PHP画图之GD库的使用——略缩图（二）

<?php
// 将图像等比放大或缩小
class resize{

private $src;
private $image;
private $width;
private $height;
private $imageType;
private $imageResize;
private $newWidth;
private $newHeight;

// 文件路径名，期待文件的宽度
public function __construct($fileName, $newWidth){

$this->src = $fileName;
$this->newWidth = $newWidth;
$this->imageType = exif_imagetype($fileName);
$this->image = $this->openImage($this->src);
if($this->image){
$this->width = imagesx($this->image);
$this->height = imagesy($this->image);
}

}

private function openImage($file){

switch ($this->imageType) {
case IMAGETYPE_GIF:
$img = imagecreatefromgif($file);
break;

case IMAGETYPE_JPEG:
$img = imagecreatefromjpeg($file);
break;

case IMAGETYPE_PNG:
$img = imagecreatefrompng($file);
break;
}

return $img;
}

private function saveImage(){

switch ($this->imageType) {
case IMAGETYPE_GIF:
header("Content-type: " . image_type_to_mime_type(IMAGETYPE_GIF));
imagegif($this->imageResize);
break;

case IMAGETYPE_JPEG:
header("Content-type: " . image_type_to_mime_type(IMAGETYPE_JPEG));
imagejpeg($this->imageResize);
break;

case IMAGETYPE_PNG:
header("Content-type: " . image_type_to_mime_type(IMAGETYPE_PNG));
imagepng($this->imageResize);
break;
}

imagedestroy($this->image);
imagedestroy($this->imageResize);
}

public function resizeImage(){

$ratio = $this->height/$this->width;
$this->newHeight = $this->newWidth*$ratio;
$this->imageResize = imagecreatetruecolor($this->newWidth, $this->newHeight);
imagecopyresampled($this->imageResize, $this->image, 0, 0, 0, 0, $this->newWidth, $this->newHeight, $this->width, $this->height);
$this->saveImage();
}

}

$img1 = new resize('GD/img/logo.png',50);
$img1->resizeImage();

?>