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强大的PHP生成缩略图函数。

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PHP中文网Original
2016-05-25 17:11:151109browse

php生成缩略图   

<?php

/**
 * 生成缩略图
 * @author yangzhiguo0903@163.com
 * @param string     源图绝对完整地址{带文件名及后缀名}
 * @param string     目标图绝对完整地址{带文件名及后缀名}
 * @param int        缩略图宽{0:此时目标高度不能为0,目标宽度为源图宽*(目标高度/源图高)}
 * @param int        缩略图高{0:此时目标宽度不能为0,目标高度为源图高*(目标宽度/源图宽)}
 * @param int        是否裁切{宽,高必须非0}
 * @param int/float  缩放{0:不缩放, 0<this<1:缩放到相应比例(此时宽高限制和裁切均失效)}
 * @return boolean
 */
function img2thumb($src_img, $dst_img, $width = 75, $height = 75, $cut = 0, $proportion = 0)
{
    if(!is_file($src_img))
    {
        return false;
    }
    $ot = fileext($dst_img);
    $otfunc = &#39;image&#39; . ($ot == &#39;jpg&#39; ? &#39;jpeg&#39; : $ot);
    $srcinfo = getimagesize($src_img);
    $src_w = $srcinfo[0];
    $src_h = $srcinfo[1];
    $type  = strtolower(substr(image_type_to_extension($srcinfo[2]), 1));
    $createfun = &#39;imagecreatefrom&#39; . ($type == &#39;jpg&#39; ? &#39;jpeg&#39; : $type);

    $dst_h = $height;
    $dst_w = $width;
    $x = $y = 0;

    /**
     * 缩略图不超过源图尺寸(前提是宽或高只有一个)
     */
    if(($width> $src_w && $height> $src_h) || ($height> $src_h && $width == 0) || ($width> $src_w && $height == 0))
    {
        $proportion = 1;
    }
    if($width> $src_w)
    {
        $dst_w = $width = $src_w;
    }
    if($height> $src_h)
    {
        $dst_h = $height = $src_h;
    }

    if(!$width && !$height && !$proportion)
    {
        return false;
    }
    if(!$proportion)
    {
        if($cut == 0)
        {
            if($dst_w && $dst_h)
            {
                if($dst_w/$src_w> $dst_h/$src_h)
                {
                    $dst_w = $src_w * ($dst_h / $src_h);
                    $x = 0 - ($dst_w - $width) / 2;
                }
                else
                {
                    $dst_h = $src_h * ($dst_w / $src_w);
                    $y = 0 - ($dst_h - $height) / 2;
                }
            }
            else if($dst_w xor $dst_h)
            {
                if($dst_w && !$dst_h)  //有宽无高
                {
                    $propor = $dst_w / $src_w;
                    $height = $dst_h  = $src_h * $propor;
                }
                else if(!$dst_w && $dst_h)  //有高无宽
                {
                    $propor = $dst_h / $src_h;
                    $width  = $dst_w = $src_w * $propor;
                }
            }
        }
        else
        {
            if(!$dst_h)  //裁剪时无高
            {
                $height = $dst_h = $dst_w;
            }
            if(!$dst_w)  //裁剪时无宽
            {
                $width = $dst_w = $dst_h;
            }
            $propor = min(max($dst_w / $src_w, $dst_h / $src_h), 1);
            $dst_w = (int)round($src_w * $propor);
            $dst_h = (int)round($src_h * $propor);
            $x = ($width - $dst_w) / 2;
            $y = ($height - $dst_h) / 2;
        }
    }
    else
    {
        $proportion = min($proportion, 1);
        $height = $dst_h = $src_h * $proportion;
        $width  = $dst_w = $src_w * $proportion;
    }

    $src = $createfun($src_img);
    $dst = imagecreatetruecolor($width ? $width : $dst_w, $height ? $height : $dst_h);
    $white = imagecolorallocate($dst, 255, 255, 255);
    imagefill($dst, 0, 0, $white);

    if(function_exists(&#39;imagecopyresampled&#39;))
    {
        imagecopyresampled($dst, $src, $x, $y, 0, 0, $dst_w, $dst_h, $src_w, $src_h);
    }
    else
    {
        imagecopyresized($dst, $src, $x, $y, 0, 0, $dst_w, $dst_h, $src_w, $src_h);
    }
    $otfunc($dst, $dst_img);
    imagedestroy($dst);
    imagedestroy($src);
    return true;
}

补充代码  

function fileext($file)
{
    return pathinfo($file, PATHINFO_EXTENSION);
}

函数的使用demo

$src_img = "./ROSI_050_002.JPG";
$dst_img = "./ROSI_050_002_thumb.jpg";
$stat = img2thumb($src_img, $dst_img, $width = 200, $height = 300, $cut = 0, $proportion = 0);
if($stat){
	echo &#39;Resize Image Success!<br />&#39;;
	echo &#39;<img src="&#39;.$dst_img.&#39;" />&#39;;	
}else{
	echo &#39;Resize Image Fail!&#39;;	
}

                   

                   

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