在PHP中動態調整大圖像縮略圖？

Question

當用戶請求照片時，將圖像動態調整爲縮略圖的最佳方式是什麼？這些圖像已經以超過3MB的jpgs上傳了？我已經知道他們請求的圖像的數據庫中的文件名，例如：photo100.jpg，所以在php中創建縮略圖，然後將新創建的縮略圖t_photo100.jpg作爲img src =將是理想的

Answer 1

您可以使用類似PHPThumb這樣的庫來達到此目的。

它使用ImageMagick（如果可用）和PHP GD Library（附帶PHP v4.3.0 +）來處理圖像。

一旦它的配置和設置，可以動態生成圖像的縮略圖，就像這樣：

<img src="/uploads/phpThumb.php?src=images/logo.png&w=100" /> 

<img src="/uploads/phpThumb.php?src=images/foobar.png&h=50&w=50&zc=1" /> 

檢查demo page了更多的選擇。

希望這會有所幫助！

Answer 2

在PHP中有功能來做到這一點。看看這個教程，看看如何調整圖像大小：http://net.tutsplus.com/tutorials/php/image-resizing-made-easy-with-php/

然後將所有的圖像請求導向到一個php文件（使用.htaccess），它可以找到請求的文件，通過調整器傳遞原始文件，然後輸出新的縮略圖

Answer 3

在我看來，最簡單的方法是使用ImageMagick的（http://phpsnips.com/snip-111#.UhT5XZJwok0）：

<?php 
// Location to upload main image: 
$mainDir = $_SERVER['DOCUMENT_ROOT'].'/images/l/'; 
// Location to create the thumb image: 
$smalDir = $_SERVER['DOCUMENT_ROOT'].'/images/s/'; 
// Command to use: 
$command = '/usr/bin/convert'; 
// Thumbnail width: 
$size = 210; 
// Make sure we have an image: 
if(isset($_POST['submit'])){ 
    if(getimagesize($_FILES['photo']['tmp_name'])){ 
     $name = $_FILES['photo']['name']; 
     $uploadfile = $mainDir . $name; 
     move_uploaded_file($_FILES['photo']['tmp_name'], $uploadfile); 
     $lrgImg = $mainDir . $name; 
     $smlImg = $smalDir . $name; 
     $imageMagick = $command . " '". $lrgImg . "' -resize '$size' '" . $smlImg . "'";   
     shell_exec($imageMagick); 
    } 
    header("Location: /test.php"); 
    exit; 
}else{ 
?> 
    <form action=" <?php echo $_SERVER['PHP_SELF']; ?> " method="post" enctype="multipart/form-data"> 
     <p><input type="file" name="photo" /></p> 
     <p><input type="submit" value="Upload!" name="submit" /></p> 
    </form> 
<?php 
    foreach(glob($smalDir.'*') as $img){ 
     echo ' <img src="'.str_replace($_SERVER['DOCUMENT_ROOT'], '',$img).'" /> '; 
    } 
} 
?> 

你可以這樣做，也是使用PHPGD（http://phpsnips.com/snip-5#.UhT5yJJwok0）：

<?php 
function createThumbnail($imageDirectory, $imageName, $thumbDirectory, $thumbWidth, $quality){ 
    $details = getimagesize("$imageDirectory/$imageName") or die('Please only upload images.'); 
    $type = preg_replace('@^.+(?<=/)(.+)$@', '$1', $details['mime']); 
    eval('$srcImg = imagecreatefrom'.$type.'("$imageDirectory/$imageName");'); 
    $thumbHeight = $details[1] * ($thumbWidth/$details[0]); 
    $thumbImg = imagecreatetruecolor($thumbWidth, $thumbHeight); 
    imagecopyresampled($thumbImg, $srcImg, 0, 0, 0, 0, $thumbWidth, $thumbHeight, 
    $details[0], $details[1]); 
    eval('image'.$type.'($thumbImg, "$thumbDirectory/$imageName"'. 
    (($type=='jpeg')?', $quality':'').');'); 
    imagedestroy($srcImg); 
    imagedestroy($thumbImg); 
} 

foreach ($_FILES["pictures"]["error"] as $key => $error) { 
    if ($error == UPLOAD_ERR_OK) { 
     $tmp_name = $_FILES["pictures"]["tmp_name"][$key]; 
     $name = $_FILES["pictures"]["name"][$key]; 
     move_uploaded_file($tmp_name, "data/$name"); 
     createThumbnail("/location/of/main/image", $name, "/location/to/store/thumb", 120, 80); 
     //120 = thumb width :: 80 = thumb quality (1-100) 
    } 
} 
?> 

Answer 4

Normaly你會使用這樣的：

<img src="/images/uploads/image50.jpg" /> 

替換像這樣的東西而產生的HTML。

<img src="image.php?img_url=<?=base_64_encode("/images/uploads/image50.jpg")?>&width=128" /> 

然後用image.php文件是這樣的：

<?php 

header("Content-Type: image/jpeg"); 

$imgUrl = base64_decode($_GET["img_url"]); 
$c = file_get_contents($imgUrl); 
$arr = getimagesizefromstring($c); 

$img = imagecreatefromstring($c); 

if (!is_array($arr)) { 
    //remote image is not available. Use default one. 
    $c = file_get_contents("include/images/nobanner.jpg"); 
} 

if (isset($_GET["width"])){ 
    //Get Width and Height 
    List($Width, $Height) = getimagesize($imgUrl); 

    //Calc new Size 
    $w = $_GET["width"]; 
    $h = $Height * ($w/$Width); 

    //Build the image 
    //Create new Base 
    $NewImageBase = imagecreatetruecolor($w, $h); 

    //copy image 
    imagecopyresampled($NewImageBase, $img, 0, 0, 0, 0, $w, $h, $Width, $Height); 
    $img = $NewImageBase; 
} 

imagejpeg($img); 
?> 

但是請記住，這將導致密集計算每次有人訪問圖像。您可以優化image.php文件，在創建完成後「保存」縮略圖，並在需要時簡單地返回該文件。

此外，這將繞過瀏覽器圖像緩存，導致每個頁面更多的流量刷新。

Answer 5

你可以看看這裏SimpleImage類：

http://www.white-hat-web-design.co.uk/blog/resizing-images-with-php/

我使用它，它是相當不錯的，簡單的。 基本上你可以做

include('SimpleImage.php'); 
$image = new SimpleImage(); 
$image->load('picture.jpg'); 
$image->resize(250,400); 
$image->save('picture2.jpg'); 

您可以一次使用此預處理並顯示新創建的圖像。

Answer 6

從Php.net：

2主要功能可能需要：

1：imagecopyresampled

<?php 
// The file 
$filename = 'test.jpg'; 

// Set a maximum height and width 
$width = 200; 
$height = 200; 

// Content type 
header('Content-Type: image/jpeg'); 

// Get new dimensions 
list($width_orig, $height_orig) = getimagesize($filename); 

$ratio_orig = $width_orig/$height_orig; 

if ($width/$height > $ratio_orig) { 
    $width = $height*$ratio_orig; 
} else { 
    $height = $width/$ratio_orig; 
} 

// Resample 
$image_p = imagecreatetruecolor($width, $height); 
$image = imagecreatefromjpeg($filename); 
imagecopyresampled($image_p, $image, 0, 0, 0, 0, $width, $height, $width_orig, $height_orig); 

// Output 
imagejpeg($image_p, null, 100); 
?> 

2：imagecopyresized

<?php 
// File and new size 
$filename = 'test.jpg'; 
$percent = 0.5; 

// Content type 
header('Content-Type: image/jpeg'); 

// Get new sizes 
list($width, $height) = getimagesize($filename); 
$newwidth = $width * $percent; 
$newheight = $height * $percent; 

// Load 
$thumb = imagecreatetruecolor($newwidth, $newheight); 
$source = imagecreatefromjpeg($filename); 

// Resize 
imagecopyresized($thumb, $source, 0, 0, 0, 0, $newwidth, $newheight, $width, $height); 

// Output 
imagejpeg($thumb); 
?>