[FFmpeg-devel] [PATCH] avfilter/drawtext: fix box sizing

[Gyan Doshi]

Test command:

ffplay -f lavfi -i "color,\
drawtext=fontfile='arial.ttf':fontcolor=white:fontsize=H/5:\
text='A string of characters':\
box=1:boxcolor=green:boxborderw=5:\
x='w-w*t/5':y=-th+h*t/10"

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From b98969d12b3f6959ab1a036f20ba649951bcd1ea Mon Sep 17 00:00:00 2001
From: Gyan Doshi <ffmpeg at gyani.pro>
Date: Tue, 10 Jul 2018 15:14:06 +0530
Subject: [PATCH] avfilter/drawtext: fix box sizing

At present, box size is clipped to frame size before being drawn,
which can lead to the box not fully covering animated text which is
longer than one or both frame dimensions.

Since ff_blend_rectangle correctly takes care of clipping, it is skipped
here which results in correct box sizing
---
 libavfilter/vf_drawtext.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavfilter/vf_drawtext.c b/libavfilter/vf_drawtext.c
index 3affa736c7..cca2cbcb88 100644
--- a/libavfilter/vf_drawtext.c
+++ b/libavfilter/vf_drawtext.c
@@ -1407,8 +1407,8 @@ static int draw_text(AVFilterContext *ctx, AVFrame *frame,
     update_color_with_alpha(s, &bordercolor, s->bordercolor);
     update_color_with_alpha(s, &boxcolor   , s->boxcolor   );
 
-    box_w = FFMIN(width - 1 , max_text_line_w);
-    box_h = FFMIN(height - 1, y + s->max_glyph_h);
+    box_w = max_text_line_w;
+    box_h = y + s->max_glyph_h;
 
     if (s->fix_bounds) {
 
-- 
2.17.1