好用的图片裁剪类

<?php

/**
* Author : smallchicken
* Time   : 2009年6月8日16:46:05
* mode 1 : 强制裁剪，生成图片严格按照需要，不足放大，超过裁剪，图片始终铺满
* mode 2 : 和1类似，但不足的时候 不放大 会产生补白，可以用png消除。
* mode 3 : 只缩放，不裁剪，保留全部图片信息，会产生补白，
* mode 4 : 只缩放，不裁剪，保留全部图片信息，生成图片大小为最终缩放后的图片有效信息的实际大小，不产生补白
* 默认补白为白色，如果要使补白成透明像素，请使用SaveAlpha()方法代替SaveImage()方法
*
* 调用方法：
*
* $ic=new ImageCrop(‘old.jpg‘,‘afterCrop.jpg‘);
* $ic->Crop(120,80,2);
* $ic->SaveImage();
* //$ic->SaveAlpha();将补白变成透明像素保存
* $ic->destory();
*
*
*/
class ImageCrop
{

    var $sImage;
    var $dImage;
    var $src_file;
    var $dst_file;
    var $src_width;
    var $src_height;
    var $src_ext;
    var $src_type;

    function ImageCrop($src_file,$dst_file=‘‘)
    {
        $this->src_file=$src_file;
        $this->dst_file=$dst_file;
        $this->LoadImage();
    }

    function SetSrcFile($src_file)
    {
        $this->src_file=$src_file;
    }

    function SetDstFile($dst_file)
    {
        $this->dst_file=$dst_file;
    }

    function LoadImage()
    {
        list($this->src_width, $this->src_height, $this->src_type) = getimagesize($this->src_file);
        switch($this->src_type)
        {
            case IMAGETYPE_JPEG :
            $this->sImage=imagecreatefromjpeg($this->src_file);
            $this->ext=‘jpg‘;
            break;
            case IMAGETYPE_PNG :
            $this->sImage=imagecreatefrompng($this->src_file);
            $this->ext=‘png‘;
            break;
            case IMAGETYPE_GIF :
            $this->sImage=imagecreatefromgif($this->src_file);
            $this->ext=‘gif‘;
            break;
            default:
            exit();
        }
    }

    function SaveImage($fileName=‘‘)
    {
        $this->dst_file=$fileName ? $fileName : $this->dst_file;
        switch($this->src_type)
        {
            case IMAGETYPE_JPEG :
            imagejpeg($this->dImage,$this->dst_file,100);
            break;
            case IMAGETYPE_PNG :
            imagepng($this->dImage,$this->dst_file);
            break;
            case IMAGETYPE_GIF :
            imagegif($this->dImage,$this->dst_file);
            break;
            default:
            break;
        }
    }

    function OutImage()
    {
        switch($this->src_type)
        {
            case IMAGETYPE_JPEG :
            header(‘Content-type: image/jpeg‘);
            imagejpeg($this->dImage);
            break;
            case IMAGETYPE_PNG :
            header(‘Content-type: image/png‘);
            imagepng($this->dImage);
            break;
            case IMAGETYPE_GIF :
            header(‘Content-type: image/gif‘);
            imagegif($this->dImage);
            break;
            default:
            break;
        }
    }

    function SaveAlpha($fileName=‘‘)
    {
        $this->dst_file=$fileName ? $fileName . ‘.png‘ : $this->dst_file .‘.png‘;
        imagesavealpha($this->dImage, true);
        imagepng($this->dImage,$this->dst_file);
    }

    function OutAlpha(){
        imagesavealpha($this->dImage, true);
        header(‘Content-type: image/png‘);
        imagepng($this->dImage);
    }   

    function destory(){
        imagedestroy($this->sImage);
        imagedestroy($this->dImage);
    }

    function Crop($dst_width,$dst_height,$mode=1,$dst_file=‘‘)
    {
        if($dst_file) $this->dst_file=$dst_file;
        $this->dImage = imagecreatetruecolor($dst_width,$dst_height);

        $bg = imagecolorallocatealpha($this->dImage,255,255,255,127);
        imagefill($this->dImage, 0, 0, $bg);
        imagecolortransparent($this->dImage,$bg);

        $ratio_w=1.0 * $dst_width / $this->src_width;
        $ratio_h=1.0 * $dst_height / $this->src_height;
        $ratio=1.0;
        switch($mode)
        {
            case 1:        // always crop
            if( ($ratio_w < 1 && $ratio_h < 1) || ($ratio_w > 1 && $ratio_h > 1))
            {
                $ratio = $ratio_w < $ratio_h ? $ratio_h : $ratio_w;
                $tmp_w = (int)($dst_width / $ratio);
                $tmp_h = (int)($dst_height / $ratio);
                $tmp_img=imagecreatetruecolor($tmp_w , $tmp_h);
                $src_x = (int) (($this->src_width-$tmp_w)/2) ;
                $src_y = (int) (($this->src_height-$tmp_h)/2) ;
                imagecopy($tmp_img, $this->sImage, 0,0,$src_x,$src_y,$tmp_w,$tmp_h);
                imagecopyresampled($this->dImage,$tmp_img,0,0,0,0,$dst_width,$dst_height,$tmp_w,$tmp_h);
                imagedestroy($tmp_img);
            }else
            {
                $ratio = $ratio_w < $ratio_h ? $ratio_h : $ratio_w;
                $tmp_w = (int)($this->src_width * $ratio);
                $tmp_h = (int)($this->src_height * $ratio);
                $tmp_img=imagecreatetruecolor($tmp_w ,$tmp_h);
                imagecopyresampled($tmp_img,$this->sImage,0,0,0,0,$tmp_w,$tmp_h,$this->src_width,$this->src_height);
                $src_x = (int)($tmp_w - $dst_width) / 2 ;
                $src_y = (int)($tmp_h - $dst_height) / 2 ;
                imagecopy($this->dImage, $tmp_img, 0,0,$src_x,$src_y,$dst_width,$dst_height);
                imagedestroy($tmp_img);
            }
            break;
            case 2:        // only small
            if($ratio_w < 1 && $ratio_h < 1)
            {
                $ratio = $ratio_w < $ratio_h ? $ratio_h : $ratio_w;
                $tmp_w = (int)($dst_width / $ratio);
                $tmp_h = (int)($dst_height / $ratio);
                $tmp_img=imagecreatetruecolor($tmp_w , $tmp_h);
                $src_x = (int) ($this->src_width-$tmp_w)/2 ;
                $src_y = (int) ($this->src_height-$tmp_h)/2 ;
                imagecopy($tmp_img, $this->sImage, 0,0,$src_x,$src_y,$tmp_w,$tmp_h);
                imagecopyresampled($this->dImage,$tmp_img,0,0,0,0,$dst_width,$dst_height,$tmp_w,$tmp_h);
                imagedestroy($tmp_img);
            }elseif($ratio_w > 1 && $ratio_h > 1)
            {
                $dst_x = (int) abs($dst_width - $this->src_width) / 2 ;
                $dst_y = (int) abs($dst_height -$this->src_height) / 2;
                imagecopy($this->dImage, $this->sImage,$dst_x,$dst_y,0,0,$this->src_width,$this->src_height);
            }else
            {
            $src_x=0;$dst_x=0;$src_y=0;$dst_y=0;
            if(($dst_width - $this->src_width) < 0)
            {
                $src_x = (int) ($this->src_width - $dst_width)/2;
                $dst_x =0;
            }else{
                $src_x =0;
                $dst_x = (int) ($dst_width - $this->src_width)/2;
            }

            if( ($dst_height -$this->src_height) < 0)
            {
                $src_y = (int) ($this->src_height - $dst_height)/2;
                $dst_y = 0;
            }else
            {
                $src_y = 0;
                $dst_y = (int) ($dst_height - $this->src_height)/2;
            }
            imagecopy($this->dImage, $this->sImage,$dst_x,$dst_y,$src_x,$src_y,$this->src_width,$this->src_height);
            }
            break;
            case 3:        // keep all image size and create need size
            if($ratio_w > 1 && $ratio_h > 1)
            {
                $dst_x = (int)(abs($dst_width - $this->src_width )/2) ;
                $dst_y = (int)(abs($dst_height- $this->src_height)/2) ;
                imagecopy($this->dImage, $this->sImage, $dst_x,$dst_y,0,0,$this->src_width,$this->src_height);
            }else
            {
                $ratio = $ratio_w > $ratio_h ? $ratio_h : $ratio_w;
                $tmp_w = (int)($this->src_width * $ratio);
                $tmp_h = (int)($this->src_height * $ratio);
                $tmp_img=imagecreatetruecolor($tmp_w ,$tmp_h);
                imagecopyresampled($tmp_img,$this->sImage,0,0,0,0,$tmp_w,$tmp_h,$this->src_width,$this->src_height);
                $dst_x = (int)(abs($tmp_w -$dst_width )/2) ;
                $dst_y = (int)(abs($tmp_h -$dst_height)/2) ;
                imagecopy($this->dImage, $tmp_img, $dst_x,$dst_y,0,0,$tmp_w,$tmp_h);
                imagedestroy($tmp_img);
            }
            break;
            case 4:        // keep all image but create actually size
            if($ratio_w > 1 && $ratio_h > 1)
            {
                $this->dImage = imagecreatetruecolor($this->src_width,$this->src_height);
                imagecopy($this->dImage, $this->sImage,0,0,0,0,$this->src_width,$this->src_height);
            }else
            {
                $ratio = $ratio_w > $ratio_h ? $ratio_h : $ratio_w;
                $tmp_w = (int)($this->src_width * $ratio);
                $tmp_h = (int)($this->src_height * $ratio);
                $this->dImage = imagecreatetruecolor($tmp_w ,$tmp_h);
                imagecopyresampled($this->dImage,$this->sImage,0,0,0,0,$tmp_w,$tmp_h,$this->src_width,$this->src_height);
            }
            break;
        }
    }// end Crop

}

?>