PHP学习笔记10GD图片处理

程序员文章站 2022-04-13 16:33:46

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  1 php
  2     //1. 图片背景管理
  3         /* imagecreatefromjpeg($filename)    从jpeg文件或者url新建一图像
  4          * imagecreatefrompng($filename)    从png文件或者url新建一图象
  5          * imagecreatefromgif($filename)    从gif文件或者url新建一图像
  6          * 用完之后要用imagedestroy()函数进行销毁    
  7          * getimagesize($filename)            返回数组,0宽1高,2类型(1GIF,2JPG,3PNG,4SWF..),3是可用于img标记的文本字符串(height="x" width="y")
  8          */
  9         //该方法用于自动识别类型并打开图片,使用传入的func函数操作图片,vars是参数列表
 10         //如果返回的是不是原image,要在func中摧毁image
 11     function imagego($filename, $func, $vars){
 12         list($width, $height, $type, $attr) = getimagesize($filename);
 13         $types = array(1=>"gif", 2=>"jpeg", 3=>"png");
 14         //组合创建图像函数名
 15         $createfrom = "imagecreatefrom".$types{$type};
 16         $image = $createfrom($filename);
 17         //对该图片进行操作
 18         $image = $func($image, $width, $height, $type, $vars);
 19         //组合输出图像函数名
 20         $output = "image".$types{$type};
 21         $filename_s = preg_split("/\\./", $filename);
 22         $filename = $filename_s{0}."_${func}.".$filename_s{1};
 23         $output($image, $filename); 
 24         
 25         imagedestroy($image);
 26     }
 27         //该方法用于在图片上加上字符串,传入一个参数表示添加的字符串
 28     function imageaddstring($image, $width, $height, $type, $vars){
 29         $string = $vars{0};
 30         $sx = ($width - imagefontwidth(5)*strlen($string))/2;
 31         $sy = ($height - imagefontheight(5))/2;
 32         $textcolor = imagecolorallocate($image, 255, 0, 0);
 33         imagestring($image, 5, $sx, $sy, $string, $textcolor);
 34         return $image;
 35     }
 36     imagego("img/1.jpg", "imageaddstring", array("Add a string on JPEG"));
 37     imagego("img/2.gif", "imageaddstring", array("Add a string on GIF"));
 38     imagego("img/3.png", "imageaddstring", array("Add a string on PNG"));
 39     
 40     //2. 图片缩放与裁剪处理
 41         /* imagecopyresized
 42          * imagecopyresampled($dst_img.$src_img,$dst_x,$dst_y,$src_x,$src_y,$dst_w,$dst_h,$src_w,$src_h)    
 43          * 以上两个函数都可以进行图片缩放,后者效果好一些.该函数可以在图像内部复制,但当区域重复时后果不可知
 44          * 如果源和目标的高宽不一样,则会自动进行缩放.
 45          * 同时,该函数也可以实现图像的裁剪.
 46          */
 47         //该方法用于缩小图片1.5倍
 48     function imagethumb($image, $width, $height, $type, $vars){
 49         $p = $vars{0};
 50         $n_image = imagecreatetruecolor($width/$p, $height/$p);
 51         imagecopyresampled($n_image, $image, 0, 0, 0, 0, $width/$p, $height/$p, $width, $height);
 52         imagedestroy($image);
 53         return $n_image;
 54     }
 55     imagego("img/1.jpg", "imagethumb", array(1.5));
 56     imagego("img/2.gif", "imagethumb", array(1.5));
 57     imagego("img/3.png", "imagethumb", array(1.5));
 58         //该方法用于实现图片的裁剪
 59     function imagecut($image, $width, $height, $type, $vars) {
 60         $n_x = $vars{0};
 61         $n_y = $vars{1};
 62         $n_width = $vars{2};
 63         $n_height = $vars{3};
 64 
 65         $n_image = imagecreatetruecolor($n_width, $n_height);
 66         imagecopyresampled($n_image, $image, 0, 0, $n_x, $n_y, $n_width, $n_height, $n_width, $n_height);
 67         imagedestroy($image);
 68         return $n_image;
 69     }
 70     imagego("img/1.jpg", "imagecut", array(200, 100, 100, 100));
 71     imagego("img/2.gif", "imagecut", array(200, 100, 100, 100));
 72     imagego("img/3.png", "imagecut", array(200, 100, 100, 100));
 73     
 74     //3. 添加图片水印
 75         /* imagecopy($dst_img,$src_img,$dst_x,$dst_y,$src_x,$src_y,$src_w,$src_h)
 76          * 将一个图片复制到另一个图片上面
 77          */
 78     function watermark($image, $width, $height, $type, $vars){
 79         $w_image = imagecreatefrompng("img/logo.png");
 80         list($src_w, $src_h) = getimagesize("img/logo.png");
 81         imagecopy($image, $w_image, $vars{0}, $vars{1}, 0, 0, $src_w, $src_h);
 82         imagedestroy($w_image);
 83         return $image;
 84     }
 85     imagego("img/1.jpg", "watermark", array(50,50));
 86     imagego("img/2.gif", "watermark", array(100,100));
 87     imagego("img/3.png", "watermark", array(150,150));
 88     
 89     //4. 图片的选装和翻转
 90         /* imagerotate($src,$degree,$bgcolor,[ignore transparent])    可选参数是否忽视透明色,返回旋转后的图片
 91          * 翻转用imagecopy按像素行或者像素列复制就可以了
 92          * 下面的函数先旋转再翻转
 93          */
 94     function rotateandturn($image, $width, $height, $type, $vars) {
 95         $angle = $vars{0};
 96         $image = imagerotate($image, $angle, 0);
 97         //选装后图片大小可能发生变化
 98         $width = imagesx($image);
 99         $height = imagesy($image);
100         $n_image = imagecreatetruecolor($width, $height);
101         //1代表x轴翻转,2代表y轴翻转,0代表不翻转
102         if ($vars{1} == 1) {
103             for ($x = 0; $x $width; $x++) {
104                 imagecopy($n_image, $image, $x, 0, $width-$x-1, 0, 1, $height);
105             }
106         } else if ($vars{1} == 2){
107             for ($x = 0; $x $height; $x++) {
108                 imagecopy($n_image, $image, 0, $x, 0, $height-$x-1, $width, 1);
109             }    
110         } else {
111             imagecopy($n_image, $image, 0, 0, 0, 0, $width, $height);
112         }
113         
114         imagedestroy($image);
115         return $n_image;
116     }
117     imagego("img/1.jpg", "rotateandturn", array(10, 0));
118     imagego("img/2.gif", "rotateandturn", array(0,1));
119     imagego("img/3.png", "rotateandturn", array(10,2));
120 ?>
121 122     
123         原图
124         125         
图中添加字符串
126         127         
图片缩放
128         129         
图片裁剪
130         131         
图片水印
132         133         
图片旋转和翻转
134         135         
136     
137