PHP根据图片制作缩略图-php手册-php.cn

php中制作缩略图的方法也很简单，是用imagecopyresampled方法根据源图制作一个小一点的图片，来看代码check_image_addthumbs.php ? php // 修改图片效果 $db = mysql_connect ('localhost','root','Ctrip07185419') or die ('can not connect to database' )

php中制作缩略图的方法也很简单，是用imagecopyresampled方法根据源图制作一个小一点的图片，来看代码check_image_addthumbs.php

<span>php 
</span><span>//</span><span>修改图片效果</span>
<span>$db</span> = <span>mysql_connect</span>('localhost','root','Ctrip07185419') or <span>die</span>('can not connect to database'<span>);
</span><span>mysql_select_db</span>('moviesite',<span>$db</span>) or <span>die</span>(<span>mysql_error</span>(<span>$db</span><span>));
</span><span>//</span><span>上传文件的路径</span>
<span>$dir</span> = 'D:\Serious\phpdev\test\images'<span>;
</span><span>//</span><span>缩略图的路径</span>
<span>$thumbdir</span> = 'D:\Serious\phpdev\test\images\thumbs'<span>;
</span><span>//</span><span>设置环境变量</span>
<span>putenv</span>('GDFONTPATH='.'C:\Windows\Fonts'<span>);
</span><span>$font</span> = "arial"<span>;

</span><span>//</span><span>upload_image.php页面传递过来的参数，如果是上传图片</span>
<span>if</span>(<span>$_POST</span>['submit'] == 'Upload'<span>)
{
    </span><span>if</span>(<span>$_FILES</span>['uploadfile']['error'] !=<span> UPLOAD_ERR_OK)
    {
        </span><span>switch</span>(<span>$_FILES</span>['uploadfile']['error'<span>])
        {
            </span><span>case</span> UPLOAD_ERR_INI_SIZE:
                <span>die</span>('The uploaded file exceeds the upload_max_filesize directive'<span>);
            </span><span>break</span><span>;
            </span><span>case</span> UPLOAD_ERR_FORM_SIZE:
                <span>die</span>('The upload file exceeds the MAX_FILE_SIZE directive that was specified in the HTML form'<span>);
            </span><span>break</span><span>;
            </span><span>case</span> UPLOAD_ERR_PARTIAL:
                <span>die</span>('The uploaded file was only partially uploaded'<span>);
            </span><span>break</span><span>;
            </span><span>case</span> UPLOAD_ERR_NO_FILE:
                <span>die</span>('No file was uploaded'<span>);
            </span><span>break</span><span>;
            </span><span>case</span> UPLOAD_ERR_NO_TMP_DIR:
                <span>die</span>('The server is missing a temporary folder'<span>);
            </span><span>break</span><span>;    
            </span><span>case</span> UPLOAD_ERR_CANT_WRITE:
                <span>die</span>('The server fail to write the uploaded file to the disk'<span>);
            </span><span>break</span><span>;        
            </span><span>case</span> UPLOAD_ERR_EXTENSION:
                <span>die</span>('The upload stopped by extension'<span>);
            </span><span>break</span><span>;                
        }
    }
    </span><span>$image_caption</span> = <span>$_POST</span>['caption'<span>];
    </span><span>$image_username</span> = <span>$_POST</span>['username'<span>];
    </span><span>$image_date</span> = <span>date</span>('Y-m-d'<span>);
    </span><span>list</span>(<span>$width</span>,<span>$height</span>,<span>$type</span>,<span>$attr</span>) = <span>getimagesize</span>(<span>$_FILES</span>['uploadfile']['tmp_name'<span>]);
    </span><span>$error</span> = 'The file you upload is not a supported filetype'<span>;
    </span><span>switch</span>(<span>$type</span><span>)
    {
        </span><span>case</span> IMAGETYPE_GIF:
            <span>$image</span> = imagecreatefromgif(<span>$_FILES</span>['uploadfile']['tmp_name']) or <span>die</span>(<span>$error</span><span>);
        </span><span>break</span><span>;
        </span><span>case</span> IMAGETYPE_JPEG:
            <span>$image</span> = imagecreatefromjpeg(<span>$_FILES</span>['uploadfile']['tmp_name']) or <span>die</span>(<span>$error</span><span>);
        </span><span>break</span><span>;
        </span><span>case</span> IMAGETYPE_PNG:
            <span>$image</span> = imagecreatefrompng(<span>$_FILES</span>['uploadfile']['tmp_name']) or <span>die</span>(<span>$error</span><span>);
        </span><span>break</span><span>;
        </span><span>default</span>:
        <span>break</span><span>;
    }
    </span><span>$query</span> = 'insert into images(image_caption,image_username,image_date) values("'.<span>$image_caption</span>.'" , "'.<span>$image_username</span>.'","'.<span>$image_date</span>.'")'<span>;
    </span><span>$result</span> = <span>mysql_query</span>(<span>$query</span>,<span>$db</span>) or <span>die</span>(<span>mysql_error</span>(<span>$db</span><span>));
    </span><span>$last_id</span> = <span>mysql_insert_id</span><span>();
    
    </span><span>//</span><span> $imagename = $last_id.'.jpg';
    // imagejpeg($image,$dir.'/'.$imagename);
    // imagedestroy($image);</span>
    
    <span>$image_id</span> = <span>$last_id</span><span>;
    imagejpeg(</span><span>$image</span> , <span>$dir</span>.'/'.<span>$image_id</span>.'.jpg'<span>);
    imagedestroy(</span><span>$image</span><span>);
}
</span><span>else</span>  <span>//</span><span>如果图片已经上传，则从数据库中取图片名字</span>
<span>{
    </span><span>$query</span> = 'select image_id,image_caption,image_username,image_date from images where image_id='.<span>$_POST</span>['id'<span>];
    </span><span>$result</span> = <span>mysql_query</span>(<span>$query</span>,<span>$db</span>) or <span>die</span>(<span>mysql_error</span>(<span>$db</span><span>));
    </span><span>extract</span>(<span>mysql_fetch_assoc</span>(<span>$result</span><span>));
    </span><span>list</span>(<span>$width</span>,<span>$height</span>,<span>$type</span>,<span>$attr</span>) = <span>getimagesize</span>(<span>$dir</span>.'/'.<span>$image_id</span>.'.jpg'<span>);
}

</span><span>//</span><span>如果是保存图片</span>
<span>if</span>(<span>$_POST</span>['submit'] == 'Save'<span>)
{
    </span><span>if</span>(<span>isset</span>(<span>$_POST</span>['id']) && <span>ctype_digit</span>(<span>$_POST</span>['id']) && <span>file_exists</span>(<span>$dir</span>.'/'.<span>$_POST</span>['id'].'.jpg'<span>))
    {
        </span><span>$image</span> = imagecreatefromjpeg(<span>$dir</span>.'/'.<span>$_POST</span>['id'].'.jpg'<span>);
    }
    </span><span>else</span><span>
    {
        </span><span>die</span>('invalid image specified'<span>);
    }
    </span><span>$effect</span> = (<span>isset</span>(<span>$_POST</span>['effect'])) ? <span>$_POST</span>['effect'] : -1<span>;
    </span><span>switch</span>(<span>$effect</span><span>)
    {
        </span><span>case</span> IMG_FILTER_NEGATE:<span>
            imagefilter(</span><span>$image</span> , IMG_FILTER_NEGATE);     <span>//</span><span>将图像中所有颜色反转</span>
        <span>break</span><span>;
        </span><span>case</span> IMG_FILTER_GRAYSCALE:<span>
            imagefilter(</span><span>$image</span> , IMG_FILTER_GRAYSCALE);  <span>//</span><span>将图像转换为灰度的</span>
        <span>break</span><span>;
        </span><span>case</span> IMG_FILTER_EMBOSS:<span>
            imagefilter(</span><span>$image</span> , IMG_FILTER_EMBOSS);     <span>//</span><span>使图像浮雕化</span>
        <span>break</span><span>;
        </span><span>case</span> IMG_FILTER_GAUSSIAN_BLUR:<span>
            imagefilter(</span><span>$image</span> , IMG_FILTER_GAUSSIAN_BLUR); <span>//</span><span>用高斯算法模糊图像</span>
        <span>break</span><span>;    
    }
    
    </span><span>if</span>(<span>isset</span>(<span>$_POST</span>['emb_caption'<span>]))
    {
        imagettftext(</span><span>$image</span> , 12 , 0 , 20 , 20 , 0 , <span>$font</span> , <span>$image_caption</span><span>);
    }
    
    </span><span>$thumb_width</span> = <span>$width</span> * 0.10<span>;
    </span><span>$thumb_height</span> = <span>$height</span> * 0.10<span>;
                   
    </span><span>//</span><span>创建一个缩略图</span>
    <span>$thumb</span> = imagecreatetruecolor(<span>$thumb_width</span>, <span>$thumb_height</span><span>);
    imagecopyresampled(</span><span>$thumb</span>, <span>$image</span>, 0, 0, 0, 0, <span>$thumb_width</span>, <span>$thumb_height</span>,    <span>$width</span>, <span>$height</span><span>);
    </span><span>//</span><span>保存原图</span>
    imagejpeg(<span>$image</span>, <span>$dir</span> . '/' . <span>$_POST</span>['id'] . '.jpg', 100<span>);
    </span><span>//</span><span>保存缩略图</span>
    imagejpeg(<span>$thumb</span>, <span>$thumbdir</span> . '/' . <span>$_POST</span>['id'] . '.jpg', 100<span>);
    imagedestroy(</span><span>$thumb</span><span>);
    </span>?>
    
        
            <title>Here is your pic!</title>
        
        
            <h1>Your image has been saved!</h1>
            <img src="images/<?php%20echo%20<span>%24_POST</span>%5B'id'%5D;?>.jpg" alt="">
        
    
<span>php 
}
</span><span>else</span><span>
{
</span>?>
    
        
            <title>Here is your pic!</title>
        
        
            <h1>So how does it feel to be famous?</h1>
            <p>Here is the picture you just uploaded to your servers:</p>
            <!--<img  src="images/<?php echo <span alt="PHP根据图片制作缩略图" >$imagename</span>;?>" alt=""   style="max-width:90%" />-->
        
    
    <span>php
        </span><span>if</span>(<span>$_POST</span>['submit'] == 'Upload'<span>)
        {
            </span><span>$imagename</span> = 'images/'.<span>$image_id</span>.'.jpg'<span>;
        }
        </span><span>else</span><span>
        {
            </span><span>$imagename</span> = 'image_effect.php?id='.<span>$image_id</span>.'&e='.<span>$_POST</span>['effect'<span>];
            </span><span>if</span>(<span>isset</span>(<span>$_POST</span>['emb_caption'<span>]))
            {
                </span><span>$imagename</span> .= '&capt='.<span>urlencode</span>(<span>$image_caption</span><span>);
            }
        }
    </span>?>
    <img src="<?php%20echo%20<span>%24imagename</span>;?>"   style="max-width:90%" alt="">

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Image save as:	$image_id?>
Height:	echo $height;?>
Widht:	echo $width;?>
Upload date:	echo $image_date;?>

You may apply a special effect to your image from the list of option below. Note:saving an image with any of the filters applied can be undone

Filter:
php echo '; if(isset($_POST['emb_caption'])) { echo ' checked="checked"'; } echo ' />Embed caption in image?'; ?>

php } ?>

缩略图放在D:\Serious\phpdev\test\images\thumbs路径下面，这里我们添加了一个gallery.php文件来陈列所有的缩略图，代码如下：

<span>php 
</span><span>$db</span> = <span>mysql_connect</span>('localhost','root','Ctrip07185419') or <span>die</span>('can not connect to database'<span>);
</span><span>mysql_select_db</span>('moviesite',<span>$db</span>) or <span>die</span>(<span>mysql_error</span>(<span>$db</span><span>));

</span><span>$dir</span> = 'images'<span>;
</span><span>$thumbdir</span> = <span>$dir</span>.'/thumbs'<span>;
</span>?>

    
        <title>Welcome to our Photo Gallery</title>
        <style type="text/css"><span>
            th{  background-color:<span>#<span>999; }
            .odd_row { background-color:<span>#<span>EEE;}
            .even_row {background-color:<span>#<span>FFF;}
        </style>
    
    
        <p>Click on any image to see it full sized.</p>

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php $result = mysql_query('select * from images') or die(mysql_error($db)); $odd = true; while($row = mysql_fetch_assoc($result)) { echo ($odd == true) ? '' : ''; $odd = !$odd; extract($row); echo ''; echo ''; echo ''; echo ''; echo ''; } ?>

Image	Caption	Uploaded By	Date uploaded
'; echo ''; echo '	'.$image_caption.'	'.$image_username.'	'.$image_date.'

来看看最后显示缩略图的效果：

PHP根据图片制作缩略图

注意下面的代码：

    <span>$thumb_width</span> = <span>$width</span> * 0.10<span>;
    </span><span>$thumb_height</span> = <span>$height</span> * 0.10<span>;
                   
    </span><span>//</span><span>创建一个缩略图</span>
    <span>$thumb</span> = imagecreatetruecolor(<span>$thumb_width</span>, <span>$thumb_height</span><span>);
    imagecopyresampled(</span><span>$thumb</span>, <span>$image</span>, 0, 0, 0, 0, <span>$thumb_width</span>, <span>$thumb_height</span>,    <span>$width</span>, <span>$height</span><span>);
    </span><span>//</span><span>保存原图</span>
    imagejpeg(<span>$image</span>, <span>$dir</span> . '/' . <span>$_POST</span>['id'] . '.jpg', 100<span>);
    </span><span>//</span><span>保存缩略图</span>
    imagejpeg(<span>$thumb</span>, <span>$thumbdir</span> . '/' . <span>$_POST</span>['id'] . '.jpg', 100<span>);
    imagedestroy(</span><span>$thumb</span>);

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我们设置缩略图的长度是原来长度的10%，宽度也是原来宽度的10%，注意保持一致，否则图片会出现失真，当然这个参数如果设置成大于1的整数，图片就会放大。