Table of Contents
回复内容:
Home Backend Development PHP Tutorial php的GD库能否按百分比压缩图片?

php的GD库能否按百分比压缩图片?

Jun 06, 2016 pm 08:24 PM
php

用php的GD库压缩图片时,可以填入具体的宽和高进行压缩。那么,能否按百分比压缩呢,比如压缩为原图的90%,80%....等?

回复内容:

用php的GD库压缩图片时,可以填入具体的宽和高进行压缩。那么,能否按百分比压缩呢,比如压缩为原图的90%,80%....等?

可以啊,中午刚给朋友搞了个压缩的,

<code>    <?php /*+-----------------------------------------------------------------------+*/
    /*+ jpg,gif,png图片等比例压缩                                             +*/
    /*+-----------------------------------------------------------------------+*/
    class RarImag{
     /**
      * 得到等比例缩放的长宽
      */
     function getNewSize($maxWidth, $maxHeight, $srcWidth, $srcHeight) {
      if($srcWidth > $maxWidth) {
       $maxWidth = $maxWidth;
       if($srcHeight > $maxHeight) {
        $maxHeight = ($srcHeight/$srcHeight) * $maxWidth;
       } else {
         $maxHeight = $srcHeight;
       }
       return array('width' => $maxWidth,'height' => $maxHeight);
      }
    
      if($srcHeight > $maxHeight) {
       $maxHeight = $maxHeight;
       if($srcWidth > $maxWidth) {
         $maxWidth = ($srcWidth/$srcHeight) * $maxHeight;
       } else {
         $maxWidth = $srcWidth;
       }
       return array('width' => $srcWidth,'height' => $maxHeight);
      }
    
      return array('width' => $srcWidth,'height' => $srcHeight);
    }
     /**
      * 等比例生成缩略图
      *
      * @param  String  $srcFile  原始文件路径
      * @param  String  $dstFile  目标文件路径
      * @param  Integer  $maxWidth  生成的目标文件的最大宽度
      * @param  Integer  $maxHeight  生成的目标文件的最大高度
      * @return  Boolean  生成成功则返回true,否则返回false
      */
     function makeThumb($srcFile, $dstFile, $maxWidth, $maxHeight) {
      if ($size = getimagesize($srcFile)) {
       $srcWidth = $size[0];
       $srcHeight = $size[1];
       $mime = $size['mime'];
       switch ($mime) {
        case 'image/jpeg';
         $isJpeg = true;
         break;
        case 'image/gif';
         $isGif = true;
         break;
        case 'image/png';
         $isPng = true;
         break;
        default:
         return false;
         break;
       }
       //header("Content-type:$mime");
       $arr = $this->getNewSize($maxWidth, $maxHeight, $srcWidth, $srcHeight);
       $thumbWidth = $arr['width'];
       $thumbHeight = $arr['height'];
       if (isset($isJpeg) && $isJpeg) {
        $dstThumbPic = imagecreatetruecolor($thumbWidth, $thumbHeight);
        $srcPic = imagecreatefromjpeg($srcFile);
        imagecopyresampled($dstThumbPic, $srcPic, 0, 0, 0, 0, $thumbWidth, $thumbHeight, $srcWidth, $srcHeight);
        imagejpeg($dstThumbPic, $dstFile, 100);
        imagedestroy($dstThumbPic);
        imagedestroy($srcPic);
        return true;
       } elseif (isset($isGif) && $isGif) {
        $dstThumbPic = imagecreatetruecolor($thumbWidth, $thumbHeight);
        //创建透明画布
        imagealphablending($dstThumbPic, true);
        imagesavealpha($dstThumbPic, true);
        $trans_colour = imagecolorallocatealpha($dstThumbPic, 0, 0, 0, 127);
        imagefill($dstThumbPic, 0, 0, $trans_colour);
        $srcPic = imagecreatefromgif($srcFile);
        imagecopyresampled($dstThumbPic, $srcPic, 0, 0, 0, 0, $thumbWidth, $thumbHeight, $srcWidth, $srcHeight);
        imagegif($dstThumbPic, $dstFile);
        imagedestroy($dstThumbPic);
        imagedestroy($srcPic);
        return true;
       } elseif (isset($isPng) && $isPng) {
        $dstThumbPic = imagecreatetruecolor($thumbWidth, $thumbHeight);
        //创建透明画布
        imagealphablending($dstThumbPic, true);
        imagesavealpha($dstThumbPic, true);
        $trans_colour = imagecolorallocatealpha($dstThumbPic, 0, 0, 0, 127);
        imagefill($dstThumbPic, 0, 0, $trans_colour);
        $srcPic = imagecreatefrompng($srcFile);
        imagecopyresampled($dstThumbPic, $srcPic, 0, 0, 0, 0, $thumbWidth, $thumbHeight, $srcWidth, $srcHeight);
        imagepng($dstThumbPic, $dstFile);
        imagedestroy($dstThumbPic);
        imagedestroy($srcPic);
        return true;
       } else {
        return false;
       }
      } else {
       return false;
      }
     }
    }
    ?></code>
Copy after login

imagejpeg() 有一个参数可以设定压缩比例
http://php.net/manual/zh/function.imagejpeg.php

Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

AI Hentai Generator

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

R.E.P.O. Energy Crystals Explained and What They Do (Yellow Crystal)
2 weeks ago By 尊渡假赌尊渡假赌尊渡假赌
Repo: How To Revive Teammates
4 weeks ago By 尊渡假赌尊渡假赌尊渡假赌
Hello Kitty Island Adventure: How To Get Giant Seeds
3 weeks ago By 尊渡假赌尊渡假赌尊渡假赌

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

CakePHP Project Configuration CakePHP Project Configuration Sep 10, 2024 pm 05:25 PM

In this chapter, we will understand the Environment Variables, General Configuration, Database Configuration and Email Configuration in CakePHP.

PHP 8.4 Installation and Upgrade guide for Ubuntu and Debian PHP 8.4 Installation and Upgrade guide for Ubuntu and Debian Dec 24, 2024 pm 04:42 PM

PHP 8.4 brings several new features, security improvements, and performance improvements with healthy amounts of feature deprecations and removals. This guide explains how to install PHP 8.4 or upgrade to PHP 8.4 on Ubuntu, Debian, or their derivati

CakePHP Date and Time CakePHP Date and Time Sep 10, 2024 pm 05:27 PM

To work with date and time in cakephp4, we are going to make use of the available FrozenTime class.

CakePHP File upload CakePHP File upload Sep 10, 2024 pm 05:27 PM

To work on file upload we are going to use the form helper. Here, is an example for file upload.

CakePHP Routing CakePHP Routing Sep 10, 2024 pm 05:25 PM

In this chapter, we are going to learn the following topics related to routing ?

Discuss CakePHP Discuss CakePHP Sep 10, 2024 pm 05:28 PM

CakePHP is an open-source framework for PHP. It is intended to make developing, deploying and maintaining applications much easier. CakePHP is based on a MVC-like architecture that is both powerful and easy to grasp. Models, Views, and Controllers gu

How To Set Up Visual Studio Code (VS Code) for PHP Development How To Set Up Visual Studio Code (VS Code) for PHP Development Dec 20, 2024 am 11:31 AM

Visual Studio Code, also known as VS Code, is a free source code editor — or integrated development environment (IDE) — available for all major operating systems. With a large collection of extensions for many programming languages, VS Code can be c

CakePHP Creating Validators CakePHP Creating Validators Sep 10, 2024 pm 05:26 PM

Validator can be created by adding the following two lines in the controller.

See all articles