[pango/no-shape-attrs: 1/2] Fix ItemProperties handling

[Matthias Clasen <matthiasc src gnome org>]

commit 52ba47d728e3ed98dfbf00d06ad9ad5980a413b2
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Oct 28 22:03:33 2019 -0400

    Fix ItemProperties handling
    
    Deal with the fact that underlines and strikethroughs
    are not constant across items, since we do not break
    runs for these properties.

 pango/pango-layout.c | 83 ++++++++++++++++++++++++++++++++++------------------
 1 file changed, 54 insertions(+), 29 deletions(-)
---
diff --git a/pango/pango-layout.c b/pango/pango-layout.c
index aa290038..aa542786 100644
--- a/pango/pango-layout.c
+++ b/pango/pango-layout.c
@@ -83,10 +83,21 @@
 typedef struct _ItemProperties ItemProperties;
 typedef struct _ParaBreakState ParaBreakState;
 
+/* Note that rise, letter_spacing, shape are constant across items,
+ * since we pass them into itemization.
+ *
+ * uline and strikethrough can vary across an item, so we collect
+ * all the values that we find.
+ *
+ * See pango_layout_get_item_properties for details.
+ */
 struct _ItemProperties
 {
-  PangoUnderline  uline;
-  gboolean        strikethrough;
+  guint uline_single   : 1;
+  guint uline_double   : 1;
+  guint uline_low      : 1;
+  guint uline_error    : 1;
+  guint strikethrough  : 1;
   gint            rise;
   gint            letter_spacing;
   gboolean        shape_set;
@@ -4879,16 +4890,20 @@ pango_layout_run_get_extents_and_height (PangoLayoutRun *run,
   PangoRectangle logical;
   ItemProperties properties;
   PangoFontMetrics *metrics = NULL;
+  gboolean has_underline;
 
   if (G_UNLIKELY (!run_ink && !run_logical))
     return;
 
   pango_layout_get_item_properties (run->item, &properties);
 
+  has_underline = properties.uline_single || properties.uline_double ||
+                  properties.uline_low || properties.uline_error;
+
   if (!run_logical && (run->item->analysis.flags & PANGO_ANALYSIS_FLAG_CENTERED_BASELINE))
     run_logical = &logical;
 
-  if (!run_logical && (properties.uline != PANGO_UNDERLINE_NONE || properties.strikethrough))
+  if (!run_logical && (has_underline || properties.strikethrough))
     run_logical = &logical;
 
   if (properties.shape_set)
@@ -4900,7 +4915,7 @@ pango_layout_run_get_extents_and_height (PangoLayoutRun *run,
     pango_glyph_string_extents (run->glyphs, run->item->analysis.font,
                                run_ink, run_logical);
 
-  if (run_ink && (properties.uline != PANGO_UNDERLINE_NONE || properties.strikethrough))
+  if (run_ink && (has_underline || properties.strikethrough))
     {
       int underline_thickness;
       int underline_position;
@@ -4937,29 +4952,17 @@ pango_layout_run_get_extents_and_height (PangoLayoutRun *run,
            }
        }
 
-      switch (properties.uline)
-       {
-       case PANGO_UNDERLINE_ERROR:
-         run_ink->height = MAX (run_ink->height,
-                                3 * underline_thickness - underline_position - run_ink->y);
-         break;
-       case PANGO_UNDERLINE_SINGLE:
-         run_ink->height = MAX (run_ink->height,
-                                underline_thickness - underline_position - run_ink->y);
-         break;
-       case PANGO_UNDERLINE_DOUBLE:
-         run_ink->height = MAX (run_ink->height,
-                                3 * underline_thickness - underline_position - run_ink->y);
-         break;
-       case PANGO_UNDERLINE_LOW:
-         run_ink->height += 2 * underline_thickness;
-         break;
-       case PANGO_UNDERLINE_NONE:
-         break;
-       default:
-         g_critical ("unknown underline mode");
-         break;
-       }
+      if (properties.uline_low)
+        run_ink->height += 2 * underline_thickness;
+      if (properties.uline_single)
+        run_ink->height = MAX (run_ink->height,
+                               underline_thickness - underline_position - run_ink->y);
+      if (properties.uline_double)
+        run_ink->height = MAX (run_ink->height,
+                                 3 * underline_thickness - underline_position - run_ink->y);
+      if (properties.uline_error)
+        run_ink->height = MAX (run_ink->height,
+                               3 * underline_thickness - underline_position - run_ink->y);
     }
 
   if (height)
@@ -5821,7 +5824,10 @@ pango_layout_get_item_properties (PangoItem      *item,
 {
   GSList *tmp_list = item->analysis.extra_attrs;
 
-  properties->uline = PANGO_UNDERLINE_NONE;
+  properties->uline_single = FALSE;
+  properties->uline_double = FALSE;
+  properties->uline_low = FALSE;
+  properties->uline_error = FALSE;
   properties->strikethrough = FALSE;
   properties->letter_spacing = 0;
   properties->rise = 0;
@@ -5836,7 +5842,26 @@ pango_layout_get_item_properties (PangoItem      *item,
       switch ((int) attr->klass->type)
        {
        case PANGO_ATTR_UNDERLINE:
-         properties->uline = ((PangoAttrInt *)attr)->value;
+          switch (((PangoAttrInt *)attr)->value)
+            {
+            case PANGO_UNDERLINE_NONE:
+              break;
+            case PANGO_UNDERLINE_SINGLE:
+              properties->uline_single = TRUE;
+              break;
+            case PANGO_UNDERLINE_DOUBLE:
+              properties->uline_double = TRUE;
+              break;
+            case PANGO_UNDERLINE_LOW:
+              properties->uline_low = TRUE;
+              break;
+            case PANGO_UNDERLINE_ERROR:
+              properties->uline_error = TRUE;
+              break;
+            default:
+              g_assert_not_reached ();
+              break;
+            }
          break;
 
        case PANGO_ATTR_STRIKETHROUGH: