sub: allow rendering OSD in ASS image format directly, simplify

Before this commit, the OSD was drawn using libass, but the resulting
bitmaps were converted to the internal mplayer OSD format. We want to
get rid of the old OSD format, because it's monochrome, and can't even
be rendered directly using modern video output methods (like with
OpenGL/Direct3D/VDPAU).

Change it so that VOs can get the ASS images directly, without
additional conversions. (This also has the consequence that the OSD can
render colors now.) Currently, this is vo_gl3 only. The other VOs still
use the old method. Also, the old OSD format is still used for all VOs
with DVD subtitles (spudec).

Rewrite sub.c. Remove all the awkward flags and bounding boxes and
change detection things. It turns out that much of that isn't needed.

Move code related to converting subtitle images to img_convert.c. (It
has to be noted that all of these conversions were already done before
in some places, and that the new code actually makes less use of them.)

1 files changed, 60 insertions, 135 deletions

diff --git a/sub/osd_libass.c b/sub/osd_libass.c
index e770215ce6..2d596a6516 100644
--- a/sub/osd_libass.c
+++ b/sub/osd_libass.c
@@ -55,117 +55,13 @@ void osd_init_backend(struct osd_state *osd)
 
 void osd_destroy_backend(struct osd_state *osd)
 {
-    if (osd) {
-        if (osd->osd_render)
-            ass_renderer_done(osd->osd_render);
-        osd->osd_render = NULL;
-        ass_library_done(osd->osd_ass_library);
-        osd->osd_ass_library = NULL;
-    }
-}
-
-static void eosd_draw_alpha_a8i8(unsigned char *src,
-                                 int src_w, int src_h,
-                                 int src_stride,
-                                 unsigned char *dst_a,
-                                 unsigned char *dst_i,
-                                 size_t dst_stride,
-                                 int dst_x, int dst_y,
-                                 uint32_t color)
-{
-    const unsigned int r = (color >> 24) & 0xff;
-    const unsigned int g = (color >> 16) & 0xff;
-    const unsigned int b = (color >>  8) & 0xff;
-    const unsigned int a = 0xff - (color & 0xff);
-
-    int gray = (r + g + b) / 3; // not correct
-
-    dst_a += dst_y * dst_stride + dst_x;
-    dst_i += dst_y * dst_stride + dst_x;
-
-    int src_skip = src_stride - src_w;
-    int dst_skip = dst_stride - src_w;
-
-    for (int y = 0; y < src_h; y++) {
-        for (int x = 0; x < src_w; x++) {
-            unsigned char as = (*src * a) >> 8;
-            unsigned char bs = (gray * as) >> 8;
-            // to mplayer scale
-            as = -as;
-
-            unsigned char *a = dst_a;
-            unsigned char *b = dst_i;
-
-            // NOTE: many special cases, because alpha=0 means transparency,
-            //       while alpha=1..255 is opaque..transparent
-            if (as) {
-                *b = ((*b * as) >> 8) + bs;
-                if (*a) {
-                    *a = (*a * as) >> 8;
-                    if (*a < 1)
-                        *a = 1;
-                } else {
-                    *a = as;
-                }
-            }
-
-            dst_a++;
-            dst_i++;
-            src++;
-        }
-        dst_a += dst_skip;
-        dst_i += dst_skip;
-        src += src_skip;
-    }
-}
-
-static void eosd_render_a8i8(unsigned char *a, unsigned char *i, size_t stride,
-                             int x, int y, ASS_Image *imgs)
-{
-    for (ASS_Image *p = imgs; p; p = p->next) {
-        eosd_draw_alpha_a8i8(p->bitmap, p->w, p->h, p->stride, a, i, stride,
-                             x + p->dst_x, y + p->dst_y, p->color);
-    }
-}
-
-static bool ass_bb(ASS_Image *imgs, int *x1, int *y1, int *x2, int *y2)
-{
-    *x1 = *y1 = INT_MAX;
-    *x2 = *y2 = INT_MIN;
-    for (ASS_Image *p = imgs; p; p = p->next) {
-        *x1 = FFMIN(*x1, p->dst_x);
-        *y1 = FFMIN(*y1, p->dst_y);
-        *x2 = FFMAX(*x2, p->dst_x + p->w);
-        *y2 = FFMAX(*y2, p->dst_y + p->h);
-    }
-    return *x1 < *x2 && *y1 < *y2;
-}
-
-static void draw_ass_osd(struct osd_state *osd, mp_osd_obj_t *obj)
-{
-    ass_set_frame_size(osd->osd_render, osd->w, osd->h);
-
-    ASS_Image *imgs = ass_render_frame(osd->osd_render, obj->osd_track, 0,
-                                       NULL);
-
-    int x1, y1, x2, y2;
-    if (!ass_bb(imgs, &x1, &y1, &x2, &y2)) {
-        obj->flags &= ~OSDFLAG_VISIBLE;
-        return;
-    }
-
-    obj->bbox.x1 = x1;
-    obj->bbox.y1 = y1;
-    obj->bbox.x2 = x2;
-    obj->bbox.y2 = y2;
-    obj->flags |= OSDFLAG_BBOX;
-    osd_alloc_buf(obj);
-
-    eosd_render_a8i8(obj->alpha_buffer, obj->bitmap_buffer, obj->stride,
-                     -x1, -y1, imgs);
+    if (osd->osd_render)
+        ass_renderer_done(osd->osd_render);
+    osd->osd_render = NULL;
+    ass_library_done(osd->osd_ass_library);
+    osd->osd_ass_library = NULL;
 }
 
-
 static void update_font_scale(ASS_Track *track, ASS_Style *style, double factor)
 {
     // duplicated from ass_mp.c
@@ -211,9 +107,16 @@ static ASS_Event *get_osd_ass_event(ASS_Track *track)
     event->Start = 0;
     event->Duration = 100;
     event->Style = track->default_style;
+    assert(event->Text == NULL);
     return event;
 }
 
+static void clear_obj(struct osd_object *obj)
+{
+    if (obj->osd_track)
+        ass_flush_events(obj->osd_track);
+}
+
 static char *append_utf8_buffer(char *buffer, uint32_t codepoint)
 {
     char data[8];
@@ -257,25 +160,27 @@ static char *mangle_ass(const char *in)
     return res;
 }
 
-void vo_update_text_osd(struct osd_state *osd, mp_osd_obj_t* obj)
+static void update_osd(struct osd_state *osd, struct osd_object *obj)
 {
+    if (!osd->osd_text[0]) {
+        clear_obj(obj);
+        return;
+    }
+
     if (!obj->osd_track)
         obj->osd_track = create_osd_ass_track(osd);
     ASS_Event *event = get_osd_ass_event(obj->osd_track);
-    event->Text = mangle_ass(osd->osd_text);
-    draw_ass_osd(osd, obj);
-    talloc_free(event->Text);
-    event->Text = NULL;
+    char *text = mangle_ass(osd->osd_text);
+    event->Text = strdup(text);
+    talloc_free(text);
 }
 
 #define OSDBAR_ELEMS 46
 
-void vo_update_text_progbar(struct osd_state *osd, mp_osd_obj_t* obj)
+static void update_progbar(struct osd_state *osd, struct osd_object *obj)
 {
-    obj->flags |= OSDFLAG_CHANGED | OSDFLAG_VISIBLE;
-
     if (vo_osd_progbar_type < 0) {
-        obj->flags &= ~OSDFLAG_VISIBLE;
+        clear_obj(obj);
         return;
     }
 
@@ -322,21 +227,16 @@ void vo_update_text_progbar(struct osd_state *osd, mp_osd_obj_t* obj)
     text = append_utf8_buffer(text, OSD_CODEPOINTS + OSD_PB_END);
 
     ASS_Event *event = get_osd_ass_event(obj->osd_track);
-    event->Text = text;
-    draw_ass_osd(osd, obj);
-    event->Text = NULL;
-
+    event->Text = strdup(text);
     talloc_free(text);
 }
 
-void vo_update_text_sub(struct osd_state *osd, mp_osd_obj_t* obj)
+static void update_sub(struct osd_state *osd, struct osd_object *obj)
 {
     struct MPOpts *opts = osd->opts;
 
-    obj->flags |= OSDFLAG_CHANGED | OSDFLAG_VISIBLE;
-
-    if (!vo_sub || !opts->sub_visibility) {
-        obj->flags &= ~OSDFLAG_VISIBLE;
+    if (!(vo_sub && opts->sub_visibility)) {
+        clear_obj(obj);
         return;
     }
 
@@ -354,14 +254,39 @@ void vo_update_text_sub(struct osd_state *osd, mp_osd_obj_t* obj)
         text = talloc_asprintf_append_buffer(text, "%s\n", vo_sub->text[n]);
 
     ASS_Event *event = get_osd_ass_event(obj->osd_track);
-    event->Text = mangle_ass(text);
-    draw_ass_osd(osd, obj);
-    talloc_free(event->Text);
-    event->Text = NULL;
-
+    char *escaped_text = mangle_ass(text);
+    event->Text = strdup(escaped_text);
+    talloc_free(escaped_text);
     talloc_free(text);
 }
 
-// unneeded
-void osd_font_invalidate(void) {}
-void osd_font_load(struct osd_state *osd) {}
+static void update_object(struct osd_state *osd, struct osd_object *obj)
+{
+    switch (obj->type) {
+    case OSDTYPE_OSD:
+        update_osd(osd, obj);
+        break;
+    case OSDTYPE_SUBTITLE:
+        update_sub(osd, obj);
+        break;
+    case OSDTYPE_PROGBAR:
+        update_progbar(osd, obj);
+        break;
+    }
+}
+
+void osd_object_get_bitmaps(struct osd_state *osd, struct osd_object *obj,
+                            struct sub_bitmaps *out_imgs)
+{
+    if (obj->force_redraw)
+        update_object(osd, obj);
+
+    *out_imgs = (struct sub_bitmaps) {0};
+    if (!obj->osd_track)
+        return;
+
+    ass_set_frame_size(osd->osd_render, osd->w, osd->h);
+    mp_ass_render_frame(osd->osd_render, obj->osd_track, 0,
+                        &obj->parts_cache, out_imgs);
+    talloc_steal(obj, obj->parts_cache);
+}