bookmarks: some chinese characters not displayed properly

[kaiceo]

Testing text mixing chinese, digital, english and punctuation is utf8 encoding, every character is checked by utf8.ValidRune and passed.
But some text encode error , i dont know where error occured, maybe i should not use utf8 encoding, or some thing wrong from utf8 encoding to utf16 by the latest commit modification
anyway, it is awesome after this commit
use package from the latest commit, test text is below
testing str.txt

[hhrutter]

This issue is related to the specific font (file) used in your PDF viewer.
Maybe some Private Use Area Unicode code points.
Unfortunately we cannot control the font used for rendering the outline tree AFAIK.

[kaiceo]

thanks for replying in time, i will do more tests, maybe figure out some solutions . more feedbacks will be supplied by then

[kaiceo]

Some wierd situation happened, three testing is below, all chinese words are usual, but some words including "尾" encode error, others like 密封 操作 and so on

f := "a919-2065308.pdf"
api.AddBookmarksFile(f, "out.pdf", []pdfcpu.Bookmark{{Title: "test", PageFrom: 1}}, pdfcpu.NewDefaultConfiguration())
api.AddBookmarksFile(f, "out.pdf", []pdfcpu.Bookmark{{Title: "测试", PageFrom: 1}}, pdfcpu.NewDefaultConfiguration())
api.AddBookmarksFile(f, "out.pdf", []pdfcpu.Bookmark{{Title: "尾巴", PageFrom: 1}}, pdfcpu.NewDefaultConfiguration())

SimSun Font.zip
a919-2065308.pdf

[kaiceo]

@hhrutter I found some differences about adding chinese bookmark by api and manual.
for example : 作

1. add bookmark by api , not displayed
   

2. add bookmark manually in acrobat pro, displayed normally

result is 2 has extra "5C", i dont know the reason

[hhrutter]

I think I know what is going here..
The string literal needs to be escaped before it is written out to the file.
I will provide a fix.

[hhrutter]

This is fixed with latest commit.
Let me know if this works for you.
Thank you for using pdfcpu 💚

[kaiceo]

it runs very well.