Author: Jonas Bilinkevicius

How to get the text width in pixels when a component doesn't have a canvas

Answer:

If a component doesn't have a Canvas property you can use the following function to 
get the text width based on the font passed.
1   
2   function GetTextWidth(CanvasOwner: TForm; Text: string; TextFont: TFont): Integer;
3   var
4     OldFont: TFont;
5   begin
6     OldFont := TFont.Create;
7     try
8       OldFont.Assign(CanvasOwner.Font);
9       CanvasOwner.Font.Assign(TextFont);
10      Result := CanvasOwner.Canvas.TextWidth(Text);
11      CanvasOwner.Font.Assign(OldFont);
12    finally
13      OldFont.Free;
14    end;
15  end;