unit Main;
interface

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

type
  TMainForm = class(TForm)
    Button1: TButton;
    procedure FormPaint(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
    Photo: TGpImage;
    PhWidth: Integer;
    PhHeight: Integer;
    Watermark: TGpImage;
    WmWidth: Integer;
    WmHeight: Integer;
    Bmp: TGpBitmap;
  public
    { Public declarations }
  end;

var
  MainForm: TMainForm;

implementation

uses GdipTypes;

{$R *.dfm}

procedure TMainForm.Button1Click(Sender: TObject);
var
  Clsid: TGUID;
  Parameters: TEncoderParameters;
  Quality: Integer;
begin
  // 设置图像品质编码参数
  Parameters.Count := 1;
  Parameters.Parameter[0].Guid := EncoderQuality;
  Parameters.Parameter[0].ValueType := EncoderParameterValueTypeLong;
  Parameters.Parameter[0].NumberOfValues := 1;
  // 设置参数的值：品质等级，最高为100，图像文件大小与品质成正比
  Quality := 100;
  Parameters.Parameter[0].Value := @Quality;

  if GetEncoderClsid('image/jpeg', Clsid) then
    Bmp.Save('WatermarkPhoto.jpg', Clsid, @Parameters);
end;

procedure TMainForm.FormCreate(Sender: TObject);
const
  ColorMatrix: TColorMatrix =
  (
    (1.0, 0.0, 0.0, 0.0, 0.0),
    (0.0, 1.0, 0.0, 0.0, 0.0),
    (0.0, 0.0, 1.0, 0.0, 0.0),
    (0.0, 0.0, 0.0, 0.3, 0.0),
    (0.0, 0.0, 0.0, 0.0, 1.0)
  );
  WorkingDirectory = '....Media';
  copyright = 'Copyright © 2008 - Maozefa';
var
  gp: TGpGraphics;
  imageAttr: TGpImageAttributes;
  strFormat: TGpStringFormat;
  font: TGpFont;
  x, y: Single;
begin
  // 读取原始图片
  Photo := TGpImage.Create(WorkingDirectory + '100_0349.jpg');
  PhWidth := Photo.Width;
  PhHeight := Photo.Height;
  // 读取水印图片
  Watermark := TGpImage.Create(WorkingDirectory + 'Watermark.bmp');
  WmWidth := Watermark.Width;
  WmHeight := Watermark.Height;
  // 建立一个新的位图，分辨率为72
  Bmp := TGpBitmap.Create(PhWidth, PhHeight, pf32bppArgb);
  Bmp.SetResolution(72, 72);
  // 建立新位图的画布，并设置图像显示质量和文本显示质量
  gp := TGpGraphics.Create(Bmp);
  gp.SmoothingMode := smAntiAlias;
  gp.TextRenderingHint := thAntiAlias;
  // 在画布上画原始图片
  gp.DrawImage(Photo, GpRect(0, 0, PhWidth, PhHeight),
               0, 0, PhWidth, PhHeight, utPixel);
  // 建立图像显示辅助类
  imageAttr := TGpImageAttributes.Create;
  // 设置透明颜色为水印图片四角的底色，水印图显示为圆角图片
  imageAttr.SetColorKey($ff00ff00, $ff00ff00, ctBitmap);
  // 设置水印图片不透明度为0.3
  imageAttr.SetColorMatrix(ColorMatrix, cfDefault, ctBitmap);
  // 在画布左上角画水印图
  gp.DrawImage(Watermark, GpRect({PhWidth - WmWidth - }10, 10, WmWidth, WmHeight),
               0, 0, WmWidth, WmHeight, utPixel, imageAttr);
  // 设置文本字体和显示格式
  font := TGpFont.Create('arial', 16, [fsBold]);
  strFormat := TGpStringFormat.Create;
  strFormat.Alignment := saCenter;
  // 在画布下方居中显示阴影文本
  x := PhWidth / 2;
  y := PhHeight - 26;
  gp.DrawString(copyright, font, Brushs[$99000000], x + 1, y + 1, strFormat);
  gp.DrawString(copyright, font, Brushs[$99ffffff], x, y, strFormat);

  font.Free;
  strFormat.Free;
  imageAttr.Free;
  gp.Free;
end;

procedure TMainForm.FormDestroy(Sender: TObject);
begin
  Photo.Free;
  Watermark.Free;
  Bmp.Free;
end;

procedure TMainForm.FormPaint(Sender: TObject);
var
  g: TGpGraphics;
begin
  g := TGpGraphics.Create(Canvas.Handle);
  // 显示原始图片
  g.DrawImage(Photo, 0, 0, PhWidth, PhHeight);
  // 显示水印原始图片
  g.TranslateTransform(0, PhHeight + 5);
  g.DrawImage(Watermark, 0, 0, WmWidth, WmHeight);
  // 显示带水印和文本的图像
  g.TranslateTransform(PhWidth, -(PhHeight + 5));
  g.DrawImage(Bmp, 0, 0, PhWidth, PhHeight);
  g.Free;
end;

end.