导读:等比例缩放的,如果你指定的尺寸和缩放的比例不一致,会用纯色填补。
本人不才,第一次分享代码,欢迎拍砖!
等比例缩放的,如果你指定的尺寸和缩放的比例不一致,会用纯色填补。本人不才,第一次分享代
码,欢迎拍砖!
复制代码代码如下:
- <?php
- /**
- * @abstract 生成图片的缩略图,可以指定任意尺寸,生成的图片为png格式
- * @example
- * $file = 'test.png';
- * $th =new Thumbnail();
- * $th->GenerateThumbnail($file, 400, 500);
- *
- */
- class Thumbnail{
- /**
- * @var string $from 源图片
- */
- private $from;
- /**
- * @var string $name 缩略图的文件名
- */
- private $name = '';
- /**
- * @var 原图宽
- */
- private $rWidth;
- /**
- * @var 原图高
- */
- private $rHeight;
- /**
- * @var 缩略图宽
- */
- private $tWidth;
- /**
- * @var 缩略图高
- */
- private $tHeight;
- /**
- * @var 实际缩放到的宽度
- */
- private $width;
- /**
- * @var 实际缩放到的高度
- */
- private $height;
-
- public function __construct(){
- try{
- if(!function_exists('gd_info')){
- throw new Exception('Must GD extension is enabled');
- }
- }
- catch(Exception $e){
- $msg = 'class ' . __CLASS__ . ' Error:' . $e->getMessage();
- echo $msg;
- exit;
- }
- }
- /**
- * @var $from 原图像
- * @var $width 生成的缩略图的宽
- * @var $height 生成缩略图的高
- * @var $name 生成的缩略图的文件名,不带后缀
- * @return string 生成的缩略图
- */
- public function GenerateThumbnail($from, $width, $height, $name=''){
- try{
- if(!file_exists($from)){
- throw new Exception('File does not exist');
- }
- if($width <= 0){
- throw new Exception('The width is invalid');
- }
- if($height <= 0){
- throw new Exception('The height is invalid');
- }
- $this->from = $from;
- $this->tWidth = $width;
- $this->tHeight = $height;
- if(!empty($name)){
- $this->name = $name;
- }
- else{
- $this->name = date('Ymd') . mt_rand(0, 9999);
- }
- $this->createThumbnail();
- }
- catch(Exception $e){
- $msg = 'class ' . __CLASS__ . ' Error:' . $e->getMessage();
- echo $msg;
- exit;
- }
- }
-
- public function getThumbnail(){
- return $this->name;
- }
-
- /**
- * 生成缩略图文件
- */
- private function createThumbnail(){
- try{
- //读取原始图像信息
- $sourceInfo = getimagesize($this->from);
- $this->rWidth = $sourceInfo[0];
- $this->rHeight = $sourceInfo[1];
- //创建缩略图图像资源句柄
- $new_pic = imagecreatetruecolor($this->tWidth, $this->tHeight);
- //原图绘制到缩略图的x、y坐标
- $x = 0;
- $y = 0;
- //创建原始图像资源句柄
- $source_pic = '';
- switch ($sourceInfo[2]){
- case 1: $source_pic = imagecreatefromgif($this->from); //gif
- break;
- case 2: $source_pic = imagecreatefromjpeg($this->from); //jpg
- break;
- case 3: $source_pic = imagecreatefrompng($this->from); //png
- break;
- default: throw new Exception('Does not support this type of image');
- }
- //计算缩放后图像实际大小
- //原图宽高均比缩略图大
- if($this->rWidth > $this->tWidth && $this->rHeight > $this->tHeight){
- $midw = ($this->rWidth - $this->tWidth) / $this->rWidth; //宽缩小的比例
- $midh = ($this->rHeight - $this->tHeight) / $this->rHeight; //高缩小的比例
- //那个缩小的比例大以那个为准
- if($midw > $midh){
- $this->width = $this->tWidth;
- $this->height = $this->rHeight - floor($this->rHeight * $midw);
- $y = ($this->tHeight - $this->height) / 2;
- }
- else{
- $this->width = $this->rWidth - floor($this->rWidth * $midh);
- $this->height = $this->tHeight;
- $x = ($this->tWidth - $this->width) / 2;
- }
- }
- //原图宽高均比缩略图小
- elseif($this->rWidth < $this->tWidth && $this->rHeight < $this->tHeight){
- $midw = ($this->tWidth - $this->rWidth) / $this->rWidth; //宽放大的比例
- $midh = ($this->tHeight - $this->rHeight) / $this->rHeight; //高放大的比例
- //那个放大的比例小以那个为准
- if($midw < $midh){
- $this->width = $this->tWidth;
- $this->height = $this->rHeight + floor($this->rHeight * $midw);
- $y = ($this->tHeight - $this->height) / 2;
- }
- else{
- $this->width = $this->rWidth + floor($this->rWidth * $midh);
- $this->height = $this->tHeight;
- $x = ($this->tWidth - $this->width) / 2;
- }
- }
- //原图宽小于缩略图宽,原图高大于缩略图高
- elseif($this->rWidth < $this->tWidth && $this->rHeight > $this->tHeight){
- $mid = ($this->rHeight - $this->tHeight) / $this->rHeight; //高缩小的比例
- $this->width = $this->rWidth - floor($this->rWidth * $mid);
- $this->height = $this->rHeight - floor($this->rHeight * $mid);
- $x = ($this->tWidth - $this->width) / 2;
- $y = ($this->tHeight - $this->height) / 2;
- }
- //原图宽大于缩略图宽,原图高小于缩略图高
- elseif($this->rWidth > $this->tWidth && $this->rHeight < $this->tHeight){
- $mid = ($this->rWidth - $this->tWidth) / $this->rWidth; //宽缩小的比例
- $this->width = $this->rWidth - floor($this->rWidth * $mid);
- $this->height = $this->rHeight - floor($this->rHeight * $mid);
- $x = ($this->tWidth - $this->width) / 2;
- $y = ($this->tHeight - $this->height) / 2;
- }
- else{
- throw new Exception('Resize error');
- }
-
- //给缩略图添加白色背景
- $bg = imagecolorallocate($new_pic, 255, 255, 255);
- imagefill($new_pic, 0, 0, $bg);
- //缩小原始图片到新建图片
- imagecopyresampled($new_pic, $source_pic, $x, $y, 0, 0, $this->width, $this->height, $this->rWidth, $this->rHeight);
- //输出缩略图到文件
- imagepng($new_pic, $this->name.'.png');
- imagedestroy($new_pic);
- imagedestroy($source_pic);
- }
- catch(Exception $e){
- $msg = 'class ' . __CLASS__ . ' Error:' . $e->getMessage();
- echo $msg;
- exit;
- }
- }
- }
-