javascript如何导出。将mxGraph生成的XML转换为图像文件？

Question

我在将mxGraph编辑器生成的xml导出到图像文件（png或jpg）时遇到问题

我试着使用PHP示例代码，结果发现生成的文件中出现了类似的错误

<b>Notice</b>:  Undefined variable: bounds in <b>php/src/canvas/mxGdCanvas.php</b> on line <b>972</b><br />
<br />
<b>Warning</b>:  Creating default object from empty value in <b>php/src/canvas/mxGdCanvas.php</b> on line <b>972</b><br />
<br />
<b>Notice</b>:  Undefined property: stdClass::$width in <b>php/src/canvas/mxGdCanvas.php</b> on line <b>972</b><br />
<br />
<b>Notice</b>:  Undefined property: stdClass::$x in <b>php/src/canvas/mxGdCanvas.php</b> on line <b>973</b><br />
<br />
<b>Notice</b>:  Undefined property: stdClass::$y in <b>php/src/canvas/mxGdCanvas.php</b> on line <b>974</b><br />

我使用的PHP代码是：

<?php
/**
 * Copyright (c) 2006, Gaudenz Alder
 */
include_once("../src/mxServer.php");

/**
 * Function: main
 *
 * Creates a graph using the API and converts it into a PNG image.
 */
function main()
{
    $format = "png";
    $filename = "diagrams/graphmodel.xml";
    $xml = file_get_contents($filename);

    $image = mxGraphViewImageReader::convert($xml, "#FFFFFF");

    header("Content-Type: image/png");
    echo mxUtils::encodeImage($image);
}

//mxConstants::$DEFAULT_FONTFAMILY = "ttf/verah.ttf";


main();
?>

我还尝试了JavaServlet，生成的图像总是空白的

还有什么我可以试试的吗？ 我知道有一个问题。NET sdk，但我希望避免使用它

谢谢