PHP 縮圖製作(Image Thumbnail) - GD Library

最近剛好需要用到一個縮圖技巧~ 所以我Google了一下~ 想找到PHP製作縮圖的方式~

而Google出來的結果發現到~ 使用官方所採用的GD library、ImageMagick 兩者較常被使用~

這裡我就直接用官方所採用的GD library來做~ 不過「聽說」ImageMagick效率較好~ 有沒有人有相關的建議呢？分享一下唄~

PHP 縮圖製作(Image Thumbnail)

HTML - 上傳頁面

<form action="ImageHandler.php" method="post" enctype="multipart/form-data">
<input type="file" name="uploadfile"/>
<input type="submit"/>

ImageHandler.php - 縮圖處理細節封裝在ImageResize.php

下述程式是以縮圖後的尺寸為「100」當基礎，所以寬度和高度的尺寸會自動地照比例縮圖~ 如果您想要客製化更多的功能~ 可以自行擴充或改寫ImageResize.php

<?php
require_once 'ImageResize.php';

$ir = new ImageResize();

$ir->readImage($_FILES['uploadfile']['tmp_name']);

$ir->thumbnailImage(100);

$ir->writeImage($_FILES['uploadfile']['name']);

$ir->destory();
?>

ImageResize.php - 處理縮圖的ImageResize Class

<?php
/**
 * Date: 2008/02/28
 * Shen(http://blog.ring.idv.tw)
 */
class ImageResize
{
	private $src_image;
	private $src_width;
	private $src_height;
	private $dest_image;
	private $dest_width;
	private $dest_height;

	function __construct(){}
	public function readImage($imgpath)
	{
		$this->src_image = imagecreatefromjpeg($imgpath);
		$size = getimagesize($imgpath);	
		$this->src_width = $size[0];
		$this->src_height = $size[1];
	}
	public function thumbnailImage($size)
	{
		if($this->src_width > $this->src_height)
		{
			$this->dest_width = $size;
			$this->dest_height = ($this->src_height/$this->src_width)*$size;
		}else{
			$this->dest_height = $size;
			$this->dest_width = ($this->src_width/$this->src_height)*$size;
		}

		$this->dest_image = imagecreatetruecolor($this->dest_width,$this->dest_height);
		imagecopyresampled($this->dest_image,$this->src_image,0,0,0,0,$this->dest_width,$this->dest_height,$this->src_width,$this->src_height);
	}
	public function writeImage($imgpath)
	{
		imagejpeg($this->dest_image,$imgpath,100);
	}
	public function destory()
	{
		imagedestroy($this->src_image);
		imagedestroy($this->dest_image);
	}
}
?>

參考資源

．PHP: Image - Manual

．How to Resize an Image Using PHP - Image Resizing Script