ImageCode函数通过GIFEncoder类实现的GIF动画的PHP源代码,有兴趣的朋友可以研究一下,PHP生成GIF动态图片验证码实例代码如下:

1. <?php
2. /**
3. * 调用示例
4. * */
5. session_start();
6. $randCode = '';
7. $chars = 'abcdefghjkmnpqrstuvwxyzABCDEFGHJKLMNPRSTUVWXYZ23456789';
8. for ( $i = 0; $i < 4; $i++ )
9. {
10. $randCode .= substr($chars, mt_rand(0, strlen($chars) - 1), 1);
11. }
12. $_SESSION['code'] = strtoupper($randCode); // 记录session
13. ImageCode($randCode, 60); // 显示GIF动画
14. /**
15. * ImageCode 生成GIF图片验证
16. * @param $string 字符串
17. * @param $width 宽度
18. * @param $height 高度
19. * */
20. function ImageCode($string = '', $width = 75, $height = 25)
21. {
22. $authstr = $string ? $string : ((time() % 2 == 0) ? mt_rand(1000, 9999) : mt_rand(10000, 99999));
23. $board_width = $width;
24. $board_height = $height;
25. // 生成一个32帧的GIF动画
26. for($i = 0; $i < 32; $i++)
27. {
28. ob_start();
29. $image = imagecreate($board_width, $board_height);
30. imagecolorallocate($image, 0,0,0);
31. // 设定文字颜色数组
32. $colorList[] = ImageColorAllocate($image, 15,73,210);
33. $colorList[] = ImageColorAllocate($image, 0,64,0);
34. $colorList[] = ImageColorAllocate($image, 0,0,64);
35. $colorList[] = ImageColorAllocate($image, 0,128,128);
36. $colorList[] = ImageColorAllocate($image, 27,52,47);
37. $colorList[] = ImageColorAllocate($image, 51,0,102);
38. $colorList[] = ImageColorAllocate($image, 0,0,145);
39. $colorList[] = ImageColorAllocate($image, 0,0,113);
40. $colorList[] = ImageColorAllocate($image, 0,51,51);
41. $colorList[] = ImageColorAllocate($image, 158,180,35);
42. $colorList[] = ImageColorAllocate($image, 59,59,59);
43. $colorList[] = ImageColorAllocate($image, 0,0,0);
44. $colorList[] = ImageColorAllocate($image, 1,128,180);
45. $colorList[] = ImageColorAllocate($image, 0,153,51);
46. $colorList[] = ImageColorAllocate($image, 60,131,1);
47. $colorList[] = ImageColorAllocate($image, 0,0,0);
48. $fontcolor = ImageColorAllocate($image, 0,0,0);
49. $gray = ImageColorAllocate($image, 245,245,245);
50. $color = imagecolorallocate($image, 255,255,255);
51. $color2 = imagecolorallocate($image, 255,0,0);
52. imagefill($image, 0, 0, $gray);
53. $space = 15; // 字符间距
54. if($i > 0) // 屏蔽第一帧
55. {
56. for ($k = 0; $k < strlen($authstr); $k++)
57. {
58. $colorRandom = mt_rand(0,sizeof($colorList)-1);
59. $float_top = rand(0,4);
60. $float_left = rand(0,3);
61. imagestring($image, 6, $space * $k, $top + $float_top, substr($authstr, $k, 1), $colorList[$colorRandom]);
62. }
63. }
64. for ($k = 0; $k < 20; $k++)
65. {
66. $colorRandom = mt_rand(0,sizeof($colorList)-1);
67. imagesetpixel($image, rand()%70 , rand()%15 , $colorList[$colorRandom]);
68. }
69. // 添加干扰线
70. for($k = 0; $k < 3; $k++)
71. {
72. $colorRandom = mt_rand(0, sizeof($colorList)-1);
73. // $todrawline = rand(0,1);
74. $todrawline = 1;
75. if($todrawline)
76. {
77. imageline($image, mt_rand(0, $board_width), mt_rand(0,$board_height), mt_rand(0,$board_width), mt_rand(0,$board_height), $colorList[$colorRandom]);
78. }
79. else
80. {
81. $w = mt_rand(0,$board_width);
82. $h = mt_rand(0,$board_width);
83. imagearc($image, $board_width - floor($w / 2) , floor($h / 2), $w, $h, rand(90,180), rand(180,270), $colorList[$colorRandom]);
84. }
85. }
86. imagegif($image);
87. imagedestroy($image);
88. $imagedata[] = ob_get_contents();
89. ob_clean();
90. ++$i;
91. }
92. $gif = new GIFEncoder($imagedata);
93. Header ('Content-type:image/gif');
94. echo $gif->GetAnimation();
95. }
96. /**
97. * GIFEncoder类
98. * */
99. Class GIFEncoder
100. {
101. var $GIF = "GIF89a"; /* GIF header 6 bytes */
102. var $VER = "GIFEncoder V2.06"; /* Encoder version */
103. var $BUF = Array ( );
104. var $LOP = 0;
105. var $DIS = 2;
106. var $COL = -1;
107. var $IMG = -1;
108. var $ERR = Array (
109. 'ERR00' =>"Does not supported function for only one image!",
110. 'ERR01' =>"Source is not a GIF image!",
111. 'ERR02' =>"Unintelligible flag ",
112. 'ERR03' =>"Could not make animation from animated GIF source",
113. );
114. function GIFEncoder ($GIF_src, $GIF_dly = 100, $GIF_lop = 0, $GIF_dis = 0, $GIF_red = 0, $GIF_grn = 0, $GIF_blu = 0, $GIF_mod = 'bin' )
115. {
116. if (!is_array($GIF_src) && !is_array($GIF_tim))
117. {
118. printf ( "%s: %s", $this->VER, $this->ERR['ERR00']);
119. exit( 0 );
120. }
121. $this->LOP = ($GIF_lop > -1) ? $GIF_lop : 0;
122. $this->DIS = ($GIF_dis > -1) ? (( $GIF_dis < 3 ) ? $GIF_dis : 3) : 2;
123. $this->COL = ($GIF_red > -1 && $GIF_grn > -1 && $GIF_blu > -1) ? ($GIF_red | ($GIF_grn << 8) | ($GIF_blu << 16)) : -1;
124. for ($i = 0, $src_count = count($GIF_src); $i < $src_count; $i++ )
125. {
126. if (strToLower( $GIF_mod ) == "url")
127. {
128. $this->BUF[] = fread (fopen($GIF_src [$i], "rb"), filesize ($GIF_src [$i]));
129. }
130. elseif(strToLower($GIF_mod) == "bin")
131. {
132. $this->BUF [ ] = $GIF_src [ $i ];
133. }
134. else
135. {
136. printf("%s: %s ( %s )!", $this->VER, $this->ERR [ 'ERR02' ], $GIF_mod);
137. exit(0);
138. }
139. if (substr($this->BUF[$i], 0, 6) != "GIF87a" && substr($this->BUF [$i], 0, 6) != "GIF89a")
140. {
141. printf( "%s: %d %s", $this->VER, $i, $this->ERR ['ERR01']);
142. exit(0);
143. }
144. for ($j = (13 + 3 * (2 << (ord($this->BUF[$i]{10}) & 0x07 ))), $k = TRUE; $k; $j++)
145. {
146. switch ($this->BUF [$i]{$j})
147. {
148. case "!":
149. if ((substr($this->BUF[$i], ($j + 3), 8)) == "NETSCAPE")
150. {
151. printf( "%s: %s ( %s source )!", $this->VER, $this->ERR ['ERR03'], ($i + 1));
152. exit( 0 );
153. }
154. break;
155. case ";":
156. $k = FALSE;
157. break;
158. }
159. }
160. }
161. GIFEncoder::GIFAddHeader();
162. for($i = 0, $count_buf = count($this->BUF); $i < $count_buf; $i++)
163. {
164. GIFEncoder::GIFAddFrames($i, $GIF_dly[$i]);
165. }
166. GIFEncoder::GIFAddFooter();
167. }
168. function GIFAddHeader ( )
169. {
170. $cmap = 0;
171. if (ord($this->BUF[0]{10}) & 0x80 )
172. {
173. $cmap = 3 * ( 2 << ( ord ( $this->BUF [ 0 ]{10} ) & 0x07 ));
174. $this->GIF .= substr ( $this->BUF [ 0 ], 6, 7);
175. $this->GIF .= substr ( $this->BUF [ 0 ], 13, $cmap);
176. $this->GIF .= "!37713NETSCAPE2.031" . GIFEncoder::GIFWord ( $this->LOP ) . "";
177. }
178. }
179. function GIFAddFrames ( $i, $d )
180. {
181. $Locals_str = 13 + 3 * (2 <<(ord($this->BUF[$i]{10}) & 0x07));
182. $Locals_end = strlen($this->BUF[$i]) - $Locals_str - 1;
183. $Locals_tmp = substr ($this->BUF[$i], $Locals_str, $Locals_end);
184. $Global_len = 2 << (ord( $this->BUF [0]{10} ) & 0x07 );
185. $Locals_len = 2 << (ord( $this->BUF[$i]{10}) & 0x07);
186. $Global_rgb = substr($this->BUF[0], 13, 3 * (2 << ( ord ( $this->BUF[0]{10} ) & 0x07)));
187. $Locals_rgb = substr ( $this->BUF[$i], 13, 3 * (2 << ( ord ( $this->BUF[$i]{10} ) & 0x07)));
188. $Locals_ext = "!xF9x04" . chr(($this->DIS << 2) + 0) . chr(($d >> 0) & 0xFF) . chr(($d >> 8) & 0xFF) . "x0x0";
189. if ( $this->COL > -1 && ord($this->BUF[$i]{10}) & 0x80)
190. {
191. for($j = 0; $j < (2 << (ord( $this->BUF[$i]{10}) & 0x07)); $j++ )
192. {
193. if(ord ($Locals_rgb{3 * $j + 0}) == ($this->COL >> 0) & 0xFF && ord ( $Locals_rgb { 3 * $j + 1 } ) == ( $this->COL >> 8 ) & 0xFF && ord ( $Locals_rgb { 3 * $j + 2 } ) == ( $this->COL >> 16 ) & 0xFF )
194. {
195. $Locals_ext = "!xF9x04" . chr(($this->DIS << 2) + 1) . chr (( $d >> 0) & 0xFF) . chr (( $d >> 8) & 0xFF) . chr ($j) . "x0";
196. break;
197. }
198. }
199. }
200. switch ( $Locals_tmp { 0 } )
201. {
202. case "!":
203. $Locals_img = substr($Locals_tmp, 8, 10);
204. $Locals_tmp = substr($Locals_tmp, 18, strlen ($Locals_tmp) - 18);
205. break;
206. case ",":
207. $Locals_img = substr($Locals_tmp, 0, 10);
208. $Locals_tmp = substr($Locals_tmp, 10, strlen($Locals_tmp) - 10);
209. break;
210. }
211. if ( ord ( $this->BUF[$i]{10} ) & 0x80 && $this->IMG > -1 )
212. {
213. if ( $Global_len == $Locals_len )
214. {
215. if ( GIFEncoder::GIFBlockCompare ( $Global_rgb, $Locals_rgb, $Global_len ) )
216. {
217. $this->GIF .= ( $Locals_ext . $Locals_img . $Locals_tmp );
218. }
219. else
220. {
221. $byte = ord ( $Locals_img{9});
222. $byte |= 0x80;
223. $byte &= 0xF8;
224. $byte |= ( ord ( $this->BUF [ 0 ]{10}) & 0x07);
225. $Locals_img{9} = chr($byte);
226. $this->GIF .= ($Locals_ext . $Locals_img . $Locals_rgb . $Locals_tmp);
227. }
228. }
229. else
230. {
231. $byte = ord($Locals_img{9});
232. $byte |= 0x80;
233. $byte &= 0xF8;
234. $byte |= (ord($this->BUF[$i]{10}) & 0x07);
235. $Locals_img {9} = chr($byte);
236. $this->GIF .= ($Locals_ext . $Locals_img . $Locals_rgb . $Locals_tmp);
237. }
238. }
239. else
240. {
241. $this->GIF .= ( $Locals_ext . $Locals_img . $Locals_tmp );
242. }
243. $this->IMG = 1;
244. }
245. function GIFAddFooter ( ) {
246. $this->GIF .= ";";
247. }
248. function GIFBlockCompare ( $GlobalBlock, $LocalBlock, $Len )
249. {
250. for ( $i = 0; $i < $Len; $i++ )
251. {
252. if($GlobalBlock { 3 * $i + 0 } != $LocalBlock { 3 * $i + 0 } || $GlobalBlock { 3 * $i + 1 } != $LocalBlock { 3 * $i + 1 } || $GlobalBlock { 3 * $i + 2 } != $LocalBlock{3 * $i + 2})
253. {
254. return ( 0 );
255. }
256. }
257. return ( 1 );
258. }
259. function GIFWord ( $int )
260. {
261. return ( chr ( $int & 0xFF ) . chr ( ( $int >> 8 ) & 0xFF ) );
262. }
263. //开源代码phpfensi.com
264. function GetAnimation ( )
265. {
266. return ($this->GIF);
267. }
268. }