GDI+ 在Delphi程序的应用 -

sogotobj

利用GDI+可以很方便的制作带水印效果的图片，网上介绍这方面的文章也很多，但鲜有Delphi的，本文参照网上文章http://www.codeproject.com/KB/GDI-plus/watermark.aspx介绍的方法，用Delphi 2007制作水印效果图片，原代码如下：
<div style="padding-right: 5.4pt; padding-left: 5.4pt; background: #e6e6e6; padding-bottom: 4px; width: 95%; padding-top: 4px;">unitMain;

interface

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

type
TMainForm=class(TForm)
Button1:TButton;
procedureFormPaint(Sender:TObject);
procedureFormCreate(Sender:TObject);
procedureFormDestroy(Sender:TObject);
procedureButton1Click(Sender:TObject);
private
{Privatedeclarations}
Photo:TGpImage;
PhWidth:Integer;
PhHeight:Integer;
Watermark:TGpImage;
WmWidth:Integer;
WmHeight:Integer;
Bmp:TGpBitmap;
public
{Publicdeclarations}
end;

var
MainForm:TMainForm;

implementation

usesGdipTypes;

{$R*.dfm}

procedureTMainForm.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;

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

procedureTMainForm.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;

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

procedureTMainForm.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.