Add horizontal displacement

Apply horizontal displacements for superscripts and subscripts
that are provided in font metrics. This noticably improves the
placement of superscripts in italics.

Currently, we only apply these displacements in post-processing,
and ignore the width changes during line-breaking. This could
be improved by moving the baseline handling into the line-breaking
proper.

1 files changed, 8 insertions, 2 deletions

diff --git a/pango/pango-glyph-item.h b/pango/pango-glyph-item.h
index baea69fc..fd8951d2 100644
--- a/pango/pango-glyph-item.h
+++ b/pango/pango-glyph-item.h
@@ -33,8 +33,12 @@ G_BEGIN_DECLS
  * PangoGlyphItem:
  * @item: corresponding `PangoItem`
  * @glyphs: corresponding `PangoGlyphString`
- * @baseline: shift of the baseline, relative to the
- *   containing lines baseline. Positive values shift upwards
+ * @y_offset: shift of the baseline, relative to the baseline
+ *   of the containing line. Positive values shift upwards
+ * @start_x_offset: horizontal displacement to apply before the
+ *   glyph item. Positive values shift right
+ * @end_x_offset: horizontal displacement to apply after th
+ *   glyph item. Positive values shift right
  *
  * A `PangoGlyphItem` is a pair of a `PangoItem` and the glyphs
  * resulting from shaping the items text.
@@ -50,6 +54,8 @@ struct _PangoGlyphItem
   PangoItem *item;
   PangoGlyphString *glyphs;
   int y_offset;
+  int start_x_offset;
+  int end_x_offset;
 };
 
 #define PANGO_TYPE_GLYPH_ITEM (pango_glyph_item_get_type ())