[pango/text-transform-3: 1/5] markup: Add a text transform attribute

[Matthias Clasen <matthiasc src gnome org>]

commit 811fb6833d239f139bb44441b3ed56873ab6b66e
Author: Matthias Clasen <mclasen redhat com>
Date:   Fri Aug 20 17:16:52 2021 -0400

    markup: Add a text transform attribute
    
    Add a PangoTextTransform enum, a PangoAttribute
    to set it on runs of text, and support for parsing
    it out of markup.

 docs/pango_markup.md     |  5 +++++
 pango/pango-attributes.c | 26 ++++++++++++++++++++++++++
 pango/pango-attributes.h | 22 ++++++++++++++++++++++
 pango/pango-markup.c     | 14 ++++++++++++++
 4 files changed, 67 insertions(+)
---
diff --git a/docs/pango_markup.md b/docs/pango_markup.md
index 03718907..c393f49c 100644
--- a/docs/pango_markup.md
+++ b/docs/pango_markup.md
@@ -196,6 +196,11 @@ line_height
   of a point).
   Available since Pango 1.50.
 
+transform
+: Specifies how characters are transformed during shaping. The values can be
+  'none', 'lowercase', 'uppercase' or 'capitalize'. Support for text transformation
+  was added in Pango 1.50.
+
 ## Convenience Tags
 
 `<b>`
diff --git a/pango/pango-attributes.c b/pango/pango-attributes.c
index 5690aeaa..6a914c7b 100644
--- a/pango/pango-attributes.c
+++ b/pango/pango-attributes.c
@@ -1411,6 +1411,32 @@ pango_attr_line_height_new_absolute (int height)
 
   return pango_attr_int_new (&klass, height);
 }
+
+/**
+ * pango_attr_text_transform_new:
+ * @transform: `PangoTextTransform` to apply
+ *
+ * Create a new attribute that influences how characters
+ * are transformed during shaping.
+ *
+ * Return value: (transfer full): the newly allocated
+ *   `PangoAttribute`, which should be freed with
+ *   [method@Pango.Attribute.destroy]
+ *
+ * Since: 1.50
+ **/
+PangoAttribute *
+pango_attr_text_transform_new (PangoTextTransform transform)
+{
+  static const PangoAttrClass klass = {
+    PANGO_ATTR_TEXT_TRANSFORM,
+    pango_attr_int_copy,
+    pango_attr_int_destroy,
+    pango_attr_int_equal
+  };
+
+  return pango_attr_int_new (&klass, transform);
+}
 /* }}} */
 /* {{{ Binding helpers */
 
diff --git a/pango/pango-attributes.h b/pango/pango-attributes.h
index e3012008..ca0f74b8 100644
--- a/pango/pango-attributes.h
+++ b/pango/pango-attributes.h
@@ -120,6 +120,7 @@ typedef enum
   PANGO_ATTR_OVERLINE_COLOR,    /* PangoAttrColor */
   PANGO_ATTR_LINE_HEIGHT,       /* PangoAttrFloat */
   PANGO_ATTR_ABSOLUTE_LINE_HEIGHT, /* PangoAttrInt */
+  PANGO_ATTR_TEXT_TRANSFORM,    /* PangoAttrInt */
 } PangoAttrType;
 
 /**
@@ -202,6 +203,25 @@ typedef enum {
   PANGO_SHOW_IGNORABLES  = 1 << 2
 } PangoShowFlags;
 
+/**
+ * PangoTextTransform:
+ * @PANGO_TEXT_TRANSFORM_NONE: Leave text unchanged
+ * @PANGO_TEXT_TRANSFORM_LOWERCASE: Display letters and numbers as lowercase
+ * @PANGO_TEXT_TRANSFORM_UPPERCASE: Display letters and numbers as uppercase
+ * @PANGO_TEXT_TRANSFORM_CAPITALIZE: Display the first character of a word
+ *   in titlecase
+ *
+ * An enumeration that affects how Pango treats characters during shaping.
+ *
+ * Since: 1.50
+ */
+typedef enum {
+  PANGO_TEXT_TRANSFORM_NONE,
+  PANGO_TEXT_TRANSFORM_LOWERCASE,
+  PANGO_TEXT_TRANSFORM_UPPERCASE,
+  PANGO_TEXT_TRANSFORM_CAPITALIZE,
+} PangoTextTransform;
+
 /**
  * PANGO_ATTR_INDEX_FROM_TEXT_BEGINNING:
  *
@@ -532,6 +552,8 @@ PANGO_AVAILABLE_IN_1_50
 PangoAttribute *        pango_attr_line_height_new              (double                       factor);
 PANGO_AVAILABLE_IN_1_50
 PangoAttribute *        pango_attr_line_height_new_absolute     (int                          height);
+PANGO_AVAILABLE_IN_1_50
+PangoAttribute *        pango_attr_text_transform_new           (PangoTextTransform transform);
 
 PANGO_AVAILABLE_IN_1_50
 PangoAttrString       * pango_attribute_as_string               (PangoAttribute              *attr);
diff --git a/pango/pango-markup.c b/pango/pango-markup.c
index a897a52d..e90294ed 100644
--- a/pango/pango-markup.c
+++ b/pango/pango-markup.c
@@ -1226,6 +1226,7 @@ span_parse_func     (MarkupData            *md G_GNUC_UNUSED,
   const char *insert_hyphens = NULL;
   const char *show = NULL;
   const char *line_height = NULL;
+  const char *transform = NULL;
 
   g_markup_parse_context_get_position (context,
                                       &line_number, &char_number);
@@ -1294,6 +1295,9 @@ span_parse_func     (MarkupData            *md G_GNUC_UNUSED,
        CHECK_ATTRIBUTE (strikethrough_color);
        CHECK_ATTRIBUTE (style);
        break;
+      case 't':
+        CHECK_ATTRIBUTE (transform);
+        break;
       case 'g':
        CHECK_ATTRIBUTE (gravity);
        CHECK_ATTRIBUTE (gravity_hint);
@@ -1637,6 +1641,16 @@ span_parse_func     (MarkupData            *md G_GNUC_UNUSED,
       add_attribute (tag, pango_attr_show_new (flags));
     }
 
+  if (G_UNLIKELY (transform))
+    {
+      PangoTextTransform tf;
+
+      if (!span_parse_enum ("transform", transform, PANGO_TYPE_TEXT_TRANSFORM, (int*)(void*)&tf, 
line_number, error))
+       goto error;
+
+      add_attribute (tag, pango_attr_text_transform_new (tf));
+    }
+
   if (G_UNLIKELY (rise))
     {
       gint n = 0;