Use TLogFont type for font.There is a property lfEscapement, You can give in tenths of degrees so 900 = 90 degrees.
eg:=
logfont:TLogFont;
with LogFont do
begin
lfHeight := 12;
lfWidth := 0;
lfEscapement := 900;
lfOrientation := 0;
lfWeight := FW_NORMAL; // default
lfItalic := 0; // no italics
lfUnderline := 0; // no underline
lfStrikeOut := 0; // no strikeout
lfCharSet := ANSI_CHARSET; //default
StrPCopy(lfFaceName, Font.Name);
lfQuality := PROOF_QUALITY;
lfOutPrecision := OUT_TT_ONLY_PRECIS;
lfClipPrecision := CLIP_DEFAULT_PRECIS; // default
lfPitchAndFamily := Variable_Pitch; // default
end;
Printer.Canvas.Font.Handle := CreateFontIndirect(LogFont);