php - 调整图像大小并将每个图像放入正方形中，保持纵横比(后端)

Question

我对 PHP 和图像没有任何经验，但我需要在上传图像时将所有图像调整为正方形。

由于我有多种产品，并且它们有不同尺寸的不同图片，我认为最好的方法是在上传过程中“标准化”它们，方法是拍摄图像并将其“适合”到 800x800 白色方 block 中，同时保持长宽比(如果最长尺寸 >800，则缩小尺寸，如果最长尺寸 <800，则重新调整尺寸)。

我最初的解决方案是通过 JavaScript 创建的，我尝试找到最大的图片并根据它调整所有其他图像的大小。不过，它不是很有用，而且可能会出错，因为如果图像加载有延迟，JS 可能无法加载图像来执行操作，从而根本不显示图像。

$product = getProductById($productid);

$filesArray = array();


if (isset($_GET['files']) && $productid > 0) {
    $error = false;
    $files = array();
    $fileName = '';

    $uploaddir = "../images/products/";
    foreach ($_FILES as $file) {
        $ext = pathinfo($file['name'], PATHINFO_EXTENSION);
        $random_name = $widgets->randomFileName();
        $randomFullFileName = $productid .'_'. $random_name . '.' . $ext;

        //copy to location
        //----------------
        //HERE I NEED TO CREATE A 800x800px SQUARE and fit the image into it
        //----------------
        if (move_uploaded_file($file['tmp_name'], $uploaddir . $randomFullFileName)) {

            //save to database
            $image_id = updateProduct('default_image', 'images/products/'.$randomFullFileName, $productid);

            if ($image_id > 0) {
                echo 'Added new image';
            } else {
                echo 'Error, unable to add. <br> Please try again.';
            }
        } else {
            echo 'Error, unable to add. <br> Please try again.';
        }
    }
}

之前:600x300

之后:800x800，用白色边框填充空间

Answer 1

您可以尝试这种方法(已测试)。它将把您的图像放入 800x800 的方形 Canvas 中，同时保持图像的纵横比。

resize_image():此函数将保持图像的宽高比。

function resize_image($img,$maxwidth,$maxheight) {
    //This function will return the specified dimension(width,height)
    //dimension[0] - width
    //dimension[1] - height

    $dimension = array();
    $imginfo = getimagesize($img);
    $imgwidth = $imginfo[0];
    $imgheight = $imginfo[1];
    if($imgwidth > $maxwidth){
        $ratio = $maxwidth/$imgwidth;
        $newwidth = round($imgwidth*$ratio);
        $newheight = round($imgheight*$ratio);
        if($newheight > $maxheight){
            $ratio = $maxheight/$newheight;
            $dimension[] = round($newwidth*$ratio);
            $dimension[] = round($newheight*$ratio);
            return $dimension;
        }else{
            $dimension[] = $newwidth;
            $dimension[] = $newheight;
            return $dimension;
        }
    }elseif($imgheight > $maxheight){
        $ratio = $maxheight/$imgheight;
        $newwidth = round($imgwidth*$ratio);
        $newheight = round($imgheight*$ratio);
        if($newwidth > $maxwidth){
            $ratio = $maxwidth/$newwidth;
            $dimension[] = round($newwidth*$ratio);
            $dimension[] = round($newheight*$ratio);
            return $dimension;
        }else{
            $dimension[] = $newwidth;
            $dimension[] = $newheight;
            return $dimension;
        }
    }else{
        $dimension[] = $imgwidth;
        $dimension[] = $imgheight;
        return $dimension;
    }
}

现在是你的代码了，

$product = getProductById($productid);

$filesArray = array();


if (isset($_GET['files']) && $productid > 0) {
    $error = false;
    $files = array();
    $fileName = '';

    $uploaddir = "../images/products/";
    foreach ($_FILES as $file) {
        $ext = pathinfo($file['name'], PATHINFO_EXTENSION);
        $random_name = $widgets->randomFileName();
        $randomFullFileName = $productid .'_'. $random_name . '.' . $ext;

        //copy to location
        //----------------
        //HERE I NEED TO CREATE A 800x800px SQUARE and fit the image into it


        // Create image from file
        $image = null;
        switch(strtolower($file['type']))
        {
            case 'image/jpeg':
                $image = imagecreatefromjpeg($file['tmp_name']);
                break;
            case 'image/png':
                $image = imagecreatefrompng($file['tmp_name']);
                break;
            case 'image/gif':
                $image = imagecreatefromgif($file['tmp_name']);
                break;
            default:
                exit('Unsupported type: '.$file['type']);
        }

        // Get current dimensions
        $old_width  = imagesx($image);
        $old_height = imagesy($image);

        // Get the new dimensions
        $dimension = resize_image($file, 800, 800);
        $new_width  = $dimension[0];
        $new_height = $dimension[1];

        // Create new empty image
        $new = imagecreatetruecolor($new_width, $new_height);

        // Resize old image into new
        imagecopyresampled($new, $image, 0, 0, 0, 0, $new_width, $new_height, $old_width, $old_height);

        // Catch and save the image
        $status = false;
        switch(strtolower($file['type']))
        {
            case 'image/jpeg':
                $status = imagejpeg($new, $uploaddir . $randomFullFileName, 90);
                break;
            case 'image/png':
                $status = imagepng($new, $uploaddir . $randomFullFileName, 0);
                break;
            case 'image/gif':
                $status = imagegif($new, $uploaddir . $randomFullFileName);
                break;
        }

        // Destroy resources
        imagedestroy($image);
        imagedestroy($new);

        //save to database
        if($status){
            $image_id = updateProduct('default_image', 'images/products/'.$randomFullFileName, $productid);

            if ($image_id > 0) {
                echo 'Added new image';
            } else {
                echo 'Error, unable to add. <br> Please try again.';
            }
        }else{
            echo 'Error, unable to add. <br> Please try again.';
        }       

        //----------------
        //if (move_uploaded_file($file['tmp_name'], $uploaddir . $randomFullFileName)) {
        //    //save to database
        //    $image_id = updateProduct('default_image', 'images/products/'.$randomFullFileName, $productid);

        //    if ($image_id > 0) {
        //        echo 'Added new image';
        //    } else {
        //        echo 'Error, unable to add. <br> Please try again.';
        //    }
        //} else {
        //    echo 'Error, unable to add. <br> Please try again.';
        //}

    }
}