如何使用GD图库将照片上传的大小调整为确切的尺寸

我已经学会了如何使用GD库上传到服务器后调整图像大小。 它工作得很好，但我需要将图像大小调整为 180 x 150 像素。 根据图像的原始大小，它有时会小于 150 或小于 180。 如何每次将图像大小调整为 180px x 150px？

PHP 上传脚本

// Access the $_FILES global variable for this specific file being uploaded
// and create local PHP variables from the $_FILES array of information
$fileName = $_FILES["uploaded_file"]["name"]; // The file name
$fileTmpLoc = $_FILES["uploaded_file"]["tmp_name"]; // File in the PHP tmp folder
$fileType = $_FILES["uploaded_file"]["type"]; // The type of file it is
$fileSize = $_FILES["uploaded_file"]["size"]; // File size in bytes
$fileErrorMsg = $_FILES["uploaded_file"]["error"]; // 0 for false... and 1 for true
$kaboom = explode(".", $fileName); // Split file name into an array using the dot
$fileExt = end($kaboom); // Now target the last array element to get the file extension
// START PHP Image Upload Error Handling --------------------------------------------------
if (!$fileTmpLoc) { // if file not chosen
echo "ERROR: Please browse for a file before clicking the upload button.";
exit();
} else if($fileSize > 5242880) { // if file size is larger than 5 Megabytes
echo "ERROR: Your file was larger than 5 Megabytes in size.";
unlink($fileTmpLoc); // Remove the uploaded file from the PHP temp folder
exit();
} else if (!preg_match("/.(gif|jpg|png)$/i", $fileName) ) {
 // This condition is only if you wish to allow uploading of specific file types    
 echo "ERROR: Your image was not .gif, .jpg, or .png.";
 unlink($fileTmpLoc); // Remove the uploaded file from the PHP temp folder
 exit();
} else if ($fileErrorMsg == 1) { // if file upload error key is equal to 1
echo "ERROR: An error occured while processing the file. Try again.";
exit();
}
// END PHP Image Upload Error Handling ----------------------------------------------------
// Place it into your "uploads" folder mow using the move_uploaded_file() function
$moveResult = move_uploaded_file($fileTmpLoc, "uploads/$fileName");
// Check to make sure the move result is true before continuing
if ($moveResult != true) {
echo "ERROR: File not uploaded. Try again.";
unlink($fileTmpLoc); // Remove the uploaded file from the PHP temp folder
exit();
}
unlink($fileTmpLoc); // Remove the uploaded file from the PHP temp folder
// ---------- Include Universal Image Resizing Function --------
include_once("ak_php_img_lib_1.0.php");
$target_file = "uploads/$fileName";
$resized_file = "uploads/resized_$fileName";
$wmax = 180;
$hmax = 151;
ak_img_resize($target_file, $resized_file, $wmax, $hmax, $fileExt);
// ----------- End Universal Image Resizing Function -----------
// Display things to the page so you can see what is happening for testing purposes
echo "The file named <strong>$fileName</strong> uploaded successfuly.<br /><br />";
echo "It is <strong>$fileSize</strong> bytes in size.<br /><br />";
echo "It is an <strong>$fileType</strong> type of file.<br /><br />";
echo "The file extension is <strong>$fileExt</strong><br /><br />";
echo "The Error Message output for this upload is: $fileErrorMsg";
?>

PHP 调整大小脚本

<?php
// Function for resizing jpg, gif, or png image files
function ak_img_resize($target, $newcopy, $w, $h, $ext) {
list($w_orig, $h_orig) = getimagesize($target);
$scale_ratio = $w_orig / $h_orig;
if (($w / $h) > $scale_ratio) {
       $w = $h * $scale_ratio;
} else {
       $h = $w / $scale_ratio;
}
$img = "";
$ext = strtolower($ext);
if ($ext == "gif"){ 
  $img = imagecreatefromgif($target);
} else if($ext =="png"){ 
  $img = imagecreatefrompng($target);
} else { 
  $img = imagecreatefromjpeg($target);
}
$tci = imagecreatetruecolor($w, $h);
// imagecopyresampled(dst_img, src_img, dst_x, dst_y, src_x, src_y, dst_w, dst_h, src_w, src_h)
imagecopyresampled($tci, $img, 0, 0, 0, 0, $w, $h, $w_orig, $h_orig);
imagejpeg($tci, $newcopy, 80);
}
?>