允许在 PHP 中裁剪和调整图像大小而不使用太多内存的图像功能 [关闭]

Posted 2023-02-25

【中文标题】允许在 PHP 中裁剪和调整图像大小而不使用太多内存的图像功能 [关闭]

【英文标题】：Image function that allows images to be cropped and resized in PHP without using so much memory [closed]

【发布时间】：2012-06-17 13:30:23

【问题描述】：

我已经在我建立的一些网站上使用了这段代码一段时间，这对画廊来说非常有用，但它会占用大量内存，并且我不断在错误日志中收到内存分配错误。有什么可以改变的来使这个脚本更好吗？

<?php
// Smart Image Resizer 1.4.1
// Resizes images, intelligently sharpens, crops based on width:height ratios, color fills
// transparent GIFs and PNGs, and caches variations for optimal performance

// Created by: Joe Lencioni (http://shiftingpixel.com)
// Date: August 6, 2008
// Based on: http://veryraw.com/history/2005/03/image-resizing-with-php/

/////////////////////
// LICENSE
/////////////////////

// I love to hear when my work is being used, so if you decide to use this, feel encouraged
// to send me an email. Smart Image Resizer is released under a Creative Commons
// Attribution-Share Alike 3.0 United States license
// (http://creativecommons.org/licenses/by-sa/3.0/us/). All I ask is that you include a link
// back to Shifting Pixel (either this page or shiftingpixel.com), but don’t worry about
// including a big link on each page if you don’t want to–one will do just nicely. Feel
// free to contact me to discuss any specifics ([e-mail]).

/////////////////////
// REQUIREMENTS
/////////////////////

// PHP and GD

/////////////////////
// PARAMETERS
/////////////////////

// Parameters need to be passed in through the URL's query string:
// image        absolute path of local image starting with "/" (e.g. /images/toast.jpg)
// width        maximum width of final image in pixels (e.g. 700)
// height       maximum height of final image in pixels (e.g. 700)
// color        (optional) background hex color for filling transparent PNGs (e.g. 900 or 16a942)
// cropratio    (optional) ratio of width to height to crop final image (e.g. 1:1 or 3:2)
// nocache      (optional) does not read image from the cache
// quality      (optional, 0-100, default: 90) quality of output image

/////////////////////
// EXAMPLES
/////////////////////

// Resizing a JPEG:
// <img src="/image.php/image-name.jpg?width=100&amp;height=100&amp;image=/path/to/image.jpg"  />

// Resizing and cropping a JPEG into a square:
// <img src="/image.php/image-name.jpg?width=100&amp;height=100&amp;cropratio=1:1&amp;image=/path/to/image.jpg"  />

// Matting a PNG with #990000:
// <img src="/image.php/image-name.png?color=900&amp;image=/path/to/image.png"  />

/////////////////////
// CODE STARTS HERE
/////////////////////

if (!isset($_GET['image']))

    header('HTTP/1.1 400 Bad Request');
    echo 'Error: no image was specified';
    exit();


define('MEMORY_TO_ALLOCATE',    '100M');
define('DEFAULT_QUALITY',       90);
define('CURRENT_DIR',           dirname(__FILE__));
define('CACHE_DIR_NAME',        '/imagecache/');
define('CACHE_DIR',             CURRENT_DIR . CACHE_DIR_NAME);
define('DOCUMENT_ROOT',         $_SERVER['DOCUMENT_ROOT']);

// Images must be local files, so for convenience we strip the domain if it's there
$image          = preg_replace('/^(s?f|ht)tps?:\/\/[^\/]+/i', '', (string) $_GET['image']);

// For security, directories cannot contain ':', images cannot contain '..' or '<', and
// images must start with '/'
if ($image0 != '/' || strpos(dirname($image), ':') || preg_match('/(\.\.|<|>)/', $image))

    header('HTTP/1.1 400 Bad Request');
    echo 'Error: malformed image path. Image paths must begin with \'/\'';
    exit();


// If the image doesn't exist, or we haven't been told what it is, there's nothing
// that we can do
if (!$image)

    header('HTTP/1.1 400 Bad Request');
    echo 'Error: no image was specified';
    exit();


// Strip the possible trailing slash off the document root
$docRoot    = preg_replace('/\/$/', '', DOCUMENT_ROOT);

if (!file_exists($docRoot . $image))

    header('HTTP/1.1 404 Not Found');
    echo 'Error: image does not exist: ' . $docRoot . $image;
    exit();


// Get the size and MIME type of the requested image
$size   = GetImageSize($docRoot . $image);
$mime   = $size['mime'];

// Make sure that the requested file is actually an image
if (substr($mime, 0, 6) != 'image/')

    header('HTTP/1.1 400 Bad Request');
    echo 'Error: requested file is not an accepted type: ' . $docRoot . $image;
    exit();


$width          = $size[0];
$height         = $size[1];

$maxWidth       = (isset($_GET['width'])) ? (int) $_GET['width'] : 0;
$maxHeight      = (isset($_GET['height'])) ? (int) $_GET['height'] : 0;

if (isset($_GET['color']))
    $color      = preg_replace('/[^0-9a-fA-F]/', '', (string) $_GET['color']);
else
    $color      = FALSE;

// If either a max width or max height are not specified, we default to something
// large so the unspecified dimension isn't a constraint on our resized image.
// If neither are specified but the color is, we aren't going to be resizing at
// all, just coloring.
if (!$maxWidth && $maxHeight)

    $maxWidth   = 99999999999999;

elseif ($maxWidth && !$maxHeight)

    $maxHeight  = 99999999999999;

elseif ($color && !$maxWidth && !$maxHeight)

    $maxWidth   = $width;
    $maxHeight  = $height;


// If we don't have a max width or max height, OR the image is smaller than both
// we do not want to resize it, so we simply output the original image and exit
if ((!$maxWidth && !$maxHeight) || (!$color && $maxWidth >= $width && $maxHeight >= $height))

    $data   = file_get_contents($docRoot . '/' . $image);

    $lastModifiedString = gmdate('D, d M Y H:i:s', filemtime($docRoot . '/' . $image)) . ' GMT';
    $etag               = md5($data);

    doConditionalGet($etag, $lastModifiedString);

    header("Content-type: $mime");
    header('Content-Length: ' . strlen($data));
    echo $data;
    exit();


// Ratio cropping
$offsetX    = 0;
$offsetY    = 0;

if (isset($_GET['cropratio']))

    $cropRatio      = explode(':', (string) $_GET['cropratio']);
    if (count($cropRatio) == 2)
    
        $ratioComputed      = $width / $height;
        $cropRatioComputed  = (float) $cropRatio[0] / (float) $cropRatio[1];

        if ($ratioComputed < $cropRatioComputed)
         // Image is too tall so we will crop the top and bottom
            $origHeight = $height;
            $height     = $width / $cropRatioComputed;
            $offsetY    = ($origHeight - $height) / 2;
        
        else if ($ratioComputed > $cropRatioComputed)
         // Image is too wide so we will crop off the left and right sides
            $origWidth  = $width;
            $width      = $height * $cropRatioComputed;
            $offsetX    = ($origWidth - $width) / 2;
        
    


// Setting up the ratios needed for resizing. We will compare these below to determine how to
// resize the image (based on height or based on width)
$xRatio     = $maxWidth / $width;
$yRatio     = $maxHeight / $height;

if ($xRatio * $height < $maxHeight)
 // Resize the image based on width
    $tnHeight   = ceil($xRatio * $height);
    $tnWidth    = $maxWidth;

else // Resize the image based on height

    $tnWidth    = ceil($yRatio * $width);
    $tnHeight   = $maxHeight;


// Determine the quality of the output image
$quality    = (isset($_GET['quality'])) ? (int) $_GET['quality'] : DEFAULT_QUALITY;

// Before we actually do any crazy resizing of the image, we want to make sure that we
// haven't already done this one at these dimensions. To the cache!
// Note, cache must be world-readable

// We store our cached image filenames as a hash of the dimensions and the original filename
$resizedImageSource     = $tnWidth . 'x' . $tnHeight . 'x' . $quality;
if ($color)
    $resizedImageSource .= 'x' . $color;
if (isset($_GET['cropratio']))
    $resizedImageSource .= 'x' . (string) $_GET['cropratio'];
$resizedImageSource     .= '-' . $image;

$resizedImage   = md5($resizedImageSource);

$resized        = CACHE_DIR . $resizedImage;

// Check the modified times of the cached file and the original file.
// If the original file is older than the cached file, then we simply serve up the cached file
if (!isset($_GET['nocache']) && file_exists($resized))

    $imageModified  = filemtime($docRoot . $image);
    $thumbModified  = filemtime($resized);

    if($imageModified < $thumbModified) 
        $data   = file_get_contents($resized);

        $lastModifiedString = gmdate('D, d M Y H:i:s', $thumbModified) . ' GMT';
        $etag               = md5($data);

        doConditionalGet($etag, $lastModifiedString);

        header("Content-type: $mime");
        header('Content-Length: ' . strlen($data));
        echo $data;
        exit();
    


// We don't want to run out of memory
ini_set('memory_limit', MEMORY_TO_ALLOCATE);

// Set up a blank canvas for our resized image (destination)
$dst    = imagecreatetruecolor($tnWidth, $tnHeight);

// Set up the appropriate image handling functions based on the original image's mime type
switch ($size['mime'])

    case 'image/gif':
        // We will be converting GIFs to PNGs to avoid transparency issues when resizing GIFs
        // This is maybe not the ideal solution, but IE6 can suck it
        $creationFunction   = 'ImageCreateFromGif';
        $outputFunction     = 'ImagePng';
        $mime               = 'image/png'; // We need to convert GIFs to PNGs
        $doSharpen          = FALSE;
        $quality            = round(10 - ($quality / 10)); // We are converting the GIF to a PNG and PNG needs a compression level of 0 (no compression) through 9
    break;

    case 'image/x-png':
    case 'image/png':
        $creationFunction   = 'ImageCreateFromPng';
        $outputFunction     = 'ImagePng';
        $doSharpen          = FALSE;
        $quality            = round(10 - ($quality / 10)); // PNG needs a compression level of 0 (no compression) through 9
    break;

    default:
        $creationFunction   = 'ImageCreateFromJpeg';
        $outputFunction     = 'ImageJpeg';
        $doSharpen          = TRUE;
    break;


// Read in the original image
$src    = $creationFunction($docRoot . $image);

if (in_array($size['mime'], array('image/gif', 'image/png')))

    if (!$color)
    
        // If this is a GIF or a PNG, we need to set up transparency
        imagealphablending($dst, false);
        imagesavealpha($dst, true);
    
    else
    
        // Fill the background with the specified color for matting purposes
        if ($color[0] == '#')
            $color = substr($color, 1);

        $background = FALSE;

        if (strlen($color) == 6)
            $background = imagecolorallocate($dst, hexdec($color[0].$color[1]), hexdec($color[2].$color[3]), hexdec($color[4].$color[5]));
        else if (strlen($color) == 3)
            $background = imagecolorallocate($dst, hexdec($color[0].$color[0]), hexdec($color[1].$color[1]), hexdec($color[2].$color[2]));
        if ($background)
            imagefill($dst, 0, 0, $background);
    


// Resample the original image into the resized canvas we set up earlier
ImageCopyResampled($dst, $src, 0, 0, $offsetX, $offsetY, $tnWidth, $tnHeight, $width, $height);

if ($doSharpen)

    // Sharpen the image based on two things:
    //  (1) the difference between the original size and the final size
    //  (2) the final size
    $sharpness  = findSharp($width, $tnWidth);

    $sharpenMatrix  = array(
        array(-1, -2, -1),
        array(-2, $sharpness + 12, -2),
        array(-1, -2, -1)
    );
    $divisor        = $sharpness;
    $offset         = 0;
    imageconvolution($dst, $sharpenMatrix, $divisor, $offset);


// Make sure the cache exists. If it doesn't, then create it
if (!file_exists(CACHE_DIR))
    mkdir(CACHE_DIR, 0755);

// Make sure we can read and write the cache directory
if (!is_readable(CACHE_DIR))

    header('HTTP/1.1 500 Internal Server Error');
    echo 'Error: the cache directory is not readable';
    exit();

else if (!is_writable(CACHE_DIR))

    header('HTTP/1.1 500 Internal Server Error');
    echo 'Error: the cache directory is not writable';
    exit();


// Write the resized image to the cache
$outputFunction($dst, $resized, $quality);

// Put the data of the resized image into a variable
ob_start();
$outputFunction($dst, null, $quality);
$data   = ob_get_contents();
ob_end_clean();

// Clean up the memory
ImageDestroy($src);
ImageDestroy($dst);

// See if the browser already has the image
$lastModifiedString = gmdate('D, d M Y H:i:s', filemtime($resized)) . ' GMT';
$etag               = md5($data);

doConditionalGet($etag, $lastModifiedString);

// Send the image to the browser with some delicious headers
header("Content-type: $mime");
header('Content-Length: ' . strlen($data));
echo $data;

function findSharp($orig, $final) // function from Ryan Rud (http://adryrun.com)

    $final  = $final * (750.0 / $orig);
    $a      = 52;
    $b      = -0.27810650887573124;
    $c      = .00047337278106508946;

    $result = $a + $b * $final + $c * $final * $final;

    return max(round($result), 0);
 // findSharp()

function doConditionalGet($etag, $lastModified)

    header("Last-Modified: $lastModified");
    header("ETag: \"$etag\"");

    $if_none_match = isset($_SERVER['HTTP_IF_NONE_MATCH']) ?
        stripslashes($_SERVER['HTTP_IF_NONE_MATCH']) : 
        false;

    $if_modified_since = isset($_SERVER['HTTP_IF_MODIFIED_SINCE']) ?
        stripslashes($_SERVER['HTTP_IF_MODIFIED_SINCE']) :
        false;

    if (!$if_modified_since && !$if_none_match)
        return;

    if ($if_none_match && $if_none_match != $etag && $if_none_match != '"' . $etag . '"')
        return; // etag is there but doesn't match

    if ($if_modified_since && $if_modified_since != $lastModified)
        return; // if-modified-since is there but doesn't match

    // Nothing has changed since their last request - serve a 304 and exit
    header('HTTP/1.1 304 Not Modified');
    exit();
 // doConditionalGet()

// old pond
// a frog jumps
// the sound of water

// —Matsuo Basho
?>

【问题讨论】：

Topic-wise 可能与 CodeReview 匹配，但他们的 FAQ 明确表示代码必须由发布者编写。它不适用于改编互联网上的随机脚本。那里也太离题了。

【参考方案1】：

如果你的服务器安装了 imagemagick，可以这样：

exec("convert $filename -quality 60 -resize x100 -gravity center -crop 100x100+0+0 +repage $newfilename");

其他：

Resize & Crop with GD2

希望对你有帮助

【参考方案2】：

是的，您可以切换到使用IMagick 扩展，这在内存处理方面要好得多。正如我 described in an old question 所说，GD 使用与图像大小成比例的内存并将其完全未压缩地保存在内存中。