PHP function to generate image thumbnails_PHP tutorial

The specific usage is as follows:

$a=thumbImage('1.jpg',200,100,'2.jpg');//将1.jpg生成宽为200，高为100的缩略图，并保存为2.jpg
print_r($a);

Print results:

Array(
[status] => 0
[file] => 1.jpg
[width] => 200
[height] => 200
[savePath] => 2.jpg
[info] => Thumbnail image generated successfully
)

$a=thumbImage('1.jpg',200,100);//将1.jpg生成宽为200，高为100的缩略图，并直接覆盖1.jpg，不生成新图片

The function code is as follows:

<?php
/*
*php生成图片缩略图的函数
*www.phpernote.com
*/
function thumbImage($file,$thumbWidth,$thumbHeight,$savePath='',$isCut=true,$quality=100){
	$result=array('status'=>0,'file'=>'','width'=>0,'height'=>0,'savePath'=>'','info'=>'');
	if(!file_exists($file)){
		return array('status'=>1,'file'=>'','width'=>0,'height'=>0,'savePath'=>'','info'=>'图片文件不存在');
	}
	//检测文件类型
	$fp=fopen($file,'rb');
	$str=fread($fp,2); //只读2字节
	fclose($fp);
	$str=@unpack("c2chars",$str);
	$typeCode=intval($str['chars1'].$str['chars2']);
	$fileType='';
	switch($typeCode){
		case 255216:
			$fileType='jpg';
		break;
		case 7173:
			$fileType='gif';
		break;
		case 6677:
			$fileType='bmp';
		break;
		case 13780:
			$fileType='png';
		break;
		default:
			$fileType=$typeCode;
		break;
	}
	if($str['chars1']=='-1'&&$str['chars2']=='-40'){
		$fileType='jpg';
	}
	if($str['chars1']=='-119'&&$str['chars2']=='80'){
		$fileType='png';
	}
	if(!in_array($fileType,array('jpg','gif','bmp','png'))){
		return array('status'=>2,'file'=>'','width'=>0,'height'=>0,'savePath'=>'','info'=>'图片文件类型不正确:'.$fileType);
	}
	//图片缩放处理
	if($fileType=='jpg'){
		$im=imagecreatefromjpeg($file);
	}
	if($fileType=='gif'){
		$im=imagecreatefromgif($file);
	}
	if($fileType=='png'){
		$im=imagecreatefrompng($file);
	}
	if(empty($savePath))
	$savePath=$file;
	$width=imagesx($im);
	$height=imagesy($im);
	if($width<$thumbWidth&&$height<$thumbHeight){
		return array('status'=>3,'file'=>'','width'=>0,'height'=>0,'savePath'=>'','info'=>'图片尺寸小于生成缩略图的尺寸');
	}
	$ratio=$width/$height;//实际图象的比例
	$thumbRatio=$thumbWidth/$thumbHeight;//改变后的图象的比例
	if($isCut){//裁切处理
		if(function_exists('imagepng')&&(str_replace('.','',PHP_VERSION)>=512)){//针对php版本大于5.12参数变化后的处理情况
			$quality=9;
		}
		if($ratio>=$thumbRatio){//高度优先
			$newimg=imagecreatetruecolor($thumbWidth,$thumbHeight);
			imagecopyresampled($newimg,$im,0,0,0,0,$thumbWidth,$thumbHeight,(($height)*$thumbRatio),$height);
			imagejpeg($newimg,$savePath,$quality);
		}
		if($ratio<$thumbRatio){//宽度优先
			$newimg=imagecreatetruecolor($thumbWidth,$thumbHeight);
			imagecopyresampled($newimg,$im,0,0,0,0,$thumbWidth,$thumbHeight,$width,(($width)/$thumbRatio));
			imagejpeg($newimg,$savePath,$quality);
		}
	}else{//不裁切处理
		if($ratio>=$thumbRatio){
			$newimg=imagecreatetruecolor($thumbWidth,($thumbWidth)/$ratio);
			imagecopyresampled($newimg,$im,0,0,0,0,$thumbWidth,($thumbWidth)/$ratio,$width,$height);
			imagejpeg($newimg,$savePath,$quality);
		}
		if($ratio<$thumbRatio){
			$newimg=imagecreatetruecolor(($thumbHeight)*$ratio,$thumbHeight);
			imagecopyresampled($newimg,$im,0,0,0,0,($thumbHeight)*$ratio,$thumbHeight,$width,$height);
			imagejpeg($newimg,$savePath,$quality);
		}
	}
	ImageDestroy($im);//www.phpernote.com/php-function/1007.html
	return array('status'=>0,'file'=>$file,'width'=>$thumbWidth,'height'=>$thumbHeight,'savePath'=>$savePath,'info'=>'缩略图片生成成功');
}

Articles you may be interested in

• PHP class method for generating image thumbnails
• PHP generates continuous numeric (letter) array function range() analysis, PHP lottery program function
• PHP generate random password function
• php method to get a list of all pictures in the content and output it
• php extract the birthday date from the ID number and verify it Whether it is a minor function
• PHP program to generate histogram (statistical chart)
• PHP to generate verification code function
• The idea and implementation method of php generating short URL

http://www.bkjia.com/PHPjc/779412.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/779412.htmlTechArticleThe specific usage is as follows: $a=thumbImage('1.jpg',200,100,'2.jpg'); //Generate a thumbnail of 1.jpg with a width of 200 and a height of 100, and save it as 2.jpgprint_r($a); Print result: Array( [status] = 0 [...