From 76f527f6d2832ced636bbe44ef7ac38aefd7aeb7 Mon Sep 17 00:00:00 2001
From: Nicolas VIVIEN <nicolas@vivien.fr>
Date: Mon, 31 Jul 2023 21:45:28 +0200
Subject: [PATCH] Fix rendering utf-8 string

Signed-off-by: Nicolas VIVIEN <nicolas@vivien.fr>
---
 src/libOpenImageIO/imagebufalgo_draw.cpp | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/src/libOpenImageIO/imagebufalgo_draw.cpp b/src/libOpenImageIO/imagebufalgo_draw.cpp
index a88aacd182..9eef064f97 100644
--- a/src/libOpenImageIO/imagebufalgo_draw.cpp
+++ b/src/libOpenImageIO/imagebufalgo_draw.cpp
@@ -2,6 +2,9 @@
 // SPDX-License-Identifier: Apache-2.0
 // https://github.com/OpenImageIO/oiio
 
+#include <string>
+#include <codecvt>
+#include <locale>
 #include <algorithm>
 #include <cmath>
 #include <limits>
@@ -887,7 +890,7 @@ static bool ft_broken        = false;
 
 // Helper: given unicode and a font face, compute its size
 static ROI
-text_size_from_unicode(cspan<uint32_t> utext, FT_Face face, int fontsize)
+text_size_from_unicode(std::u32string& utext, FT_Face face, int fontsize)
 {
     int y = 0;
     int x = 0;
@@ -989,6 +992,8 @@ ImageBufAlgo::text_size(string_view text, int fontsize, string_view font_)
     // Thread safety
     lock_guard ft_lock(ft_mutex);
 
+    std::wstring_convert<std::codecvt_utf8<char32_t>, char32_t> conv_utf8_utf32;
+
     std::string font;
     bool ok = resolve_font(font_, font);
     if (!ok) {
@@ -1009,9 +1014,8 @@ ImageBufAlgo::text_size(string_view text, int fontsize, string_view font_)
         return size;  // couldn't set the character size
     }
 
-    std::vector<uint32_t> utext;
-    utext.reserve(text.size());
-    Strutil::utf8_to_unicode(text, utext);
+    // Convert the UTF to 32 bit unicode
+    std::u32string utext = conv_utf8_utf32.from_bytes(text);
     size = text_size_from_unicode(utext, face, fontsize);
 
     FT_Done_Face(face);
@@ -1039,6 +1043,8 @@ ImageBufAlgo::render_text(ImageBuf& R, int x, int y, string_view text,
     // Thread safety
     lock_guard ft_lock(ft_mutex);
 
+    std::wstring_convert<std::codecvt_utf8<char32_t>, char32_t> conv_utf8_utf32;
+
     std::string font;
     bool ok = resolve_font(font_, font);
     if (!ok) {
@@ -1081,9 +1087,7 @@ ImageBufAlgo::render_text(ImageBuf& R, int x, int y, string_view text,
     }
 
     // Convert the UTF to 32 bit unicode
-    std::vector<uint32_t> utext;
-    utext.reserve(text.size());
-    Strutil::utf8_to_unicode(text, utext);
+    std::u32string utext = conv_utf8_utf32.from_bytes(text);
 
     // Compute the size that the text will render as, into an ROI
     ROI textroi     = text_size_from_unicode(utext, face, fontsize);