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PHP根据图片制作缩略图
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 $db = mysql_connect(‘localhost‘,‘root‘,‘Ctrip07185419‘) or die(‘can not connect to database‘); mysql_select_db(‘moviesite‘,$db) or die(mysql_error($db)); //上传文件的路径 $dir = ‘D:\Serious\phpdev\test\images‘; //缩略图的路径 $thumbdir = ‘D:\Serious\phpdev\test\images\thumbs‘; //设置环境变量 putenv(‘GDFONTPATH=‘.‘C:\Windows\Fonts‘); $font = "arial"; //upload_image.php页面传递过来的参数，如果是上传图片 if($_POST[‘submit‘] == ‘Upload‘) { if($_FILES[‘uploadfile‘][‘error‘] != UPLOAD_ERR_OK) { switch($_FILES[‘uploadfile‘][‘error‘]) { case UPLOAD_ERR_INI_SIZE: die(‘The uploaded file exceeds the upload_max_filesize directive‘); break; case UPLOAD_ERR_FORM_SIZE: die(‘The upload file exceeds the MAX_FILE_SIZE directive that was specified in the HTML form‘); break; case UPLOAD_ERR_PARTIAL: die(‘The uploaded file was only partially uploaded‘); break; case UPLOAD_ERR_NO_FILE: die(‘No file was uploaded‘); break; case UPLOAD_ERR_NO_TMP_DIR: die(‘The server is missing a temporary folder‘); break; case UPLOAD_ERR_CANT_WRITE: die(‘The server fail to write the uploaded file to the disk‘); break; case UPLOAD_ERR_EXTENSION: die(‘The upload stopped by extension‘); break; } } $image_caption = $_POST[‘caption‘]; $image_username = $_POST[‘username‘]; $image_date = date(‘Y-m-d‘); list($width,$height,$type,$attr) = getimagesize($_FILES[‘uploadfile‘][‘tmp_name‘]); $error = ‘The file you upload is not a supported filetype‘; switch($type) { case IMAGETYPE_GIF: $image = imagecreatefromgif($_FILES[‘uploadfile‘][‘tmp_name‘]) or die($error); break; case IMAGETYPE_JPEG: $image = imagecreatefromjpeg($_FILES[‘uploadfile‘][‘tmp_name‘]) or die($error); break; case IMAGETYPE_PNG: $image = imagecreatefrompng($_FILES[‘uploadfile‘][‘tmp_name‘]) or die($error); break; default: break; } $query = ‘insert into images(image_caption,image_username,image_date) values("‘.$image_caption.‘" , "‘.$image_username.‘","‘.$image_date.‘")‘; $result = mysql_query($query,$db) or die(mysql_error($db)); $last_id = mysql_insert_id(); // $imagename = $last_id.‘.jpg‘; // imagejpeg($image,$dir.‘/‘.$imagename); // imagedestroy($image); $image_id = $last_id; imagejpeg($image , $dir.‘/‘.$image_id.‘.jpg‘); imagedestroy($image); } else //如果图片已经上传，则从数据库中取图片名字 { $query = ‘select image_id,image_caption,image_username,image_date from images where image_id=‘.$_POST[‘id‘]; $result = mysql_query($query,$db) or die(mysql_error($db)); extract(mysql_fetch_assoc($result)); list($width,$height,$type,$attr) = getimagesize($dir.‘/‘.$image_id.‘.jpg‘); } //如果是保存图片 if($_POST[‘submit‘] == ‘Save‘) { if(isset($_POST[‘id‘]) && ctype_digit($_POST[‘id‘]) && file_exists($dir.‘/‘.$_POST[‘id‘].‘.jpg‘)) { $image = imagecreatefromjpeg($dir.‘/‘.$_POST[‘id‘].‘.jpg‘); } else { die(‘invalid image specified‘); } $effect = (isset($_POST[‘effect‘])) ? $_POST[‘effect‘] : -1; switch($effect) { case IMG_FILTER_NEGATE: imagefilter($image , IMG_FILTER_NEGATE); //将图像中所有颜色反转 break; case IMG_FILTER_GRAYSCALE: imagefilter($image , IMG_FILTER_GRAYSCALE); //将图像转换为灰度的 break; case IMG_FILTER_EMBOSS: imagefilter($image , IMG_FILTER_EMBOSS); //使图像浮雕化 break; case IMG_FILTER_GAUSSIAN_BLUR: imagefilter($image , IMG_FILTER_GAUSSIAN_BLUR); //用高斯算法模糊图像 break; } if(isset($_POST[‘emb_caption‘])) { imagettftext($image , 12 , 0 , 20 , 20 , 0 , $font , $image_caption); } $thumb_width = $width * 0.10; $thumb_height = $height * 0.10; //创建一个缩略图 $thumb = imagecreatetruecolor($thumb_width, $thumb_height); imagecopyresampled($thumb, $image, 0, 0, 0, 0, $thumb_width, $thumb_height, $width, $height); //保存原图 imagejpeg($image, $dir . ‘/‘ . $_POST[‘id‘] . ‘.jpg‘, 100); //保存缩略图 imagejpeg($thumb, $thumbdir . ‘/‘ . $_POST[‘id‘] . ‘.jpg‘, 100); imagedestroy($thumb); ?> <html> <head> <title>Here is your pic!</title> </head> <body> <h1>Your image has been saved!</h1> <img src="http://www.mamicode.com/images/<?php echo $_POST[‘id‘];?>.jpg" /> </body> </html> <?php } else { ?> <html> <head> <title>Here is your pic!</title> </head> <body> <h1>So how does it feel to be famous?</h1> <p>Here is the picture you just uploaded to your servers:</p> <!--<img src="http://www.mamicode.com/images/<?php echo $imagename;?>" style="float:left;" />--> </body> </html> <?php if($_POST[‘submit‘] == ‘Upload‘) { $imagename = ‘images/‘.$image_id.‘.jpg‘; } else { $imagename = ‘image_effect.php?id=‘.$image_id.‘&e=‘.$_POST[‘effect‘]; if(isset($_POST[‘emb_caption‘])) { $imagename .= ‘&capt=‘.urlencode($image_caption); } } ?> <img src="http://www.mamicode.com/<?php echo $imagename;?>" style="float:left;" /> <table> <tr> <td>Image save as:</td> <td><?php $image_id?></td> </tr> <tr> <td>Height:</td> <td><?php echo $height;?></td> </tr> <tr> <td>Widht:</td> <td><?php echo $width;?></td> </tr> <tr> <td>Upload date:</td> <td><?php echo $image_date;?></td> </tr> </table> <p>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 <em>can be undone</em> </p> <form action="<?php echo $_SERVER[‘PHP_SELF‘];?>" method="post"> <div> <input type="hidden" name="id" value="http://www.mamicode.com/<?php echo $image_id;?>"/> Filter:<select name="effect" id=""> <option value="http://www.mamicode.com/-1">None</option> <?php echo ‘<option value="http://www.mamicode.com/‘.IMG_FILTER_GRAYSCALE.‘" ‘; if(isset($_POST[‘effect‘]) && $_POST[‘effect‘] == IMG_FILTER_GRAYSCALE) { echo ‘selected="selected"‘; } echo ‘ >Black and white</option>‘; echo ‘<option value="http://www.mamicode.com/‘.IMG_FILTER_GAUSSIAN_BLUR.‘"‘; if(isset($_POST[‘effect‘]) && $_POST[‘effect‘] == IMG_FILTER_GAUSSIAN_BLUR) { echo ‘ selected="selected"‘; } echo ‘>Blur</option>‘; echo ‘<option value="http://www.mamicode.com/‘.IMG_FILTER_EMBOSS.‘"‘; if(isset($_POST[‘effect‘]) && $_POST[‘effect‘] == IMG_FILTER_EMBOSS) { echo ‘selected="selected"‘; } echo ‘>Emboss</option>‘; echo ‘<option value="http://www.mamicode.com/‘.IMG_FILTER_NEGATE.‘"‘; if(isset($_POST[‘effect‘]) && $_POST[‘effect‘] == IMG_FILTER_NEGATE) { echo ‘selected="selected"‘; } echo ‘>Negative</option>‘; ?> </select><br /> <?php echo ‘<input type="checkbox" name="emb_caption"‘; if(isset($_POST[‘emb_caption‘])) { echo ‘ checked="checked"‘; } echo ‘ />Embed caption in image?‘; ?> <input type="submit" value="http://www.mamicode.com/Preview" name="submit" /><br /><br /> <input type="submit" value="http://www.mamicode.com/Save" name="submit" /> </div> </form> <?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：
<?php $db = mysql_connect(‘localhost‘,‘root‘,‘Ctrip07185419‘) or die(‘can not connect to database‘); mysql_select_db(‘moviesite‘,$db) or die(mysql_error($db)); $dir = ‘images‘; $thumbdir = $dir.‘/thumbs‘; ?> <html> <head> <title>Welcome to our Photo Gallery</title> <style type="text/css"> th{ background-color:#999; } .odd_row { background-color:#EEE;} .even_row {background-color:#FFF;} </style> </head> <body> <p>Click on any image to see it full sized.</p> <table style="width:100%"> <tr> <th>Image</th> <th>Caption</th> <th>Uploaded By</th> <th>Date uploaded</th> </tr> <?php $result = mysql_query(‘select * from images‘) or die(mysql_error($db)); $odd = true; while($row = mysql_fetch_assoc($result)) { echo ($odd == true) ? ‘<tr class="odd_row">‘ : ‘<tr class="even_row">‘; $odd = !$odd; extract($row); echo ‘<td><a href="http://www.mamicode.com/‘ . $dir . ‘/‘ . $image_id.‘.jpg">‘; echo ‘<img src="http://www.mamicode.com/‘ . $thumbdir . ‘/‘ . $image_id . ‘.jpg" />‘; echo ‘</a></td>‘; echo ‘<td>‘.$image_caption.‘</td>‘; echo ‘<td>‘.$image_username.‘</td>‘; echo ‘<td>‘.$image_date.‘</td>‘; echo ‘</tr>‘; } ?> </table> </body> </html>
来看看最后显示缩略图的效果：
注意下面的代码：
$thumb_width = $width * 0.10; $thumb_height = $height * 0.10; //创建一个缩略图 $thumb = imagecreatetruecolor($thumb_width, $thumb_height); imagecopyresampled($thumb, $image, 0, 0, 0, 0, $thumb_width, $thumb_height, $width, $height); //保存原图 imagejpeg($image, $dir . ‘/‘ . $_POST[‘id‘] . ‘.jpg‘, 100); //保存缩略图 imagejpeg($thumb, $thumbdir . ‘/‘ . $_POST[‘id‘] . ‘.jpg‘, 100); imagedestroy($thumb);
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。
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