fix: fix Font Preview crash if opened manually

2026-07-18 10:21:22 +02:00
parent 7c8b7a5cf7
commit 796ed46d12
3 changed files with 17 additions and 3 deletions
@@ -124,7 +124,10 @@ struct TrueTypeFont {
        montauk::read(fd, data, 0, size);
        montauk::close(fd);

-        if (!stbtt_InitFont(&info, data, stbtt_GetFontOffsetForIndex(data, 0))) {
+        // stbtt_GetFontOffsetForIndex returns -1 for non-font data; passing
+        // that into stbtt_InitFont makes it dereference data + (uint32)-1.
+        int off = stbtt_GetFontOffsetForIndex(data, 0);
+        if (off < 0 || !stbtt_InitFont(&info, data, off)) {
            montauk::free(data);
            data = nullptr;
            return false;