How to enum font sizes like TFontDialog does

Problem/Question/Abstract:

I would like to get all font sizes for the given font like TFontDialog does. Minimum and maximum font size would be nice, too.

Answer:

Note that the list of font sizes for Truetype fonts is just an arbitrary selection of often-used sizes, you can scale these fonts to nearly any size.

Example for the use of EnumFontFamilies. Project requires two listboxes on the form, nothing else.

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    ListBox1: TListBox;
    ListBox2: TListBox;
    procedure FormCreate(Sender: TObject);
    procedure ListBox1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.FormCreate(Sender: TObject);
begin
  listbox1.items.assign(screen.fonts);
end;

function EnumProc(var elf: TEnumLogFont; var ntm: TNewTextmetric;
  fonttype: Integer; listbox: TListbox): Integer; stdcall;
var
  S: string;
begin
  if fonttype = TRUETYPE_FONTTYPE then
  begin
    listbox.Items.Add(Format('Name: %s', [elf.elfFullName]));
    listbox.Items.Add(Format('Style: %s', [elf.elfStyle]));
  end
  else
    listbox.Items.Add(Format('Name: %s', [elf.elfLogfont.lfFacename]));
  listbox.Items.Add(Format('Size: %d', [elf.elfLogFont.lfHeight]));
  listbox.Items.Add(Format('Weight: %d', [elf.elfLogFont.lfWeight]));
  if elf.elfLogFont.lfItalic <> 0 then
    listbox.Items.Add('This font is italic');
  case fonttype of
    DEVICE_FONTTYPE: S := 'device font';
    RASTER_FONTTYPE: S := 'raster font';
    TRUETYPE_FONTTYPE: S := 'truetype font'
  else
    S := 'unknown font type';
  end;
  listbox.Items.Add(Format('This is a %s', [S]));
  Result := 1;
end;

procedure TForm1.ListBox1Click(Sender: TObject);
begin
  listbox2.clear;
  with listbox1 do
    if ItemIndex >= 0 then
      EnumFontFamilies(Self.Canvas.Handle, PChar(Items[ItemIndex]),
        @EnumProc, Longint(listbox2));
end;

end.