<?php
/**
 * Created by PhpStorm.
 * User: Administrator
 * Date: 2016/1/11
 * Time: 14:34
 */

namespace common\library;

/**
 * 缩略图生成类，使用示例：
 **/
class ImageResize
{
    private $localimage;//原图路径
    private $remoteimage;//缩略图保存路径
    private $localinfo;//原图属性
    private $error;

    function resize($localimg, $remoteimg, $x, $y)
    {
        //检测是否支持gd图像处理
        if (!$this->_checkenv()) {
            return false;
        }
        $this->localimage = $localimg;
        $this->remoteimage = $remoteimg;
        $this->localinfo = getimagesize($this->localimage); //获取本地图像的信息
        return $this->_resize($x, $y);
    }

    function cut_resize($localimg, $remoteimg, $x, $y){
        //检测是否支持gd图像处理
        if (!$this->_checkenv()) {
            return false;
        }
        $this->localimage = $localimg;
        $this->remoteimage = $remoteimg;
        $this->localinfo = getimagesize($this->localimage); //获取本地图像的信息

       return $this->_resizeAndCut($x,$y);
    }


    /**
     * 检测当前环境是否支持GD
     * @return bool
     */
    private function _checkenv()
    {
        if (!function_exists('gd_info')) {
            $this->error[] = "当前环境不支持GD图像处理，请先安装GD库并开启PHP相关扩展";
            return false;
        }
        return true;
    }

    /**
     * @param $x
     * @param $y
     * @return bool
     */
    private function _resize($x, $y)
    {
        if (!$this->localinfo) {
            $this->error[] = "本地图像文件不存在";
            return false;
        }
        //创建图像句柄
        $im = @$this->_create($this->localinfo[2]);
        if (!$im) {
            $this->error[] = "当前GD库不支持图像类型：{$this->localinfo['mime']}";
            return false;
        }
        $dstsize = $this->_dstsize($x, $y);
        $dstim = @imagecreatetruecolor($dstsize["width"], $dstsize["height"]);
        if($this->localinfo[2] == 3)
            $whitecolor = @imagecolorallocatealpha($dstim, 255, 255, 255, 127);
        else
            $whitecolor = @imagecolorallocatealpha($dstim, 0, 0, 0, 127);
        imagefill($dstim, 0, 0, $whitecolor);
        $re = @imagecopyresampled($dstim, $im, 0, 0, 0, 0, $dstsize["width"], $dstsize["height"], $this->localinfo[0], $this->localinfo[1]);
        if (!$re) {
            $this->error[] = "图像重新采样失败";
            return false;
        }
        if (!imagejpeg($dstim, $this->remoteimage)) {
            if (!imagepng($dstim, $this->remoteimage)) {
                if (!imagegif($dstim, $this->remoteimage)) {
                    $this->error[] = "保存缩略图到{$this->remoteimage}失败,请检查gd环境是否正常和缩略图文件夹的写入权限。";
                    return false;
                }
            }
        }
        $this->error[] = "success";
        return true;
    }

    /**
     * 修改图片尺寸并裁剪为正方形
     * @param $x
     * @param $y
     * @return bool
     */
    private function _resizeAndCut($x,$y){
        if (!$this->localinfo) {
            $this->error[] = "本地图像文件不存在";
            return false;
        }
        //创建图像句柄
        $im = @$this->_create($this->localinfo[2]);
        if (!$im) {
            $this->error[] = "当前GD库不支持图像类型：{$this->localinfo['mime']}";
            return false;
        }
        $dstsize = $this->_dstsize($x, $y);
        $dstposition = $this->_initPosition($this->localinfo[0],$this->localinfo[1]);
        $dstminsize = min($dstsize);
        $srcminsize = min($this->localinfo[0],$this->localinfo[1]);
        $dstim = @imagecreatetruecolor($dstminsize, $dstminsize);
        $whitecolor = @imagecolorallocatealpha($dstim, 0, 0, 0, 127);
        imagefill($dstim, 0, 0, $whitecolor);
        $re = @imagecopyresampled($dstim, $im, 0, 0, $dstposition['x'], $dstposition['y'], $dstminsize, $dstminsize, $srcminsize, $srcminsize);
        if (!$re) {
            $this->error[] = "图像重新采样失败";
            return false;
        }
        if (!imagejpeg($dstim, $this->remoteimage)) {
            if (!imagepng($dstim, $this->remoteimage)) {
                if (!imagegif($dstim, $this->remoteimage)) {
                    $this->error[] = "保存缩略图到{$this->remoteimage}失败,请检查gd环境是否正常和缩略图文件夹的写入权限。";
                    return false;
                }
            }
        }
        $this->error[] = "success";
        return true;

    }

    /**
     *
     * 根据本地图片类型，创建图片资源
     * @param $code 图像类型代码
     * @return resource/boolean 成功则返回resourse失败则返回false
     */
    private function _create($code)
    {
        $src = $this->localimage;
        switch ($code) {
            case 1:
                return imagecreatefromgif($src);
                break;
            case 2:
                return imagecreatefromjpeg($src);
                break;
            case 3:
                return imagecreatefrompng($src);
                break;
            default:
                return false;
                break;
        }
    }

    /**
     * 计算长宽
     * @param $x
     * @param $y
     */
    private function _dstsize($x, $y)
    {
        list($srcwidth, $srcheight) = $this->localinfo;
        if (($srcwidth / $srcheight) < ($x / $y)) {
            $x = floor($y * $srcwidth / $srcheight);
        } else {
            $y = floor($x * $srcheight / $srcwidth);
        }
        $dstsize["width"] = $x;
        $dstsize["height"] = $y;
        return $dstsize;
    }


    /**
     ** 获取最后一条错误信息
     * * return string
     **/
    function GetLastError()
    {
        return array_pop($this->error);
    }


    /**
     * * 获取所有错误信息
     * * return array
     * */
    function GetAllError()
    {
        return $this->error;
    }

    function test(){

    }


    /**
     * 计算初始坐标
     * @return array
     */
    function _initPosition($x,$y,$init = ''){
        $local = ['x'=>'','y'=>''];
        if(bccomp($x,$y) == -1){
            $local['x'] = '0';
            $local['y'] = bcsub($y,$x,2)/2;
        }else{
            $local['y'] = '0';
            $local['x'] = bcsub($x,$y,2)/2;
        }

        return $local;
    }
}