Add Chinese support

[dongweigogo]

I've seen some suggestions for adding Chinese support, but all have been closed. So, I raise it once again because that will benefit a lot of people!
And I found that another package (https://github.com/signintech/gopdf) has supported some utf-8 languages. Does that help in fixing this issue here?

[jung-kurt]

Does that help in fixing this issue here?

It may. But since font management touches so much of gofpdf, it may be more beneficial to consider a new branch that carries over features from gofpdf and lays them on top of gopdf.

[nanjj]

	pdf := gofpdf.New("P", "mm", "A4", "")
	pdf.AddUTF8Font("NotoSansSC-Regular", "", "NotoSansSC-Regular.ttf")
	pdf.SetFont("NotoSansSC-Regular", "", 16)
	pdf.Cell(49, 10, "中文，你好！")

You can download the NotoSansSC-Regular.ttf file from https://github.com/jsntn/webfonts/, put it under your current directory.

[chy168]

Just ran into this problem, thanks the hints from @nanjj.

I would like to provide another open source family "Source Han Sans" font for Japanese, Korean, Simplified Chinese, and Traditional Chinese.

Note for Traditional Chinese and Japanese developers, there is a TTF converted version base on Source Han Sans. Download .ttf from here https://github.com/ButTaiwan/gensen-font