How to implement proportional scaling of images in php

Mainly introduces how to use PHP to scale pictures. You can specify the width and length of scaling required for the original image.

This article introduces the method of image compression in PHP. Readers You can refer to or improve it according to the specific application, and directly upload the code. The function of imgzip($src,$newwid,$newhei) brings in the original image, the width required for scaling, and the length of scaling.

<?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[1]);
//销毁原始图片
 imagedestroy($image);
//直接输出图片文件

 header("Content-type: ".$imgInfo[&#39;mime&#39;]);
 imagejpeg($images2);
//保存图片 到新文件
 imagejpeg($images2, &#39;new.jpg&#39;, 100); //10代码输出图片的质量 0-100 100质量最高
//销毁
 imagedestroy($images2);
}
imgzip($src,$newwid,$newhei);
?>

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What I share with you below is the code for image scaling using PHP. Friends can integrate it into the image upload

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);
?>

Use a browser to run Afterwards, there will be a q1.jpg in the directory at the same level as index.php. This image is a scaled image. The path can be changed in the source code. You can also put it in your own project or write a method.

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