Load ThumborUrl from an image url

Hi,
I was wondering, is it possible to load an url into a ThumborUrl Class, to then perform other actions on it?

For example (pseudo code):

```php
$filename = "//example.org/****thumbor-signature***/0x95:300x395/300x300/http://path-to-image.jpg";

$image = Thumbor\Url\Builder::construct(THUMBOR_SERVER, THUMBOR_SECRET, $filename);
echo $image; // will output the same as $filename;

$image->resize(500,500);
echo $image; // will output //example.org/****NEW-thumbor-signature***/0x95:300x395/500x500/http://path-to-image.jpg
```

I suppose this is not possible, but (for me) it would be a nice add-on...

Thanks!
Ben

查看 Thumbor\Url\Builder 類別，了解它目前如何根據參數建構 URL。此功能需要解析現有的 Thumbor URL，以擷取其元件（簽章、篩選器、尺寸、原始影像 URL）。先檢查 Builder 的建構函式和方法，看看可以在哪裡加入解析邏輯。檢查是否已有用於 URL 建構的測試，以便擴充這些測試來涵蓋解析。

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