Vanara/Windows.Forms/Controls/TrackBarEx.cs

using System;
using System.ComponentModel;
using System.ComponentModel.Design;
using System.ComponentModel.Design.Serialization;
using System.Diagnostics;
using System.Drawing;
using System.Drawing.Design;
using System.Globalization;
using System.Linq;
using System.Reflection;
using System.Windows.Forms;
using Vanara.Extensions;
using Vanara.PInvoke;
using static Vanara.PInvoke.ComCtl32;
using static Vanara.PInvoke.Macros;
using static Vanara.PInvoke.User32;

namespace Vanara.Windows.Forms
{
	/// <summary>
	/// Extends the <see cref="TrackBar"/> class to provide full native-control functionality, including tick marks and value, and custom drawing.
	/// </summary>
	/// <seealso cref="System.Windows.Forms.TrackBar"/>
	public class TrackBarEx : TrackBar
	{
		private bool autoTicks = true;
		private int cumulativeWheelData;
		private int lastValue;
		private bool limitThumbToSel, showSel;
		private int requestedDim;
		private int selMin, selMax, thumbLength = -1;
		private int[] ticks;

		/// <summary>Initializes a new instance of the <see cref="TrackBarEx"/> class.</summary>
		public TrackBarEx()
		{
			SetStyle(ControlStyles.SupportsTransparentBackColor, true);
			BackColorChanged += (o, a) => { if (IsHandleCreated) RecreateHandle(); };
			requestedDim = PreferredDimension;
		}

		/// <summary>
		/// Occurs when the channel for a <see cref="TrackBarEx"/> needs to be drawn and the <see cref="OwnerDraw"/> property is set to <c>true</c>.
		/// </summary>
		[Category("Drawing")]
		public event PaintEventHandler DrawChannel;

		/// <summary>
		/// Occurs when the thumb for a <see cref="TrackBarEx"/> needs to be drawn and the <see cref="OwnerDraw"/> property is set to <c>true</c>.
		/// </summary>
		[Category("Drawing")]
		public event PaintEventHandler DrawThumb;

		/// <summary>
		/// Occurs when the ticks for a <see cref="TrackBarEx"/> need to be drawn and the <see cref="OwnerDraw"/> property is set to <c>true</c>.
		/// </summary>
		[Category("Drawing")]
		public event PaintEventHandler DrawTics;

		/// <summary>Gets or sets a value indicating whether to draw ticks based on the <see cref="TrackBar.TickFrequency"/> interval.</summary>
		/// <value><c>true</c> if automatic ticks should be shown; otherwise, <c>false</c>.</value>
		[DefaultValue(true), Category("Appearance"), Description("Specifies whether to automatically draw tick marks at the frequency defined by TickFreqency.")]
		public bool AutoTicks
		{
			get => autoTicks;
			set
			{
				if (autoTicks == value) return;
				autoTicks = value;
				if (IsHandleCreated) RecreateHandle();
			}
		}

		/// <summary>Gets the bounds of the channel (slider track).</summary>
		/// <value>The channel bounds.</value>
		[Browsable(false), DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
		public Rectangle ChannelBounds
		{
			get
			{
				var r = new RECT();
				if (IsHandleCreated)
					SendMsg(TrackBarMessage.TBM_GETCHANNELRECT, ref r);
				return r;
			}
		}

		/// <summary>Gets or sets a value indicating whether to limit thumb movement to the selection.</summary>
		/// <value><c>true</c> if movement is limited to selection; otherwise, <c>false</c>.</value>
		[DefaultValue(false), Category("Appearance"), Description("Indicates if thumb movement is limited to the selection range.")]
		public bool LimitThumbToSelection
		{
			get => limitThumbToSel;
			set
			{
				if (limitThumbToSel == value) return;
				limitThumbToSel = value;
				if (!showSel) return;
				if (Value < SelectionStart)
					Value = SelectionStart;
				else if (Value > SelectionEnd)
					Value = SelectionEnd;
			}
		}

		/// <summary>Gets or sets a value indicating the horizontal or vertical orientation of the track bar.</summary>
		[DefaultValue(Orientation.Horizontal), Category("Appearance"), Description("Indicates orientation of the trackbar.")]
		public new Orientation Orientation
		{
			get => base.Orientation;
			set
			{
				//valid values are 0x0 to 0x1
				if (value != Orientation.Horizontal && value != Orientation.Vertical)
					throw new InvalidEnumArgumentException(nameof(Orientation), (int)value, typeof(Orientation));

				if (base.Orientation != value)
				{
					if (value == Orientation.Horizontal)
						Width = requestedDim;
					else
						Height = requestedDim;

					base.Orientation = value;

					if (IsHandleCreated)
						AdjustSize();
				}
			}
		}

		/// <summary>Gets or sets a value indicating whether the control is drawn by the operating system or by code that you provide.</summary>
		/// <value>
		/// <c>true</c> if the control is drawn by code that you provide; <c>false</c> if the control is drawn by the operating system. The
		/// default is <c>false</c>.
		/// </value>
		[DefaultValue(false), Category("Behavior"), Description("Specifies whether to custom draw the trackbar.")]
		public bool OwnerDraw { get; set; }

		/// <summary>Gets or sets the upper limit of the selection range this TrackBar is working with.</summary>
		/// <value>
		/// The logical position at which the selection ends. This value must be less than or equal to the value of the <see
		/// cref="TrackBar.Maximum"/> property.
		/// </value>
		[DefaultValue(0), Category("Behavior"), Description("The ending logical position of the current selection range in a trackbar.")]
		public int SelectionEnd
		{
			get => selMax;
			set => SetSelectionRange(selMin, value);
		}

		/// <summary>Gets or sets the lower limit of the selection range this TrackBar is working with.</summary>
		/// <value>
		/// The logical position at which the selection starts. This value must be greater than or equal to the value of the <see
		/// cref="TrackBar.Minimum"/> property.
		/// </value>
		[DefaultValue(0), Category("Behavior"), Description("The starting logical position of the current selection range in a trackbar.")]
		public int SelectionStart
		{
			get => selMin;
			set => SetSelectionRange(value, selMax);
		}

		/// <summary>
		/// Gets or sets a value indicating whether to show the selection area defined by <see cref="SelectionStart"/> and <see cref="SelectionEnd"/>.
		/// </summary>
		/// <value><c>true</c> if showing selection area; otherwise, <c>false</c>.</value>
		[DefaultValue(false), Category("Appearance"), Description("Indicates if the TaskBar shows a selection range.")]
		public bool ShowSelection
		{
			get => showSel;
			set
			{
				if (showSel == value) return;
				showSel = value;
				if (IsHandleCreated) RecreateHandle();
			}
		}

		/// <summary>Gets the bounds of the thumb slider in its current position.</summary>
		/// <value>The thumb bounds.</value>
		[Browsable(false), DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
		public Rectangle ThumbBounds
		{
			get
			{
				var r = new RECT();
				if (IsHandleCreated)
					SendMsg(TrackBarMessage.TBM_GETTHUMBRECT, ref r);
				return r;
			}
		}

		/// <summary>Gets or sets the length of the thumb, overriding the default.</summary>
		/// <value>
		/// The length of the thumb. This is the vertical length if the orientation is horizontal and the horizontal length if the
		/// orientation is vertical.
		/// </value>
		[Category("Appearance"), Description("The length of the slider in a trackbar.")]
		public int ThumbLength
		{
			get => IsHandleCreated ? SendMsg(TrackBarMessage.TBM_GETTHUMBLENGTH).ToInt32() : (thumbLength == -1 ? (TickStyle == TickStyle.Both ? 21 : 19) : thumbLength);
			set
			{
				if (thumbLength == value) return;
				thumbLength = value;
				if (IsHandleCreated) RecreateHandle();
			}
		}

		/// <summary>Gets or sets an array that contains the positions of the tick marks for a trackbar.</summary>
		/// <value>
		/// The elements of the array specify the logical positions of the trackbar's tick marks, not including the first and last tick
		/// marks created by the trackbar. The logical positions can be any of the integer values in the trackbar's range of minimum to
		/// maximum slider positions.
		/// </value>
		[Category("Appearance"), Description("Indicates the logical values of the trackbar where ticks are drawn.")]
		[Browsable(false)]
		//[DesignerSerializationVisibility(DesignerSerializationVisibility.Visible)]
		//[Editor(typeof(ArrayEditor), typeof(UITypeEditor))]
		//[TypeConverter(typeof(ArrayConverter))]
		public int[] TickPositions
		{
			get
			{
				var tickCnt = 0;
				if (!IsHandleCreated || TickStyle == TickStyle.None || 0 == (tickCnt = SendMsg(TrackBarMessage.TBM_GETNUMTICS).ToInt32()))
					return new int[0];
				var ptr = SendMsg(TrackBarMessage.TBM_GETPTICS);
				return ptr.ToIEnum<int>(tickCnt - 2).OrderBy(i => i).Distinct().ToArray();
			}
			set
			{
				if (value != null && value.Length > 0)
				{
					if (TickStyle == TickStyle.None) throw new ArgumentException("Tick positions cannot be set when TickStyle is None.");
					if (value.Min() < Minimum || value.Max() > Maximum) throw new ArgumentOutOfRangeException(nameof(TickPositions), "All values must be between Minimum and Maximum range values.");
				}
				ticks = value ?? new int[0];
				if (IsHandleCreated)
					RecreateHandle();
			}
		}

		/// <inheritdoc/>
		protected override CreateParams CreateParams
		{
			get
			{
				var cp = base.CreateParams;
				cp.Style |= (int)TrackBarStyle.TBS_NOTIFYBEFOREMOVE;
				cp.Style = showSel ? cp.Style | (int)TrackBarStyle.TBS_ENABLESELRANGE : cp.Style & ~(int)TrackBarStyle.TBS_ENABLESELRANGE;
				cp.Style = BackColor == Color.Transparent ? cp.Style | (int)TrackBarStyle.TBS_TRANSPARENTBKGND : cp.Style & ~(int)TrackBarStyle.TBS_TRANSPARENTBKGND;
				cp.Style = thumbLength >= 0 ? cp.Style | (int)TrackBarStyle.TBS_FIXEDLENGTH : cp.Style & ~(int)TrackBarStyle.TBS_FIXEDLENGTH;
				cp.Style = autoTicks && TickStyle != TickStyle.None ? cp.Style | (int)TrackBarStyle.TBS_AUTOTICKS : cp.Style & ~(int)TrackBarStyle.TBS_AUTOTICKS;
				return cp;
			}
		}

		/// <inheritdoc/>
		protected override Size DefaultSize => new Size(104, PreferredDimension);

		private int PreferredDimension
		{
			get
			{
				var track = TickStyle == TickStyle.None ? 6 : (TickStyle == TickStyle.Both ? 22 : 14);
				return ThumbLength + track;
			}
		}

		/// <summary>Sets the starting and ending positions for the available selection range in a trackbar.</summary>
		/// <param name="rangeMin">The starting logical position for the selection range.</param>
		/// <param name="rangeMax">The ending logical position for the selection range.</param>
		/// <param name="redrawAll">
		/// If this parameter is TRUE, the trackbar is redrawn after the selection range is set. If this parameter is FALSE, the message
		/// sets the selection range but does not redraw the trackbar.
		/// </param>
		public void SetSelectionRange(int rangeMin, int rangeMax, bool redrawAll = true)
		{
			if (rangeMin == selMin && rangeMax == selMax) return;
			if (rangeMin < 0) throw new ArgumentOutOfRangeException(nameof(rangeMin));
			if (rangeMax < 0 || rangeMax < rangeMin) throw new ArgumentOutOfRangeException(nameof(rangeMax));
			if (rangeMin == rangeMax)
			{
				ShowSelection = false;
			}
			else
			{
				ShowSelection = true;
				if (rangeMin < Minimum) rangeMin = Minimum;
				if (rangeMin > Maximum) rangeMax = Maximum;
			}
			selMin = rangeMin;
			selMax = rangeMax;
			SendMsg(TrackBarMessage.TBM_SETSELEND, 0, rangeMax);
			SendMsg(TrackBarMessage.TBM_SETSELSTART, redrawAll ? 1 : 0, rangeMin);
		}

		/// <summary>Adjusts the size of the control.</summary>
		protected virtual void AdjustSize()
		{
			if (IsHandleCreated)
			{
				var saveDim = requestedDim;
				try
				{
					if (Orientation == Orientation.Horizontal)
						Height = AutoSize ? PreferredDimension : saveDim;
					else
						Width = AutoSize ? PreferredDimension : saveDim;
				}
				finally
				{
					requestedDim = saveDim;
				}
			}
		}

		/// <inheritdoc/>
		protected override void OnAutoSizeChanged(EventArgs e)
		{
			base.OnAutoSizeChanged(e);
			AdjustSize();
		}

		/// <summary>Raises the <see cref="E:DrawChannel"/> event.</summary>
		/// <param name="pe">The <see cref="PaintEventArgs"/> instance containing the event data.</param>
		/// <returns>
		/// If overwritten, the method should return <c>true</c> to indicate that all drawing has been done by the method and the system
		/// should not draw this item. If this method returns <c>false</c>, the system will draw the item.
		/// </returns>
		protected virtual bool OnDrawChannel(PaintEventArgs pe)
		{
			DrawChannel?.Invoke(this, pe);
			return DrawChannel != null;
		}

		/// <summary>Raises the <see cref="E:DrawThumb"/> event.</summary>
		/// <param name="pe">The <see cref="PaintEventArgs"/> instance containing the event data.</param>
		/// <returns>
		/// If overwritten, the method should return <c>true</c> to indicate that all drawing has been done by the method and the system
		/// should not draw this item. If this method returns <c>false</c>, the system will draw the item.
		/// </returns>
		protected virtual bool OnDrawThumb(PaintEventArgs pe)
		{
			DrawThumb?.Invoke(this, pe);
			return DrawThumb != null;
		}

		/// <summary>Raises the <see cref="E:DrawTics"/> event.</summary>
		/// <param name="pe">The <see cref="PaintEventArgs"/> instance containing the event data.</param>
		/// <returns>
		/// If overwritten, the method should return <c>true</c> to indicate that all drawing has been done by the method and the system
		/// should not draw this item. If this method returns <c>false</c>, the system will draw the item.
		/// </returns>
		protected virtual bool OnDrawTics(PaintEventArgs pe)
		{
			DrawTics?.Invoke(this, pe);
			return DrawTics != null;
		}

		/// <inheritdoc/>
		protected override void OnHandleCreated(EventArgs e)
		{
			base.OnHandleCreated(e);
			if (showSel)
			{
				SendMsg(TrackBarMessage.TBM_SETSELEND, 0, selMax);
				SendMsg(TrackBarMessage.TBM_SETSELSTART, 1, selMin);
			}
			if (thumbLength >= 0)
				SendMsg(TrackBarMessage.TBM_SETTHUMBLENGTH, thumbLength);
			SendMsg(TrackBarMessage.TBM_CLEARTICS);
			if (ticks != null && TickStyle != TickStyle.None)
				foreach (var t in ticks)
					SendMsg(TrackBarMessage.TBM_SETTIC, 0, t);
			AdjustSize();
		}

		/// <summary>Raises the <see cref="Control.MouseWheel"/> event.</summary>
		/// <param name="e">A <see cref="MouseEventArgs"/> that contains the event data.</param>
		protected override void OnMouseWheel(MouseEventArgs e)
		{
			const int WHEEL_DELTA = 120;
			var hme = e as HandledMouseEventArgs;
			if (hme != null)
			{
				if (hme.Handled) return;
				hme.Handled = true;
			}

			if ((ModifierKeys & (Keys.Shift | Keys.Alt)) != 0 || MouseButtons != MouseButtons.None)
				return; // Do not scroll when Shift or Alt key is down, or when a mouse button is down.

			var wheelScrollLines = SystemInformation.MouseWheelScrollLines;
			if (wheelScrollLines == 0) return; // Do not scroll when the user system setting is 0 lines per notch

			Debug.Assert(cumulativeWheelData > -WHEEL_DELTA, "cumulativeWheelData is too small");
			Debug.Assert(cumulativeWheelData < WHEEL_DELTA, "cumulativeWheelData is too big");
			cumulativeWheelData += e.Delta;

			var partialNotches = cumulativeWheelData / (float)WHEEL_DELTA;

			if (wheelScrollLines == -1)
				wheelScrollLines = TickFrequency;

			// Evaluate number of bands to scroll
			var scrollBands = (int)(wheelScrollLines * partialNotches);

			if (scrollBands != 0)
			{
				int absScrollBands;
				if (scrollBands > 0)
				{
					absScrollBands = scrollBands;
					Value = Math.Min(absScrollBands + Value, showSel && limitThumbToSel ? selMax : Maximum);
					cumulativeWheelData -= (int)(scrollBands * (WHEEL_DELTA / (float)wheelScrollLines));
				}
				else
				{
					absScrollBands = -scrollBands;
					Value = Math.Max(Value - absScrollBands, showSel && limitThumbToSel ? selMin : Minimum);
					cumulativeWheelData -= (int)(scrollBands * (WHEEL_DELTA / (float)wheelScrollLines));
				}
			}

			if (e.Delta != Value)
			{
				OnScroll(EventArgs.Empty);
				OnValueChanged(EventArgs.Empty);
			}
		}

		/// <summary>Raises the <see cref="E:System.Windows.Forms.TrackBar.ValueChanged"/> event.</summary>
		/// <param name="e">The <see cref="T:System.EventArgs"/> that contains the event data.</param>
		protected override void OnValueChanged(EventArgs e)
		{
			base.OnValueChanged(e);
			Debug.WriteLine($">> TB ValueChg={Value} from {lastValue}");
			lastValue = Value;
		}

		/// <summary>Sends the supplied message and parameters to the underlying TRACKBAR system control.</summary>
		/// <param name="msg">The Windows message identifier.</param>
		/// <param name="wParam">The wParam.</param>
		/// <param name="lParam">The lParam.</param>
		/// <returns>The result value defined for the message.</returns>
		protected IntPtr SendMsg(TrackBarMessage msg, int wParam = 0, int lParam = 0) => IsHandleCreated ? SendMessage(Handle, (uint)msg, (IntPtr)wParam, (IntPtr)lParam) : IntPtr.Zero;

		/// <inheritdoc/>
		protected override void SetBoundsCore(int x, int y, int width, int height, BoundsSpecified specified)
		{
			requestedDim = Orientation == Orientation.Horizontal ? height : width;

			if (AutoSize)
			{
				if (Orientation == Orientation.Horizontal)
				{
					if ((specified & BoundsSpecified.Height) != BoundsSpecified.None)
						height = PreferredDimension;
				}
				else
				{
					if ((specified & BoundsSpecified.Width) != BoundsSpecified.None)
						width = PreferredDimension;
				}
			}
			// Call base method on Control and not TrackBar
			typeof(Control).GetMethod("SetBoundsCore", BindingFlags.Instance | BindingFlags.NonPublic).InvokeNotOverride(this, x, y, width, height, specified);
		}

		/// <inheritdoc/>
		protected override void WndProc(ref Message m)
		{
			var msg = (WindowMessage)m.Msg;
			//Debug.WriteLine($"TB WndProc: Msg={msg}");
			if (msg == (WindowMessage.WM_NOTIFY | WindowMessage.WM_REFLECT))
			{
				if (OwnerDraw)
				{
					var hdr = (NMHDR)m.GetLParam(typeof(NMHDR));
					if (hdr.code == (int)CommonControlNotification.NM_CUSTOMDRAW)
					{
						var cd = (NMCUSTOMDRAW)m.GetLParam(typeof(NMCUSTOMDRAW));
						Debug.WriteLine($"{new TimeSpan(Environment.TickCount)} TBCustDraw: {cd.dwDrawStage}, {cd.dwItemSpec.ToInt32()}, {cd.uItemState}, {(Rectangle)cd.rc}");
						m.Result = new IntPtr((int)CustomDraw(ref cd));
						return;
					}
				}
			}
			else if (msg == (WindowMessage.WM_HSCROLL | WindowMessage.WM_REFLECT) || msg == (WindowMessage.WM_VSCROLL | WindowMessage.WM_REFLECT))
			{
				var pos = Value;
				var code = (TrackBarScrollNotification)LOWORD(m.WParam);
				Debug.WriteLine($"TB_SCROLL: pos={pos}, lastPos={lastValue}, code={code}, sel={showSel}, limit={limitThumbToSel}, selMin={selMin}, selMax={selMax}");
				if (showSel && limitThumbToSel)
				{
					if (pos > selMax) SendMsg(TrackBarMessage.TBM_SETPOS, 1, selMax);
					else if (pos < selMin) SendMsg(TrackBarMessage.TBM_SETPOS, 1, selMin);
				}
				if (code != TrackBarScrollNotification.TB_THUMBPOSITION && code != TrackBarScrollNotification.TB_ENDTRACK && lastValue != Value)
				{
					var e = new ScrollEventArgs((ScrollEventType)code, lastValue, pos, m.Msg == (int)WindowMessage.WM_HSCROLL ? ScrollOrientation.HorizontalScroll : ScrollOrientation.VerticalScroll);
					OnScroll(e);
					OnValueChanged(EventArgs.Empty);
				}
				return;
			}
			base.WndProc(ref m);
		}

		private CustomDrawResponse CustomDraw(ref NMCUSTOMDRAW cd)
		{
			switch (cd.dwDrawStage)
			{
				case CustomDrawStage.CDDS_PREPAINT:
					return CustomDrawResponse.CDRF_NOTIFYITEMDRAW; // | CustomDrawResponse.CDRF_NOTIFYPOSTPAINT;

				case CustomDrawStage.CDDS_ITEMPREPAINT:
					switch ((TrackBarCustomDraw)cd.dwItemSpec.ToInt32())
					{
						case TrackBarCustomDraw.TBCD_CHANNEL:
							using (var g = Graphics.FromHdc((IntPtr)cd.hdc))
							{
								if (OnDrawChannel(new PaintEventArgs(g, cd.rc)))
									return CustomDrawResponse.CDRF_SKIPDEFAULT;
							}
							break;

						case TrackBarCustomDraw.TBCD_THUMB:
							using (var g = Graphics.FromHdc((IntPtr)cd.hdc))
							{
								if (OnDrawThumb(new PaintEventArgs(g, cd.rc)))
									return CustomDrawResponse.CDRF_SKIPDEFAULT;
							}
							break;

						case TrackBarCustomDraw.TBCD_TICS:
							using (var g = Graphics.FromHdc((IntPtr)cd.hdc))
							{
								if (OnDrawTics(new PaintEventArgs(g, cd.rc)))
									return CustomDrawResponse.CDRF_SKIPDEFAULT;
							}
							break;
					}
					break;
			}
			return CustomDrawResponse.CDRF_DODEFAULT;
		}

		private void ResetThumbLength()
		{
			thumbLength = -1;
			if (IsHandleCreated) RecreateHandle();
		}

		private void ResetTickPositions() => TickPositions = new int[0];

		private IntPtr SendMsg(TrackBarMessage msg, ref RECT rect) => SendMessage(Handle, (uint)msg, IntPtr.Zero, ref rect);

		private bool ShouldSerializeThumbLength() => thumbLength >= 0;

		private bool ShouldSerializeTickPositions() => ticks != null && ticks.Length > 0;
	}
}