本文介绍了php在上传时或上传之前调整图像大小的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着跟版网的小编来一起学习吧！
问题描述
在上传之前或上传期间如何调整图片大小?
how would i resize the image before or during the upload?
<?php
// Start a session for error reporting
session_start();
?>
<?php
// Check, if username session is NOT set then this page will jump to login page
if (!isset($_SESSION['username'])) {
header('Location: index.html');
exit;
}
// *** Include the class
include("resize-class.php");
// Call our connection file
include('config.php');
// Check to see if the type of file uploaded is a valid image type
function is_valid_type($file)
{
// This is an array that holds all the valid image MIME types
$valid_types = array("image/jpg", "image/JPG", "image/jpeg", "image/bmp", "image/gif", "image/png");
if (in_array($file['type'], $valid_types))
return 1;
return 0;
}
// Just a short function that prints out the contents of an array in a manner that's easy to read
// I used this function during debugging but it serves no purpose at run time for this example
function showContents($array)
{
echo "<pre>";
print_r($array);
echo "</pre>";
}
// Set some constants
// Grab the User ID we sent from our form
$user_id = $_SESSION['username'];
$category = $_POST['category'];
// This variable is the path to the image folder where all the images are going to be stored
// Note that there is a trailing forward slash
$TARGET_PATH = "img/users/$category/$user_id/";
if (! is_dir($TARGET_PATH)) {
mkdir($TARGET_PATH, 0775, true);
}
// Get our POSTed variables
$fname = $_POST['fname'];
$lname = $_POST['lname'];
$contact = $_POST['contact'];
$price = $_POST['price'];
$conditional = $_POST['conditional'];
$image = $_FILES['image'];
// Build our target path full string. This is where the file will be moved do
// i.e. images/picture.jpg
$TARGET_PATH .= $image['name'];
// Make sure all the fields from the form have inputs
if ( $fname == "" || $lname == "" || $image['name'] == "" || $category['category'] == "" || $conditional['conditional'] == "" || $price['price'] == "" )
{
$_SESSION['error'] = "All fields required";
header("Location: securedpage1.php");
exit;
}
// Check to make sure that our file is actually an image
// You check the file type instead of the extension because the extension can easily be faked
if (!is_valid_type($image))
{
$_SESSION['error'] = "You must upload a jpeg, gif, or bmp";
header("Location: securedpage1.php");
exit;
}
// Here we check to see if a file with that name already exists
// You could get past filename problems by appending a timestamp to the filename and then continuing
if (file_exists($TARGET_PATH))
{
$_SESSION['error'] = "A file with that name already exists";
header("Location: securedpage1.php");
exit;
}
// Lets attempt to move the file from its temporary directory to its new home
if (move_uploaded_file($image['tmp_name'], $TARGET_PATH))
{
// NOTE: This is where a lot of people make mistakes.
// We are *not* putting the image into the database; we are putting a reference to the file's location on the server
$imagename = $image['name'];
$sql = "insert into people (price, contact, category, username, fname, lname, expire, filename, conditional, posttime) values (:price, :contact, :category, :user_id, :fname, :lname, now() + INTERVAL 1 MONTH, :imagename, :conditional, now())";
$q = $conn->prepare($sql) or die("failed!");
$q->bindParam(':price', $price, PDO::PARAM_STR);
$q->bindParam(':contact', $contact, PDO::PARAM_STR);
$q->bindParam(':category', $category, PDO::PARAM_STR);
$q->bindParam(':user_id', $user_id, PDO::PARAM_STR);
$q->bindParam(':fname', $fname, PDO::PARAM_STR);
$q->bindParam(':lname', $lname, PDO::PARAM_STR);
$q->bindParam(':imagename', $imagename, PDO::PARAM_STR);
$q->bindParam(':conditional', $conditional, PDO::PARAM_STR);
$q->execute();
$sql1 = "UPDATE people SET firstname = (SELECT firstname FROM user WHERE username=:user_id1) WHERE username=:user_id2";
$q = $conn->prepare($sql1) or die("failed!");
$q->bindParam(':user_id1', $user_id, PDO::PARAM_STR);
$q->bindParam(':user_id2', $user_id, PDO::PARAM_STR);
$q->execute();
$sql2 = "UPDATE people SET surname = (SELECT surname FROM user WHERE username=:user_id1) WHERE username=:user_id2";
$q = $conn->prepare($sql2) or die("failed!");
$q->bindParam(':user_id1', $user_id, PDO::PARAM_STR);
$q->bindParam(':user_id2', $user_id, PDO::PARAM_STR);
$q->execute();
header("Location: success.php");
exit;
}
else
{
// A common cause of file moving failures is because of bad permissions on the directory attempting to be written to
// Make sure you chmod the directory to be writeable
$_SESSION['error'] = "Could not upload file. Check read/write permissions on the directory";
header("Location: securedpage1.php");
exit;
}
?>
推荐答案
试试这个代码可能对你有帮助
Try this code this may help you
在这个变量中$resizeObj = new resize('sample.png');你需要链接你上传的图片url
in this variable $resizeObj = new resize('sample.png'); you need to link your uploaded picture url
Imagerezise.php
<?php
// *** Include the class
include("resize-class.php");
// *** 1) Initialise / load image
$resizeObj = new resize('sample.png');
// *** 2) Resize image (options: exact, portrait, landscape, auto, crop)
$resizeObj -> resizeImage(200, 200, 'crop');
// *** 3) Save image
$resizeObj -> saveImage('sample-resizeda.jpg', 1000);
?>
resize-class.php
<?php
# ========================================================================#
# Requires : Requires PHP5, GD library.
# Usage Example:
# include("resize_class.php");
# $resizeObj = new resize('images/cars/large/input.jpg');
# $resizeObj -> resizeImage(150, 100, 0);
# $resizeObj -> saveImage('images/cars/large/output.jpg', 100);
# ========================================================================#
class resize
{
// *** Class variables
private $image;
private $width;
private $height;
private $imageResized;
function __construct($fileName)
{
// *** Open up the file
$this->image = $this->openImage($fileName);
// *** Get width and height
$this->width = imagesx($this->image);
$this->height = imagesy($this->image);
}
## --------------------------------------------------------
private function openImage($file)
{
// *** Get extension
$extension = strtolower(strrchr($file, '.'));
switch($extension)
{
case '.jpg':
case '.jpeg':
$img = @imagecreatefromjpeg($file);
break;
case '.gif':
$img = @imagecreatefromgif($file);
break;
case '.png':
$img = @imagecreatefrompng($file);
break;
default:
$img = false;
break;
}
return $img;
}
## --------------------------------------------------------
public function resizeImage($newWidth, $newHeight, $option="auto")
{
// *** Get optimal width and height - based on $option
$optionArray = $this->getDimensions($newWidth, $newHeight, $option);
$optimalWidth = $optionArray['optimalWidth'];
$optimalHeight = $optionArray['optimalHeight'];
// *** Resample - create image canvas of x, y size
$this->imageResized = imagecreatetruecolor($optimalWidth, $optimalHeight);
imagecopyresampled($this->imageResized, $this->image, 0, 0, 0, 0, $optimalWidth, $optimalHeight, $this->width, $this->height);
// *** if option is 'crop', then crop too
if ($option == 'crop') {
$this->crop($optimalWidth, $optimalHeight, $newWidth, $newHeight);
}
}
## --------------------------------------------------------
private function getDimensions($newWidth, $newHeight, $option)
{
switch ($option)
{
case 'exact':
$optimalWidth = $newWidth;
$optimalHeight= $newHeight;
break;
case 'portrait':
$optimalWidth = $this->getSizeByFixedHeight($newHeight);
$optimalHeight= $newHeight;
break;
case 'landscape':
$optimalWidth = $newWidth;
$optimalHeight= $this->getSizeByFixedWidth($newWidth);
break;
case 'auto':
$optionArray = $this->getSizeByAuto($newWidth, $newHeight);
$optimalWidth = $optionArray['optimalWidth'];
$optimalHeight = $optionArray['optimalHeight'];
break;
case 'crop':
$optionArray = $this->getOptimalCrop($newWidth, $newHeight);
$optimalWidth = $optionArray['optimalWidth'];
$optimalHeight = $optionArray['optimalHeight'];
break;
}
return array('optimalWidth' => $optimalWidth, 'optimalHeight' => $optimalHeight);
}
## --------------------------------------------------------
private function getSizeByFixedHeight($newHeight)
{
$ratio = $this->width / $this->height;
$newWidth = $newHeight * $ratio;
return $newWidth;
}
private function getSizeByFixedWidth($newWidth)
{
$ratio = $this->height / $this->width;
$newHeight = $newWidth * $ratio;
return $newHeight;
}
private function getSizeByAuto($newWidth, $newHeight)
{
if ($this->height < $this->width)
// *** Image to be resized is wider (landscape)
{
$optimalWidth = $newWidth;
$optimalHeight= $this->getSizeByFixedWidth($newWidth);
}
elseif ($this->height > $this->width)
// *** Image to be resized is taller (portrait)
{
$optimalWidth = $this->getSizeByFixedHeight($newHeight);
$optimalHeight= $newHeight;
}
else
// *** Image to be resizerd is a square
{
if ($newHeight < $newWidth) {
$optimalWidth = $newWidth;
$optimalHeight= $this->getSizeByFixedWidth($newWidth);
} else if ($newHeight > $newWidth) {
$optimalWidth = $this->getSizeByFixedHeight($newHeight);
$optimalHeight= $newHeight;
} else {
// *** Sqaure being resized to a square
$optimalWidth = $newWidth;
$optimalHeight= $newHeight;
}
}
return array('optimalWidth' => $optimalWidth, 'optimalHeight' => $optimalHeight);
}
## --------------------------------------------------------
private function getOptimalCrop($newWidth, $newHeight)
{
$heightRatio = $this->height / $newHeight;
$widthRatio = $this->width / $newWidth;
if ($heightRatio < $widthRatio) {
$optimalRatio = $heightRatio;
} else {
$optimalRatio = $widthRatio;
}
$optimalHeight = $this->height / $optimalRatio;
$optimalWidth = $this->width / $optimalRatio;
return array('optimalWidth' => $optimalWidth, 'optimalHeight' => $optimalHeight);
}
## --------------------------------------------------------
private function crop($optimalWidth, $optimalHeight, $newWidth, $newHeight)
{
// *** Find center - this will be used for the crop
$cropStartX = ( $optimalWidth / 2) - ( $newWidth /2 );
$cropStartY = ( $optimalHeight/ 2) - ( $newHeight/2 );
$crop = $this->imageResized;
//imagedestroy($this->imageResized);
// *** Now crop from center to exact requested size
$this->imageResized = imagecreatetruecolor($newWidth , $newHeight);
imagecopyresampled($this->imageResized, $crop , 0, 0, $cropStartX, $cropStartY, $newWidth, $newHeight , $newWidth, $newHeight);
}
## --------------------------------------------------------
public function saveImage($savePath, $imageQuality="100")
{
// *** Get extension
$extension = strrchr($savePath, '.');
$extension = strtolower($extension);
switch($extension)
{
case '.jpg':
case '.jpeg':
if (imagetypes() & IMG_JPG) {
imagejpeg($this->imageResized, $savePath, $imageQuality);
}
break;
case '.gif':
if (imagetypes() & IMG_GIF) {
imagegif($this->imageResized, $savePath);
}
break;
case '.png':
// *** Scale quality from 0-100 to 0-9
$scaleQuality = round(($imageQuality/100) * 9);
// *** Invert quality setting as 0 is best, not 9
$invertScaleQuality = 9 - $scaleQuality;
if (imagetypes() & IMG_PNG) {
imagepng($this->imageResized, $savePath, $invertScaleQuality);
}
break;
// ... etc
default:
// *** No extension - No save.
break;
}
imagedestroy($this->imageResized);
}
## --------------------------------------------------------
}
?>
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