Bug 363510 – Ability to query whether a PangoLayout is effectively

2007-01-16  Behdad Esfahbod  <behdad@gnome.org>

        Bug 363510 – Ability to query whether a PangoLayout is effectively
        ellipsized (as opposed to the set_ellpisize()/get_ellipsize() methods
        which only set a request, or return the set request respectively)
        Patch from Milosz Derezynski

        * pango/pango-layout.h:
        * pango/ellipsize.c (_pango_layout_line_ellipsize):
        * pango/pango-layout-private.h:
        * pango/pango-layout.c (pango_layout_init), (pango_layout_copy),
        (pango_layout_is_ellipsized), (pango_layout_clear_lines),
        (pango_layout_line_postprocess):
        New public function:

                pango_layout_is_ellipsized()

        * pango/pango.def:
        * docs/tmpl/layout.sgml:
        * docs/pango-sections.txt:
        Update.


svn path=/trunk/; revision=2150

5 files changed, 44 insertions, 5 deletions

diff --git a/pango/ellipsize.c b/pango/ellipsize.c
index b1523afe..e392d3c9 100644
--- a/pango/ellipsize.c
+++ b/pango/ellipsize.c
@@ -717,17 +717,20 @@ current_width (EllipsizeState *state)
  * 
  * Given a #PangoLayoutLine with the runs still in logical order, ellipsize
  * it according the layout's policy to fit within the set width of the layout.
+ *
+ * Return value: whether the line had to be ellipsized
  **/
-void
+gboolean
 _pango_layout_line_ellipsize (PangoLayoutLine *line,
 			      PangoAttrList   *attrs)
 {
   EllipsizeState state;
   int goal_width;
+  gboolean is_ellipsized = FALSE;
 
   if (line->layout->ellipsize == PANGO_ELLIPSIZE_NONE ||
       line->layout->width < 0)
-    return;
+    goto ret;
 
   init_state (&state, line, attrs);
 
@@ -750,7 +753,10 @@ _pango_layout_line_ellipsize (PangoLayoutLine *line,
   
   g_slist_free (line->runs);
   line->runs = get_run_list (&state);
+  is_ellipsized = TRUE;
 
  out:
   free_state (&state);
+ ret:
+  return is_ellipsized;
 }
diff --git a/pango/pango-layout-private.h b/pango/pango-layout-private.h
index 75913940..56370c1a 100644
--- a/pango/pango-layout-private.h
+++ b/pango/pango-layout-private.h
@@ -52,6 +52,7 @@ struct _PangoLayout
   
   guint wrap : 2;		/* PangoWrapMode */
   guint ellipsize : 2;		/* PangoEllipsizeMode */
+  guint is_ellipsized : 1;	/* Whether the layout has any ellipsized lines */
 
   /* some caching */
   guint logical_rect_cached : 1;
@@ -72,7 +73,7 @@ struct _PangoLayout
 
 G_END_DECLS
 
-void _pango_layout_line_ellipsize (PangoLayoutLine *line,
+gboolean _pango_layout_line_ellipsize (PangoLayoutLine *line,
 				   PangoAttrList   *attrs);
 PangoLayoutLine* _pango_layout_iter_get_line_readonly (PangoLayoutIter *iter);
 
diff --git a/pango/pango-layout.c b/pango/pango-layout.c
index 52b9dccf..e708d555 100644
--- a/pango/pango-layout.c
+++ b/pango/pango-layout.c
@@ -200,6 +200,7 @@ pango_layout_init (PangoLayout *layout)
 
   layout->wrap = PANGO_WRAP_WORD;
   layout->ellipsize = PANGO_ELLIPSIZE_NONE;
+  layout->is_ellipsized = FALSE;
 }
 
 static void
@@ -306,7 +307,7 @@ pango_layout_copy (PangoLayout *src)
   layout->wrap = src->wrap;  
   layout->ellipsize = src->ellipsize;
   
-  /* log_attrs, lines fields are updated by check_lines */
+  /* is_ellipsized, log_attrs, lines fields are updated by check_lines */
 
   return layout;
 }
@@ -845,6 +846,32 @@ pango_layout_get_ellipsize (PangoLayout *layout)
 }
 
 /**
+ * pango_layout_is_ellipsized:
+ * @layout: a #PangoLayout
+ * 
+ * Queries whether the layout had to ellipsize any paragraphs.
+ *
+ * This can only return %TRUE if the ellipsization mode for @layout
+ * is not %PANGO_ELLIPSIZE_NONE, a positive width is set on @layout,
+ * and there were paragraphs exceeding that width that had to be
+ * ellipsized.
+ *
+ * Return value: %TRUE if any paragraphs had to be ellipsized, %FALSE
+ * otherwise.
+ *
+ * Since: 1.16
+ */
+gboolean
+pango_layout_is_ellipsized (PangoLayout *layout)
+{
+  g_return_if_fail (layout != NULL);
+
+  pango_layout_check_lines (layout);
+
+  return layout->is_ellipsized;
+}
+
+/**
  * pango_layout_set_text:
  * @layout: a #PangoLayout
  * @text: a valid UTF-8 string
@@ -2456,6 +2483,8 @@ pango_layout_get_pixel_size (PangoLayout *layout,
 static void
 pango_layout_clear_lines (PangoLayout *layout)
 {
+  layout->is_ellipsized = FALSE;
+
   if (layout->lines)
     {
       GSList *tmp_list = layout->lines;
@@ -4571,7 +4600,8 @@ pango_layout_line_postprocess (PangoLayoutLine *line,
 
   /* Ellipsize the line if necessary
    */
-  _pango_layout_line_ellipsize (line, state->attrs);
+  if (_pango_layout_line_ellipsize (line, state->attrs))
+    line->layout->is_ellipsized = TRUE;
   
   /* Now convert logical to visual order
    */
diff --git a/pango/pango-layout.h b/pango/pango-layout.h
index 6e24a565..5a73c537 100644
--- a/pango/pango-layout.h
+++ b/pango/pango-layout.h
@@ -153,6 +153,7 @@ gboolean       pango_layout_get_single_paragraph_mode (PangoLayout
 void               pango_layout_set_ellipsize (PangoLayout        *layout,
 					       PangoEllipsizeMode  ellipsize);
 PangoEllipsizeMode pango_layout_get_ellipsize (PangoLayout        *layout);
+gboolean pango_layout_is_ellipsized           (PangoLayout *layout);
 
 void           pango_layout_context_changed (PangoLayout    *layout);
 
diff --git a/pango/pango.def b/pango/pango.def
index 7b3aa3ec..3ea0951e 100644
--- a/pango/pango.def
+++ b/pango/pango.def
@@ -238,6 +238,7 @@ EXPORTS
 	pango_layout_get_wrap
 	pango_layout_index_to_line_x
 	pango_layout_index_to_pos
+	pango_layout_is_ellipsized
 	pango_layout_iter_at_last_line
 	pango_layout_iter_free
 	pango_layout_iter_get_baseline