該類實(shí)現(xiàn)代碼如下：

  1using system.drawing;
  2using system.drawing.drawing2d;
  3using system.drawing.imaging;
  4
  5namespace ycweb.controls.utility
  6{
  7    /**//// <summary>
  8    /// watermark
  9    /// </summary>
 10    public class watermark
 11    {
 12        private int _width;
 13        private int _height;
 14        private string _fontfamily;
 15        private int _fontsize;
 16        private bool _adaptable;
 17        private fontstyle _fontstyle;
 18        private bool _shadow;
 19        private string _backgroundimage;
 20        private color _bgcolor;
 21        private int _left;
 22        private string _resultimage;
 23        private string _text;
 24        private int _top;
 25        private int _alpha;
 26        private int _red;
 27        private int _green;
 28        private int _blue;
 29        private long _quality;
 30
 31
 32
 33        public watermark()
 34        {
 35            //
 36            // todo: add constructor logic here
 37            //
 38            _width=460;
 39            _height=30;
 40            _fontfamily = "華文行楷";
 41            _fontsize = 20;
 42            _fontstyle=fontstyle.regular;
 43            _adaptable=true;
 44            _shadow=false;
 45            _left = 0;
 46            _top = 0;
 47            _alpha = 255;
 48            _red = 0;
 49            _green = 0;
 50            _blue = 0;
 51            _backgroundimage="";
 52            _quality=100;
 53            _bgcolor=color.fromargb(255,229,229,229);
 54           
 55        }
 56
 57        /**//// <summary>
 58        /// 字體
 59        /// </summary>
 60        public string fontfamily
 61        {
 62            set { this._fontfamily = value; }
 63        }
 64
 65        /**//// <summary>
 66        /// 文字大小
 67        /// </summary>
 68        public int fontsize
 69        {
 70            set { this._fontsize = value; }
 71        }
 72
 73        /**//// <summary>
 74        /// 文字風(fēng)格
 75        /// </summary>
 76        public fontstyle fontstyle
 77        {
 78            get{return _fontstyle;}
 79            set{_fontstyle = value;}
 80        }
 81
 82        /**//// <summary>
 83        /// 透明度0-255,255表示不透明
 84        /// </summary>
 85        public int alpha
 86        {
 87            get { return _alpha; }
 88            set { _alpha = value; }
 89        }
 90
 91        /**//// <summary>
 92        /// 水印文字是否使用陰影
 93        /// </summary>
 94        public bool shadow
 95        {
 96            get { return _shadow; }
 97            set { _shadow = value; }
 98        }
 99
100        public int red
101        {
102            get { return _red; }
103            set { _red = value; }
104        }
105
106        public int green
107        {
108            get { return _green; }
109            set { _green = value; }
110        }
111
112        public int blue
113        {
114            get { return _blue; }
115            set { _blue = value; }
116        }
117
118        /**//// <summary>
119        /// 底圖
120        /// </summary>
121        public string backgroundimage
122        {
123            set { this._backgroundimage = value; }
124        }
125
126        /**//// <summary>
127        /// 水印文字的左邊距
128        /// </summary>
129        public int left
130        {
131            set { this._left = value; }
132        }
133
134       
135        /**//// <summary>
136        /// 水印文字的頂邊距
137        /// </summary>
138        public int top
139        {
140            set { this._top = value; }
141        }
142
143        /**//// <summary>
144        /// 生成后的圖片
145        /// </summary>
146        public string resultimage
147        {
148            set { this._resultimage = value; }
149        }
150
151        /**//// <summary>
152        /// 水印文本
153        /// </summary>
154        public string text
155        {
156            set { this._text = value; }
157        }
158
159       
160        /**//// <summary>
161        /// 生成圖片的寬度
162        /// </summary>
163        public int width
164        {
165            get { return _width; }
166            set { _width = value; }
167        }
168
169        /**//// <summary>
170        /// 生成圖片的高度
171        /// </summary>
172        public int height
173        {
174            get { return _height; }
175            set { _height = value; }
176        }
177
178        /**//// <summary>
179        /// 若文字太大，是否根據(jù)背景圖來調(diào)整文字大小，默認(rèn)為適應(yīng)
180        /// </summary>
181        public bool adaptable
182        {
183            get { return _adaptable; }
184            set { _adaptable = value; }
185        }
186
187        public color bgcolor
188        {
189            get { return _bgcolor; }
190            set { _bgcolor = value; }
191        }
192
193        /**//// <summary>
194        /// 輸出圖片質(zhì)量，質(zhì)量范圍0-100,類型為long
195        /// </summary>
196        public long quality
197        {
198            get { return _quality; }
199            set { _quality = value; }
200        }
201
202        /**//// <summary>
203        /// 立即生成水印效果圖
204        /// </summary>
205        /// <returns>生成成功返回true,否則返回false</returns>
206        public bool create()
207        {
208            try
209            {
210                bitmap bitmap;
211                graphics g;
212
213                //使用純背景色
214                if(this._backgroundimage.trim()=="")
215                {
216                    bitmap = new bitmap(this._width, this._height, pixelformat.format64bppargb);
217                    g = graphics.fromimage(bitmap);
218                    g.clear(this._bgcolor);
219                }
220                else
221                {
222                    bitmap = new bitmap(image.fromfile(this._backgroundimage));
223                    g = graphics.fromimage(bitmap);
224                }
225                g.smoothingmode = smoothingmode.highquality;
226                g.interpolationmode = interpolationmode.highqualitybicubic;
227                g.compositingquality=compositingquality.highquality;
228
229                font f = new font(_fontfamily, _fontsize,_fontstyle);
230                sizef size = g.measurestring(_text, f);
231               
232                // 調(diào)整文字大小直到能適應(yīng)圖片尺寸
233                while(_adaptable==true && size.width > bitmap.width)
234                {
235                    _fontsize--;
236                    f = new font(_fontfamily, _fontsize, _fontstyle);
237                    size = g.measurestring(_text, f);
238                }
239               
240                brush b = new solidbrush(color.fromargb(_alpha, _red, _green, _blue));
241                stringformat strformat = new stringformat();
242                strformat.alignment = stringalignment.near;
243
244                if(this._shadow)
245                {
246                    brush b2=new solidbrush(color.fromargb(90, 0, 0, 0));
247                    g.drawstring(_text, f, b2,_left+2, _top+1);
248                }
249                g.drawstring(_text, f, b, new pointf(_left, _top), strformat);
250               
251                bitmap.save(this._resultimage, imageformat.jpeg);
252                bitmap.dispose();
253                g.dispose();
254                return true;
255            }
256            catch
257            {
258                return false;
259            }
260        }
261    }
262
263
264}
調(diào)用則相當(dāng)簡(jiǎn)單，在此不予贅述，特把我使用的效果抓個(gè)圖，以供大家參考