Zhao Zhili via ffmpeg-devel (HE12026-03-23):
> PR #22589 opened by Zhao Zhili (quink)
> URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/22589
> Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/22589.patch
>
> GET_UTF8 advances the pointer past the newline byte before the
> newline check, so shape_text_hb receives text that includes the
> newline character. Since HarfBuzz does not treat U+000A as
> default-ignorable, it gets shaped into a .notdef glyph.
>
> Fixes #21565
>
> Reported-by: scriptituk <[email protected]>
> Signed-off-by: Zhao Zhili <[email protected]>
>
>
> >From 2dcdd7b42f80263c59dc61fe58ded22f4d35140d Mon Sep 17 00:00:00 2001
> From: Zhao Zhili <[email protected]>
> Date: Mon, 23 Mar 2026 20:10:12 +0800
> Subject: [PATCH] avfilter/vf_drawtext: fix newline rendered as .notdef glyph
>
> GET_UTF8 advances the pointer past the newline byte before the
> newline check, so shape_text_hb receives text that includes the
> newline character. Since HarfBuzz does not treat U+000A as
> default-ignorable, it gets shaped into a .notdef glyph.
>
> Fixes #21565
>
> Reported-by: scriptituk <[email protected]>
> Signed-off-by: Zhao Zhili <[email protected]>
> ---
> libavfilter/vf_drawtext.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/libavfilter/vf_drawtext.c b/libavfilter/vf_drawtext.c
> index 2812de37f5..5d2a301859 100644
> --- a/libavfilter/vf_drawtext.c
> +++ b/libavfilter/vf_drawtext.c
> @@ -1452,13 +1452,14 @@ continue_on_failed:
> s->tab_clusters[tab_idx++] = i;
> *p = ' ';
> }
> + const uint8_t *p_before = p;
I would have written:
size_t len = p - start;
> GET_UTF8(code, *p ? *p++ : 0, code = 0xfffd; goto
> continue_on_failed2;);
> continue_on_failed2:
> if (ff_is_newline(code) || code == 0) {
> TextLine *cur_line = &s->lines[line_count];
> HarfbuzzData *hb = &cur_line->hb_data;
> cur_line->cluster_offset = line_offset;
> - ret = shape_text_hb(s, hb, start, p - start);
> + ret = shape_text_hb(s, hb, start, p_before - start);
> if (ret != 0) {
> goto done;
> }
Looks ok any way, thanks.
I still have not taken the time to configure access to the forge
thingie.
Regards,
--
Nicolas George
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