[FFmpeg-devel] [PATCH] libavfilter/vf_drawtext: add letter_spacing as an evaluated parameter
When enabled it will add pixels (or subtract if given a negative value) between
each letters,
set use_kerning to false,
and add the pixels to text_w.
Signed-off-by: Mark Ren
---
libavfilter/vf_drawtext.c | 24
1 file changed, 20 insertions(+), 4 deletions(-)
diff --git a/libavfilter/vf_drawtext.c b/libavfilter/vf_drawtext.c
index 71ab851462..ec8313820d 100644
--- a/libavfilter/vf_drawtext.c
+++ b/libavfilter/vf_drawtext.c
@@ -183,6 +183,7 @@ typedef struct DrawTextContext {
unsigned int fontsize; ///< font size to use
unsigned int default_fontsize; ///< default font size to use
+int letter_spacing; ///< letter spacing in pixels
int line_spacing; ///< lines spacing in pixels
short int draw_box; ///< draw box around text - true or false
int boxborderw; ///< box border width
@@ -208,6 +209,8 @@ typedef struct DrawTextContext {
char *a_expr;
AVExpr *a_pexpr;
int alpha;
+char* letter_spacing_expr; ///< expression for letter spacing
+AVExpr* letter_spacing_pexpr; ///< parsed expression for letter spacing
AVLFG prng;///< random
char *tc_opt_string; ///< specified timecode option string
AVRational tc_rate;///< frame rate for timecode
@@ -237,6 +240,7 @@ static const AVOption drawtext_options[]= {
{"shadowcolor", "set shadow color", OFFSET(shadowcolor.rgba),
AV_OPT_TYPE_COLOR, {.str="black"}, 0, 0, FLAGS},
{"box", "set box", OFFSET(draw_box),
AV_OPT_TYPE_BOOL, {.i64=0}, 0,1 , FLAGS},
{"boxborderw", "set box border width", OFFSET(boxborderw),
AV_OPT_TYPE_INT,{.i64=0}, INT_MIN, INT_MAX , FLAGS},
+{"letter_spacing", "set letter spacing in pixels",
OFFSET(letter_spacing_expr), AV_OPT_TYPE_STRING, {.str="0"}, 0, 0, FLAGS},
{"line_spacing", "set line spacing in pixels", OFFSET(line_spacing),
AV_OPT_TYPE_INT,{.i64=0}, INT_MIN, INT_MAX,FLAGS},
{"fontsize","set font size",OFFSET(fontsize_expr),
AV_OPT_TYPE_STRING, {.str=NULL}, 0, 0 , FLAGS},
{"x", "set x expression", OFFSET(x_expr),
AV_OPT_TYPE_STRING, {.str="0"}, 0, 0, FLAGS},
@@ -812,7 +816,7 @@ static av_cold int init(AVFilterContext *ctx)
FT_STROKER_LINEJOIN_ROUND, 0);
}
-s->use_kerning = FT_HAS_KERNING(s->face);
+s->use_kerning = FT_HAS_KERNING(s->face) && !s->letter_spacing;
/* load the fallback glyph with code 0 */
load_glyph(ctx, NULL, 0);
@@ -857,8 +861,9 @@ static av_cold void uninit(AVFilterContext *ctx)
av_expr_free(s->y_pexpr);
av_expr_free(s->a_pexpr);
av_expr_free(s->fontsize_pexpr);
+av_expr_free(s->letter_spacing_pexpr);
-s->x_pexpr = s->y_pexpr = s->a_pexpr = s->fontsize_pexpr = NULL;
+s->x_pexpr = s->y_pexpr = s->a_pexpr = s->fontsize_pexpr =
s->letter_spacing_pexpr = NULL;
av_freep(&s->positions);
s->nb_positions = 0;
@@ -903,13 +908,16 @@ static int config_input(AVFilterLink *inlink)
av_expr_free(s->x_pexpr);
av_expr_free(s->y_pexpr);
av_expr_free(s->a_pexpr);
-s->x_pexpr = s->y_pexpr = s->a_pexpr = NULL;
+av_expr_free(s->letter_spacing_pexpr);
+s->x_pexpr = s->y_pexpr = s->a_pexpr = s->letter_spacing_pexpr = NULL;
if ((ret = av_expr_parse(&s->x_pexpr, expr = s->x_expr, var_names,
NULL, NULL, fun2_names, fun2, 0, ctx)) < 0 ||
(ret = av_expr_parse(&s->y_pexpr, expr = s->y_expr, var_names,
NULL, NULL, fun2_names, fun2, 0, ctx)) < 0 ||
(ret = av_expr_parse(&s->a_pexpr, expr = s->a_expr, var_names,
+ NULL, NULL, fun2_names, fun2, 0, ctx)) < 0 ||
+(ret = av_expr_parse(&s->letter_spacing_pexpr, expr =
s->letter_spacing_expr, var_names,
NULL, NULL, fun2_names, fun2, 0, ctx)) < 0) {
av_log(ctx, AV_LOG_ERROR, "Failed to parse expression: %s \n", expr);
return AVERROR(EINVAL);
@@ -1525,6 +1533,9 @@ continue_on_invalid2:
dummy.fontsize = s->fontsize;
glyph = av_tree_find(s->glyphs, &dummy, glyph_cmp, NULL);
+/* letter spacing */
+x += s->letter_spacing;
+
/* kerning */
if (s->use_kerning && prev_glyph && glyph->code) {
FT_Get_Kerning(s->face, prev_glyph->code, glyph->code,
@@ -1539,7 +1550,12 @@ continue_on_invalid2:
Re: [FFmpeg-devel] [PATCH] libavfilter/vf_drawtext: add letter_spacing as an evaluated parameter
Ah alright I see. When might that push come through and is there somewhere
I can look at the kind of changes in the meantime?
On Mon, Jun 19, 2023 at 12:39 PM Paul B Mahol wrote:
>
>
> On Mon, Jun 19, 2023 at 6:34 PM Mark Ren wrote:
>
>> When enabled it will add pixels (or subtract if given a negative value)
>> between each letters,
>> set use_kerning to false,
>> and add the pixels to text_w.
>>
>
> Conflicts with big drawtext filter set that will be pushed soon.
>
>
>>
>> Signed-off-by: Mark Ren
>> ---
>> libavfilter/vf_drawtext.c | 24
>> 1 file changed, 20 insertions(+), 4 deletions(-)
>>
>> diff --git a/libavfilter/vf_drawtext.c b/libavfilter/vf_drawtext.c
>> index 71ab851462..ec8313820d 100644
>> --- a/libavfilter/vf_drawtext.c
>> +++ b/libavfilter/vf_drawtext.c
>> @@ -183,6 +183,7 @@ typedef struct DrawTextContext {
>> unsigned int fontsize; ///< font size to use
>> unsigned int default_fontsize; ///< default font size to use
>>
>> +int letter_spacing; ///< letter spacing in pixels
>> int line_spacing; ///< lines spacing in pixels
>> short int draw_box; ///< draw box around text - true or
>> false
>> int boxborderw; ///< box border width
>> @@ -208,6 +209,8 @@ typedef struct DrawTextContext {
>> char *a_expr;
>> AVExpr *a_pexpr;
>> int alpha;
>> +char* letter_spacing_expr; ///< expression for letter spacing
>> +AVExpr* letter_spacing_pexpr; ///< parsed expression for letter
>> spacing
>> AVLFG prng;///< random
>> char *tc_opt_string; ///< specified timecode option string
>> AVRational tc_rate;///< frame rate for timecode
>> @@ -237,6 +240,7 @@ static const AVOption drawtext_options[]= {
>> {"shadowcolor", "set shadow color", OFFSET(shadowcolor.rgba),
>> AV_OPT_TYPE_COLOR, {.str="black"}, 0, 0, FLAGS},
>> {"box", "set box", OFFSET(draw_box),
>> AV_OPT_TYPE_BOOL, {.i64=0}, 0,1 , FLAGS},
>> {"boxborderw", "set box border width", OFFSET(boxborderw),
>> AV_OPT_TYPE_INT,{.i64=0}, INT_MIN, INT_MAX , FLAGS},
>> +{"letter_spacing", "set letter spacing in pixels",
>> OFFSET(letter_spacing_expr), AV_OPT_TYPE_STRING, {.str="0"}, 0, 0, FLAGS},
>> {"line_spacing", "set line spacing in pixels",
>> OFFSET(line_spacing), AV_OPT_TYPE_INT,{.i64=0}, INT_MIN,
>> INT_MAX,FLAGS},
>> {"fontsize","set font size",OFFSET(fontsize_expr),
>> AV_OPT_TYPE_STRING, {.str=NULL}, 0, 0 , FLAGS},
>> {"x", "set x expression", OFFSET(x_expr),
>> AV_OPT_TYPE_STRING, {.str="0"}, 0, 0, FLAGS},
>> @@ -812,7 +816,7 @@ static av_cold int init(AVFilterContext *ctx)
>> FT_STROKER_LINEJOIN_ROUND, 0);
>> }
>>
>> -s->use_kerning = FT_HAS_KERNING(s->face);
>> +s->use_kerning = FT_HAS_KERNING(s->face) && !s->letter_spacing;
>>
>> /* load the fallback glyph with code 0 */
>> load_glyph(ctx, NULL, 0);
>> @@ -857,8 +861,9 @@ static av_cold void uninit(AVFilterContext *ctx)
>> av_expr_free(s->y_pexpr);
>> av_expr_free(s->a_pexpr);
>> av_expr_free(s->fontsize_pexpr);
>> +av_expr_free(s->letter_spacing_pexpr);
>>
>> -s->x_pexpr = s->y_pexpr = s->a_pexpr = s->fontsize_pexpr = NULL;
>> +s->x_pexpr = s->y_pexpr = s->a_pexpr = s->fontsize_pexpr =
>> s->letter_spacing_pexpr = NULL;
>>
>> av_freep(&s->positions);
>> s->nb_positions = 0;
>> @@ -903,13 +908,16 @@ static int config_input(AVFilterLink *inlink)
>> av_expr_free(s->x_pexpr);
>> av_expr_free(s->y_pexpr);
>> av_expr_free(s->a_pexpr);
>> -s->x_pexpr = s->y_pexpr = s->a_pexpr = NULL;
>> +av_expr_free(s->letter_spacing_pexpr);
>> +s->x_pexpr = s->y_pexpr = s->a_pexpr = s->letter_spacing_pexpr =
>> NULL;
>>
>> if ((ret = av_expr_parse(&s->x_pexpr, expr = s->x_expr, var_names,
>> NULL, NULL, fun2_names, fun2, 0, ctx)) < 0
>> ||
>> (ret = av_expr_parse(&s->y_pexpr
