javascript - 如何以像素为单位获取上传图像分辨率？ (上传前)

Question

上传前如何获得以像素为单位的图像分辨率？有什么解决方案可以按我的意愿制作吗？没有改变这段代码的大变化？请!代码只限制文件大小。但我需要以像素为单位限制文件大小和分辨率!

对不起!我的英语知识太差了。我希望你能理解这一点。谢谢!

 <?php
if (isset($_POST['submit'])) {
    $j = 0; //Variable for indexing uploaded image 

    $target_path = "uploads/"; //Declaring Path for uploaded images
    for ($i = 0; $i < count($_FILES['file']['name']); $i++) {//loop to get individual element from the array

        $validextensions = array("jpeg", "jpg", "png", "gif");  //Extensions which are allowed
        $ext = explode('.', basename($_FILES['file']['name'][$i]));//explode file name from dot(.) 
        $file_extension = end($ext); //store extensions in the variable

        $target_path = $target_path . md5(uniqid()) . "." . $ext[count($ext) - 1];//set the target path with a new name of image
        $j = $j + 1;//increment the number of uploaded images according to the files in array       

      if (($_FILES["file"]["size"][$i] < 500000) //Approx. 500kb files can be uploaded.
                && in_array($file_extension, $validextensions)) {
            if (move_uploaded_file($_FILES['file']['tmp_name'][$i], $target_path)) {//if file moved to uploads folder
                echo $j. ').<span id="noerror">Image uploaded successfully!.</span><br/><br/>';
            } else {//if file was not moved.
                echo $j. ').<span id="error">please try again!.</span><br/><br/>';
            }
        } else {//if file size and file type was incorrect.
            echo $j. ').<span id="error">***Invalid file Size or Type***</span><br/><br/>';
        }
    }
}
?>

Answer 1

使用getimagesize function :

list($width, $height, $type, $attr) = getimagesize($_FILES['file']);

现在您可以访问图像的 $width 和 $height。