaseButton.Y = 0;
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_decreaseButton.X = 0;
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_decreaseButton.Width = Dim.Fill ();
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_decreaseButton.Height = 1;
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_decreaseButton.Title = Glyphs.UpArrow.ToString ();
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_slider.X = 0;
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_slider.Y = 1;
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_slider.Width = Dim.Fill ();
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_increaseButton.Y = Pos.AnchorEnd ();
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_increaseButton.X = 0;
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_increaseButton.Width = Dim.Fill ();
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_increaseButton.Height = 1;
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_increaseButton.Title = Glyphs.DownArrow.ToString ();
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}
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else
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{
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_decreaseButton.Y = 0;
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_decreaseButton.X = 0;
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_decreaseButton.Width = 1;
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_decreaseButton.Height = Dim.Fill ();
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_decreaseButton.Title = Glyphs.LeftArrow.ToString ();
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_slider.Y = 0;
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_slider.X = 1;
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_slider.Height = Dim.Fill ();
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_increaseButton.Y = 0;
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_increaseButton.X = Pos.AnchorEnd ();
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_increaseButton.Width = 1;
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_increaseButton.Height = Dim.Fill ();
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_increaseButton.Title = Glyphs.RightArrow.ToString ();
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}
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}
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#region IOrientation members
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private readonly OrientationHelper _orientationHelper;
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/// <inheritdoc/>
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public Orientation Orientation
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{
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get => _orientationHelper.Orientation;
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set => _orientationHelper.Orientation = value;
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}
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/// <inheritdoc/>
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public event EventHandler<CancelEventArgs<Orientation>>? OrientationChanging;
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/// <inheritdoc/>
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public event EventHandler<EventArgs<Orientation>>? OrientationChanged;
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/// <inheritdoc/>
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public void OnOrientationChanged (Orientation newOrientation)
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{
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TextDirection = Orientation == Orientation.Vertical ? TextDirection.TopBottom_LeftRight : TextDirection.LeftRight_TopBottom;
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TextAlignment = Alignment.Center;
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VerticalTextAlignment = Alignment.Center;
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X = 0;
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Y = 0;
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if (Orientation == Orientation.Vertical)
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{
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Width = 1;
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Height = Dim.Fill ();
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}
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else
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{
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Width = Dim.Fill ();
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Height = 1;
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}
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_slider.Orientation = newOrientation;
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PositionSubviews ();
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}
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#endregion
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private bool _autoHide = true;
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/// <summary>
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/// Gets or sets whether <see cref="View.Visible"/> will be set to <see langword="false"/> if the dimension of the
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/// scroll bar is greater than or equal to <see cref="Size"/>.
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/// </summary>
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public bool AutoHide
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{
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get => _autoHide;
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set
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{
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if (_autoHide != value)
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{
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_autoHide = value;
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if (!AutoHide)
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{
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Visible = true;
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}
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SetNeedsLayout ();
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}
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}
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}
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public bool KeepContentInAllViewport
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{
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//get => _scroll.KeepContentInAllViewport;
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//set => _scroll.KeepContentInAllViewport = value;
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get;
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set;
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}
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/// <summary>
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/// Gets or sets whether the Scroll will show the percentage the slider
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/// takes up within the <see cref="Size"/>.
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/// </summary>
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public bool ShowPercent
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{
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get => _slider.ShowPercent;
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set => _slider.ShowPercent = value;
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}
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private int? _viewportDimension;
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/// <summary>
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/// Gets or sets the size of the viewport into the content being scrolled, bounded by <see cref="Size"/>.
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/// </summary>
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/// <remarks>
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/// If not explicitly set, will be the appropriate dimension of the Scroll's Frame.
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/// </remarks>
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public int ViewportDimension
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{
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get
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{
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if (_viewportDimension.HasValue)
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{
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return _viewportDimension.Value;
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}
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return Orientation == Orientation.Vertical ? Frame.Height : Frame.Width;
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}
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set => _viewportDimension = value;
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}
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private int _size;
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/// <summary>
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/// Gets or sets the size of the content that can be scrolled.
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/// </summary>
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public int Size
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{
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get => _size;
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set
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{
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if (value == _size || value < 0)
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{
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return;
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}
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_size = value;
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OnSizeChanged (_size);
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SizeChanged?.Invoke (this, new (in _size));
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SetNeedsLayout ();
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}
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}
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/// <summary>Called when <see cref="Size"/> has changed. </summary>
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protected virtual void OnSizeChanged (int size) { }
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/// <summary>Raised when <see cref="Size"/> has changed.</summary>
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public event EventHandler<EventArgs<int>>? SizeChanged;
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#region SliderPosition
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private void SliderOnPositionChanged (object? sender, EventArgs<int> e)
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{
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if (ViewportDimension == 0)
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{
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return;
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}
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int pos = e.CurrentValue;
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RaiseSliderPositionChangeEvents (_slider.Position, pos);
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}
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private void SliderOnScroll (object? sender, EventArgs<int> e)
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{
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if (ViewportDimension == 0)
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{
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return;
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}
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int calculatedSliderPos = CalculateSliderPosition (_contentPosition, e.CurrentValue >= 0 ? NavigationDirection.Forward : NavigationDirection.Backward);
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int sliderScrolledAmount = e.CurrentValue;
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int scrolledAmount = CalculateContentPosition (sliderScrolledAmount);
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RaiseSliderPositionChangeEvents (calculatedSliderPos, _slider.Position);
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ContentPosition = _contentPosition + scrolledAmount;
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}
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/// <summary>
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/// Gets or sets the position of the start of the Scroll slider, within the Viewport.
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/// </summary>
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public int GetSliderPosition () => CalculateSliderPosition (_contentPosition);
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private void RaiseSliderPositionChangeEvents (int calculatedSliderPosition, int newSliderPosition)
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{
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if (calculatedSliderPosition == newSliderPosition)
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{
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return;
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}
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// This sets the slider position and clamps the value
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_slider.Position = newSliderPosition;
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OnSliderPositionChanged (newSliderPosition);
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SliderPositionChanged?.Invoke (this, new (in newSliderPosition));
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}
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/// <summary>Called when the slider position has changed.</summary>
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protected virtual void OnSliderPositionChanged (int position) { }
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/// <summary>Raised when the slider position has changed.</summary>
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public event EventHandler<EventArgs<int>>? SliderPositionChanged;
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private int CalculateSliderPosition (int contentPosition, NavigationDirection direction = NavigationDirection.Forward)
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{
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if (Size - ViewportDimension == 0)
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{
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return 0;
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}
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int scrollBarSize = Orientation == Orientation.Vertical ? Viewport.Height : Viewport.Width;
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double newSliderPosition = (double)contentPosition / (Size - ViewportDimension) * (scrollBarSize - _slider.Size - _slider.ShrinkBy);
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return direction == NavigationDirection.Forward ? (int)Math.Floor (newSliderPosition) : (int)Math.Ceiling (newSliderPosition);
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}
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private int CalculateContentPosition (int sliderPosition)
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{
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int scrollBarSize = Orientation == Orientation.Vertical ? Viewport.Height : Viewport.Width;
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return (int)Math.Round ((double)(sliderPosition) / (scrollBarSize - _slider.Size - _slider.ShrinkBy) * (Size - ViewportDimension));
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}
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#endregion SliderPosition
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#region ContentPosition
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private int _contentPosition;
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/// <summary>
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/// Gets or sets the position of the slider relative to <see cref="Size"/>.
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/// </summary>
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/// <remarks>
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/// <para>
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/// The content position is clamped to 0 and <see cref="Size"/> minus <see cref="ViewportDimension"/>.
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/// </para>
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/// <para>
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/// Setting will result in the <see cref="ContentPositionChanging"/> and <see cref="ContentPositionChanged"/>
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/// events being raised.
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/// </para>
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/// </remarks>
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public int ContentPosition
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{
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get => _contentPosition;
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set
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{
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if (value == _contentPosition)
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{
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return;
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}
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// Clamp the value between 0 and Size - ViewportDimension
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int newContentPosition = (int)Math.Clamp (value, 0, Math.Max (0, Size - ViewportDimension));
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NavigationDirection direction = newContentPosition >= _contentPosition ? NavigationDirection.Forward : NavigationDirection.Backward;
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if (OnContentPositionChanging (_contentPosition, newContentPosition))
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{
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return;
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}
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CancelEventArgs<int> args = new (ref _contentPosition, ref newContentPosition);
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ContentPositionChanging?.Invoke (this, args);
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if (args.Cancel)
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{
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return;
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}
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int distance = newContentPosition - _contentPosition;
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_contentPosition = newContentPosition;
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OnContentPositionChanged (_contentPosition);
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ContentPositionChanged?.Invoke (this, new (in _contentPosition));
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OnScrolled (distance);
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Scrolled?.Invoke (this, new (in distance));
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int currentSliderPosition = _slider.Position;
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int calculatedSliderPosition = CalculateSliderPosition (_contentPosition, direction);
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_slider.MoveToPosition (calculatedSliderPosition);
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RaiseSliderPositionChangeEvents (currentSliderPosition, _slider.Position);
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}
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}
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/// <summary>
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/// Called when <see cref="ContentPosition"/> is changing. Return true to cancel the change.
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/// </summary>
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protected virtual bool OnContentPositionChanging (int currentPos, int newPos) { return false; }
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/// <summary>
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/// Raised when the <see cref="ContentPosition"/> is changing. Set <see cref="CancelEventArgs.Cancel"/> to
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/// <see langword="true"/> to prevent the position from being changed.
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/// </summary>
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public event EventHandler<CancelEventArgs<int>>? ContentPositionChanging;
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/// <summary>Called when <see cref="ContentPosition"/> has changed.</summary>
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protected virtual void OnContentPositionChanged (int position) { }
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/// <summary>Raised when the <see cref="ContentPosition"/> has changed.</summary>
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public event EventHandler<EventArgs<int>>? ContentPositionChanged;
|
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|
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/// <summary>Called when <see cref="ContentPosition"/> has changed. Indicates how much to scroll.</summary>
|
||||
protected virtual void OnScrolled (int distance) { }
|
||||
|
||||
/// <summary>Raised when the <see cref="ContentPosition"/> has changed. Indicates how much to scroll.</summary>
|
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public event EventHandler<EventArgs<int>>? Scrolled;
|
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|
||||
#endregion ContentPosition
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|
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/// <inheritdoc/>
|
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protected override bool OnClearingViewport ()
|
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{
|
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if (Orientation == Orientation.Vertical)
|
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{
|
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FillRect (Viewport with { Y = Viewport.Y + 1, Height = Viewport.Height - 2 }, Glyphs.Stipple);
|
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}
|
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else
|
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{
|
||||
FillRect (Viewport with { X = Viewport.X + 1, Width = Viewport.Width - 2 }, Glyphs.Stipple);
|
||||
}
|
||||
|
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return true;
|
||||
}
|
||||
|
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// TODO: Change this to work OnMouseEvent with continuouse press and grab so it's continous.
|
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/// <inheritdoc/>
|
||||
protected override bool OnMouseClick (MouseEventArgs args)
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{
|
||||
// Check if the mouse click is a single click
|
||||
if (!args.IsSingleClicked)
|
||||
{
|
||||
return false;
|
||||
}
|
||||
|
||||
int sliderCenter;
|
||||
int distanceFromCenter;
|
||||
|
||||
if (Orientation == Orientation.Vertical)
|
||||
{
|
||||
sliderCenter = 1 + _slider.Frame.Y + _slider.Frame.Height / 2;
|
||||
distanceFromCenter = args.Position.Y - sliderCenter;
|
||||
}
|
||||
else
|
||||
{
|
||||
sliderCenter = 1 + _slider.Frame.X + _slider.Frame.Width / 2;
|
||||
distanceFromCenter = args.Position.X - sliderCenter;
|
||||
}
|
||||
|
||||
#if PROPORTIONAL_SCROLL_JUMP
|
||||
// BUGBUG: This logic mostly works to provide a proportional jump. However, the math
|
||||
// BUGBUG: falls apart in edge cases. Most other scroll bars (e.g. Windows) do not do prooportional
|
||||
// BUGBUG: Thus, this is disabled and we just jump a page each click.
|
||||
// Ratio of the distance to the viewport dimension
|
||||
double ratio = (double)Math.Abs (distanceFromCenter) / (ViewportDimension);
|
||||
// Jump size based on the ratio and the total content size
|
||||
int jump = (int)(ratio * (Size - ViewportDimension));
|
||||
#else
|
||||
int jump = (ViewportDimension);
|
||||
#endif
|
||||
// Adjust the content position based on the distance
|
||||
if (distanceFromCenter < 0)
|
||||
{
|
||||
ContentPosition = Math.Max (0, ContentPosition - jump);
|
||||
}
|
||||
else
|
||||
{
|
||||
ContentPosition = Math.Min (Size - _slider.ViewportDimension, ContentPosition + jump);
|
||||
}
|
||||
|
||||
return true;
|
||||
}
|
||||
|
||||
|
||||
|
||||
/// <summary>
|
||||
/// Gets or sets the amount each mouse hweel event will incremenet/decrement the <see cref="ContentPosition"/>.
|
||||
/// </summary>
|
||||
/// <remarks>
|
||||
/// The default is 1.
|
||||
/// </remarks>
|
||||
public int Increment { get; set; } = 1;
|
||||
|
||||
/// <inheritdoc/>
|
||||
protected override bool OnMouseEvent (MouseEventArgs mouseEvent)
|
||||
{
|
||||
if (SuperView is null)
|
||||
{
|
||||
return false;
|
||||
}
|
||||
|
||||
if (!mouseEvent.IsWheel)
|
||||
{
|
||||
return false;
|
||||
}
|
||||
|
||||
if (Orientation == Orientation.Vertical)
|
||||
{
|
||||
if (mouseEvent.Flags.HasFlag (MouseFlags.WheeledDown))
|
||||
{
|
||||
ContentPosition += Increment;
|
||||
}
|
||||
|
||||
if (mouseEvent.Flags.HasFlag (MouseFlags.WheeledUp))
|
||||
{
|
||||
ContentPosition -= Increment;
|
||||
}
|
||||
}
|
||||
else
|
||||
{
|
||||
if (mouseEvent.Flags.HasFlag (MouseFlags.WheeledRight))
|
||||
{
|
||||
ContentPosition += Increment;
|
||||
}
|
||||
|
||||
if (mouseEvent.Flags.HasFlag (MouseFlags.WheeledLeft))
|
||||
{
|
||||
ContentPosition -= Increment;
|
||||
}
|
||||
}
|
||||
|
||||
return true;
|
||||
}
|
||||
|
||||
/// <inheritdoc/>
|
||||
public bool EnableForDesign ()
|
||||
{
|
||||
OrientationChanged += (sender, args) =>
|
||||
{
|
||||
if (args.CurrentValue == Orientation.Vertical)
|
||||
{
|
||||
Width = 1;
|
||||
Height = Dim.Fill ();
|
||||
}
|
||||
else
|
||||
{
|
||||
Width = Dim.Fill ();
|
||||
Height = 1;
|
||||
}
|
||||
};
|
||||
|
||||
Width = 1;
|
||||
Height = Dim.Fill ();
|
||||
Size = 250;
|
||||
|
||||
return true;
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user