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drawtext: introduce rand(min, max) 

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
This commit is contained in:
Luca Barbato 2011-12-05 00:56:21 +01:00
parent 73585620b8
commit f5edfc9e92
1 changed files with 27 additions and 7 deletions
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34
libavfilter/vf_drawtext.c
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@ -34,9 +34,11 @@
#include "libavutil/eval.h"
#include "libavutil/opt.h"
#include "libavutil/mathematics.h"
#include "libavutil/random_seed.h"
#include "libavutil/parseutils.h"
#include "libavutil/pixdesc.h"
#include "libavutil/tree.h"
#include "libavutil/lfg.h"
#include "avfilter.h"
#include "drawutils.h"
@ -62,6 +64,22 @@ static const char *var_names[] = {
NULL
};
static const char *fun2_names[] = {
"rand",
};
static double drand(void *opaque, double min, double max)
{
return val = min + (max-min) / UINT_MAX * av_lfg_get(opaque);
}
typedef double (*eval_func2)(void *, double a, double b);
static const eval_func2 fun2[] = {
drand,
NULL
};
enum var_name {
VAR_E,
VAR_PHI,
@ -119,6 +137,7 @@ typedef struct {
char *d_expr;
AVExpr *d_pexpr;
int draw; ///< set to zero to prevent drawing
AVLFG prng; ///< random
} DrawTextContext;
#define OFFSET(x) offsetof(DrawTextContext, x)
@ -559,13 +578,14 @@ static int config_input(AVFilterLink *inlink)
dtext->var_values[VAR_N] = 0;
dtext->var_values[VAR_T] = NAN;
av_lfg_init(&dtext->prng, av_get_random_seed());
if ((ret = av_expr_parse(&dtext->x_pexpr, dtext->x_expr, var_names,
NULL, NULL, NULL, NULL, 0, ctx)) < 0 ||
NULL, NULL, fun2_names, fun2, 0, ctx)) < 0 ||
(ret = av_expr_parse(&dtext->y_pexpr, dtext->y_expr, var_names,
NULL, NULL, NULL, NULL, 0, ctx)) < 0 ||
NULL, NULL, fun2_names, fun2, 0, ctx)) < 0 ||
(ret = av_expr_parse(&dtext->d_pexpr, dtext->d_expr, var_names,
NULL, NULL, NULL, NULL, 0, ctx)) < 0)
NULL, NULL, fun2_names, fun2, 0, ctx)) < 0)
return AVERROR(EINVAL);
if ((ret =
@ -792,14 +812,14 @@ static void start_frame(AVFilterLink *inlink, AVFilterBufferRef *inpicref)
dtext->var_values[VAR_T] = inpicref->pts == AV_NOPTS_VALUE ?
NAN : inpicref->pts * av_q2d(inlink->time_base);
dtext->var_values[VAR_X] =
av_expr_eval(dtext->x_pexpr, dtext->var_values, NULL);
av_expr_eval(dtext->x_pexpr, dtext->var_values, &dtext->prng);
dtext->var_values[VAR_Y] =
av_expr_eval(dtext->y_pexpr, dtext->var_values, NULL);
av_expr_eval(dtext->y_pexpr, dtext->var_values, &dtext->prng);
dtext->var_values[VAR_X] =
av_expr_eval(dtext->x_pexpr, dtext->var_values, NULL);
av_expr_eval(dtext->x_pexpr, dtext->var_values, &dtext->prng);
dtext->draw = fail ? 0 :
av_expr_eval(dtext->d_pexpr, dtext->var_values, NULL);
av_expr_eval(dtext->d_pexpr, dtext->var_values, &dtext->prng);
normalize_double(&dtext->x, dtext->var_values[VAR_X]);
normalize_double(&dtext->y, dtext->var_values[VAR_Y]);