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vf_drawtext: make x and y options parametric 

Address trac issue #378.
tags/n0.9
Stefano Sabatini 14 years ago
parent
163854bca0
commit
482ce0ce4e
3 changed files with 236 additions and 21 deletions
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  1. +93
    -3
      doc/filters.texi
  2. +1
    -1
      libavfilter/avfilter.h
  3. +142
    -17
      libavfilter/vf_drawtext.c

+ 93
- 3
doc/filters.texi View File

@@ -738,10 +738,13 @@ parameter @var{text}.
If both text and textfile are specified, an error is thrown.

@item x, y
The offsets where text will be drawn within the video frame.
Relative to the top/left border of the output image.
The expressions which specify the offsets where text will be drawn
within the video frame. They are relative to the top/left border of the
output image.

The default value of @var{x} and @var{y} is 0.
The default value of @var{x} and @var{y} is "0".

See below for the list of accepted constants.

@item fontsize
The font size to be used for drawing text.
@@ -809,6 +812,66 @@ The size in number of spaces to use for rendering the tab.
Default value is 4.
@end table

The parameters for @var{x} and @var{y} are expressions containing the
following constants:

@table @option
@item E, PI, PHI
the corresponding mathematical approximated values for e
(euler number), pi (greek PI), PHI (golden ratio)

@item w, h
the input width and heigth

@item tw, text_w
the width of the rendered text

@item th, text_h
the height of the rendered text

@item lh, line_h
the height of each text line

@item sar
input sample aspect ratio

@item dar
input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}

@item hsub, vsub
horizontal and vertical chroma subsample values. For example for the
pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.

@item max_glyph_w
maximum glyph width, that is the maximum width for all the glyphs
contained in the rendered text

@item max_glyph_h
maximum glyph height, that is the maximum height for all the glyphs
contained in the rendered text, it is equivalent to @var{ascent} -
@var{descent}.

@item max_glyph_a, ascent

the maximum distance from the baseline to the highest/upper grid
coordinate used to place a glyph outline point, for all the rendered
glyphs.
It is a positive value, due to the grid's orientation with the Y axis
upwards.

@item max_glyph_d, descent
the maximum distance from the baseline to the lowest grid coordinate
used to place a glyph outline point, for all the rendered glyphs.
This is a negative value, due to the grid's orientation, with the Y axis
upwards.

@item n
the number of input frame, starting from 0

@item t
timestamp expressed in seconds, NAN if the input timestamp is unknown
@end table

Some examples follow.

@itemize
@@ -835,6 +898,33 @@ drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test
Note that the double quotes are not necessary if spaces are not used
within the parameter list.

@item
Show the text at the center of the video frame:
@example
drawtext=fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
@end example

@item
Show a text line sliding from right to left in the last row of the video
frame. The file @file{LONG_LINE} is assumed to contain a single line
with no newlines.
@example
drawtext=fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t
@end example

@item
Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
@example
drawtext=fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
@end example

@item
Draw a single green letter "g", at the center of the input video.
The glyph baseline is placed at half screen height.
@example
drawtext=fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent
@end example

@end itemize

For more information about libfreetype, check:


+ 1
- 1
libavfilter/avfilter.h View File

@@ -30,7 +30,7 @@

#define LIBAVFILTER_VERSION_MAJOR 2
#define LIBAVFILTER_VERSION_MINOR 43
#define LIBAVFILTER_VERSION_MICRO 4
#define LIBAVFILTER_VERSION_MICRO 5

#define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
LIBAVFILTER_VERSION_MINOR, \


+ 142
- 17
libavfilter/vf_drawtext.c View File

@@ -30,6 +30,7 @@
#include <time.h>

#include "libavutil/colorspace.h"
#include "libavutil/eval.h"
#include "libavutil/file.h"
#include "libavutil/opt.h"
#include "libavutil/parseutils.h"
@@ -45,6 +46,54 @@
#include FT_FREETYPE_H
#include FT_GLYPH_H

static const char *var_names[] = {
"E",
"PHI",
"PI",
"w", ///< width of the input video
"h", ///< height of the input video
"tw", "text_w", ///< width of the rendered text
"th", "text_h", ///< height of the rendered text
"max_glyph_w", ///< max glyph width
"max_glyph_h", ///< max glyph height
"max_glyph_a", "ascent", ///< max glyph ascent
"max_glyph_d", "descent", ///< min glyph descent
"line_h", "lh", ///< line height, same as max_glyph_h
"sar",
"dar",
"hsub",
"vsub",
"x",
"y",
"n", ///< number of frame
"t", ///< timestamp expressed in seconds
NULL
};

enum var_name {
VAR_E,
VAR_PHI,
VAR_PI,
VAR_W,
VAR_H,
VAR_TW, VAR_TEXT_W,
VAR_TH, VAR_TEXT_H,
VAR_MAX_GLYPH_W,
VAR_MAX_GLYPH_H,
VAR_MAX_GLYPH_A, VAR_ASCENT,
VAR_MAX_GLYPH_D, VAR_DESCENT,
VAR_LINE_H, VAR_LH,
VAR_SAR,
VAR_DAR,
VAR_HSUB,
VAR_VSUB,
VAR_X,
VAR_Y,
VAR_N,
VAR_T,
VAR_VARS_NB
};

typedef struct {
const AVClass *class;
uint8_t *fontfile; ///< font to be used
@@ -57,6 +106,11 @@ typedef struct {
char *textfile; ///< file with text to be drawn
int x; ///< x position to start drawing text
int y; ///< y position to start drawing text
char *x_expr; ///< expression for x position
char *y_expr; ///< expression for y position
AVExpr *x_pexpr, *y_pexpr; ///< parsed expressions for x and y
int max_glyph_w; ///< max glyph width
int max_glyph_h; ///< max glyph heigth
int shadowx, shadowy;
unsigned int fontsize; ///< font size to use
char *fontcolor_string; ///< font color as string
@@ -82,6 +136,7 @@ typedef struct {
uint8_t rgba_map[4]; ///< map RGBA offsets to the positions in the packed RGBA format
uint8_t *box_line[4]; ///< line used for filling the box background
int64_t basetime; ///< base pts time in the real world for display
double var_values[VAR_VARS_NB];
} DrawTextContext;

#define OFFSET(x) offsetof(DrawTextContext, x)
@@ -95,8 +150,8 @@ static const AVOption drawtext_options[]= {
{"shadowcolor", "set shadow color", OFFSET(shadowcolor_string), FF_OPT_TYPE_STRING, {.str=NULL}, CHAR_MIN, CHAR_MAX },
{"box", "set box", OFFSET(draw_box), FF_OPT_TYPE_INT, {.dbl=0}, 0, 1 },
{"fontsize", "set font size", OFFSET(fontsize), FF_OPT_TYPE_INT, {.dbl=16}, 1, INT_MAX },
{"x", "set x", OFFSET(x), FF_OPT_TYPE_INT, {.dbl=0}, 0, INT_MAX },
{"y", "set y", OFFSET(y), FF_OPT_TYPE_INT, {.dbl=0}, 0, INT_MAX },
{"x", "set x expression", OFFSET(x_expr), FF_OPT_TYPE_STRING, {.str="0"}, CHAR_MIN, CHAR_MAX },
{"y", "set y expression", OFFSET(y_expr), FF_OPT_TYPE_STRING, {.str="0"}, CHAR_MIN, CHAR_MAX },
{"shadowx", "set x", OFFSET(shadowx), FF_OPT_TYPE_INT, {.dbl=0}, INT_MIN, INT_MAX },
{"shadowy", "set y", OFFSET(shadowy), FF_OPT_TYPE_INT, {.dbl=0}, INT_MIN, INT_MAX },
{"tabsize", "set tab size", OFFSET(tabsize), FF_OPT_TYPE_INT, {.dbl=4}, 0, INT_MAX },
@@ -348,12 +403,18 @@ static av_cold void uninit(AVFilterContext *ctx)
DrawTextContext *dtext = ctx->priv;
int i;

av_expr_free(dtext->x_pexpr); dtext->x_pexpr = NULL;
av_expr_free(dtext->y_pexpr); dtext->y_pexpr = NULL;

av_freep(&dtext->fontfile);
av_freep(&dtext->text);
av_freep(&dtext->expanded_text);
av_freep(&dtext->fontcolor_string);
av_freep(&dtext->boxcolor_string);
av_freep(&dtext->positions);
av_freep(&dtext->x_expr);
av_freep(&dtext->y_expr);

dtext->nb_positions = 0;
av_freep(&dtext->shadowcolor_string);
av_tree_enumerate(dtext->glyphs, NULL, NULL, glyph_enu_free);
@@ -371,6 +432,7 @@ static av_cold void uninit(AVFilterContext *ctx)

static int config_input(AVFilterLink *inlink)
{
AVFilterContext *ctx = inlink->dst;
DrawTextContext *dtext = inlink->dst->priv;
const AVPixFmtDescriptor *pix_desc = &av_pix_fmt_descriptors[inlink->format];
int ret;
@@ -398,6 +460,26 @@ static int config_input(AVFilterLink *inlink)
dtext->shadowcolor[3] = rgba[3];
}

dtext->var_values[VAR_E] = M_E;
dtext->var_values[VAR_PHI] = M_PHI;
dtext->var_values[VAR_PI] = M_PI;
dtext->var_values[VAR_W] = inlink->w;
dtext->var_values[VAR_H] = inlink->h;
dtext->var_values[VAR_SAR] = inlink->sample_aspect_ratio.num ? av_q2d(inlink->sample_aspect_ratio) : 1;
dtext->var_values[VAR_DAR] = (double)inlink->w / inlink->h * dtext->var_values[VAR_SAR];
dtext->var_values[VAR_HSUB] = 1<<pix_desc->log2_chroma_w;
dtext->var_values[VAR_VSUB] = 1<<pix_desc->log2_chroma_h;
dtext->var_values[VAR_X] = NAN;
dtext->var_values[VAR_Y] = NAN;
dtext->var_values[VAR_N] = 0;
dtext->var_values[VAR_T] = NAN;

if ((ret = av_expr_parse(&dtext->x_pexpr, dtext->x_expr, var_names,
NULL, NULL, NULL, NULL, 0, ctx)) < 0 ||
(ret = av_expr_parse(&dtext->y_pexpr, dtext->y_expr, var_names,
NULL, NULL, NULL, NULL, 0, ctx)) < 0)
return AVERROR(EINVAL);

return 0;
}

@@ -441,6 +523,9 @@ static inline int draw_glyph_yuv(AVFilterBufferRef *picref, FT_Bitmap *bitmap,

for (r = 0; r < bitmap->rows && r+y < height; r++) {
for (c = 0; c < bitmap->width && c+x < width; c++) {
if (c+x < 0 || r+y < 0)
continue;

/* get intensity value in the glyph bitmap (source) */
src_val = GET_BITMAP_VAL(r, c);
if (!src_val)
@@ -471,6 +556,8 @@ static inline int draw_glyph_rgb(AVFilterBufferRef *picref, FT_Bitmap *bitmap,

for (r = 0; r < bitmap->rows && r+y < height; r++) {
for (c = 0; c < bitmap->width && c+x < width; c++) {
if (c+x < 0 || r+y < 0)
continue;
/* get intensity value in the glyph bitmap (source) */
src_val = GET_BITMAP_VAL(r, c);
if (!src_val)
@@ -521,7 +608,7 @@ static int draw_glyphs(DrawTextContext *dtext, AVFilterBufferRef *picref,
{
char *text = dtext->expanded_text;
uint32_t code = 0;
int i;
int i, x1, y1;
uint8_t *p;
Glyph *glyph = NULL;

@@ -540,13 +627,16 @@ static int draw_glyphs(DrawTextContext *dtext, AVFilterBufferRef *picref,
glyph->bitmap.pixel_mode != FT_PIXEL_MODE_GRAY)
return AVERROR(EINVAL);

x1 = dtext->positions[i].x+dtext->x+x;
y1 = dtext->positions[i].y+dtext->y+y;

if (dtext->is_packed_rgb) {
draw_glyph_rgb(picref, &glyph->bitmap,
dtext->positions[i].x+x, dtext->positions[i].y+y, width, height,
x1, y1, width, height,
dtext->pixel_step[0], rgbcolor, dtext->rgba_map);
} else {
draw_glyph_yuv(picref, &glyph->bitmap,
dtext->positions[i].x+x, dtext->positions[i].y+y, width, height,
x1, y1, width, height,
yuvcolor, dtext->hsub, dtext->vsub);
}
}
@@ -560,11 +650,12 @@ static int draw_text(AVFilterContext *ctx, AVFilterBufferRef *picref,
DrawTextContext *dtext = ctx->priv;
uint32_t code = 0, prev_code = 0;
int x = 0, y = 0, i = 0, ret;
int text_height;
int max_text_line_w = 0, len;
int box_w, box_h;
char *text = dtext->text;
uint8_t *p;
int str_w = 0, len;
int y_min = 32000, y_max = -32000;
int x_min = 32000, x_max = -32000;
FT_Vector delta;
Glyph *glyph = NULL, *prev_glyph = NULL;
Glyph dummy = { 0 };
@@ -607,8 +698,8 @@ static int draw_text(AVFilterContext *ctx, AVFilterBufferRef *picref,
dtext->nb_positions = len;
}

x = dtext->x;
y = dtext->y;
x = 0;
y = 0;

/* load and cache glyphs */
for (i = 0, p = text; *p; i++) {
@@ -622,8 +713,11 @@ static int draw_text(AVFilterContext *ctx, AVFilterBufferRef *picref,

y_min = FFMIN(glyph->bbox.yMin, y_min);
y_max = FFMAX(glyph->bbox.yMax, y_max);
x_min = FFMIN(glyph->bbox.xMin, x_min);
x_max = FFMAX(glyph->bbox.xMax, x_max);
}
text_height = y_max - y_min;
dtext->max_glyph_h = y_max - y_min;
dtext->max_glyph_w = x_max - x_min;

/* compute and save position for each glyph */
glyph = NULL;
@@ -636,9 +730,9 @@ static int draw_text(AVFilterContext *ctx, AVFilterBufferRef *picref,

prev_code = code;
if (is_newline(code)) {
str_w = FFMAX(str_w, x - dtext->x);
y += text_height;
x = dtext->x;
max_text_line_w = FFMAX(max_text_line_w, x);
y += dtext->max_glyph_h;
x = 0;
continue;
}

@@ -661,12 +755,31 @@ static int draw_text(AVFilterContext *ctx, AVFilterBufferRef *picref,
else x += glyph->advance;
}

str_w = FFMIN(width - dtext->x - 1, FFMAX(str_w, x - dtext->x));
y = FFMIN(y + text_height, height - 1);
max_text_line_w = FFMAX(x, max_text_line_w);

dtext->var_values[VAR_TW] = dtext->var_values[VAR_TEXT_W] = max_text_line_w;
dtext->var_values[VAR_TH] = dtext->var_values[VAR_TEXT_H] = y + dtext->max_glyph_h;

dtext->var_values[VAR_MAX_GLYPH_W] = dtext->max_glyph_w;
dtext->var_values[VAR_MAX_GLYPH_H] = dtext->max_glyph_h;
dtext->var_values[VAR_MAX_GLYPH_A] = dtext->var_values[VAR_ASCENT ] = y_max;
dtext->var_values[VAR_MAX_GLYPH_D] = dtext->var_values[VAR_DESCENT] = y_min;

dtext->var_values[VAR_LINE_H] = dtext->var_values[VAR_LH] = dtext->max_glyph_h;

dtext->x = dtext->var_values[VAR_X] = av_expr_eval(dtext->x_pexpr, dtext->var_values, NULL);
dtext->y = dtext->var_values[VAR_Y] = av_expr_eval(dtext->y_pexpr, dtext->var_values, NULL);
dtext->x = dtext->var_values[VAR_X] = av_expr_eval(dtext->x_pexpr, dtext->var_values, NULL);

dtext->x &= ~((1 << dtext->hsub) - 1);
dtext->y &= ~((1 << dtext->vsub) - 1);

box_w = FFMIN(width - 1 , max_text_line_w);
box_h = FFMIN(height - 1, y + dtext->max_glyph_h);

/* draw box */
if (dtext->draw_box)
drawbox(picref, dtext->x, dtext->y, str_w, y-dtext->y,
drawbox(picref, dtext->x, dtext->y, box_w, box_h,
dtext->box_line, dtext->pixel_step, dtext->boxcolor_rgba,
dtext->hsub, dtext->vsub, dtext->is_packed_rgb, dtext->rgba_map);

@@ -688,9 +801,21 @@ static void null_draw_slice(AVFilterLink *link, int y, int h, int slice_dir) { }
static void end_frame(AVFilterLink *inlink)
{
AVFilterLink *outlink = inlink->dst->outputs[0];
AVFilterContext *ctx = inlink->dst;
DrawTextContext *dtext = inlink->dst->priv;
AVFilterBufferRef *picref = inlink->cur_buf;

draw_text(inlink->dst, picref, picref->video->w, picref->video->h);
dtext->var_values[VAR_T] = picref->pts == AV_NOPTS_VALUE ?
NAN : picref->pts * av_q2d(inlink->time_base);

draw_text(ctx, picref, picref->video->w, picref->video->h);

av_log(ctx, AV_LOG_DEBUG, "n:%d t:%f text_w:%d text_h:%d x:%d y:%d\n",
(int)dtext->var_values[VAR_N], dtext->var_values[VAR_T],
(int)dtext->var_values[VAR_TEXT_W], (int)dtext->var_values[VAR_TEXT_H],
dtext->x, dtext->y);

dtext->var_values[VAR_N] += 1.0;

avfilter_draw_slice(outlink, 0, picref->video->h, 1);
avfilter_end_frame(outlink);


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