<?php

// +----------------------------------------------------------------------

// | TOPThink [ WE CAN DO IT JUST THINK ]

// +----------------------------------------------------------------------

// | Copyright (c) 2010 http://topthink.com All rights reserved.

// +----------------------------------------------------------------------

// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )

// +----------------------------------------------------------------------

// | Author: 麦当苗儿 <zuojiazi.cn@gmail.com> <http://www.zjzit.cn>

// +----------------------------------------------------------------------

// | ImageGd.class.php 2013-03-05

// +----------------------------------------------------------------------



class ImageGd{

    /**

     * 图像资源对象

     * @var resource

     */

    private $img;



    /**

     * 图像信息，包括width,height,type,mime,size

     * @var array

     */

    private $info;



    /**

     * 构造方法，可用于打开一张图像

     * @param string $imgname 图像路径

     */

    public function __construct($imgname = null) {

        $imgname && $this->open($imgname);

    }



    /**

     * 打开一张图像

     * @param  string $imgname 图像路径

     */

    public function open($imgname){

        //检测图像文件

        if(!is_file($imgname)) throw new Exception('不存在的图像文件');



        //获取图像信息

        $info = getimagesize($imgname);



        //检测图像合法性

        if(false === $info || (IMAGETYPE_GIF === $info[2] && empty($info['bits']))){

            throw new Exception('非法图像文件');

        }



        //设置图像信息

        $this->info = array(

            'width'  => $info[0],

            'height' => $info[1],

            'type'   => image_type_to_extension($info[2], false),

            'mime'   => $info['mime'],

        );



        //销毁已存在的图像

        empty($this->img) || imagedestroy($this->img);



        //打开图像

        if('gif' == $this->info['type']){

            require_once 'GIF.class.php';

            $this->gif = new GIF($imgname);

            $this->img = imagecreatefromstring($this->gif->image());

        } else {

            $fun = "imagecreatefrom{$this->info['type']}";

            $this->img = $fun($imgname);

        }

    }



    /**

     * 保存图像

     * @param  string  $imgname   图像保存名称

     * @param  string  $type      图像类型

     * @param  boolean $interlace 是否对JPEG类型图像设置隔行扫描

     */

    public function save($imgname, $type = null, $interlace = true){

        if(empty($this->img)) throw new Exception('没有可以被保存的图像资源');



        //自动获取图像类型

        if(is_null($type)){

            $type = $this->info['type'];

        } else {

            $type = strtolower($type);

        }



        //JPEG图像设置隔行扫描

        if('jpeg' == $type || 'jpg' == $type){

            $type = 'jpeg';

            imageinterlace($this->img, $interlace);

        }



        //保存图像

        if('gif' == $type && !empty($this->gif)){

            $this->gif->save($imgname);

        } else {

            $fun = "image{$type}";

            $fun($this->img, $imgname);

        }

    }



    /**

     * 返回图像宽度

     * @return integer 图像宽度

     */

    public function width(){

        if(empty($this->img)) throw new Exception('没有指定图像资源');

        return $this->info['width'];

    }



    /**

     * 返回图像高度

     * @return integer 图像高度

     */

    public function height(){

        if(empty($this->img)) throw new Exception('没有指定图像资源');

        return $this->info['height'];

    }



    /**

     * 返回图像类型

     * @return string 图像类型

     */

    public function type(){

        if(empty($this->img)) throw new Exception('没有指定图像资源');

        return $this->info['type'];

    }



    /**

     * 返回图像MIME类型

     * @return string 图像MIME类型

     */

    public function mime(){

        if(empty($this->img)) throw new Exception('没有指定图像资源');

        return $this->info['mime'];

    }



    /**

     * 返回图像尺寸数组 0 - 图像宽度，1 - 图像高度

     * @return array 图像尺寸

     */

    public function size(){

        if(empty($this->img)) throw new Exception('没有指定图像资源');

        return array($this->info['width'], $this->info['height']);

    }



    /**

     * 裁剪图像

     * @param  integer $w      裁剪区域宽度

     * @param  integer $h      裁剪区域高度

     * @param  integer $x      裁剪区域x坐标

     * @param  integer $y      裁剪区域y坐标

     * @param  integer $width  图像保存宽度

     * @param  integer $height 图像保存高度

     */

    public function crop($w, $h, $x = 0, $y = 0, $width = null, $height = null){

        if(empty($this->img)) throw new Exception('没有可以被裁剪的图像资源');



        //设置保存尺寸

        empty($width)  && $width  = $w;

        empty($height) && $height = $h;



        do {

            //创建新图像

            $img = imagecreatetruecolor($width, $height);

            // 调整默认颜色

            $color = imagecolorallocate($img, 255, 255, 255);

            imagefill($img, 0, 0, $color);



            //裁剪

            imagecopyresampled($img, $this->img, 0, 0, $x, $y, $width, $height, $w, $h);

            imagedestroy($this->img); //销毁原图



            //设置新图像

            $this->img = $img;

        } while(!empty($this->gif) && $this->gifNext());



        $this->info['width']  = $width;

        $this->info['height'] = $height;

    }



    /**

     * 生成缩略图

     * @param  integer $width  缩略图最大宽度

     * @param  integer $height 缩略图最大高度

     * @param  integer $type   缩略图裁剪类型

     */

    public function thumb($width, $height, $type = THINKIMAGE_THUMB_SCALE){

        if(empty($this->img)) throw new Exception('没有可以被缩略的图像资源');



        //原图宽度和高度

        $w = $this->info['width'];

        $h = $this->info['height'];



        /* 计算缩略图生成的必要参数 */

        switch ($type) {

            /* 等比例缩放 */

            case THINKIMAGE_THUMB_SCALE:

                //原图尺寸小于缩略图尺寸则不进行缩略

                if($w < $width && $h < $height) return;



                //计算缩放比例

                $scale = min($width/$w, $height/$h);

                

                //设置缩略图的坐标及宽度和高度

                $x = $y = 0;

                $width  = $w * $scale;

                $height = $h * $scale;

                break;



            /* 居中裁剪 */

            case THINKIMAGE_THUMB_CENTER:

                //计算缩放比例

                $scale = max($width/$w, $height/$h);



                //设置缩略图的坐标及宽度和高度

                $w = $width/$scale;

                $h = $height/$scale;

                $x = ($this->info['width'] - $w)/2;

                $y = ($this->info['height'] - $h)/2;

                break;



            /* 左上角裁剪 */

            case THINKIMAGE_THUMB_NORTHWEST:

                //计算缩放比例

                $scale = max($width/$w, $height/$h);



                //设置缩略图的坐标及宽度和高度

                $x = $y = 0;

                $w = $width/$scale;

                $h = $height/$scale;

                break;



            /* 右下角裁剪 */

            case THINKIMAGE_THUMB_SOUTHEAST:

                //计算缩放比例

                $scale = max($width/$w, $height/$h);



                //设置缩略图的坐标及宽度和高度

                $w = $width/$scale;

                $h = $height/$scale;

                $x = $this->info['width'] - $w;

                $y = $this->info['height'] - $h;

                break;



            /* 填充 */

            case THINKIMAGE_THUMB_FILLED:

                //计算缩放比例

                if($w < $width && $h < $height){

                    $scale = 1;

                } else {

                    $scale = min($width/$w, $height/$h);

                }



                //设置缩略图的坐标及宽度和高度

                $neww = $w * $scale;

                $newh = $h * $scale;

                $posx = ($width  - $w * $scale)/2;

                $posy = ($height - $h * $scale)/2;



                do{

                    //创建新图像

                    $img = imagecreatetruecolor($width, $height);

                    // 调整默认颜色

                    $color = imagecolorallocate($img, 255, 255, 255);

                    imagefill($img, 0, 0, $color);



                    //裁剪

                    imagecopyresampled($img, $this->img, $posx, $posy, $x, $y, $neww, $newh, $w, $h);

                    imagedestroy($this->img); //销毁原图

                    $this->img = $img;

                } while(!empty($this->gif) && $this->gifNext());

                

                $this->info['width']  = $width;

                $this->info['height'] = $height;

                return;



            /* 固定 */

            case THINKIMAGE_THUMB_FIXED:

                $x = $y = 0;

                break;



            default:

                throw new Exception('不支持的缩略图裁剪类型');

        }



        /* 裁剪图像 */

        $this->crop($w, $h, $x, $y, $width, $height);

    }



    /**

     * 添加水印

     * @param  string  $source 水印图片路径

     * @param  integer $locate 水印位置

     * @param  integer $alpha  水印透明度

     */

    public function water($source, $locate = THINKIMAGE_WATER_SOUTHEAST){

        //资源检测

        if(empty($this->img)) throw new Exception('没有可以被添加水印的图像资源');

        if(!is_file($source)) throw new Exception('水印图像不存在');



        //获取水印图像信息

        $info = getimagesize($source);

        if(false === $info || (IMAGETYPE_GIF === $info[2] && empty($info['bits']))){

            throw new Exception('非法水印文件');

        }



        //创建水印图像资源

        $fun   = 'imagecreatefrom' . image_type_to_extension($info[2], false);

        $water = $fun($source);



        //设定水印图像的混色模式

        imagealphablending($water, true);



        /* 设定水印位置 */

        switch ($locate) {

            /* 右下角水印 */

            case THINKIMAGE_WATER_SOUTHEAST:

                $x = $this->info['width'] - $info[0]-190;

                $y = $this->info['height'] - $info[1]-160;

                break;



            /* 左下角水印 */

            case THINKIMAGE_WATER_SOUTHWEST:

                $x = 0;

                $y = $this->info['height'] - $info[1];

                break;



            /* 左上角水印 */

            case THINKIMAGE_WATER_NORTHWEST:

                $x = 136;

				$y = 70;

                break;



            /* 右上角水印 */

            case THINKIMAGE_WATER_NORTHEAST:

                $x = $this->info['width'] - $info[0];

                $y = 0;

                break;



            /* 居中水印 */

            case THINKIMAGE_WATER_CENTER:

                $x = ($this->info['width'] - $info[0])/2;

                $y = ($this->info['height'] - $info[1])/2;

                break;



            /* 下居中水印 */

            case THINKIMAGE_WATER_SOUTH:

                $x = ($this->info['width'] - $info[0])/2;

                $y = $this->info['height'] - $info[0];

                break;



            /* 右居中水印 */

            case THINKIMAGE_WATER_EAST:

                $x = $this->info['width'] - $info[0];

                $y = ($this->info['height'] - $info[1])/2;

                break;



            /* 上居中水印 */

            case THINKIMAGE_WATER_NORTH:

                $x = ($this->info['width'] - $info[0])/2;

                $y = 0;

                break;



            /* 左居中水印 */

            case THINKIMAGE_WATER_WEST:

                $x = 0;

                $y = ($this->info['height'] - $info[1])/2;

                break;



            default:

                /* 自定义水印坐标 */

                if(is_array($locate)){

                    list($x, $y) = $locate;

                } else {

                    throw new Exception('不支持的水印位置类型');

                }

        }



        do{

            //添加水印

            $src = imagecreatetruecolor($info[0], $info[1]);

            // 调整默认颜色

            $color = imagecolorallocate($src, 255, 255, 255);

            imagefill($src, 0, 0, $color);



            imagecopy($src, $this->img, 0, 0, $x, $y, $info[0], $info[1]);

            imagecopy($src, $water, 0, 0, 0, 0, $info[0], $info[1]);

            imagecopymerge($this->img, $src, $x, $y, 0, 0, $info[0], $info[1], 100);



            //销毁零时图片资源

            imagedestroy($src);

        } while(!empty($this->gif) && $this->gifNext());



        //销毁水印资源

        imagedestroy($water);

    }



    /**

     * 图像添加文字

     * @param  string  $text   添加的文字

     * @param  string  $font   字体路径

     * @param  integer $size   字号

     * @param  string  $color  文字颜色

     * @param  integer $locate 文字写入位置

     * @param  integer $offset 文字相对当前位置的偏移量

     * @param  integer $angle  文字倾斜角度

     */

    public function text($text, $font, $size, $color = '#00000000', 

        $locate = THINKIMAGE_WATER_SOUTHEAST, $offset = 0, $angle = 0){

        //资源检测

        if(empty($this->img)) throw new Exception('没有可以被写入文字的图像资源');

        if(!is_file($font)) throw new Exception("不存在的字体文件：{$font}");



        //获取文字信息

        $info = imagettfbbox($size, $angle, $font, $text);

        $minx = min($info[0], $info[2], $info[4], $info[6]); 

        $maxx = max($info[0], $info[2], $info[4], $info[6]); 

        $miny = min($info[1], $info[3], $info[5], $info[7]); 

        $maxy = max($info[1], $info[3], $info[5], $info[7]); 



        /* 计算文字初始坐标和尺寸 */

        $x = $minx;

        $y = abs($miny);

        $w = $maxx - $minx;

        $h = $maxy - $miny;



        /* 设定文字位置 */

        switch ($locate) {

            /* 右下角文字 */

            case THINKIMAGE_WATER_SOUTHEAST:

                $x += $this->info['width']  - $w;

                $y += $this->info['height'] - $h;

                break;



            /* 左下角文字 */

            case THINKIMAGE_WATER_SOUTHWEST:

                $y += $this->info['height'] - $h;

                break;



            /* 左上角文字 */

            case THINKIMAGE_WATER_NORTHWEST:

				$x += 320;

				$y += 74;

                break;



            /* 右上角文字 */

            case THINKIMAGE_WATER_NORTHEAST:

                $x += $this->info['width'] - $w;

                break;



            /* 居中文字 */

            case THINKIMAGE_WATER_CENTER:

                $x += ($this->info['width']  - $w)/2;

                $y += ($this->info['height'] - $h)/2;

                break;



            /* 下居中文字 */

            case THINKIMAGE_WATER_SOUTH:

                $x += ($this->info['width'] - $w)/2;

                $y += $this->info['height'] - $h;

                break;



            /* 右居中文字 */

            case THINKIMAGE_WATER_EAST:

                $x += $this->info['width'] - $w;

                $y += ($this->info['height'] - $h)/2;

                break;



            /* 上居中文字 */

            case THINKIMAGE_WATER_NORTH:

                $x += ($this->info['width'] - $w)/2;

                break;



            /* 左居中文字 */

            case THINKIMAGE_WATER_WEST:

                $y += ($this->info['height'] - $h)/2;

                break;



            default:

                /* 自定义文字坐标 */

                if(is_array($locate)){

                    list($posx, $posy) = $locate;

                    $x += $posx;

                    $y += $posy;

                } else {

                    throw new Exception('不支持的文字位置类型');

                }

        }



        /* 设置偏移量 */

        if(is_array($offset)){

            $offset = array_map('intval', $offset);

            list($ox, $oy) = $offset;

        } else{

            $offset = intval($offset);

            $ox = $oy = $offset;

        }



        /* 设置颜色 */

        if(is_string($color) && 0 === strpos($color, '#')){

            $color = str_split(substr($color, 1), 2);

            $color = array_map('hexdec', $color);

            if(empty($color[3]) || $color[3] > 127){

                $color[3] = 0;

            }

        } elseif (!is_array($color)) {

            throw new Exception('错误的颜色值');

        }



        do{

            /* 写入文字 */

            $col = imagecolorallocatealpha($this->img, $color[0], $color[1], $color[2], $color[3]);

            imagettftext($this->img, $size, $angle, $x + $ox, $y + $oy, $col, $font, $text);

        } while(!empty($this->gif) && $this->gifNext());

    }



    /* 切换到GIF的下一帧并保存当前帧，内部使用 */

    private function gifNext(){

        ob_start();

        ob_implicit_flush(0);

        imagegif($this->img);

        $img = ob_get_clean();



        $this->gif->image($img);

        $next = $this->gif->nextImage();



        if($next){

            $this->img = imagecreatefromstring($next);

            return $next;

        } else {

            $this->img = imagecreatefromstring($this->gif->image());

            return false;

        }

    }



    /**

     * 锐化图片

     * @param  integer $radius 锐化角度

     * @param  integer $sigma  锐化偏差

     */

    public function sharp($radius = 0, $sigma = 1){

        // GD库暂不支持图片锐化

        // 保留此方法避免切换操作库出错

    }



    /**

     * 析构方法，用于销毁图像资源

     */

    public function __destruct() {

        empty($this->img) || imagedestroy($this->img);

    }

}