图片自动缩放

CSS

JQuery

PHP无损缩放

PHP裁剪

p img {
    padding: 0;
    max-width: 100%;
    }

p img {
max-width:600px;
width: expression(this.width > 600 ? “600px” : true);
height:auto;
}

$(document).ready(function(){
    $('div').autoResize({height:750});
});  
jQuery.fn.autoResize = function(options)
{
    var opts = {
        'width' : 700,
        'height': 750
    }
    var opt = $.extend(true, {},opts,options || {});
    width = opt.width;
    height = opt.height;
    $('img',this).each(function(){
        var image = new Image();
        image.src = $(this).attr('src');   if(image.width > 0 && image.height > 0 ){
            var image_rate = 1;
            if( (width / image.width) < (height / image.height)){
                image_rate = width / image.width ;
            }else{
                image_rate = height / image.height ;
            }
            if ( image_rate <= 1){
                $(this).width(image.width * image_rate);
                $(this).height(image.height * image_rate);
            }
        }
    });
}

 

/*
* @param String $name 要缩放的文件路径
* @param String $filename 生成的文件路径
* @param Int $new_w 新图片宽度
* @param Int $new_h 新图片高度
*/
function createthumb($name,$filename,$new_w,$new_h)
    {
        $file_extension = strtolower(pathinfo($name, PATHINFO_EXTENSION));
        
        if (preg_match("/jpg|jpeg/",$file_extension)){$src_img=imagecreatefromjpeg($name);}
        if (preg_match("/png/",$file_extension)){$src_img=imagecreatefrompng($name);}
        if (preg_match("/gif/",$file_extension)){$src_img=imagecreatefromgif($name);}
        $old_x=imageSX($src_img);
        $old_y=imageSY($src_img);
        $old_per = $old_x/$old_y;
        $new_per = $new_w/$new_h;
        if($new_per >= $old_per){
            $thumb_w = $old_x * ($new_h/$old_y);
            $thumb_h = $new_h;
            $pst_x = ($new_w-$thumb_w)/2;
            $pst_y = 0;
        }else{
            $thumb_w=$new_w;
            $thumb_h = $old_y * ($new_w/$old_x);
            $pst_y = ($new_h-$thumb_h)/2;
            $pst_x = 0;
        }
        $dst_img=ImageCreateTrueColor($new_w,$new_h);
        //颜色
        $backgroung_color = imagecolorallocate($dst_img, 0xFF, 0xFF, 0xFF);
        
        if($new_per >= $old_per){
            imagefilledrectangle ($dst_img , 0 , 0 , $pst_x , $new_h , $backgroung_color);
            imagefilledrectangle ($dst_img , $pst_x+$thumb_w , 0 , $new_w , $new_h , $backgroung_color);
        }else{
            imagefilledrectangle ($dst_img , 0 , 0 , $new_w , $pst_y , $backgroung_color);
            imagefilledrectangle ($dst_img , 0 , $new_h-$pst_y, $new_w , $new_h , $backgroung_color);
        }
        imagecopyresampled($dst_img,$src_img,$pst_x,$pst_y,0,0,$thumb_w,$thumb_h,$old_x,$old_y); 
        if (preg_match("/png/",$file_extension))
        {
            imagepng($dst_img,$filename); 
        } elseif (preg_match("/gif/",$file_extension))
        {
            imagegif($dst_img,$filename); 
        } else {
            imagejpeg($dst_img,$filename); 
        }
        imagedestroy($dst_img); 
        imagedestroy($src_img); 
    }