在我的一个应用程序中，我正在使用下面的代码片段将上传的图像复制到目录中。它工作正常，但复制大图像（> 2MB）需要比理想时间更多的时间，我真的不需要这么大的图像，所以，我正在寻找一种方法来调整图像的大小。如何使用PHP实现这一目标？
<?php
$uploadDirectory = 'images/0001/';
$randomNumber = rand(0, 99999);
$filename = basename($_FILES['userfile']['name']);
$filePath = $uploadDirectory.md5($randomNumber.$filename);
// Check if the file was sent through HTTP POST.
if (is_uploaded_file($_FILES['userfile']['tmp_name']) == true) {
// Validate the file size, accept files under 5 MB (~5e+6 bytes).
if ($_FILES['userfile']['size'] <= 5000000) {
// Move the file to the path specified.
if (move_uploaded_file($_FILES['userfile']['tmp_name'], $filePath) == true) {
// ...
}
}
}
?>
答案 0 :(得分：31)
最后，我发现了一种符合我需求的方法。以下代码片段会将图像调整为指定的宽度，自动计算高度以保持比例。
$image = $_FILES["image"]["tmp_name"];
$resizedDestination = $uploadDirectory.md5($randomNumber.$filename)."_RESIZED.jpg";
copy($_FILES, $resizedDestination);
$imageSize = getImageSize($image);
$imageWidth = $imageSize[0];
$imageHeight = $imageSize[1];
$DESIRED_WIDTH = 100;
$proportionalHeight = round(($DESIRED_WIDTH * $imageHeight) / $imageWidth);
$originalImage = imageCreateFromJPEG($image);
$resizedImage = imageCreateTrueColor($DESIRED_WIDTH, $proportionalHeight);
imageCopyResampled($images_fin, $originalImage, 0, 0, 0, 0, $DESIRED_WIDTH+1, $proportionalHeight+1, $imageWidth, $imageHeight);
imageJPEG($resizedImage, $resizedDestination);
imageDestroy($originalImage);
imageDestroy($resizedImage);
对于其他寻求完整示例的人，请创建两个文件：
<!-- send.html -->
<html>
<head>
<title>Simple File Upload</title>
</head>
<body>
<center>
<div style="margin-top:50px; padding:20px; border:1px solid #CECECE;">
Select an image.
<br/>
<br/>
<form action="receive.php" enctype="multipart/form-data" method="post">
<input type="file" name="image" size="40">
<input type="submit" value="Send">
</form>
</div>
</center>
</body>
<?php
// receive.php
$randomNumber = rand(0, 99999);
$uploadDirectory = "images/";
$filename = basename($_FILES['file_contents']['name']);
$destination = $uploadDirectory.md5($randomNumber.$filename).".jpg";
echo "File path:".$filePath."<br/>";
if (is_uploaded_file($_FILES["image"]["tmp_name"]) == true) {
echo "File successfully received through HTTP POST.<br/>";
// Validate the file size, accept files under 5 MB (~5e+6 bytes).
if ($_FILES['image']['size'] <= 5000000) {
echo "File size: ".$_FILES["image"]["size"]." bytes.<br/>";
// Resize and save the image.
$image = $_FILES["image"]["tmp_name"];
$resizedDestination = $uploadDirectory.md5($randomNumber.$filename)."_RESIZED.jpg";
copy($_FILES, $resizedDestination);
$imageSize = getImageSize($image);
$imageWidth = $imageSize[0];
$imageHeight = $imageSize[1];
$DESIRED_WIDTH = 100;
$proportionalHeight = round(($DESIRED_WIDTH * $imageHeight) / $imageWidth);
$originalImage = imageCreateFromJPEG($image);
$resizedImage = imageCreateTrueColor($DESIRED_WIDTH, $proportionalHeight);
imageCopyResampled($images_fin, $originalImage, 0, 0, 0, 0, $DESIRED_WIDTH+1, $proportionalHeight+1, $imageWidth, $imageHeight);
imageJPEG($resizedImage, $resizedDestination);
imageDestroy($originalImage);
imageDestroy($resizedImage);
// Save the original image.
if (move_uploaded_file($_FILES['image']['tmp_name'], $destination) == true) {
echo "Copied the original file to the specified destination.<br/>";
}
}
}
?>
答案 1 :(得分：8)
我做了一个函数来将图像大小调整一半，代码如下。
function imgResize($path) {
$x = getimagesize($path);
$width = $x['0'];
$height = $x['1'];
$rs_width = $width / 2;//resize to half of the original width.
$rs_height = $height / 2;//resize to half of the original height.
switch ($x['mime']) {
case "image/gif":
$img = imagecreatefromgif($path);
break;
case "image/jpg":
case "image/jpeg":
$img = imagecreatefromjpeg($path);
break;
case "image/png":
$img = imagecreatefrompng($path);
break;
}
$img_base = imagecreatetruecolor($rs_width, $rs_height);
imagecopyresized($img_base, $img, 0, 0, 0, 0, $rs_width, $rs_height, $width, $height);
$path_info = pathinfo($path);
switch ($path_info['extension']) {
case "gif":
imagegif($img_base, $path);
break;
case "jpg":
case "jpeg":
imagejpeg($img_base, $path);
break;
case "png":
imagepng($img_base, $path);
break;
}
}
你可以用下面的方式调用这个函数。
$img = imgResize('c:/dir/image.png');
答案 2 :(得分：6)
对于所有保持透明度并且非常易于使用的图像类型，有一个非常简单的图像重新调整大小功能
退房：
https://github.com/Nimrod007/PHP_image_resize
希望这会有所帮助
答案 3 :(得分：3)
ImageMagick是在PHP中调整图像大小的最快且可能是最好的方法。查看不同的示例here。此示例显示了如何resize and image on upload。
答案 4 :(得分：0)
您还可以使用x * y / width方法调整大小，然后调用imagecopyresampled（），如http://www.virtualsecrets.com/upload-resize-image-php-mysql.html所示。该页面还将图像（调整大小后）通过PDO放入mySQL。
答案 5 :(得分：0)
感谢Mateus Nunes！ 我编辑了他的工作以使透明的png工作：
$source = $_FILES["..."]["tmp_name"];
$destination = 'abc/def/ghi.png';
$maxsize = 45;
$size = getimagesize($source);
$width_orig = $size[0];
$height_orig = $size[1];
unset($size);
$height = $maxsize+1;
$width = $maxsize;
while($height > $maxsize){
$height = round($width*$height_orig/$width_orig);
$width = ($height > $maxsize)?--$width:$width;
}
unset($width_orig,$height_orig,$maxsize);
$images_orig = imagecreatefromstring( file_get_contents($source) );
$photoX = imagesx($images_orig);
$photoY = imagesy($images_orig);
$images_fin = imagecreatetruecolor($width,$height);
imagesavealpha($images_fin,true);
$trans_colour = imagecolorallocatealpha($images_fin,0,0,0,127);
imagefill($images_fin,0,0,$trans_colour);
unset($trans_colour);
ImageCopyResampled($images_fin,$images_orig,0,0,0,0,$width+1,$height+1,$photoX,$photoY);
unset($photoX,$photoY,$width,$height);
imagepng($images_fin,$destination);
unset($destination);
ImageDestroy($images_orig);
ImageDestroy($images_fin);