lavfi/drawtext: add alias "expr_int_format" to expansion function "eif"

Reviewed-by: Stefano Sabatini <stefasab@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

doc/filters.texi

@@ -3916,7 +3916,7 @@ example the text size is not known when evaluating the expression, so
 the constants @var{text_w} and @var{text_h} will have an undefined
 value.
 
-@item eif
+@item expr_int_format, eif
 Evaluate the expression's value and output as formatted integer.
 
 First argument is expression to be evaluated, same as for @var{expr} function.

libavfilter/vf_drawtext.c

@@ -949,7 +949,7 @@ static int func_eval_expr_int_format(AVFilterContext *ctx, AVBPrint *bp,
     if (argc == 3) {
         ret = sscanf(argv[2], "%u", &positions);
         if (ret != 1) {
-            av_log(ctx, AV_LOG_ERROR, "eif(): Invalid number of positions"
+            av_log(ctx, AV_LOG_ERROR, "expr_int_format(): Invalid number of positions"
                     " to print: '%s'\n", argv[2]);
             return AVERROR(EINVAL);
         }
@@ -982,6 +982,7 @@ static const struct drawtext_function {
 } functions[] = {
     { "expr",      1, 1, 0,   func_eval_expr },
     { "e",         1, 1, 0,   func_eval_expr },
+    { "expr_int_format", 2, 3, 0, func_eval_expr_int_format },
     { "eif",       2, 3, 0,   func_eval_expr_int_format },
     { "pict_type", 0, 0, 0,   func_pict_type },
     { "pts",       0, 2, 0,   func_pts      },