sd_lavc, sd_spu: make dvdsub stretching conditional on --stretch-dvd-subs.

We found that the stretching - although it usually improves the looks of
the fonts - is incorrect.

On DVD, subtitles can cover the full area of the picture, and they have
the same pixel aspect as the movie itself.

Too bad many commercially released DVDs use bitmap fonts made with the
wrong pixel aspect (i.e. assuming 1:1) - --stretch-dvd-subs will make
these more pretty then.

1 files changed, 5 insertions, 4 deletions

diff --git a/sub/spudec.c b/sub/spudec.c
index 56d7ca1eae..5d58b3664c 100644
--- a/sub/spudec.c
+++ b/sub/spudec.c
@@ -644,6 +644,7 @@ void spudec_set_forced_subs_only(void * const this, const unsigned int flag)
 }
 
 void spudec_get_indexed(void *this, struct mp_osd_res *dim,
+                        double xstretch, double ystretch,
                         struct sub_bitmaps *res)
 {
     spudec_handle_t *spu = this;
@@ -656,10 +657,10 @@ void spudec_get_indexed(void *this, struct mp_osd_res *dim,
     if (spudec_visible(spu) && !empty) {
         double xscale = (double) (dim->w - dim->ml - dim->mr) / spu->orig_frame_width;
         double yscale = (double) (dim->h - dim->mt - dim->mb) / spu->orig_frame_height;
-        part->x = part->x * xscale + dim->ml;
-        part->y = part->y * yscale + dim->mt;
-        part->dw = part->w * xscale;
-        part->dh = part->h * yscale;
+        part->x = part->x * xscale * xstretch + dim->ml + dim->w * (0.5 - 0.5 * xstretch);
+        part->y = part->y * yscale * ystretch + dim->mt + dim->h * (0.5 - 0.5 * ystretch);
+        part->dw = part->w * xscale * xstretch;
+        part->dh = part->h * yscale * ystretch;
         res->num_parts = 1;
         res->scaled = true;
     }