在PHP中调整图像大小

我想写一些PHP代码,自动调整通过表单上传到147x147px的任何图像,但我不知道如何去做(我是一个相对的PHP新手).

到目前为止,我已成功上传图片,识别文件类型并清理名称,但我想将调整大小功能添加到代码中.例如,我有一个2.3MB的测试图像,尺寸为1331×1331,我希望代码可以缩小尺寸,我猜测它也会大大压缩图像的文件大小.

到目前为止,我有以下内容：

if ($_FILES) {
                //Put file properties into variables
                $file_name = $_FILES['profile-image']['name'];
                $file_size = $_FILES['profile-image']['size'];
                $file_tmp_name = $_FILES['profile-image']['tmp_name'];

                //Determine filetype
                switch ($_FILES['profile-image']['type']) {
                    case 'image/jpeg': $ext = "jpg"; break;
                    case 'image/png': $ext = "png"; break;
                    default: $ext = ''; break;
                }

                if ($ext) {
                    //Check filesize
                    if ($file_size < 500000) {
                        //Process file - clean up filename and move to safe location
                        $n = "$file_name";
                        $n = ereg_replace("[^A-Za-z0-9.]", "", $n);
                        $n = strtolower($n);
                        $n = "avatars/$n";
                        move_uploaded_file($file_tmp_name, $n);
                    } else {
                        $bad_message = "Please ensure your chosen file is less than 5MB.";
                    }
                } else {
                    $bad_message = "Please ensure your image is of filetype .jpg or.png.";
                }
            }
$query = "INSERT INTO users (image) VALUES ('$n')";
mysql_query($query) or die("Insert failed. " . mysql_error() . "<br />" . $query);

解决方法:

您需要使用PHP的ImageMagick或GD函数来处理图像.

以GD为例,它就像……一样简单

function resize_image($file, $w, $h, $crop=FALSE) {
    list($width, $height) = getimagesize($file);
    $r = $width / $height;
    if ($crop) {
        if ($width > $height) {
            $width = ceil($width-($width*abs($r-$w/$h)));
        } else {
            $height = ceil($height-($height*abs($r-$w/$h)));
        }
        $newwidth = $w;
        $newheight = $h;
    } else {
        if ($w/$h > $r) {
            $newwidth = $h*$r;
            $newheight = $h;
        } else {
            $newheight = $w/$r;
            $newwidth = $w;
        }
    }
    $src = imagecreatefromjpeg($file);
    $dst = imagecreatetruecolor($newwidth, $newheight);
    imagecopyresampled($dst, $src, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);

    return $dst;
}

你可以调用这个函数,就像这样……

$img = resize_image(‘/path/to/some/image.jpg’, 200, 200);

从个人经验来看,GD的图像重新采样确实大大减少了文件大小,特别是在重新采样原始数码相机图像时.

标签：php,image-resizing,image-processing,image-upload
来源： https://codeday.me/bug/20190911/1803650.html