[pango/tab-align: 2/7] tabs: Add other tab alignments

[Matthias Clasen <matthiasc src gnome org>]

commit 2bc403c143635875d25df85ad2f7791badd7e28e
Author: Matthias Clasen <mclasen redhat com>
Date:   Sun Nov 28 16:24:35 2021 -0500

    tabs: Add other tab alignments
    
    Add right, center, decimal tab alignments and support
    them in serialization. They are not implemented yet.

 pango/pango-tabs.c | 37 +++++++++++++++++++++++++++++++++++--
 pango/pango-tabs.h | 28 +++++++++++++++++-----------
 2 files changed, 52 insertions(+), 13 deletions(-)
---
diff --git a/pango/pango-tabs.c b/pango/pango-tabs.c
index c126ec91..47ac95c3 100644
--- a/pango/pango-tabs.c
+++ b/pango/pango-tabs.c
@@ -278,7 +278,6 @@ pango_tab_array_set_tab (PangoTabArray *tab_array,
 {
   g_return_if_fail (tab_array != NULL);
   g_return_if_fail (tab_index >= 0);
-  g_return_if_fail (alignment == PANGO_TAB_LEFT);
   g_return_if_fail (location >= 0);
 
   if (tab_index >= tab_array->size)
@@ -399,6 +398,14 @@ pango_tab_array_to_string (PangoTabArray *tab_array)
     {
       if (i > 0)
         g_string_append_c (s, ' ');
+
+      if (tab_array->tabs[i].alignment == PANGO_TAB_RIGHT)
+        g_string_append (s, "right:");
+      else if (tab_array->tabs[i].alignment == PANGO_TAB_CENTER)
+        g_string_append (s, "center:");
+      else if (tab_array->tabs[i].alignment == PANGO_TAB_DECIMAL)
+        g_string_append (s, "decimal:");
+
       g_string_append_printf (s, "%d", tab_array->tabs[i].location);
       if (tab_array->positions_in_pixels)
         g_string_append (s, "px");
@@ -446,13 +453,39 @@ pango_tab_array_from_string (const char *text)
     {
       char *endp;
       gint64 pos;
+      PangoTabAlign align;
+
+      if (g_str_has_prefix (p, "left:"))
+        {
+          align = PANGO_TAB_LEFT;
+          p += strlen ("left:");
+        }
+      else if (g_str_has_prefix (p, "right:"))
+        {
+          align = PANGO_TAB_RIGHT;
+          p += strlen ("right:");
+        }
+      else if (g_str_has_prefix (p, "center:"))
+        {
+          align = PANGO_TAB_CENTER;
+          p += strlen ("center:");
+        }
+      else if (g_str_has_prefix (p, "decimal:"))
+        {
+          align = PANGO_TAB_DECIMAL;
+          p += strlen ("decimal:");
+        }
+      else
+        {
+          align = PANGO_TAB_LEFT;
+        }
 
       pos = g_ascii_strtoll (p, &endp, 10);
       if (pos < 0 ||
           (pixels && *endp != 'p') ||
           (!pixels && !g_ascii_isspace (*endp) && *endp != '\0')) goto fail;
 
-      pango_tab_array_set_tab (array, i, PANGO_TAB_LEFT, pos);
+      pango_tab_array_set_tab (array, i, align, pos);
       i++;
 
       p = (const char *)endp;
diff --git a/pango/pango-tabs.h b/pango/pango-tabs.h
index d2a68d5a..81ac1550 100644
--- a/pango/pango-tabs.h
+++ b/pango/pango-tabs.h
@@ -30,21 +30,27 @@ typedef struct _PangoTabArray PangoTabArray;
 
 /**
  * PangoTabAlign:
- * @PANGO_TAB_LEFT: the tab stop appears to the left of the text.
+ * @PANGO_TAB_LEFT: the text appears to the right of the tab stop position
+ * @PANGO_TAB_RIGHT: the text appears to the left of the tab stop position
+ *   until the available space is filled
+ * @PANGO_TAB_CENTER: the text is centered at the tab stop position
+ *   until the available space is filled
+ * @PANGO_TAB_DECIMAL: text before the first '.' appears to the left of the
+ *   tab stop position (until the available space is filled), the rest to
+ *   the right
  *
- * `PangoTabAlign` specifies where a tab stop appears relative to the text.
+ * `PangoTabAlign` specifies where the text appears relative to the tab stop
+ * position.
+ *
+ * Support for tab alignments other than %PANGO_TAB_LEFT was added
+ * in Pango 1.50.
  */
 typedef enum
 {
-  PANGO_TAB_LEFT
-
-  /* These are not supported now, but may be in the
-   * future.
-   *
-   *  PANGO_TAB_RIGHT,
-   *  PANGO_TAB_CENTER,
-   *  PANGO_TAB_NUMERIC
-   */
+  PANGO_TAB_LEFT,
+  PANGO_TAB_RIGHT,
+  PANGO_TAB_CENTER,
+  PANGO_TAB_DECIMAL
 } PangoTabAlign;
 
 #define PANGO_TYPE_TAB_ARRAY (pango_tab_array_get_type ())