How to add a triangle marker to any cell corner of SpreadsheetGear grid?

Question

This is a SpreadsheetGear Grid specific question. I know you can add a comment to a cell and the cell gets red triangle marker at the top right corner automatically. But I have a need to add a small triangle (different color) to any cell corner to indicate something special. Is it possible to do it?

UPATE: This is what I got for adding a triangle to any corner of the cell based on Daniel's suggestion.

    public void AddTriangleShapeToCorner(IWorksheet worksheet, int row, int col, CellCorners cellCorner)
    {
        const double width = 5, height = 5;
        double xOffset = 0, yOffset = 0;

        IWorksheetWindowInfo windowInfo = worksheet.WindowInfo;

        if (cellCorner == CellCorners.TopRight || cellCorner == CellCorners.BottomRight)
        {
            col++;
            xOffset = width;
        }
        if (cellCorner == CellCorners.BottomLeft || cellCorner == CellCorners.BottomRight)
        {
            row++;
            yOffset = height;
        }
        double top = windowInfo.RowToPoints(row) - yOffset;
        double left = windowInfo.ColumnToPoints(col) - xOffset;

        IShape shape = worksheet.Shapes.AddShape(AutoShapeType.RightTriangle, left, top, width, height);
        shape.Line.Visible = false;         // line at top-left corner is not sharp, so turn it off.
        shape.Placement = Placement.Move;   // make the shape move with cell. NOTE: it doesn't work for top-right and bottom-right corners.
        if (cellCorner == CellCorners.TopLeft || cellCorner == CellCorners.TopRight)
            shape.VerticalFlip = true;
        if (cellCorner == CellCorners.TopRight || cellCorner == CellCorners.BottomRight)
            shape.HorizontalFlip = true;
    }

Answer 1

You can use the IShapes AddShape method. For the type, you can use AutoShapeType.RightTriangle.

Here is an example:

private void AddTriangleShape(SpreadsheetGear.IWorksheet worksheet, int iRow, int iCol)
{
  SpreadsheetGear.IWorksheetWindowInfo windowInfo = worksheet.WindowInfo;

  // Calculate the left, top, width and height of the button by 
  // converting row and column coordinates to points.  Use fractional 
  // values to get coordinates in between row and column boundaries.
  double left = windowInfo.ColumnToPoints(iCol);
  double top = windowInfo.RowToPoints(iRow + 0.5);
  double right = windowInfo.ColumnToPoints(iCol + 0.1);
  double bottom = windowInfo.RowToPoints(iRow + 0.9);
  double width = right - left;
  double height = bottom - top;

  worksheet.Shapes.AddShape(SpreadsheetGear.Shapes.AutoShapeType.RightTriangle, left, top, width, height);
}