Detailed explanation of php proportional scaling image examples

This article mainly introduces the relevant information of PHP proportional scaling pictures

Go directly to the code, imgzip($src,$newwid,$newhei)function What is brought in are the original image, the width required for scaling, and the length of scaling. The code is all noted

<?php 

//压缩图片 缩略图

$src= "xiezheng.jpg";
$newwid=640;
$newhei= 480;
function imgzip($src,$newwid,$newhei){
 $imgInfo = getimagesize($src);

 $imgType = image_type_to_extension($imgInfo[2], false);

 $fun = "imagecreatefrom{$imgType}";

//声明图片 打开图片 在内存中
 $image = $fun($src);
//方便配置长度宽度、高度，设置框为变量wid,高度为hei
 $wid=$imgInfo[0];
 $hei=$imgInfo[1];
//判断长度和宽度，以方便等比缩放,规格按照500, 320
 if($wid>$hei){
  $wid=$newwid;
  $hei=$newwid/($wid/$hei);
 }else {
  $wid = $newhei * ($wid / $hei);
  $hei = $newhei;
 }

//在内存中建立一张图片
 $images2 = imagecreatetruecolor($newwid, $newhei); //建立一个500*320的图片

//将原图复制到新建图片中
//imagecopyresampled($dst_image, $src_image, $dst_x, $dst_y, $src_x, $src_y, $dst_w, $dst_h, $src_w, $src_h)

 imagecopyresampled($images2, $image, 0, 0, 0, 0, $wid,$hei, $imgInfo[0],$imgInfo[0]);

//销毁原始图片
 imagedestroy($image);


//直接输出图片文件

 header("Content-type: ".$imgInfo[‘mime‘]);
 imagejpeg($images2);

//保存图片 到新文件
 imagejpeg($images2, ‘new.jpg‘, 100); //10代码输出图片的质量 0-100 100质量最高

//销毁
 imagedestroy($images2);
}
imgzip($src,$newwid,$newhei);


?>

Effect

Before compression

##After compression

The following is another method

Create a new file index.php, you need to have a picture q.jpg in the statistics directory (the name of the picture can be changed according to the source code)

The source code is as follows:

<?php
$filename="q.jpg";
$per=0.3;
list($width, $height)=getimagesize($filename);
$n_w=$width*$per;
$n_h=$height*$per;
$new=imagecreatetruecolor($n_w, $n_h);
$img=imagecreatefromjpeg($filename);
//拷贝部分图像并调整
imagecopyresized($new, $img,0, 0,0, 0,$n_w, $n_h, $width, $height);
//图像输出新图片、另存为
imagejpeg($new, "q1.jpg");
imagedestroy($new);
imagedestroy($img);
?>

After running it with a browser, there will be q1.jpg in the directory at the same level as index.php. This picture is a scaled picture. The path can be found in the source code. To make changes inside, you can put it in your own project or write a method

The above is the detailed content of Detailed explanation of php proportional scaling image examples. For more information, please follow other related articles on the PHP Chinese website!