[pango/baseline-shift: 4/5] markup: Change <sup> and <sub>

[Matthias Clasen <matthiasc src gnome org>]

commit fb3ba7ad8f371e5750fdf4d24bf0aea98653471b
Author: Matthias Clasen <mclasen redhat com>
Date:   Sun Aug 29 16:37:02 2021 -0400

    markup: Change <sup> and <sub>
    
    Use the new baseline-shift and font-scale attributes
    to reimplement <sup> and <sub>.
    
    Now they take font metrics into account and nest
    properly.

 pango/pango-markup.c           | 22 ++++------------------
 tests/markups/valid-4.expected |  8 ++++----
 2 files changed, 8 insertions(+), 22 deletions(-)
---
diff --git a/pango/pango-markup.c b/pango/pango-markup.c
index 54c08c67..791e71fd 100644
--- a/pango/pango-markup.c
+++ b/pango/pango-markup.c
@@ -1833,8 +1833,6 @@ s_parse_func        (MarkupData            *md G_GNUC_UNUSED,
   return TRUE;
 }
 
-#define SUPERSUB_RISE 5000
-
 static gboolean
 sub_parse_func      (MarkupData            *md G_GNUC_UNUSED,
                     OpenTag               *tag,
@@ -1845,14 +1843,8 @@ sub_parse_func      (MarkupData            *md G_GNUC_UNUSED,
 {
   CHECK_NO_ATTRS("sub");
 
-  /* Shrink font, and set a negative rise */
-  if (tag)
-    {
-      tag->scale_level_delta -= 1;
-      tag->scale_level -= 1;
-    }
-
-  add_attribute (tag, pango_attr_rise_new (-SUPERSUB_RISE));
+  add_attribute (tag, pango_attr_font_scale_new (PANGO_FONT_SCALE_SUBSCRIPT));
+  add_attribute (tag, pango_attr_baseline_shift_new (PANGO_BASELINE_SHIFT_SUBSCRIPT));
 
   return TRUE;
 }
@@ -1867,14 +1859,8 @@ sup_parse_func      (MarkupData            *md G_GNUC_UNUSED,
 {
   CHECK_NO_ATTRS("sup");
 
-  /* Shrink font, and set a positive rise */
-  if (tag)
-    {
-      tag->scale_level_delta -= 1;
-      tag->scale_level -= 1;
-    }
-
-  add_attribute (tag, pango_attr_rise_new (SUPERSUB_RISE));
+  add_attribute (tag, pango_attr_font_scale_new (PANGO_FONT_SCALE_SUPERSCRIPT));
+  add_attribute (tag, pango_attr_baseline_shift_new (PANGO_BASELINE_SHIFT_SUPERSCRIPT));
 
   return TRUE;
 }
diff --git a/tests/markups/valid-4.expected b/tests/markups/valid-4.expected
index 0391ec8e..a9e16728 100644
--- a/tests/markups/valid-4.expected
+++ b/tests/markups/valid-4.expected
@@ -18,8 +18,8 @@ range 16 29
 [16,41]strikethrough=1
 range 29 32
 [16,41]strikethrough=1
-[29,32]scale=0.833333
-[29,32]rise=-5000
+[29,32]font-scale=2
+[29,32]baseline-shift=2
 range 32 33
 [16,41]strikethrough=1
 range 33 38
@@ -27,8 +27,8 @@ range 33 38
 [33,38]scale=0.833333
 range 38 41
 [16,41]strikethrough=1
-[38,41]scale=0.833333
-[38,41]rise=5000
+[38,41]font-scale=1
+[38,41]baseline-shift=1
 range 41 42
 range 42 45
 [42,54]family=Monospace