show the column text in an empty cell when hovering over it in TAStudio

Author: SuuperW

src/BizHawk.Client.EmuHawk/CustomControls/InputRoll/InputRoll.Drawing.cs

@@ -189,6 +189,7 @@ private void DrawData(List<RollColumn> visibleColumns, int firstVisibleRow, int
 			_renderer.PrepDrawString(Font, _foreColor);
 
 			Cell currentCell = new();
+			Cell mouseCell = ShowColumnTextOnHover ? CurrentCell : null;
 			if (HorizontalOrientation)
 			{
 				for (int j = 0; j < visibleColumns.Count; j++)
@@ -223,20 +224,28 @@ private void DrawData(List<RollColumn> visibleColumns, int firstVisibleRow, int
 
 						bool rePrep = false;
 						Color foreColor = _foreColor;
+						Font font = Font;
 						currentCell.Column = col;
 						currentCell.RowIndex = f + startRow;
 						if (_selectedItems.Contains(currentCell))
 						{
 							foreColor = SystemColors.HighlightText;
 							rePrep = true;
 						}
+						if (text.Length == 0 && mouseCell == currentCell)
+						{
+							font = new Font(Font, FontStyle.Regular);
+							foreColor = SystemColors.GrayText;
+							text = col.Text;
+							rePrep = true;
+						}
 						if (col.Rotatable || rePrep)
 						{
-							_renderer.PrepDrawString(Font, foreColor, rotate: col.Rotatable);
+							_renderer.PrepDrawString(font, foreColor, rotate: col.Rotatable);
 							rePrep = true;
 						}
 
-						int textWidth = (int)_renderer.MeasureString(text, Font).Width;
+						int textWidth = (int)_renderer.MeasureString(text, font).Width;
 						if (col.Rotatable)
 						{
 							// Center Text
@@ -287,13 +296,26 @@ private void DrawData(List<RollColumn> visibleColumns, int firstVisibleRow, int
 						QueryItemText(this, f + startRow, column, out var text, ref strOffsetX, ref strOffsetY);
 
 						bool rePrep = false;
+						Color foreColor = _foreColor;
+						Font font = Font;
 						currentCell.Column = column;
 						currentCell.RowIndex = f + startRow;
 						if (_selectedItems.Contains(currentCell))
 						{
-							_renderer.PrepDrawString(Font, SystemColors.HighlightText);
+							foreColor = SystemColors.HighlightText;
 							rePrep = true;
 						}
+						if (text.Length == 0 && mouseCell == currentCell)
+						{
+							font = new Font(Font, FontStyle.Regular);
+							foreColor = SystemColors.GrayText;
+							text = column.Text;
+							rePrep = true;
+						}
+						if (rePrep)
+						{
+							_renderer.PrepDrawString(font, foreColor);
+						}
 
 						DrawString(text, new Rectangle(point.X + strOffsetX, point.Y + strOffsetY, column.Width, ColumnHeight));
 

src/BizHawk.Client.EmuHawk/CustomControls/InputRoll/InputRoll.cs

@@ -237,6 +237,13 @@ public int CellHeightPadding
 		[DefaultValue(true)]
 		public bool GridLines { get; set; } = true;
 
+		/// <summary>
+		/// Gets or sets a value indicating whether empty cells will display their column's text when the mouse cursor is placed over them
+		/// </summary>
+		[DefaultValue(false)]
+		[Category("Appearance")]
+		public bool ShowColumnTextOnHover { get; set; }
+
 		/// <summary>
 		/// Gets or sets a value indicating whether the control is horizontal or vertical
 		/// </summary>

src/BizHawk.Client.EmuHawk/tools/TAStudio/TAStudio.ListView.cs

@@ -182,6 +182,7 @@ private InputRoll MakeInputRoll(int? insertAfter = null)
 				InputPaintingMode = true,
 				LetKeysModifySelection = true,
 				Rotatable = true,
+				ShowColumnTextOnHover = true,
 				// user configurable
 				AlwaysScroll = Settings.FollowCursorAlwaysScroll,
 				Font = Settings.TasViewFont,
@@ -1280,13 +1281,9 @@ private void TasView_PointedCellChanged(object sender, InputRoll.CellEventArgs e
 			InputRoll roll = (InputRoll)sender;
 			toolTip1.SetToolTip(roll, null);
 
-			if (e.NewCell.RowIndex is null)
-			{
-				return;
-			}
-
-			if (!MouseButtonHeld)
+			if (e.NewCell.RowIndex is null || !MouseButtonHeld)
 			{
+				SetTasViewRowCount(); // redraw
 				return;
 			}