Introduce bitmap runs

Prepare for run-based rendering. In the parser, increment a run id
according to relevant style changes (color, border, shadow, etc.) to
mark the points where a new bitmap needs to be started. Modify the line
wrapper to increment the run ids of each glyph after a break.
Add functions to calculate the render size of runs for rasterization.

1 files changed, 13 insertions, 0 deletions

diff --git a/libass/ass_parse.c b/libass/ass_parse.c
index d9fcb76..a0181bd 100644
--- a/libass/ass_parse.c
+++ b/libass/ass_parse.c
@@ -255,6 +255,7 @@ static char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
         else
             val = -1.;
         change_border(render_priv, val, render_priv->state.border_y);
+        render_priv->state.bm_run_id++;
     } else if (mystrcmp(&p, "ybord")) {
         double val;
         if (mystrtod(&p, &val))
@@ -269,6 +270,7 @@ static char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
         else
             val = 0.;
         render_priv->state.shadow_x = val;
+        render_priv->state.bm_run_id++;
     } else if (mystrcmp(&p, "yshad")) {
         double val;
         if (mystrtod(&p, &val))
@@ -276,6 +278,7 @@ static char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
         else
             val = 0.;
         render_priv->state.shadow_y = val;
+        render_priv->state.bm_run_id++;
     } else if (mystrcmp(&p, "fax")) {
         double val;
         if (mystrtod(&p, &val))
@@ -327,6 +330,7 @@ static char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
             render_priv->state.blur = val;
         } else
             render_priv->state.blur = 0.0;
+        render_priv->state.bm_run_id++;
         // ASS standard tags
     } else if (mystrcmp(&p, "fsc")) {
         char tp = *p++;
@@ -387,6 +391,7 @@ static char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
         } else
             val = -1.;          // reset to default
         change_border(render_priv, val, val);
+        render_priv->state.bm_run_id++;
     } else if (mystrcmp(&p, "move")) {
         double x1, x2, y1, y2;
         long long t1, t2, delta_t, t;
@@ -488,6 +493,7 @@ static char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
             change_alpha(&render_priv->state.c[3],
                          render_priv->state.style->BackColour, pwr);
         }
+        render_priv->state.bm_run_id++;
         // FIXME: simplify
     } else if (mystrcmp(&p, "an")) {
         int val;
@@ -678,6 +684,7 @@ static char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
             val = render_priv->state.style->PrimaryColour;
         ass_msg(render_priv->library, MSGL_DBG2, "color: %X", val);
         change_color(&render_priv->state.c[0], val, pwr);
+        render_priv->state.bm_run_id++;
     } else if ((*p >= '1') && (*p <= '4') && (++p)
                && (mystrcmp(&p, "c") || mystrcmp(&p, "a"))) {
         char n = *(p - 2);
@@ -707,9 +714,11 @@ static char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
         switch (cmd) {
         case 'c':
             change_color(render_priv->state.c + cidx, val, pwr);
+            render_priv->state.bm_run_id++;
             break;
         case 'a':
             change_alpha(render_priv->state.c + cidx, val >> 24, pwr);
+            render_priv->state.bm_run_id++;
             break;
         default:
             ass_msg(render_priv->library, MSGL_WARN, "Bad command: %c%c",
@@ -729,6 +738,7 @@ static char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
             render_priv->state.be = val;
         } else
             render_priv->state.be = 0;
+        render_priv->state.bm_run_id++;
     } else if (mystrcmp(&p, "b")) {
         int b;
         if (mystrtoi(&p, &b)) {
@@ -777,18 +787,21 @@ static char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
         } else
             val = 0.;
         render_priv->state.shadow_x = render_priv->state.shadow_y = val;
+        render_priv->state.bm_run_id++;
     } else if (mystrcmp(&p, "s")) {
         int val;
         if (mystrtoi(&p, &val) && val)
             render_priv->state.flags |= DECO_STRIKETHROUGH;
         else
             render_priv->state.flags &= ~DECO_STRIKETHROUGH;
+        render_priv->state.bm_run_id++;
     } else if (mystrcmp(&p, "u")) {
         int val;
         if (mystrtoi(&p, &val) && val)
             render_priv->state.flags |= DECO_UNDERLINE;
         else
             render_priv->state.flags &= ~DECO_UNDERLINE;
+        render_priv->state.bm_run_id++;
     } else if (mystrcmp(&p, "pbo")) {
         double val = 0;
         if (mystrtod(&p, &val))