Question of Canvas to PDF size (关于Canvas生成PDF文档尺寸的疑问)

[Simon7520]

Question:
I use createCanvas(width, height, 'pdf') to create a canvas for painting, then I use toBuffer('application/pdf') to generate a pdf document.The size unit of canvas should be px, while the size unit of PDF document is cm. I don't understand how the width and height here are related to the width and height of PDF document? Is it converted using the default 72dpi,at least the result I ran locally looks like this?

我使用createCanvas（width，height，'pdf'）创建画布进行绘画，然后使用toBuffer（'application/pdf'）生成pdf文档。画布的大小单位应该是px，而PDF文档的大小单位是cm。我不明白这里的宽度和高度与PDF文档的宽度和长度有什么关系？难道是使用默认的72dpi来进行转换的吗？至少我本地运行的结果看起来是这样。

Can someone answer the question for me？