From: Grigori Goronzy <greg@blackbox>
Date: Thu, 12 Aug 2010 20:15:10 +0000 (+0200)
Subject: Add support for \fs+ and \fs- syntax
X-Git-Tag: 0.9.12~16
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=4d64333a58be5e57834fad576de23f95612a2604;p=libass

Add support for \fs+ and \fs- syntax

These forms can be used to add or subtract a value from the
current font size instead of setting a new font size. Animations
are supported, but not recommended, as they won't be fluid due to
grid-fitting/hinting.
---

diff --git a/libass/ass_parse.c b/libass/ass_parse.c
index 776416d..40aaf04 100644
--- a/libass/ass_parse.c
+++ b/libass/ass_parse.c
@@ -359,6 +359,22 @@ static char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
                 render_priv->state.hspacing * (1 - pwr) + val * pwr;
         else
             render_priv->state.hspacing = render_priv->state.style->Spacing;
+    } else if (mystrcmp(&p, "fs+")) {
+        double val;
+        if (mystrtod(&p, &val)) {
+            val = render_priv->state.font_size + pwr * val;
+        } else
+            val = render_priv->state.style->FontSize;
+        if (render_priv->state.font)
+            change_font_size(render_priv, val);
+    } else if (mystrcmp(&p, "fs-")) {
+        double val;
+        if (mystrtod(&p, &val))
+            val = render_priv->state.font_size - pwr * val;
+        else
+            val = render_priv->state.style->FontSize;
+        if (render_priv->state.font)
+            change_font_size(render_priv, val);
     } else if (mystrcmp(&p, "fs")) {
         double val;
         if (mystrtod(&p, &val))