php对图片文件的操作主要是利用gd库扩展。当我们频繁利用php对图片进行操作时，会自然封装很多函数，否则会写太多重复的代码。当有很多对图片的相关函数的时候，我们可以考虑将这些函数也整理一下，因而就有了封装成类的想法。
操作图片主要历经四个步骤：
- 打开图片
- 操作图片
- 输出图片
- 销毁图片
1,3,4三个步骤每次都要写，每次又都差不多。真正需要变通的只有操作图片的这一步骤了。操作图片又往往通过1或多个主要的GD函数来完成。
本文封装类里面的四种方法，文字水印（imagettftext()），图片水印（imagecopymerge()），图片压缩，图片剪切(imagecopyresampled())，其余的常用GD函数便不赘述。直接上代码：
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<?<span>php
</span><span>class</span><span> Image
{
</span><span>private</span><span> $info;
</span><span>private</span><span> $image;
</span><span>public</span><span> $type;
</span><span>public</span><span> function __construct($src)
{
$</span><span>this</span>->info=<span>getimagesize($src);
$</span><span>this</span>->type=image_type_to_extension($<span>this</span>->info[<span>'</span><span>2</span><span>'</span>],<span>false</span><span>);
$fun</span>=<span>"</span><span>imagecreatefrom{$this->type}</span><span>"</span><span>;
$</span><span>this</span>->image=<span>$fun($src);
}
</span><span>/*</span><span>*
* 文字水印
* @param [type] $font 字体
* @param [type] $content 内容
* @param [type] $size 文字大小
* @param [type] $col 文字颜色（四元数组）
* @param array $location 位置
* @param integer $angle 倾斜角度
* @return [type]
</span><span>*/</span><span>public</span> function fontMark($font,$content,$size,$col,$location,$angle=<span>0</span><span>){
$col</span>=imagecolorallocatealpha($<span>this</span>->image, $col[<span>'</span><span>0</span><span>'</span>], $col[<span>'</span><span>1</span><span>'</span>], $col[<span>'</span><span>2</span><span>'</span>],$col[<span>'</span><span>3</span><span>'</span><span>]);
imagettftext($</span><span>this</span>->image, $size, $angle, $location[<span>'</span><span>0</span><span>'</span>], $location[<span>'</span><span>1</span><span>'</span><span>], $col,$font,$content);
}
</span><span>/*</span><span>*
* 图片水印
* @param [type] $imageMark 水印图片地址
* @param [type] $dst 水印图片在原图片中的位置
* @param [type] $pct 透明度
* @return [type]
</span><span>*/</span><span>public</span><span> function imageMark($imageMark,$dst,$pct){
$info2</span>=<span>getimagesize($imageMark);
$type</span>=image_type_to_extension($info2[<span>'</span><span>2</span><span>'</span>],<span>false</span><span>);
$func2</span>=<span>"</span><span>imagecreatefrom</span><span>"</span><span>.$type;
$water</span>=<span>$func2($imageMark);
imagecopymerge($</span><span>this</span>->image, $water, $dst[<span>0</span>], $dst[<span>1</span>], <span>0</span>, <span>0</span>, $info2[<span>'</span><span>0</span><span>'</span>], $info2[<span>'</span><span>1</span><span>'</span><span>], $pct);
imagedestroy($water);
}
</span><span>/*</span><span>*
* 压缩图片
* @param [type] $thumbSize 压缩图片大小
* @return [type] [description]
</span><span>*/</span><span>public</span><span> function thumb($thumbSize){
$imageThumb</span>=imagecreatetruecolor($thumbSize[<span>0</span>], $thumbSize[<span>1</span><span>]);
imagecopyresampled($imageThumb, $</span><span>this</span>->image, <span>0</span>, <span>0</span>, <span>0</span>, <span>0</span>, $thumbSize[<span>0</span>], $thumbSize[<span>1</span>], $<span>this</span>->info[<span>'</span><span>0</span><span>'</span>], $<span>this</span>->info[<span>'</span><span>1</span><span>'</span><span>]);
imagedestroy($</span><span>this</span>-><span>image);
$</span><span>this</span>->image=<span>$imageThumb;
}
</span><span>/*</span><span>*
* 裁剪图片
* @param [type] $cutSize 裁剪大小
* @param [type] $location 裁剪位置
* @return [type] [description]
</span><span>*/</span><span>public</span><span> function cut($cutSize,$location){
$imageCut</span>=imagecreatetruecolor($cutSize[<span>0</span>],$cutSize[<span>1</span><span>]);
imagecopyresampled($imageCut, $</span><span>this</span>->image, <span>0</span>, <span>0</span>, $location[<span>0</span>], $location[<span>1</span>],$cutSize[<span>0</span>],$cutSize[<span>1</span>],$cutSize[<span>0</span>],$cutSize[<span>1</span><span>]);
imagedestroy($</span><span>this</span>-><span>image);
$</span><span>this</span>->image=<span>$imageCut;
}
</span><span>/*</span><span>*
* 展现图片
* @return [type] [description]
</span><span>*/</span><span>public</span><span> function show(){
header(</span><span>"</span><span>content-type:</span><span>"</span>.$<span>this</span>->info[<span>'</span><span>mime</span><span>'</span><span>]);
$funn</span>=<span>"</span><span>image</span><span>"</span>.$<span>this</span>-><span>type;
$funn($</span><span>this</span>-><span>image);
}
</span><span>/*</span><span>*
* 保存图片
* @param [type] $newname 新图片名
* @return [type] [description]
</span><span>*/</span><span>public</span><span> function save($newname){
header(</span><span>"</span><span>content-type:</span><span>"</span>.$<span>this</span>->info[<span>'</span><span>mime</span><span>'</span><span>]);
$funn</span>=<span>"</span><span>image</span><span>"</span>.$<span>this</span>-><span>type;
$funn($</span><span>this</span>->image,$newname.<span>'</span><span>.</span><span>'</span>.$<span>this</span>-><span>type);
}
</span><span>public</span><span> function __destruct(){
imagedestroy($</span><span>this</span>-><span>image);
}
}
</span>?>如果还需要其他操作，只需要再往这个类里面添加就好啦~~
以上就介绍了php图片水印添加，压缩，剪切类的封装，包括了方面的内容，希望对PHP教程有兴趣的朋友有所帮助。
