php图片压缩指定大小指定体积kb代码-php代码-BFW代码库

代码语言：php

代码描述：php图片压缩指定大小指定体积kb代码

下面为部分代码预览，完整代码请点击下载或在bfwstudio webide中打开

<?php
/**
* 图片压缩类：通过缩放来压缩。
* 如果要保持源图比例，把参数$percent保持为1即可。
* 即使原比例压缩，也可大幅度缩小。数码相机4M图片。也可以缩为700KB左右。如果缩小比例，则体积会更小。
* 结果：可保存、可直接显示。
*/
class imgcompress
{
    private $image;
    private $imageinfo;

    /**
    * [compressImg 图片压缩操作]
    * @param  [type]  $url      [图片路径]
    * @param  integer $percent  [缩放比例（或缩放后尺寸）]
    * @param  string  $saveName [保存文件名称（可不带扩展名，用源图扩展名）]
    * @return [type]            [description]
    */
    public function compressImg($url, $percent = 1, $saveName = '') {
        $re = $this->_openImage($url);
        if ($this->imageinfo) {
            $this->_thumpImage($percent);
            if (!empty($saveName)) {
                $this->_saveImage($url, $saveName); //保存
            } else {
                $url != $saveName && $this->_showImage();
            }
            return true;
        } else {
            return false;
        }
    }

    /**
    * 内部：打开图片
    */
    private function _openImage($url) {
        $image = @file_get_contents($url); // 将 logo 读取到字符串中
        if (!$image)
            return false;

        $imagedetail = getimagesizefromstring($image);
        list($width, $height, $type, $attr) = $imagedetail;
        if (!$width)
            return false;

        $this->imageinfo = array(
            'width' => $width,
            'height' => $height,
            'type' => image_type_to_extension($type, false),
            'attr' => $attr
        );
        $this->image = imagecreatefromstring($image); // 从字符串中的图像流新建一图像
    }

    /**
    * 内部：操作图片
    */
    private function _thumpImage($percent) {
        if ($percent > 1 && $percent < $this->imageinfo['height'] && $percent < $this->imageinfo['width']) {
            if ($this->imageinfo['height'] < $this->imageinfo['width']) {
                $percent = $percent / $this->imageinfo['height'];
            } else {
                $percent = $percent / $this->imageinfo['width'];
            }
        }
        $ratio = $percent > 1 ? 1 : $percent;
        $new_width = $this->imageinfo['width'] * $ratio;
        $new_height = $this->imageinfo['height'] * $ratio;
        $image_thump = imagecreatetruecolor($new_width, $new_height);
        //将原图复制带图片载体上面，并且按照一定比例压缩,极大的保持了清晰度
        imagecopyresampled($image_thump, $this->image, 0, 0, 0, 0, $new_width, $new_height, $this->imageinfo['width'], $this->imageinfo['height']);
        imagedestroy($this->image);
        $this->image = $image_thump;
    }

    /**
    * 输出图片:保存图片则用saveImage()
    */
    private function _showImage() {
        header('Content-Type: image/'.$this->imageinfo['type']);
        $funcs = "image".$this->imageinfo['type'];
        $funcs($this->image);
    }


    /**
    *图片压缩到指定的体积大小
    * $original_file 原始图片路径
    * $resized_file 压缩后图片路径
    * $max_file_size 压缩大小 单位kb
    * $image_quality 图片质量 1-100
    */
    public function compresstosize($original_file, $resized_file, $max_file_size, $image_quality = 100) {


        $original_image = imagecreatefromjpeg($original_file);



        do {
            $temp_stream = fopen('php://temp', 'w+');
            $saved = imagejpeg($original_image, $tem.........完整代码请登录后点击上方下载按钮下载查看