[pango/small-caps: 10/11] itemize: Handle PANGO_FONT_SCALE_PETITE_CAPS

[Matthias Clasen <matthiasc src gnome org>]

commit 9f691c300fb83b985c133d6bbf04a894d3c292dc
Author: Matthias Clasen <mclasen redhat com>
Date:   Sat Nov 6 23:51:09 2021 -0400

    itemize: Handle PANGO_FONT_SCALE_PETITE_CAPS
    
    For lack of a better idea, simply multiply the
    value we use for Small Caps by 0.8.
    
    This is not used by anything yet.

 pango/itemize.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)
---
diff --git a/pango/itemize.c b/pango/itemize.c
index e8267725..f115abdf 100644
--- a/pango/itemize.c
+++ b/pango/itemize.c
@@ -1103,6 +1103,18 @@ collect_font_scale (PangoContext  *context,
                   else
                      entry->scale = 0.8;
                   break;
+                case PANGO_FONT_SCALE_PETITE_CAPS:
+                  if (hb_font &&
+                      hb_ot_metrics_get_position (hb_font,
+                                                  HB_OT_METRICS_TAG_CAP_HEIGHT,
+                                                  &cap_height) &&
+                      hb_ot_metrics_get_position (hb_font,
+                                                  HB_OT_METRICS_TAG_X_HEIGHT,
+                                                  &x_height))
+                     entry->scale = 0.8 * x_height / (double) cap_height;
+                  else
+                     entry->scale = 0.8 * 0.8;
+                  break;
                 default:
                   g_assert_not_reached ();
                 }