Delphi/Lazarus: Specify TextWidth and TextHeight without Canvas

When I am faced with that issue, I am creating a bitmap within the function at which I can process my measurements. After processing, I can delete (free) this bitmap in case that I do not need it anymore.

Here is a function to get the width (TextWidth) of a font:

function GetTextWidth(AText: string): integer;
var
  bmp: TBitmap;
begin
  bmp := TBitmap.Create;
  try
    bmp.Canvas.Font.Assign(self.Font);
    result := bmp.Canvas.TextWidth(AText);
  finally
    bmp.Free;
  end;
end;

And here is a function to get the height (TextHeight):

function GetTextHeight(AText: string): integer;
var
  bmp: TBitmap;
begin
  bmp := TBitmap.Create;
  try
    bmp.Canvas.Font.Assign(self.Font);
    result := bmp.Canvas.TextHeight(AText);
  finally
    bmp.Free;
  end;
end;

In both functions, we are taking over the font from Form1, but of course, it is also possible to use and set any other font to bmp.Canvas.Font within the function. For example like that:

function GetTextWidth(AText, AFontName: string; 
  AFontSize: integer): integer;
var
  bmp: TBitmap;
begin
  bmp := TBitmap.Create;
  try
    bmp.Canvas.Font.Name := AFont;
    bmp.Canvas.Font.Size := AFontSize;
    result := bmp.Canvas.TextWidth(AText);
  finally
    bmp.Free;
  end;
end;

In this function, we can also pass the name of the font as well as the font size as parameter.

However, if you only want to set the size of a Button, you can also do that by setting the property AutoSize to TRUE. If this is the case, the button automatically adjusts to the containing text.
Last update on 2022-07-21 | Created on 2016-01-18