我正在做一个网站，让用户能够跟踪他们最喜欢的乐队。该网站的功能之一是允许用户上传他们去过的任何演出的照片，然后将照片保存到一个文件中，图像位置存储在数据库中。
我的问题是我需要能够在保存时调整图像的大小，因为当有许多图片时，页面需要很长时间才能加载。
我知道这里有很多这样的问题，但我只是不确定如何修改我必须这样做的代码。
这是最好的方法还是我应该使用缩略图?由于图像将显示在一个图库中，如果有很多，那么页面将加载较慢
我的php知识有限，所以任何帮助都是感激的
这是我现在的代码:
<?php
///UPLOAD IMAGES
$sql = "SELECT * FROM photouploads WHERE BandID ='$bandid'";
$result = mysql_query($sql,$connect)or die ($error1);
$row = mysql_num_rows($result);
$userid=$_SESSION['userid'];
if (isset($_POST['submit']))
{
$name = $bandid."(".++$row.").jpg";
$tmp_name=$_FILES['photo']['tmp_name'];
if ($name)
{
//start upload
$location="Photouploads/".$name;
if (move_uploaded_file($tmp_name,$location))
{
mysql_query("INSERT INTO photouploads (BandID,UserID,ImageLocation)
VALUES ('$bandid', '$userid', '$location')") ;
}
}
else
;
}
和我的形式:
<input type='file' name='photo' id='photo'>
<input type='submit' class='submitLink' name='submit' id='submit'value='upload'>
</form>";
?>
这是我过去使用过的一个非常基本的PHP图像大小调整类。您需要安装并启用PHP GD2模块才能使其工作。
用法:
$resized = ImageResizer::resizeExistingImage($_FILES['photo']['tmp_name'],
null,
500,
500,
100);
if (!$resized){
throw new Exception('Could not resize image');
}
echo '<pre>';
print_r($resized);
echo '</pre>';
类:
class ImageResizer
{
const RESULT_RESIZE_NOT_REQUIRED = 'resize_not_required';
const RESULT_RESIZE_SUCCESSFUL = 'resize_successful';
private static $_filePath = null;
private static $_newPath = null;
private static $_maxwidth = null;
private static $_maxheight = null;
private static $_quality = null;
private static $_newWidth = null;
private static $_newHeight = null;
private static $_actualWidth = null;
private static $_actualHeight = null;
/**
* Takes an image (from a file path) and resizes it. The newly resized image
* can then either be created in a different location, therefore maintainig
* the original file. Or can be created in the original location, therefore
* overwriting the original file.
*
*
* @static
* @access public
* @param string $filePath The file path of the image to resize
* @param string $newPath The file path where the resized image will
* be created. Null to overwrite original.
* @param integer $maxwidth The maximum height of the resized image
* @param integer $maxheight The maximum width of the resized image
* @param integer $quality The quality of the image
*/
public static function resizeExistingImage($filePath,
$newPath = null,
$maxwidth = 1000,
$maxheight = 1000,
$quality = 100)
{
if (is_null($newPath)) {
$newPath = $filePath;
}
$gdImage = getimagesize($filePath);
$actualWidth = $gdImage[0];
$actualHeight = $gdImage[1];
// Do we even need to resize the image!?
if ($actualWidth <= $maxwidth && $actualHeight <= $maxheight){
return array('result' => self::RESULT_RESIZE_NOT_REQUIRED,
'newHeight' => $actualHeight,
'newWidth' => $actualWidth);
}
$ratio = $actualWidth / $maxwidth;
// echo "ratio : ".$ratio."<br />";
// echo "Current dimensions: ".$actualWidth." : ".$actualHeight." : <br />";
// set the defaults:
$newWidth = intval($actualWidth);
$newHeight = intval($actualHeight);
if ($actualWidth > $maxwidth) {
$newWidth = intval($maxwidth);
$newHeight = intval($actualHeight / $ratio);
}
// echo "After width process, dimensions: ".$newWidth." : ".$newHeight." : <br />";
// once we've got the size width, is the height now small enough?
if ($newHeight > $maxheight) {
// set a new ratio
$ratio = $newHeight / $maxheight;
$newWidth = intval($newWidth / $ratio);
$newHeight = intval($maxheight);
}
// echo "New dimensions: ".$newWidth." : ".$newHeight." : <br />";
// Assign the class vars
self::$_filePath = $filePath;
self::$_newPath = $newPath;
self::$_maxwidth = $maxwidth;
self::$_maxheight = $maxheight;
self::$_quality = $quality;
self::$_newWidth = $newWidth;
self::$_newHeight = $newHeight;
self::$_actualWidth = $actualWidth;
self::$_actualHeight = $actualHeight;
switch (strtolower($gdImage['mime'])) {
case 'image/jpeg':
self::_createFromJpeg();
break;
case 'image/pjpeg':
self::_createFromPJpeg();
break;
case 'image/png':
self::_createFromPng();
break;
case 'image/gif':
self::_createFromGif();
break;
default:
throw new Exception('Mime Type ''' . $gdImage['mime'] . ''' not supported');
break;
}
return array('result' => self::RESULT_RESIZE_SUCCESSFUL,
'newHeight' => $newHeight,
'newWidth' => $newWidth);
}
/**
* Resizes images of type image/jpeg.
*
* @static
* @access private
* @return void
*/
private static function _createFromJpeg()
{
$img = imagecreatefromjpeg(self::$_filePath);
$new_img = imagecreatetruecolor(self::$_newWidth, self::$_newHeight);
imagecopyresampled($new_img,
$img,
0,
0,
0,
0,
self::$_newWidth,
self::$_newHeight,
self::$_actualWidth,
self::$_actualHeight);
imagejpeg($new_img, self::$_newPath, self::$_quality);
}
/**
* Resizes images of type image/jpeg.
*
* @static
* @access private
* @return void
*/
private static function _createFromPJpeg()
{
$img = imagecreatefromjpeg(self::$_filePath);
imageinterlace($img, 1);
$new_img = imagecreatetruecolor(self::$_newWidth, self::$_newHeight);
imagecopyresampled($new_img,
$img,
0,
0,
0,
0,
self::$_newWidth,
self::$_newHeight,
self::$_actualWidth,
self::$_actualHeight);
imagejpeg($new_img, self::$_newPath, self::$_quality);
}
/**
* Resizes images of type image/png.
*
* @static
* @access private
* @return void
*/
private static function _createFromPng()
{
$img = imagecreatefrompng(self::$_filePath);
$new_img = imagecreatetruecolor(self::$_newWidth, self::$_newHeight);
imagecopyresampled($new_img,
$img,
0,
0,
0,
0,
self::$_newWidth,
self::$_newHeight,
self::$_actualWidth,
self::$_actualHeight);
imagepng($new_img, self::$_newPath);
}
/**
* Resizes images of type image/gif.
*
* @static
* @access private
* @return void
*/
private static function _createFromGif()
{
$img = imagecreatefromgif(self::$_filePath);
$new_img = imagecreatetruecolor(self::$_newWidth, self::$_newHeight);
imagecopyresampled($new_img,
$img,
0,
0,
0,
0,
self::$_newWidth,
self::$_newHeight,
self::$_actualWidth,
self::$_actualHeight);
imagegif($new_img, self::$_newPath);
}
}
希望对你有帮助。
检索所有数据来查找新图像的名称是非常低效的。更好的解决方案是插入一条不存储文件名的记录，并从auto_increment id生成文件名(使用基本路径/some/where/photoploads/$bandid/)。
如果这还不是你最大的性能问题，那么很快就会了。
减少图片的大小也是一个好主意——就像检查重复一样。
如果有很多，那么页面将加载较慢
延迟加载下面的图片-有很多现成的脚本可以做到这一点(例如)