TOPIC:

I am using the following Xamarin module for Android.
github.com/RadaeePDF-Jugaad/RadaeePDF-Xa...id/RadaeePDF-Xamarin
  
Garbled characters occur in Japanese PDF files.
Font substitution does not seem to be working.
　
Is this a bug?
Also, is there any problem with the following fixes?


There seems to be a problem with the following files.

• RadaeePDF-Xamarin/Jars/ViewLib.aar

The font substitution problem was solved by using "RadaeePDF AndroidStudio 3.55.4", available from the following link, and replacing the above file.
www.radaeepdf.com/download/category/1-android

The fixes are as follows

•  Fixed a problem that could override the default font for GB1.
•  Changed the priority of the default font for CJK.

      Note: For Japan1, we expect that the risk of garbled characters is lower if Noto Sans CJK Regular is set rather than DroidSansFallback. (This is just a prediction.)
               GB1, CNS1, and Korea1 have also been revised to match the changes in Japna1.

After line 758 of RadaeePDF-Android\PDFSample\ViewLib\src\main\java\com\radaee\pdf\Global.java

• Before

    // set default font for Simplified Chinese. 简体
    if (!setDefaultFont("GB1", "DroidSansFallback", true) &&
        !setDefaultFont("GB1", "Noto Sans CJK SC Regular", true) &&
        !setDefaultFont("GB1", "DroidSansChinese", true) &&
        !setDefaultFont("GB1", "Noto Sans SC Regular", true) && face_name != null)
        setDefaultFont("GB1", face_name, true);
    if (!setDefaultFont("GB1", "DroidSansFallback", false) &&
        !setDefaultFont("GB1", "Noto Sans CJK SC Regular", false) &&
        !setDefaultFont("GB1", "Noto Sans SC Regular", false) && face_name != null)
        setDefaultFont("GB1", face_name, false);

    // set default font for Traditional Chinese. 繁體
    if (!setDefaultFont("CNS1", "DroidSansFallback", true) &&
        !setDefaultFont("GB1", "Noto Sans CJK TC Regular", true) &&
        !setDefaultFont("CNS1", "Noto Sans TC Regular", true) && face_name != null)
        setDefaultFont("CNS1", face_name, true);
    if (!setDefaultFont("CNS1", "DroidSansFallback", false) &&
        !setDefaultFont("GB1", "Noto Sans CJK TC Regular", false) &&
        !setDefaultFont("CNS1", "Noto Sans TC Regular", false) && face_name != null)
        setDefaultFont("CNS1", face_name, false);

    // set default font for Japanese.
    if (!setDefaultFont("Japan1", "DroidSansFallback", true) &&
        !setDefaultFont("GB1", "Noto Sans CJK JP Regular", true) &&
        !setDefaultFont("Japan1", "Noto Sans JP Regular", true) && face_name != null)
        setDefaultFont("Japan1", face_name, true);
    if (!setDefaultFont("Japan1", "DroidSansFallback", false) &&
        !setDefaultFont("GB1", "Noto Sans CJK JP Regular", false) &&
        !setDefaultFont("Japan1", "Noto Sans JP Regular", false) && face_name != null)
        setDefaultFont("Japan1", face_name, false);

    // set default font for Korean.
    if (!setDefaultFont("Korea1", "DroidSansFallback", true) &&
        !setDefaultFont("GB1", "Noto Sans CJK KR Regular", true) &&
        !setDefaultFont("Korea1", "Noto Sans KR Regular", true) && face_name != null)
        setDefaultFont("Korea1", face_name, true);
    if (!setDefaultFont("Korea1", "DroidSansFallback", false) &&
        !setDefaultFont("GB1", "Noto Sans CJK KR Regular", false) &&
        !setDefaultFont("Korea1", "Noto Sans KR Regular", false) && face_name != null)
        setDefaultFont("Korea1", face_name, false);

• After

    if (!setDefaultFont("GB1", "Noto Sans CJK SC Regular", true) &&
            !setDefaultFont("GB1", "DroidSansChinese", true) &&
            !setDefaultFont("GB1", "Noto Sans SC Regular", true) &&
            !setDefaultFont("GB1", "DroidSansFallback", true) && face_name != null)
        setDefaultFont("GB1", face_name, true);
    if (!setDefaultFont("GB1", "Noto Sans CJK SC Regular", false) &&
            !setDefaultFont("GB1", "Noto Sans SC Regular", false) &&
            !setDefaultFont("GB1", "DroidSansFallback", false) && face_name != null)
        setDefaultFont("GB1", face_name, false);

    // set default font for Traditional Chinese. 繁體
    if (!setDefaultFont("CNS1", "Noto Sans CJK TC Regular", true) &&
            !setDefaultFont("CNS1", "Noto Sans TC Regular", true) &&
            !setDefaultFont("CNS1", "DroidSansFallback", true) && face_name != null)
        setDefaultFont("CNS1", face_name, true);
    if (!setDefaultFont("CNS1", "Noto Sans CJK TC Regular", false) &&
            !setDefaultFont("CNS1", "Noto Sans TC Regular", false) &&
            !setDefaultFont("CNS1", "DroidSansFallback", false) && face_name != null)
        setDefaultFont("CNS1", face_name, false);

    // set default font for Japanese.
    if (!setDefaultFont("Japan1", "Noto Sans CJK JP Regular", true) &&
            !setDefaultFont("Japan1", "Noto Sans JP Regular", true) &&
            !setDefaultFont("Japan1", "DroidSansFallback", true) && face_name != null)
        setDefaultFont("Japan1", face_name, true);
    if (!setDefaultFont("Japan1", "Noto Sans CJK JP Regular", false) &&
            !setDefaultFont("Japan1", "Noto Sans JP Regular", false) &&
            !setDefaultFont("Japan1", "DroidSansFallback", false) && face_name != null)
        setDefaultFont("Japan1", face_name, false);

    // set default font for Korean.
    if (!setDefaultFont("Korea1", "Noto Sans CJK KR Regular", true) &&
            !setDefaultFont("Korea1", "Noto Sans KR Regular", true) &&
            !setDefaultFont("Korea1", "DroidSansFallback", true) && face_name != null)
        setDefaultFont("Korea1", face_name, true);
    if (!setDefaultFont("Korea1", "Noto Sans CJK KR Regular", false) &&
            !setDefaultFont("Korea1", "Noto Sans KR Regular", false) &&
            !setDefaultFont("Korea1", "DroidSansFallback", false) && face_name != null)
        setDefaultFont("Korea1", face_name, false);


Thank you in advance.
 

dear user:
thanks, we have found some problems:

shall change to:the method call "setDefaultFont("GB1", "Noto Sans CJK JP Regular", true)" is wrong for Japan1.we will update this issue in next demo version.

Thank you Hinata (OP) for posting this. I was looking into this and I noticed that your suggestions appear to be implemented in the latest version of the library. I wanted to add my own discoveries and suggestions as well.

I discovered that the font /system/fonts/NotoSansCJK-Regular.ttc on Samsung devices (at least the Galaxy Note 9 and Galaxy Tab S4) does not include the word "Regular" in the font names. For example, for Simplified Chinese it's just "Noto Sans CJK SC" rather than "Noto Sans CJK SC Regular".

However, when I looked into the latest version of NotoSansCJK-Regular.ttc available here from www.google.com/get/noto/help/cjk/, the fonts do include "Regular" in the font names.

So, we changed our settings to the following:// set default font for Simplified Chinese. 简体
if (!setDefaultFont("GB1", "Noto Sans CJK SC Regular", true) &&
!setDefaultFont("GB1", "Noto Sans CJK SC", true) &&
!setDefaultFont("GB1", "Noto Sans SC Regular", true) &&
!setDefaultFont("GB1", "Noto Sans SC", true) &&
!setDefaultFont("GB1", "DroidSansChinese", true) &&
!setDefaultFont("GB1", "DroidSansFallback", true) && face_name != null)
setDefaultFont("GB1", face_name, true);
if (!setDefaultFont("GB1", "Noto Sans CJK SC Regular", false) &&
!setDefaultFont("GB1", "Noto Sans CJK SC", false) &&
!setDefaultFont("GB1", "Noto Sans SC Regular", false) &&
!setDefaultFont("GB1", "Noto Sans SC", false) &&
!setDefaultFont("GB1", "DroidSansChinese", false) &&
!setDefaultFont("GB1", "DroidSansFallback", false) && face_name != null)
setDefaultFont("GB1", face_name, false);

// set default font for Traditional Chinese. 繁體
if (!setDefaultFont("CNS1", "Noto Sans CJK TC Regular", true) &&
!setDefaultFont("CNS1", "Noto Sans CJK TC", true) &&
!setDefaultFont("CNS1", "Noto Sans TC Regular", true) &&
!setDefaultFont("CNS1", "Noto Sans TC", true) &&
!setDefaultFont("CNS1", "DroidSansFallback", true) && face_name != null)
setDefaultFont("CNS1", face_name, true);
if (!setDefaultFont("CNS1", "Noto Sans CJK TC Regular", false) &&
!setDefaultFont("CNS1", "Noto Sans CJK TC", false) &&
!setDefaultFont("CNS1", "Noto Sans TC Regular", false) &&
!setDefaultFont("CNS1", "Noto Sans TC", false) &&
!setDefaultFont("CNS1", "DroidSansFallback", false) && face_name != null)
setDefaultFont("CNS1", face_name, false);

// set default font for Japanese.
if (!setDefaultFont("Japan1", "Noto Sans CJK JP Regular", true) &&
!setDefaultFont("Japan1", "Noto Sans CJK JP", true) &&
!setDefaultFont("Japan1", "Noto Sans JP Regular", true) &&
!setDefaultFont("Japan1", "Noto Sans JP", true) &&
!setDefaultFont("Japan1", "DroidSansFallback", true) && face_name != null)
setDefaultFont("Japan1", face_name, true);
if (!setDefaultFont("Japan1", "Noto Sans CJK JP Regular", false) &&
!setDefaultFont("Japan1", "Noto Sans CJK JP", false) &&
!setDefaultFont("Japan1", "Noto Sans JP Regular", false) &&
!setDefaultFont("Japan1", "Noto Sans JP", false) &&
!setDefaultFont("Japan1", "DroidSansFallback", false) && face_name != null)
setDefaultFont("Japan1", face_name, false);

// set default font for Korean.
if (!setDefaultFont("Korea1", "Noto Sans CJK KR Regular", true) &&
!setDefaultFont("Korea1", "Noto Sans CJK KR", true) &&
!setDefaultFont("Korea1", "Noto Sans KR Regular", true) &&
!setDefaultFont("Korea1", "Noto Sans KR", true) &&
!setDefaultFont("Korea1", "DroidSansFallback", true) && face_name != null)
setDefaultFont("Korea1", face_name, true);
if (!setDefaultFont("Korea1", "Noto Sans CJK KR Regular", false) &&
!setDefaultFont("Korea1", "Noto Sans CJK KR", false) &&
!setDefaultFont("Korea1", "Noto Sans KR Regular", false) &&
!setDefaultFont("Korea1", "Noto Sans KR", false) &&
!setDefaultFont("Korea1", "DroidSansFallback", false) && face_name != null)
setDefaultFont("Korea1", face_name, false);


I tested this on the Samsung Galaxy Note 9 and Samsung Galaxy Tab S4 and was able to correctly render PDFs with Asian fonts that previously did not render correctly.

I hope this will help others. Please let me know if you see any issues with these changes.
 

thanks, we will fix in demo project.