Question

I’m looking for a simple component that displays mathematical expressions in Delphi. When I started out I thought it would be easy to find something on the net, but it turns out it was harder than anticipated. There are lots and lots of components that will parse mathematical expressions, but few (none?) that will display them.

Ideally I would like a component as simple as a TLabel, where I could set the caption to some expression and it would be displayed correctly, but some sort of library that let’s me draw expressions to a canvas would also be sufficient for my needs.

Update:

I’m not talking about plotting graphs of functions or something like that. I want to display (for instance)

(X^2+3)/X

like this:

Solution:

MBo’s answer was just what I was looking for. Some people may be put off by the fact that all comments and documentation are in Russian, but don’t let that scare you. It was really easy to use.

Installation: Unzip the files (at least “ExprMake.pas” and “ExprDraw.pas”) to a directory in your library path. That’s it.

Use: I haven’t experimented extensively with it, but these few lines demonstrates how easy it is.

procedure TForm1.Button1Click(Sender: TObject);
var
  vExprC : TExprClass;
  vExprB : TExprBuilder;
begin
  vExprB := TExprBuilder.Create;
  try
    vExprC := vExprB.BuildExpr('(X^2+3)/X');
    vExprC.Canvas := Canvas;
    vExprC.Font.Size := 50;
    vExprC.Draw(10,10,ehLeft,evTop);
  finally
    vExprC.Free;
    vExprB.Free;
  end;
end;

Answer 1

Native Delphi module by Anton Grigoriev to draw mathematical expressions. Assistant program – in Russian. This is how it looks.

Addition about credits:
Modules are free. The author asks only to mention (AboutBox etc) that mathematical expressions have been drawn by means of ExprDraw and ExprMake modules, written by Anton Grigoriev
(raw translation from readme.txt)