Merge branch 'hinted-metrics-fixes' into 'main'

Hinted metrics fixes

Closes #626

See merge request GNOME/pango!518

3 files changed, 54 insertions, 18 deletions

diff --git a/pango/pango-types.h b/pango/pango-types.h
index f18225ba..ed86f699 100644
--- a/pango/pango-types.h
+++ b/pango/pango-types.h
@@ -107,6 +107,32 @@ typedef guint32 PangoGlyph;
  */
 
 /**
+ * PANGO_UNITS_FLOOR:
+ * @d: a dimension in Pango units.
+ *
+ * Rounds a dimension down to whole device units, but does not
+ * convert it to device units.
+ *
+ * Return value: rounded down dimension in Pango units.
+ * Since: 1.50
+ */
+#define PANGO_UNITS_FLOOR(d)                \
+  ((d) & ~(PANGO_SCALE - 1))
+
+/**
+ * PANGO_UNITS_CEIL:
+ * @d: a dimension in Pango units.
+ *
+ * Rounds a dimension up to whole device units, but does not
+ * convert it to device units.
+ *
+ * Return value: rounded up dimension in Pango units.
+ * Since: 1.50
+ */
+#define PANGO_UNITS_CEIL(d)                 \
+  (((d) + (PANGO_SCALE - 1)) & ~(PANGO_SCALE - 1))
+
+/**
  * PANGO_UNITS_ROUND:
  * @d: a dimension in Pango units.
  *
diff --git a/pango/pangocairo-font.c b/pango/pangocairo-font.c
index 597a320d..c2bcc51b 100644
--- a/pango/pangocairo-font.c
+++ b/pango/pangocairo-font.c
@@ -817,13 +817,13 @@ _pango_cairo_font_private_glyph_extents_cache_init (PangoCairoFontPrivate *cf_pr
   if (cf_priv->is_hinted)
     {
       if (cf_priv->font_extents.y < 0)
-        cf_priv->font_extents.y = PANGO_UNITS_ROUND (cf_priv->font_extents.y - PANGO_SCALE/2);
+        cf_priv->font_extents.y = PANGO_UNITS_FLOOR (cf_priv->font_extents.y);
       else
-        cf_priv->font_extents.y = PANGO_UNITS_ROUND (cf_priv->font_extents.y + PANGO_SCALE/2);
+        cf_priv->font_extents.y = PANGO_UNITS_CEIL (cf_priv->font_extents.y);
       if (cf_priv->font_extents.height < 0)
-        cf_priv->font_extents.height = PANGO_UNITS_ROUND (cf_priv->font_extents.height - PANGO_SCALE/2);
+        cf_priv->font_extents.height = PANGO_UNITS_FLOOR (extents.ascender) - PANGO_UNITS_CEIL (extents.descender);
       else
-        cf_priv->font_extents.height = PANGO_UNITS_ROUND (cf_priv->font_extents.height + PANGO_SCALE/2);
+        cf_priv->font_extents.height = PANGO_UNITS_CEIL (extents.ascender) - PANGO_UNITS_FLOOR (extents.descender);
     }
 
   if (PANGO_GRAVITY_IS_IMPROPER (cf_priv->gravity))
diff --git a/tests/testmisc.c b/tests/testmisc.c
index 555f0dce..1aa90948 100644
--- a/tests/testmisc.c
+++ b/tests/testmisc.c
@@ -634,9 +634,11 @@ test_empty_line_height (void)
 {
   PangoContext *context;
   PangoLayout *layout;
+  PangoFontDescription *description;
   PangoRectangle ext1, ext2, ext3;
   cairo_font_options_t *options;
   int hint;
+  int size;
 
   if (strcmp (G_OBJECT_TYPE_NAME (pango_cairo_font_map_get_default ()), "PangoCairoCoreTextFontMap") == 0)
     {
@@ -645,33 +647,41 @@ test_empty_line_height (void)
     }
 
   context = pango_font_map_create_context (pango_cairo_font_map_get_default ());
+  description = pango_font_description_new ();
 
-  for (hint = CAIRO_HINT_METRICS_OFF; hint <= CAIRO_HINT_METRICS_ON; hint++)
+  for (size = 10; size <= 20; size++)
     {
-      options = cairo_font_options_create ();
-      cairo_font_options_set_hint_metrics (options, hint);
-      pango_cairo_context_set_font_options (context, options);
-      cairo_font_options_destroy (options);
+      pango_font_description_set_size (description, size);
 
-      layout = pango_layout_new (context);
+      for (hint = CAIRO_HINT_METRICS_OFF; hint <= CAIRO_HINT_METRICS_ON; hint++)
+        {
+          options = cairo_font_options_create ();
+          cairo_font_options_set_hint_metrics (options, hint);
+          pango_cairo_context_set_font_options (context, options);
+          cairo_font_options_destroy (options);
 
-      pango_layout_get_extents (layout, NULL, &ext1);
+          layout = pango_layout_new (context);
+          pango_layout_set_font_description (layout, description);
 
-      pango_layout_set_text (layout, "a", 1);
+          pango_layout_get_extents (layout, NULL, &ext1);
 
-      pango_layout_get_extents (layout, NULL, &ext2);
+          pango_layout_set_text (layout, "a", 1);
 
-      g_assert_cmpint (ext1.height, ==, ext2.height);
+          pango_layout_get_extents (layout, NULL, &ext2);
 
-      pango_layout_set_text (layout, "Pg", 1);
+          g_assert_cmpint (ext1.height, ==, ext2.height);
 
-      pango_layout_get_extents (layout, NULL, &ext3);
+          pango_layout_set_text (layout, "Pg", 1);
 
-      g_assert_cmpint (ext2.height, ==, ext3.height);
+          pango_layout_get_extents (layout, NULL, &ext3);
 
-      g_object_unref (layout);
+          g_assert_cmpint (ext2.height, ==, ext3.height);
+
+          g_object_unref (layout);
+        }
     }
 
+  pango_font_description_free (description);
   g_object_unref (context);
 }