时间：2021-07-01 10:21:17 帮助过：15人阅读
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本文介绍下，php实现的一个缩略图类，支持加载图片文件与加载图片字符串，按比例拉伸等，代码后面有调用示例供参考。
分享个php缩略图类，可以实现如下的功能： 1，支持加载图片文件和加载图片字符串 2，可以将缩略图输出到浏览器和保持缩略图文件 3，支持gif，png，jpeg类型的缩略 4，可以设定是否按比例来拉伸代码如下：
maxWidth = $maxWidth;
$this->maxHeight = $maxHeight;
$this->scale = $scale;
$this->inflate = $inflate;
$this->types = array(
'image/jpeg',
'image/png',
'image/gif'
);
//加载MIME类型图像的函数名称
$this->imgLoaders = array(
'image/jpeg' => 'imagecreatefromjpeg',
'image/png' => 'imagecreatefrompng',
'image/gif' => 'imagecreatefromgif'
);
//储存创建MIME类型图片的函数名称
$this->imgCreators = array(
'image/jpeg' => 'imagejpeg',
'image/png' => 'imagepng',
'image/gif' => 'imagegif'
);
}
/**
* 文件方式加载图片
* @param string $image 源图片
* @return bool
*/
public function loadFile($image){
if(!$dims = @getimagesize($image)){
trigger_error("源图片不存在");
}
if(in_array($dims['mime'], $this->types)){
$loader = $this->imgLoaders[$dims['mime']];
$this->source = $loader($image);
$this->sourceWidth = $dims[0];
$this->sourceHeight = $dims[1];
$this->sourceMime = $dims['mime'];
$this->initThumb();
return TRUE;
}else{
trigger_error('不支持'.$dims['mime']."图片类型");
}
}
/**
* 字符串方式加载图片
* @param string $image 字符串
* @param string $mime 图片类型
* @return type
*/
public function loadData($image,$mime){
if(in_array($mime, $this->types)){
if($this->source = @imagecreatefromstring($image)){
$this->sourceWidth = imagesx($this->source);
$this->sourceHeight = imagesy($this->source);
$this->sourceMime = $mime;
$this->initThumb();
return TRUE;
}else{
trigger_error("不能从字符串加载图片");
}
}else{
trigger_error("不支持".$mime."图片格式");
}
}
/**
* 生成缩略图
* @param string $file 文件名。如果不为空则储存为文件，否则直接输出到浏览器
*/
public function buildThumb($file = null){
$creator = $this->imgCreators[$this->sourceMime];
if(isset($file)){
return $creator($this->thumb,$file);
}else{
return $creator($this->thumb);
}
}
/**
* 处理缩放
*/
public function initThumb(){
if($this->scale){
if($this->sourceWidth > $this->sourceHeight){
$this->thumbWidth = $this->maxWidth;
$this->thumbHeight = floor($this->sourceHeight*($this->maxWidth/$this->sourceWidth));
}elseif($this->sourceWidth < $this->sourceHeight){
$this->thumbHeight = $this->maxHeight;
$this->thumbWidth = floor($this->sourceWidth*($this->maxHeight/$this->sourceHeight));
}else{
$this->thumbWidth = $this->maxWidth;
$this->thumbHeight = $this->maxHeight;
}
}
$this->thumb = imagecreatetruecolor($this->thumbWidth, $this->thumbHeight);
if($this->sourceWidth <= $this->maxWidth && $this->sourceHeight <= $this->maxHeight && $this->inflate == FALSE){
$this->thumb = $this->source;
}else{
imagecopyresampled($this->thumb, $this->source, 0, 0, 0, 0, $this->thumbWidth, $this->thumbHeight,
$this->sourceWidth, $this->sourceHeight);
}
}
public function getMine(){
return $this->sourceMime;
}
public function getThumbWidth(){
return $this->thumbWidth;
}
public function getThumbHeight(){
return $this->thumbHeight;
}
}
/**
* 缩略图类调用示例(文件)
*/
$thumb = new Thumbnail(200, 200);
$thumb->loadFile('wap.gif');
header('Content-Type:'.$thumb->getMine());
$thumb->buildThumb();
/**
* 缩略图类调用示例(字符串)
*/
$thumb = new Thumbnail(200, 200);
$image = file_get_contents('wap.gif');
$thumb->loadData($image, 'image/jpeg');
$thumb->buildThumb('wap_thumb.gif');
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