How to include Custom Fonts？

[Hankyin]

I just want to use a new ttf Font, because the default font do not support CJK.
but I do not find any API to load a new font, so How to include Custom Fonts？

in NanoGUI document, I find something.

# Including Custom Fonts

NanoGUI uses the [Roboto](https://fonts.google.com/specimen/Roboto) font for text, and [Entypo](http://www.entypo.com/) font for icons. If you wish to add your own custom font, all you need is a True Type file (a .ttf extension). NanoGUI will glob all fonts found in resources by expanding resources/*.ttf. So if you had the directory structure

myproject/
    CMakeLists.txt      <- where this code is
    fonts/
        superfont.ttf
    ext/
        nanogui/
            resources/

You simply need to copy the superfont.ttf to NanoGUI’s resources directory:

file(
  COPY ${CMAKE_CURRENT_SOURCE_DIR}/fonts/superfont.ttf
  DESTINATION ${CMAKE_CURRENT_SOURCE_DIR}/ext/nanogui/resources/superfont.ttf
)

When you build the code, there should be a file nanogui_resources.h generated. If everything worked, your new font should have been included.

Does this mean I have to recomplie NanoGUI?
but I don't want to recomplie this library, who can help me please。 /(ㄒoㄒ)/~~

[sunduk]

Use nvgCreateFont method to load extra font(.ttf) files.
You don't need to recompile this library to support CJK.

example code :

// Change multibyte to UTF8.
// reference : https://doitnow-man.tistory.com/entry/%EC%9C%88%EB%8F%84%EC%9A%B0-window-%ED%94%84%EB%A1%9C%EA%B7%B8%EB%9E%98%EB%B0%8D-%ED%95%9C%EA%B8%80-%EC%B2%98%EB%A6%AC-c
std::string MultiByteToUtf8(std::string multibyte_str)
{
    char* pszIn = new char[multibyte_str.length() + 1];
    strncpy_s(pszIn, multibyte_str.length() + 1, multibyte_str.c_str(), multibyte_str.length());

    std::string resultString;

    int nLenOfUni = 0, nLenOfUTF = 0;
    wchar_t* uni_wchar = NULL;
    char* pszOut = NULL;

    // 1. ANSI(multibyte) Length
    if ((nLenOfUni = MultiByteToWideChar(CP_ACP, 0, pszIn, (int)strlen(pszIn), NULL, 0)) <= 0)
        return "";

    uni_wchar = new wchar_t[nLenOfUni + 1];
    memset(uni_wchar, 0x00, sizeof(wchar_t) * (nLenOfUni + 1));

    // 2. ANSI(multibyte) ---> unicode
    nLenOfUni = MultiByteToWideChar(CP_ACP, 0, pszIn, (int)strlen(pszIn), uni_wchar, nLenOfUni);

    // 3. utf8 Length
    if ((nLenOfUTF = WideCharToMultiByte(CP_UTF8, 0, uni_wchar, nLenOfUni, NULL, 0, NULL, NULL)) <= 0)
    {
        delete[] uni_wchar;
        return "";
    }

    pszOut = new char[nLenOfUTF + 1];
    memset(pszOut, 0, sizeof(char) * (nLenOfUTF + 1));

    // 4. unicode ---> utf8
    nLenOfUTF = WideCharToMultiByte(CP_UTF8, 0, uni_wchar, nLenOfUni, pszOut, nLenOfUTF, NULL, NULL);
    pszOut[nLenOfUTF] = 0;
    resultString = pszOut;

    delete[] uni_wchar;
    delete[] pszOut;

    return resultString;
}

class ExampleApplication : public nanogui::Screen {
public:
    ExampleApplication() : nanogui::Screen(Eigen::Vector2i(1024, 768), "NanoGUI Test") {
        using namespace nanogui;

        // 1. Load your ttf file, name it.
        nvgCreateFont(mNVGContext, "NanumGothic", "../resources/nanum-gothic/NanumGothic.ttf");
        nvgCreateFont(mNVGContext, "NanumGothic-bold", "../resources/nanum-gothic/NanumGothicBold.ttf");

        Window *window = new Window(this, "Button demo");
        window->setPosition(Vector2i(15, 15));
        window->setLayout(new GroupLayout());

        /* No need to store a pointer, the data structure will be automatically
           freed when the parent window is deleted */

        // 2. Use like this.
        new Label(window, MultiByteToUtf8("한국어,中國語,日本語,English"), "NanumGothic-bold");
        ...
};

[stuaxo]

Nice, this looks like a handy thing to have an example for in the codebase.