fpSpread1.Sheets[0].Cells[1, 3].Text = "Test"; //Cell has to have value
fpSpread1.Sheets[0].Cells[1, 3].Border = new FarPoint.Win.ComplexBorder(new FarPoint.Win.ComplexBorderSide(Color.Red, 2));// Cell has to have border
FarPoint.Win.Spread.CellType.TextCellType cellType = new FarPoint.Win.Spread.CellType.TextCellType();
cellType.TextOrientation = FarPoint.Win.TextOrientation.TextRotateCustom;
cellType.TextRotationAngle = 60; // Cell has to have rotation angle to see the effect.
fpSpread1.Sheets[0].Cells[1, 3].CellType = cellType;
fpSpread1.Sheets[0].EnableDiagonalLine = true;