Implemented the font family listing on Windows.

build/GNUbasemsvc.mk

@@ -65,7 +65,7 @@ else
 endif
 	@echo ====== Compiled $<
 
-$(OBJDIR)/%.cpp.o: $$(subst _,/,%).c $(HFILES) | $(OBJDIR)
+$(OBJDIR)/%.cpp.o: $$(subst _,/,%).cpp $(HFILES) | $(OBJDIR)
 ifeq ($(NODEBUG),1)
 	@cl /Fo:$@ /c $< $(CXXFLAGS)
 else

windows/drawtext.cpp

@@ -18,3 +18,85 @@ void uninitDrawText(void)
 {
 	dwfactory->Release();
 }
+
+struct uiDrawFontFamilies {
+	IDWriteFontCollection *fonts;
+	WCHAR userLocale[LOCALE_NAME_MAX_LENGTH];
+	int userLocaleSuccess;
+};
+
+uiDrawFontFamilies *uiDrawListFontFamilies(void)
+{
+	uiDrawFontFamilies *ff;
+	HRESULT hr;
+
+	ff = uiNew(uiDrawFontFamilies);
+	// always get the latest available font information
+	hr = dwfactory->GetSystemFontCollection(&(ff->fonts), TRUE);
+	if (hr != S_OK)
+		logHRESULT("error getting list of system fonts in uiDrawListFontFamilies()", hr);
+	ff->userLocaleSuccess = GetUserDefaultLocaleName(ff->userLocale, LOCALE_NAME_MAX_LENGTH);
+	return ff;
+}
+
+uintmax_t uiDrawFontFamiliesNumFamilies(uiDrawFontFamilies *ff)
+{
+	return ff->fonts->GetFontFamilyCount();
+}
+
+char *uiDrawFontFamiliesFamily(uiDrawFontFamilies *ff, uintmax_t n)
+{
+	IDWriteFontFamily *family;
+	IDWriteLocalizedStrings *names;
+	UINT32 index;
+	BOOL exists;
+	UINT32 length;
+	WCHAR *wname;
+	char *name;
+	HRESULT hr;
+
+	hr = ff->fonts->GetFontFamily(n, &family);
+	if (hr != S_OK)
+		logHRESULT("error getting font out of collection in uiDrawFontFamiliesFamily()", hr);
+	hr = family->GetFamilyNames(&names);
+	if (hr != S_OK)
+		logHRESULT("error getting names of font out in uiDrawFontFamiliesFamily()", hr);
+
+	// this is complex, but we ignore failure conditions to allow fallbacks
+	// 1) If the user locale name was successfully retrieved, try it
+	// 2) If the user locale name was not successfully retrieved, or that locale's string does not exist, or an error occurred, try L"en-us", the US English locale
+	// 3) And if that fails, assume the first one
+	// This algorithm is straight from MSDN: https://msdn.microsoft.com/en-us/library/windows/desktop/dd368214%28v=vs.85%29.aspx
+	// For step 2 to work, start by setting hr to S_OK and exists to FALSE.
+	// TODO does it skip step 2 entirely if step 1 fails? rewrite it to be a more pure conversion of the MSDN code?
+	hr = S_OK;
+	exists = FALSE;
+	if (ff->userLocaleSuccess != 0)
+		hr = names->FindLocaleName(ff->userLocale, &index, &exists);
+	if (hr != S_OK || (hr == S_OK && !exists))
+		hr = names->FindLocaleName(L"en-us", &index, &exists);
+	if (!exists)
+		index = 0;
+
+	hr = names->GetStringLength(index, &length);
+	if (hr != S_OK)
+		logHRESULT("error getting length of font name in uiDrawFontFamiliesFamily()", hr);
+	// GetStringLength() does not include the null terminator, but GetString() does
+	wname = (WCHAR *) uiAlloc((length + 1) * sizeof (WCHAR), "WCHAR[]");
+	hr = names->GetString(index, wname, length + 1);
+	if (hr != S_OK)
+		logHRESULT("error getting font name in uiDrawFontFamiliesFamily()", hr);
+
+	name = toUTF8(wname);
+
+	uiFree(wname);
+	names->Release();
+	family->Release();
+	return name;
+}
+
+void uiDrawFreeFontFamilies(uiDrawFontFamilies *ff)
+{
+	ff->fonts->Release();
+	uiFree(ff);
+}