本例效果图:




代码文件:
unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    ListBox1: TListBox;
    procedure FormPaint(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure ListBox1Click(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

uses GDIPOBJ, GDIPAPI;

var
  FontName: string = '宋体';

procedure TForm1.FormCreate(Sender: TObject);
var
  str: string;
begin
  ListBox1.Align := alRight;
  for str in Screen.Fonts do
    if str[1] <> '@' then
      ListBox1.Items.Add(str);
end;

procedure TForm1.FormPaint(Sender: TObject);
var
  g: TGPGraphics;
  b: TGPBrush;
  font: TGPFont;
  fontFamily: TGPFontFamily;
begin
  g := TGPGraphics.Create(Canvas.Handle);
  b := TGPSolidBrush.Create(aclRed);
  fontFamily := TGPFontFamily.Create(FontName);
  font := TGPFont.Create(fontFamily, 48, FontStyleBold);

  g.DrawString('Delphi', -1, font, MakePoint(5.0,20.0), b);
  Text := Format('Height: %f', [font.GetHeight(g)]);

  fontFamily.Free;
  font.Free;
  b.Free;
  g.Free;
end;

procedure TForm1.ListBox1Click(Sender: TObject);
begin
  FontName := ListBox1.Items[ListBox1.ItemIndex];
  Repaint;
end;

end.
窗体文件:
object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Form1'
  ClientHeight = 126
  ClientWidth = 375
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  Position = poDesktopCenter
  OnCreate = FormCreate
  OnPaint = FormPaint
  PixelsPerInch = 96
  TextHeight = 13
  object ListBox1: TListBox
    Left = 242
    Top = 8
    Width = 121
    Height = 97
    ItemHeight = 13
    TabOrder = 0
    OnClick = ListBox1Click
  end
end