xlibtest.cpp

#include <unistd.h>
#include <X11/Xlib.h>
#include <X11/Xft/Xft.h>

#include <string>
#include <iostream>

int main() {
    if (setlocale(LC_CTYPE, "") == 0) {
        std::cerr << "Can't set locale" << std::endl;
        exit(1);
    }

    Display *display = XOpenDisplay(nullptr);

    if (!display) {
        exit(2);
    }

    uint32_t screen = DefaultScreen(display);
    Window root = RootWindow(display, screen);

    Window window = XCreateSimpleWindow(display, root, 0, 0, 200, 100, 0, 0, 0x00'00'00);

    GC gc = XCreateGC(display, window, GCForeground, (XGCValues[]){ 0xFF'FF'FF });
    XSetForeground(display, gc, 0xFFFFFF);

    XftFont *font = XftFontOpen(display, screen, XFT_FAMILY, XftTypeString, "NasuM", XFT_SIZE, XftTypeDouble, 64.0, nullptr);
    XftDraw *draw = XftDrawCreate(display, window, DefaultVisual(display, screen), DefaultColormap(display, screen));
    XftColor color = { 0, { 0xC000, 0xFF00, 0xEE00 } };

    std::string hello = u8"こんにちは，世界！";

    XGlyphInfo glyph_info;
    XftTextExtentsUtf8(display, font, (const FcChar8*)hello.c_str(), hello.size(), &glyph_info);

    XMapWindow(display, window);

    XFlush(display);

    XSelectInput(display, window, ExposureMask | ButtonPressMask);

    while(true) {
        XEvent event;
        XNextEvent(display, &event);
        switch (event.type) {
            case Expose: {
                XftDrawStringUtf8(draw, &color, font, 10, 10 + glyph_info.height, (const FcChar8*)hello.c_str(), hello.size());
            }
        }
    }

    XCloseDisplay(display);

    return 0;
}