php生成图片缩略图类程序

发布:smiling　来源: PHP粉丝网　添加日期：2014-08-18 15:32:12　浏览: 评论：0　

缩略图用得最多的是我们上传图片时生成一张小图,这样就可以很好的解决图片大小或影响网站整体美观的问题了,下面介绍的生成图片缩略图类都不支持图片上传,我们要先上传再调用此类来操作.

使用如下类就可以生成图片缩略图,代码如下:

<?php

class resizeimage

{

    //图片类型

    var $type;

    //实际宽度

    var $width;

    //实际高度

    var $height;

    //改变后的宽度

    var $resize_width;

    //改变后的高度

    var $resize_height;

    //是否裁图

    var $cut;

    //源图象

    var $srcimg;

    //目标图象地址

    var $dstimg;

    //临时创建的图象

    var $im;

    function resizeimage($img, $wid, $hei,$c,$dstpath)

    {

        $this->srcimg = $img;

        $this->resize_width = $wid;

        $this->resize_height = $hei;

        $this->cut = $c;

        //图片的类型



$this->type = strtolower(substr(strrchr($this->srcimg,"."),1));

        //初始化图象

        $this->initi_img();

        //目标图象地址

        $this -> dst_img($dstpath);

        //--

        $this->width = imagesx($this->im);

        $this->height = imagesy($this->im);

        //生成图象

        $this->newimg();

        ImageDestroy ($this->im);

    }

    function newimg()

    {

        //改变后的图象的比例

        $resize_ratio = ($this->resize_width)/($this->resize_height);

        //实际图象的比例

        $ratio = ($this->width)/($this->height);

        if(($this->cut)=="1")

        //裁图

        {

            if($ratio>=$resize_ratio)

            //高度优先

            {

                $newimg = imagecreatetruecolor($this->resize_width,$this->resize_height);

                imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width,$this-

>resize_height, (($this->height)*$resize_ratio), $this->height);

                ImageJpeg ($newimg,$this->dstimg);

            }

            if($ratio<$resize_ratio)

            //宽度优先

            {

                $newimg = imagecreatetruecolor($this->resize_width,$this->resize_height);

                imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width, $this-

>resize_height, $this->width, (($this->width)/$resize_ratio));

                ImageJpeg ($newimg,$this->dstimg);

            }

        }

        else

        //不裁图

        {

            if($ratio>=$resize_ratio)

            {

                $newimg = imagecreatetruecolor($this->resize_width,($this->resize_width)/$ratio);

                imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width, ($this-

>resize_width)/$ratio, $this->width, $this->height);

                ImageJpeg ($newimg,$this->dstimg);

            }

            if($ratio<$resize_ratio)

            {

                $newimg = imagecreatetruecolor(($this->resize_height)*$ratio,$this->resize_height);

                imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, ($this->resize_height)*$ratio,

//开源代码phpfensi.com

$this->resize_height, $this->width, $this->height);

                ImageJpeg ($newimg,$this->dstimg);

            }

        }

    }

    //初始化图象

    function initi_img()

    {

        if($this->type=="jpg")

        {

            $this->im = imagecreatefromjpeg($this->srcimg);

        }

        if($this->type=="gif")

        {

            $this->im = imagecreatefromgif($this->srcimg);

        }

        if($this->type=="png")

        {

            $this->im = imagecreatefrompng($this->srcimg);

        }

    }

    //图象目标地址

    function dst_img($dstpath)

    {

        $full_length  = strlen($this->srcimg);

        $type_length  = strlen($this->type);

        $name_length  = $full_length-$type_length;

        $name         = substr($this->srcimg,0,$name_length-1);

        $this->dstimg = $dstpath;

//echo $this->dstimg;

    }

}

?>

类的调用方法:

$resizeimage = new resizeimage("图片源文件地址", "200", "100", "0","缩略图地址");

就只用上面的一句话,就能生成缩略图,其中,源文件和缩略图地址可以相同,200,100分别代表宽和高.

实例2:PHP缩略图等比例无损压缩,可填充空白区域补充色,代码如下:

<?php

error_reporting( E_ALL );

// 测试

imagezoom('1.jpg', '2.jpg', 400, 300, '#FFFFFF');

/*

    php缩略图函数：

        等比例无损压缩，可填充补充色 author: 华仔

    主持格式：

        bmp 、jpg 、gif、png

    param:

        @srcimage : 要缩小的图片

        @dstimage : 要保存的图片

        @dst_width: 缩小宽

        @dst_height: 缩小高

        @backgroundcolor: 补充色  如：#FFFFFF  支持 6位  不支持3位

*/

function imagezoom( $srcimage, $dstimage,  $dst_width, $dst_height, $backgroundcolor ) {



        // 中文件名乱码

        if ( PHP_OS == 'WINNT' ) {

                $srcimage = iconv('UTF-8', 'GBK', $srcimage);

                $dstimage = iconv('UTF-8', 'GBK', $dstimage);

        }



    $dstimg = imagecreatetruecolor( $dst_width, $dst_height );

    $color = imagecolorallocate($dstimg

        , hexdec(substr($backgroundcolor, 1, 2))

        , hexdec(substr($backgroundcolor, 3, 2))

        , hexdec(substr($backgroundcolor, 5, 2))

    );

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



    if ( !$arr=getimagesize($srcimage) ) {

                echo "要生成缩略图的文件不存在";

                exit;

        }



    $src_width = $arr[0];

    $src_height = $arr[1];

    $srcimg = null;

    $method = getcreatemethod( $srcimage );

    if ( $method ) {

        eval( '$srcimg = ' . $method . ';' );

    }



    $dst_x = 0;

    $dst_y = 0;

    $dst_w = $dst_width;

    $dst_h = $dst_height;

    if ( ($dst_width / $dst_height - $src_width / $src_height) > 0 ) {

        $dst_w = $src_width * ( $dst_height / $src_height );

        $dst_x = ( $dst_width - $dst_w ) / 2;

    } elseif ( ($dst_width / $dst_height - $src_width / $src_height) < 0 ) {

        $dst_h = $src_height * ( $dst_width / $src_width );

        $dst_y = ( $dst_height - $dst_h ) / 2;

    }

    imagecopyresampled($dstimg, $srcimg, $dst_x

        , $dst_y, 0, 0, $dst_w, $dst_h, $src_width, $src_height);



    // 保存格式

    $arr = array(

        'jpg' => 'imagejpeg'

        , 'jpeg' => 'imagejpeg'

        , 'png' => 'imagepng'

        , 'gif' => 'imagegif'

        , 'bmp' => 'imagebmp'

    );

    $suffix = strtolower( array_pop(explode('.', $dstimage ) ) );

    if (!in_array($suffix, array_keys($arr)) ) {

        echo "保存的文件名错误";

        exit;

    } else {

        eval( $arr[$suffix] . '($dstimg, "'.$dstimage.'");' );

    }



    imagejpeg($dstimg, $dstimage);



    imagedestroy($dstimg);

    imagedestroy($srcimg);



}

function getcreatemethod( $file ) {

        $arr = array(

                '474946' => "imagecreatefromgif('$file')"

                , 'FFD8FF' => "imagecreatefromjpeg('$file')"

                , '424D' => "imagecreatefrombmp('$file')"

                , '89504E' => "imagecreatefrompng('$file')"

        );

        $fd = fopen( $file, "rb" );

        $data = fread( $fd, 3 );



        $data = str2hex( $data );



        if ( array_key_exists( $data, $arr ) ) {

                return $arr[$data];

        } elseif ( array_key_exists( substr($data, 0, 4), $arr ) ) {

                return $arr[substr($data, 0, 4)];

        } else {

                return false;

        }

}

function str2hex( $str ) {

        $ret = "";



        for( $i = 0; $i < strlen( $str ) ; $i++ ) {

                $ret .= ord($str[$i]) >= 16 ? strval( dechex( ord($str[$i]) ) )

                        : '0'. strval( dechex( ord($str[$i]) ) );

        }



        return strtoupper( $ret );

}

// BMP 创建函数  php本身无

function imagecreatefrombmp($filename)

{

   if (! $f1 = fopen($filename,"rb")) return FALSE;

   $FILE = unpack("vfile_type/Vfile_size/Vreserved/Vbitmap_offset", fread($f1,14));

   if ($FILE['file_type'] != 19778) return FALSE;

   $BMP = unpack('Vheader_size/Vwidth/Vheight/vplanes/vbits_per_pixel'.

                 '/Vcompression/Vsize_bitmap/Vhoriz_resolution'.

                 '/Vvert_resolution/Vcolors_used/Vcolors_important', fread($f1,40));

   $BMP['colors'] = pow(2,$BMP['bits_per_pixel']);

   if ($BMP['size_bitmap'] == 0) $BMP['size_bitmap'] = $FILE['file_size'] - $FILE['bitmap_offset'];

   $BMP['bytes_per_pixel'] = $BMP['bits_per_pixel']/8;

   $BMP['bytes_per_pixel2'] = ceil($BMP['bytes_per_pixel']);

   $BMP['decal'] = ($BMP['width']*$BMP['bytes_per_pixel']/4);

   $BMP['decal'] -= floor($BMP['width']*$BMP['bytes_per_pixel']/4);

   $BMP['decal'] = 4-(4*$BMP['decal']);

   if ($BMP['decal'] == 4) $BMP['decal'] = 0;



   $PALETTE = array();

   if ($BMP['colors'] < 16777216)

   {

    $PALETTE = unpack('V'.$BMP['colors'], fread($f1,$BMP['colors']*4));

   }



   $IMG = fread($f1,$BMP['size_bitmap']);

   $VIDE = chr(0);

   $res = imagecreatetruecolor($BMP['width'],$BMP['height']);

   $P = 0;

   $Y = $BMP['height']-1;

   while ($Y >= 0)

   {

        $X=0;

        while ($X < $BMP['width'])

        {

         if ($BMP['bits_per_pixel'] == 24)

            $COLOR = unpack("V",substr($IMG,$P,3).$VIDE);

         elseif ($BMP['bits_per_pixel'] == 16)

         {

            $COLOR = unpack("n",substr($IMG,$P,2));

            $COLOR[1] = $PALETTE[$COLOR[1]+1];

         }

         elseif ($BMP['bits_per_pixel'] == 8)

         {

            $COLOR = unpack("n",$VIDE.substr($IMG,$P,1));

            $COLOR[1] = $PALETTE[$COLOR[1]+1];

         }

         elseif ($BMP['bits_per_pixel'] == 4)

         {

            $COLOR = unpack("n",$VIDE.substr($IMG,floor($P),1));

            if (($P*2)%2 == 0) $COLOR[1] = ($COLOR[1] >> 4) ; else $COLOR[1] = ($COLOR[1] & 0x0F);

            $COLOR[1] = $PALETTE[$COLOR[1]+1];

         }

         elseif ($BMP['bits_per_pixel'] == 1)

         {

            $COLOR = unpack("n",$VIDE.substr($IMG,floor($P),1));

            if     (($P*8)%8 == 0) $COLOR[1] =  $COLOR[1]        >>7;

            elseif (($P*8)%8 == 1) $COLOR[1] = ($COLOR[1] & 0x40)>>6;

            elseif (($P*8)%8 == 2) $COLOR[1] = ($COLOR[1] & 0x20)>>5;

            elseif (($P*8)%8 == 3) $COLOR[1] = ($COLOR[1] & 0x10)>>4;

            elseif (($P*8)%8 == 4) $COLOR[1] = ($COLOR[1] & 0x8)>>3;

            elseif (($P*8)%8 == 5) $COLOR[1] = ($COLOR[1] & 0x4)>>2;

            elseif (($P*8)%8 == 6) $COLOR[1] = ($COLOR[1] & 0x2)>>1;

            elseif (($P*8)%8 == 7) $COLOR[1] = ($COLOR[1] & 0x1);

            $COLOR[1] = $PALETTE[$COLOR[1]+1];

         }

         else

            return FALSE;

         imagesetpixel($res,$X,$Y,$COLOR[1]);

         $X++;

         $P += $BMP['bytes_per_pixel'];

        }

        $Y--;

        $P+=$BMP['decal'];

   }

   fclose($f1);

return $res;

}

// BMP 保存函数，php本身无

function imagebmp ($im, $fn = false)

{

    if (!$im) return false;



    if ($fn === false) $fn = 'php://output';

    $f = fopen ($fn, "w");

    if (!$f) return false;



    $biWidth = imagesx ($im);

    $biHeight = imagesy ($im);

    $biBPLine = $biWidth * 3;

    $biStride = ($biBPLine + 3) & ~3;

    $biSizeImage = $biStride * $biHeight;

    $bfOffBits = 54;

    $bfSize = $bfOffBits + $biSizeImage;



    fwrite ($f, 'BM', 2);

    fwrite ($f, pack ('VvvV', $bfSize, 0, 0, $bfOffBits));



    fwrite ($f, pack ('VVVvvVVVVVV', 40, $biWidth, $biHeight, 1, 24, 0, $biSizeImage, 0, 0, 0, 0));



    $numpad = $biStride - $biBPLine;

    for ($y = $biHeight - 1; $y >= 0; --$y)

    {

        for ($x = 0; $x < $biWidth; ++$x)

        {

            $col = imagecolorat ($im, $x, $y);

            fwrite ($f, pack ('V', $col), 3);

        }

        for ($i = 0; $i < $numpad; ++$i)

            fwrite ($f, pack ('C', 0));

    }

    fclose ($f);

    return true;

}

?>