main.rs

extern crate dwrite;
extern crate kernel32;
extern crate winapi;

use dwrite::DWriteCreateFactory;
use kernel32::GetUserDefaultLocaleName;
use std::{mem, ptr};
use winapi::dwrite::{DWRITE_FACTORY_TYPE_SHARED};
use winapi::dwrite::{IDWriteFactory, IDWriteFontCollection, IDWriteFontFamily, IDWriteLocalizedStrings};
use winapi::dwrite::UuidOfIDWriteFactory;
use winapi::minwindef::{BOOL, FALSE};
use winapi::unknwnbase::IUnknown;
use winapi::winerror::S_OK;

fn main() {
    let mut factory: *mut IUnknown = ptr::null_mut();
    unsafe {
        let hr = DWriteCreateFactory(
            DWRITE_FACTORY_TYPE_SHARED,
            &UuidOfIDWriteFactory,
            &mut factory);
        assert!(hr == S_OK);

        let factory: *mut IDWriteFactory = mem::transmute(factory);
        let mut font_collection: *mut IDWriteFontCollection = ptr::null_mut();
        let hr = (*factory).GetSystemFontCollection(&mut font_collection, FALSE);
        assert!(hr == S_OK);

        let family_count = (*font_collection).GetFontFamilyCount();
        println!("{} font families", family_count);

        for i in 0..family_count {
            let mut family: *mut IDWriteFontFamily = ptr::null_mut();
            let hr = (*font_collection).GetFontFamily(i, &mut family);
            assert!(hr == S_OK);

            let mut family_names: *mut IDWriteLocalizedStrings = ptr::null_mut();
            let hr = (*family).GetFamilyNames(&mut family_names);
            assert!(hr == S_OK);

            let mut locale: [winapi::wchar_t; 85] = [0; 85];
            let res = GetUserDefaultLocaleName(locale.as_mut_ptr(), 85);
            assert!(res != 0);

            let mut index: u32 = 0;
            let mut exists: BOOL = FALSE;
            let hr = (*family_names).FindLocaleName(locale.as_ptr(), &mut index, &mut exists);
            assert!(hr == S_OK);

            if exists == FALSE {
                index = 0;
            }

            let mut length: u32 = 0;
            let hr = (*family_names).GetStringLength(index, &mut length);
            assert!(hr == S_OK);

            let mut name: Vec<winapi::wchar_t> = Vec::with_capacity(length as usize + 1);
            let hr = (*family_names).GetString(index, name.as_mut_ptr(), length + 1);
            assert!(hr == 0);
            name.set_len(length as usize+ 1);

            let name = String::from_utf16(&name).ok().unwrap();
            println!("{}", name);

            (*family_names).Release();
            (*family).Release();
        }

        (*font_collection).Release();
        (*factory).Release();
    }
}