[pango/fix-small-caps-line-height: 47/48] Add some private api

[Matthias Clasen <matthiasc src gnome org>]

commit 6770050e74cf83830e255f1d1e9b574feb5a60fc
Author: Matthias Clasen <mclasen redhat com>
Date:   Sun Dec 19 10:39:37 2021 -0500

    Add some private api
    
    Add some api to let us store another font in
    a PangoAnalysis. This will be used in the following
    commits.

 pango/pango-item-private.h | 22 ++++++++++++++++++++++
 pango/pango-item.c         | 41 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 63 insertions(+)
---
diff --git a/pango/pango-item-private.h b/pango/pango-item-private.h
index 6e20953f..9d2fa805 100644
--- a/pango/pango-item-private.h
+++ b/pango/pango-item-private.h
@@ -38,6 +38,24 @@ G_BEGIN_DECLS
 
 #define PANGO_ANALYSIS_FLAG_HAS_CHAR_OFFSET (1 << 7)
 
+typedef struct _PangoAnalysisPrivate PangoAnalysisPrivate;
+
+struct _PangoAnalysisPrivate
+{
+  gpointer reserved;
+  PangoFont *size_font;
+  PangoFont *font;
+
+  guint8 level;
+  guint8 gravity;
+  guint8 flags;
+
+  guint8 script;
+  PangoLanguage *language;
+
+  GSList *extra_attrs;
+};
+
 typedef struct _PangoItemPrivate PangoItemPrivate;
 
 #if defined(__x86_64__) && !defined(__ILP32__)
@@ -74,6 +92,10 @@ void               pango_analysis_collect_features    (const PangoAnalysis
                                                        guint                       length,
                                                        guint                      *num_features);
 
+void               pango_analysis_set_size_font       (PangoAnalysis              *analysis,
+                                                       PangoFont                  *font);
+PangoFont *        pango_analysis_get_size_font       (const PangoAnalysis        *analysis);
+
 GList *            pango_itemize_with_font            (PangoContext               *context,
                                                        PangoDirection              base_dir,
                                                        const char                 *text,
diff --git a/pango/pango-item.c b/pango/pango-item.c
index 2b2664c5..d7291a08 100644
--- a/pango/pango-item.c
+++ b/pango/pango-item.c
@@ -324,3 +324,44 @@ pango_analysis_collect_features (const PangoAnalysis *analysis,
         }
     }
 }
+
+/*< private >
+ * pango_analysis_set_size_font:
+ * @analysis: a `PangoAnalysis`
+ * @font: a `PangoFont`
+ *
+ * Sets the font to use for determining the line height.
+ *
+ * This is used when scaling fonts for emulated Small Caps,
+ * to preserve the original line height.
+ */
+void
+pango_analysis_set_size_font (PangoAnalysis *analysis,
+                              PangoFont     *font)
+{
+  PangoAnalysisPrivate *priv = (PangoAnalysisPrivate *)analysis;
+
+  if (priv->size_font)
+    g_object_unref (priv->size_font);
+  priv->size_font = font;
+  if (priv->size_font)
+    g_object_ref (priv->size_font);
+}
+
+/*< private >
+ * pango_analysis_get_size_font:
+ * @analysis: a `PangoAnalysis`
+ *
+ * Gets the font to use for determining line height.
+ *
+ * If this returns `NULL`, use analysis->font.
+ *
+ * Returns: (nullable) (transfer none): the font
+ */
+PangoFont *
+pango_analysis_get_size_font (const PangoAnalysis *analysis)
+{
+  PangoAnalysisPrivate *priv = (PangoAnalysisPrivate *)analysis;
+
+  return priv->size_font;
+}