在不使用第三方库的情况下在 PHP 中调整图像大小? [英] Resize images in PHP without using third-party libraries?
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问题描述
在我的一个应用程序中，我使用下面的代码片段将上传的图像复制到一个目录中.它工作正常，但复制大图像(> 2MB)比理想情况需要更多的时间，我真的不需要这么大的图像，所以，我正在寻找一种调整图像大小的方法.如何使用 PHP 实现这一点?
解决方案
最后，我找到了一种适合我需求的方法.下面的代码片段会将图像调整为指定的宽度，并自动计算高度以保持比例.
$image = $_FILES["image"]["tmp_name"];$resizedDestination = $uploadDirectory.md5($randomNumber.$filename)."_RESIZED.jpg";复制($_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);对于寻求完整示例的其他人，请创建两个文件:
<头><title>简单文件上传</title><身体><中心><div style="margin-top:50px; padding:20px; border:1px solid #CECECE;">选择图像.<br/><br/><form action="receive.php" enctype="multipart/form-data" method="post"><input type="file" name="image" size="40"><输入类型=提交"值=发送"></表单></中心>
In one of my applications, I'm using the code snippet below to copy uploaded images to a directory. It works fine but copying large images (> 2MB) takes more time than ideal and I really don't need images this big, so, I'm looking for a way to resize the images. How to achieve this using PHP?
<?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) {
// ...
}
}
}
?>
解决方案
Finally, I've discovered a way that fit my needs. The following snippet will resize an image to the specified width, automatically calculating the height in order to keep the proportion.
$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);
To anyone else seeking a complete example, create two files:
<!-- 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/>";
}
}
}
?>
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