Merge branch 'serializer2' into 'main'

Add layout serialization api

See merge request GNOME/pango!513

55 files changed, 1540 insertions, 344 deletions

diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 3b9f5200..6195501c 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -8,7 +8,7 @@ stages:
 variables:
   COMMON_MESON_FLAGS: "--fatal-meson-warnings --werror"
   MESON_TEST_TIMEOUT_MULTIPLIER: 2
-  FEDORA_IMAGE: registry.gitlab.gnome.org/gnome/pango/fedora:v6
+  FEDORA_IMAGE: registry.gitlab.gnome.org/gnome/pango/fedora:v7
 
 .only-default:
   only:
diff --git a/.gitlab-ci/fedora.Dockerfile b/.gitlab-ci/fedora.Dockerfile
index ebb1e6b5..e905deee 100644
--- a/.gitlab-ci/fedora.Dockerfile
+++ b/.gitlab-ci/fedora.Dockerfile
@@ -26,6 +26,7 @@ RUN dnf -y install \
     harfbuzz-devel \
     hicolor-icon-theme \
     itstool \
+    json-glib-devel \
     libasan \
     lcov \
     libthai-devel \
diff --git a/meson.build b/meson.build
index 37bcf6cb..4a6b128c 100644
--- a/meson.build
+++ b/meson.build
@@ -232,6 +232,7 @@ harfbuzz_req_version = '>= 2.6.0'
 fontconfig_req_version = '>= 2.13.0'
 xft_req_version = '>= 2.0.0'
 cairo_req_version = '>= 1.12.10'
+json_glib_version = '>= 1.6.0'
 
 # libm
 mathlib_dep = cc.find_library('m', required: false)
@@ -251,6 +252,10 @@ fribidi_dep = dependency('fribidi', version: fribidi_req_version,
                          default_options: ['docs=false'])
 pango_deps += fribidi_dep
 
+json_glib_dep = dependency('json-glib-1.0', version: json_glib_version,
+                           fallback: ['json-glib', 'json_glib_dep'])
+pango_deps += json_glib_dep
+
 thai_dep = dependency('libthai', version: libthai_req_version, required: get_option('libthai'))
 if thai_dep.found()
   pango_conf.set('HAVE_LIBTHAI', 1)
diff --git a/pango.supp b/pango.supp
index 98450af4..9b542534 100644
--- a/pango.supp
+++ b/pango.supp
@@ -19,6 +19,14 @@
   fun:_cairo_ft_font_options_substitute
 }
 
+{
+  pango 3
+  Memcheck:Leak
+  fun:calloc
+  ...
+  fun:pango_language_from_string
+}
+
 # Fontconfig
 {
    FcFontSetList
@@ -84,6 +92,13 @@
   ...
   fun:g_intern_static_string
 }
+{
+  glib GThread
+  Memcheck:Leak
+  fun:calloc
+  ...
+  fun:g_thread_new_internal
+}
 
 # libthai
 {
diff --git a/pango/meson.build b/pango/meson.build
index 084de229..7c7bb280 100644
--- a/pango/meson.build
+++ b/pango/meson.build
@@ -27,6 +27,7 @@ pango_sources = [
   'pango-utils.c',
   'reorder-items.c',
   'shape.c',
+  'serializer.c',
 ]
 
 pango_headers = [
diff --git a/pango/pango-attributes.c b/pango/pango-attributes.c
index 13468963..cfaf9b17 100644
--- a/pango/pango-attributes.c
+++ b/pango/pango-attributes.c
@@ -2802,7 +2802,7 @@ pango_attr_list_from_string (const char *text)
 
       p = endp + strspn (endp, " ");
 
-      endp = (char *)strpbrk (p, " ");
+      endp = (char *)p + strcspn (p, " ");
       attr_type = get_attr_type_by_nick (p, endp - p);
 
       p = endp + strspn (endp, " ");
@@ -2929,8 +2929,7 @@ pango_attr_list_from_string (const char *text)
           break;
 
         case PANGO_ATTR_SHAPE:
-          endp = (char *)strpbrk (p, ",\n");
-          p = endp  + strspn (endp, " ");
+          endp = (char *)p + strcspn (p, ",\n");
           continue; /* FIXME */
 
         case PANGO_ATTR_SCALE:
diff --git a/pango/pango-layout.h b/pango/pango-layout.h
index e28f9295..502f5e29 100644
--- a/pango/pango-layout.h
+++ b/pango/pango-layout.h
@@ -351,6 +351,31 @@ GSList *         pango_layout_get_lines            (PangoLayout    *layout);
 PANGO_AVAILABLE_IN_1_16
 GSList *         pango_layout_get_lines_readonly   (PangoLayout    *layout);
 
+#define PANGO_LAYOUT_SERIALIZE_ERROR (pango_layout_serialize_error_quark ())
+
+typedef enum {
+  PANGO_LAYOUT_SERIALIZE_INVALID,
+  PANGO_LAYOUT_SERIALIZE_INVALID_SYNTAX,
+  PANGO_LAYOUT_SERIALIZE_INVALID_VALUE,
+  PANGO_LAYOUT_SERIALIZE_MISSING_VALUE,
+} PangoLayoutSerializeError;
+
+PANGO_AVAILABLE_IN_1_50
+GQuark          pango_layout_serialize_error_quark (void);
+
+PANGO_AVAILABLE_IN_1_50
+GBytes *        pango_layout_serialize             (PangoLayout    *layout);
+
+PANGO_AVAILABLE_IN_1_50
+PangoLayout *   pango_layout_deserialize           (PangoContext   *context,
+                                                    GBytes         *bytes,
+                                                    GError        **error);
+
+PANGO_AVAILABLE_IN_1_50
+gboolean        pango_layout_write_to_file          (PangoLayout   *layout,
+                                                     const char    *filename,
+                                                     GError       **error);
+
 
 #define PANGO_TYPE_LAYOUT_LINE (pango_layout_line_get_type ())
 
diff --git a/pango/serializer.c b/pango/serializer.c
new file mode 100644
index 00000000..576e6cf6
--- /dev/null
+++ b/pango/serializer.c
@@ -0,0 +1,935 @@
+/* Pango
+ * serializer.c: Code to serialize various Pango objects
+ *
+ * Copyright (C) 2021 Red Hat, Inc
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include "config.h"
+
+#include <pango/pango-layout.h>
+#include <pango/pango-layout-private.h>
+#include <pango/pango-enum-types.h>
+
+#include <json-glib/json-glib.h>
+
+/* {{{ Error handling */
+
+G_DEFINE_QUARK(pango-layout-serialize-error-quark, pango_layout_serialize_error)
+
+/* }}} */
+/* {{{ Serialization */
+
+static GType
+get_enum_type (PangoAttrType attr_type)
+{
+  switch ((int)attr_type)
+    {
+    case PANGO_ATTR_STYLE: return PANGO_TYPE_STYLE;
+    case PANGO_ATTR_WEIGHT: return PANGO_TYPE_WEIGHT;
+    case PANGO_ATTR_VARIANT: return PANGO_TYPE_VARIANT;
+    case PANGO_ATTR_STRETCH: return PANGO_TYPE_STRETCH;
+    case PANGO_ATTR_GRAVITY: return PANGO_TYPE_GRAVITY;
+    case PANGO_ATTR_GRAVITY_HINT: return PANGO_TYPE_GRAVITY_HINT;
+    case PANGO_ATTR_UNDERLINE: return PANGO_TYPE_UNDERLINE;
+    case PANGO_ATTR_OVERLINE: return PANGO_TYPE_OVERLINE;
+    case PANGO_ATTR_BASELINE_SHIFT: return PANGO_TYPE_BASELINE_SHIFT;
+    case PANGO_ATTR_FONT_SCALE: return PANGO_TYPE_FONT_SCALE;
+    case PANGO_ATTR_TEXT_TRANSFORM: return PANGO_TYPE_TEXT_TRANSFORM;
+    default: return G_TYPE_INVALID;
+    }
+}
+
+static void
+add_enum_value (JsonBuilder   *builder,
+                GType          type,
+                int            value,
+                gboolean       allow_extra)
+{
+  GEnumClass *enum_class;
+  GEnumValue *enum_value;
+
+  enum_class = g_type_class_ref (type);
+  enum_value = g_enum_get_value (enum_class, value);
+
+  if (enum_value)
+    json_builder_add_string_value (builder, enum_value->value_nick);
+  else if (allow_extra)
+    {
+      char buf[128];
+      g_snprintf (buf, 128, "%d", value);
+      json_builder_add_string_value (builder, buf);
+    }
+  else
+    json_builder_add_string_value (builder, "ERROR");
+
+}
+
+static void
+add_attribute (JsonBuilder    *builder,
+               PangoAttribute *attr)
+{
+  char *str;
+
+  json_builder_begin_object (builder);
+
+  if (attr->start_index != PANGO_ATTR_INDEX_FROM_TEXT_BEGINNING)
+    {
+      json_builder_set_member_name (builder, "start");
+      json_builder_add_int_value (builder, (int)attr->start_index);
+    }
+  if (attr->end_index != PANGO_ATTR_INDEX_TO_TEXT_END)
+    {
+      json_builder_set_member_name (builder, "end");
+      json_builder_add_int_value (builder, (int)attr->end_index);
+    }
+  json_builder_set_member_name (builder, "type");
+  add_enum_value (builder, PANGO_TYPE_ATTR_TYPE, attr->klass->type, FALSE);
+
+  json_builder_set_member_name (builder, "value");
+  switch (attr->klass->type)
+    {
+    default:
+    case PANGO_ATTR_INVALID:
+      g_assert_not_reached ();
+    case PANGO_ATTR_LANGUAGE:
+      json_builder_add_string_value (builder, pango_language_to_string (((PangoAttrLanguage*)attr)->value));
+      break;
+    case PANGO_ATTR_FAMILY:
+    case PANGO_ATTR_FONT_FEATURES:
+      json_builder_add_string_value (builder, ((PangoAttrString*)attr)->value);
+      break;
+    case PANGO_ATTR_STYLE:
+    case PANGO_ATTR_VARIANT:
+    case PANGO_ATTR_STRETCH:
+    case PANGO_ATTR_UNDERLINE:
+    case PANGO_ATTR_OVERLINE:
+    case PANGO_ATTR_GRAVITY:
+    case PANGO_ATTR_GRAVITY_HINT:
+    case PANGO_ATTR_TEXT_TRANSFORM:
+    case PANGO_ATTR_FONT_SCALE:
+      add_enum_value (builder, get_enum_type (attr->klass->type), ((PangoAttrInt*)attr)->value, FALSE);
+      break;
+    case PANGO_ATTR_WEIGHT:
+    case PANGO_ATTR_BASELINE_SHIFT:
+      add_enum_value (builder, get_enum_type (attr->klass->type), ((PangoAttrInt*)attr)->value, TRUE);
+      break;
+    case PANGO_ATTR_SIZE:
+    case PANGO_ATTR_RISE:
+    case PANGO_ATTR_LETTER_SPACING:
+    case PANGO_ATTR_ABSOLUTE_SIZE:
+    case PANGO_ATTR_FOREGROUND_ALPHA:
+    case PANGO_ATTR_BACKGROUND_ALPHA:
+    case PANGO_ATTR_SHOW:
+    case PANGO_ATTR_WORD:
+    case PANGO_ATTR_SENTENCE:
+    case PANGO_ATTR_ABSOLUTE_LINE_HEIGHT:
+      json_builder_add_int_value (builder, ((PangoAttrInt*)attr)->value);
+      break;
+    case PANGO_ATTR_FONT_DESC:
+      str = pango_font_description_to_string (((PangoAttrFontDesc*)attr)->desc);
+      json_builder_add_string_value (builder, str);
+      g_free (str);
+      break;
+    case PANGO_ATTR_FOREGROUND:
+    case PANGO_ATTR_BACKGROUND:
+    case PANGO_ATTR_UNDERLINE_COLOR:
+    case PANGO_ATTR_OVERLINE_COLOR:
+    case PANGO_ATTR_STRIKETHROUGH_COLOR:
+      str = pango_color_to_string (&((PangoAttrColor*)attr)->color);
+      json_builder_add_string_value (builder, str);
+      g_free (str);
+      break;
+    case PANGO_ATTR_STRIKETHROUGH:
+    case PANGO_ATTR_FALLBACK:
+    case PANGO_ATTR_ALLOW_BREAKS:
+    case PANGO_ATTR_INSERT_HYPHENS:
+      json_builder_add_boolean_value (builder, ((PangoAttrInt*)attr)->value != 0);
+      break;
+    case PANGO_ATTR_SHAPE:
+      json_builder_add_string_value (builder, "shape");
+      break;
+    case PANGO_ATTR_SCALE:
+    case PANGO_ATTR_LINE_HEIGHT:
+      json_builder_add_double_value (builder, ((PangoAttrFloat*)attr)->value);
+    }
+
+  json_builder_end_object (builder);
+}
+
+static void
+add_attr_list (JsonBuilder   *builder,
+               PangoAttrList *attrs)
+{
+  GSList *attributes, *l;
+
+  json_builder_begin_array (builder);
+
+  attributes = pango_attr_list_get_attributes (attrs);
+  for (l = attributes; l; l = l->next)
+    {
+      PangoAttribute *attr = l->data;
+      add_attribute (builder, attr);
+    }
+  g_slist_free_full (attributes, (GDestroyNotify) pango_attribute_destroy);
+
+  json_builder_end_array (builder);
+}
+
+static void
+add_tab_array (JsonBuilder   *builder,
+               PangoTabArray *tabs)
+{
+  json_builder_begin_object (builder);
+
+  json_builder_set_member_name (builder, "positions-in-pixels");
+  json_builder_add_boolean_value (builder, pango_tab_array_get_positions_in_pixels (tabs));
+  json_builder_set_member_name (builder, "positions");
+  json_builder_begin_array (builder);
+  for (int i = 0; i < pango_tab_array_get_size (tabs); i++)
+    {
+      int pos;
+      pango_tab_array_get_tab (tabs, i, NULL, &pos);
+      json_builder_add_int_value (builder, pos);
+    }
+  json_builder_end_array (builder);
+
+  json_builder_end_object (builder);
+}
+
+static JsonNode *
+layout_to_json (PangoLayout *layout)
+{
+  JsonBuilder *builder;
+  JsonNode *root;
+
+  builder = json_builder_new_immutable ();
+
+  json_builder_begin_object (builder);
+
+  json_builder_set_member_name (builder, "text");
+  json_builder_add_string_value (builder, layout->text);
+
+  if (layout->attrs)
+    {
+      json_builder_set_member_name (builder, "attributes");
+      add_attr_list (builder, layout->attrs);
+    }
+
+  if (layout->font_desc)
+    {
+      char *str = pango_font_description_to_string (layout->font_desc);
+      json_builder_set_member_name (builder, "font");
+      json_builder_add_string_value (builder, str);
+      g_free (str);
+    }
+
+  if (layout->tabs)
+    {
+      json_builder_set_member_name (builder, "tabs");
+      add_tab_array (builder, layout->tabs);
+    }
+
+  if (layout->justify)
+    {
+      json_builder_set_member_name (builder, "justify");
+      json_builder_add_boolean_value (builder, TRUE);
+    }
+
+  if (layout->justify_last_line)
+    {
+      json_builder_set_member_name (builder, "justify-last-line");
+      json_builder_add_boolean_value (builder, TRUE);
+    }
+
+  if (layout->single_paragraph)
+    {
+      json_builder_set_member_name (builder, "single-paragraph");
+      json_builder_add_boolean_value (builder, TRUE);
+    }
+
+  if (!layout->auto_dir)
+    {
+      json_builder_set_member_name (builder, "auto-dir");
+      json_builder_add_boolean_value (builder, FALSE);
+    }
+
+  if (layout->alignment != PANGO_ALIGN_LEFT)
+    {
+      json_builder_set_member_name (builder, "alignment");
+      add_enum_value (builder, PANGO_TYPE_ALIGNMENT, layout->alignment, FALSE);
+    }
+
+  if (layout->wrap != PANGO_WRAP_WORD)
+    {
+      json_builder_set_member_name (builder, "wrap");
+      add_enum_value (builder, PANGO_TYPE_WRAP_MODE, layout->wrap, FALSE);
+    }
+
+  if (layout->ellipsize != PANGO_ELLIPSIZE_NONE)
+    {
+      json_builder_set_member_name (builder, "ellipsize");
+      add_enum_value (builder, PANGO_TYPE_ELLIPSIZE_MODE, layout->ellipsize, FALSE);
+    }
+
+  if (layout->width != -1)
+    {
+      json_builder_set_member_name (builder, "width");
+      json_builder_add_int_value (builder, layout->width);
+    }
+
+  if (layout->height != -1)
+    {
+      json_builder_set_member_name (builder, "height");
+      json_builder_add_int_value (builder, layout->height);
+    }
+
+  if (layout->indent != 0)
+    {
+      json_builder_set_member_name (builder, "indent");
+      json_builder_add_int_value (builder, layout->indent);
+    }
+
+  if (layout->spacing != 0)
+    {
+      json_builder_set_member_name (builder, "spacing");
+      json_builder_add_int_value (builder, layout->spacing);
+    }
+
+  if (layout->line_spacing != 0.)
+    {
+      json_builder_set_member_name (builder, "line-spacing");
+      json_builder_add_double_value (builder, layout->line_spacing);
+    }
+
+  json_builder_end_object (builder);
+
+  root = json_builder_get_root (builder);
+  g_object_unref (builder);
+
+  return root;
+}
+
+/* }}} */
+/* {{{ Deserialization */
+
+static int
+get_enum_value (GType       type,
+                const char *str,
+                gboolean    allow_extra)
+{
+  GEnumClass *enum_class;
+  GEnumValue *enum_value;
+
+  enum_class = g_type_class_ref (type);
+  enum_value = g_enum_get_value_by_nick (enum_class, str);
+
+  if (enum_value)
+    return enum_value->value;
+
+  if (allow_extra)
+    {
+      gint64 value;
+      char *endp;
+
+      value = g_ascii_strtoll (str, &endp, 10);
+      if (*endp == '\0')
+        return value;
+    }
+
+  return -1;
+}
+
+static PangoAttribute *
+json_to_attribute (JsonReader  *reader,
+                   GError     **error)
+{
+  PangoAttribute *attr = NULL;
+  PangoAttrType type = PANGO_ATTR_INVALID;
+  guint start = PANGO_ATTR_INDEX_FROM_TEXT_BEGINNING;
+  guint end = PANGO_ATTR_INDEX_TO_TEXT_END;
+  PangoFontDescription *desc;
+  PangoColor color;
+
+  if (!json_reader_is_object (reader))
+    {
+      g_set_error (error,
+                   PANGO_LAYOUT_SERIALIZE_ERROR, PANGO_LAYOUT_SERIALIZE_INVALID_SYNTAX,
+                   "Attribute must be a Json object");
+      return NULL;
+    }
+
+  if (json_reader_read_member (reader, "start"))
+    start = json_reader_get_int_value (reader);
+  json_reader_end_member (reader);
+
+  if (json_reader_read_member (reader, "end"))
+    end = json_reader_get_int_value (reader);
+  json_reader_end_member (reader);
+
+  if (json_reader_read_member (reader, "type"))
+    {
+      type = get_enum_value (PANGO_TYPE_ATTR_TYPE, json_reader_get_string_value (reader), FALSE);
+      if (type == -1 || type == PANGO_ATTR_INVALID)
+        {
+          g_set_error (error,
+                       PANGO_LAYOUT_SERIALIZE_ERROR, PANGO_LAYOUT_SERIALIZE_INVALID_VALUE,
+                       "Attribute \"type\" invalid: %s",
+                       json_reader_get_string_value (reader));
+          return NULL;
+        }
+      json_reader_end_member (reader);
+    }
+  else
+    {
+      g_set_error (error,
+                   PANGO_LAYOUT_SERIALIZE_ERROR, PANGO_LAYOUT_SERIALIZE_MISSING_VALUE,
+                   "Attribute \"type\" missing");
+      json_reader_end_member (reader);
+      return NULL;
+    }
+
+  if (!json_reader_read_member (reader, "value"))
+    {
+      g_set_error (error,
+                   PANGO_LAYOUT_SERIALIZE_ERROR, PANGO_LAYOUT_SERIALIZE_MISSING_VALUE,
+                   "Attribute \"value\" missing");
+      json_reader_end_member (reader);
+      return NULL;
+    }
+
+  switch (type)
+    {
+    default:
+    case PANGO_ATTR_INVALID:
+      g_assert_not_reached ();
+
+    case PANGO_ATTR_LANGUAGE:
+      attr = pango_attr_language_new (pango_language_from_string (json_reader_get_string_value (reader)));
+      break;
+    case PANGO_ATTR_FAMILY:
+      attr = pango_attr_family_new (json_reader_get_string_value (reader));
+      break;
+    case PANGO_ATTR_STYLE:
+      attr = pango_attr_style_new (get_enum_value (PANGO_TYPE_STYLE, json_reader_get_string_value (reader), FALSE));
+      break;
+    case PANGO_ATTR_WEIGHT:
+      attr = pango_attr_weight_new (get_enum_value (PANGO_TYPE_WEIGHT, json_reader_get_string_value (reader), TRUE));
+      break;
+    case PANGO_ATTR_VARIANT:
+      attr = pango_attr_variant_new (get_enum_value (PANGO_TYPE_VARIANT, json_reader_get_string_value (reader), FALSE));
+      break;
+    case PANGO_ATTR_STRETCH:
+      attr = pango_attr_stretch_new (get_enum_value (PANGO_TYPE_STRETCH, json_reader_get_string_value (reader), FALSE));
+      break;
+    case PANGO_ATTR_SIZE:
+      attr = pango_attr_size_new (json_reader_get_int_value (reader));
+      break;
+    case PANGO_ATTR_FONT_DESC:
+      desc = pango_font_description_from_string (json_reader_get_string_value (reader));
+      attr = pango_attr_font_desc_new (desc);
+      pango_font_description_free (desc);
+      break;
+    case PANGO_ATTR_FOREGROUND:
+      pango_color_parse (&color, json_reader_get_string_value (reader));
+      attr = pango_attr_foreground_new (color.red, color.green, color.blue);
+      break;
+    case PANGO_ATTR_BACKGROUND:
+      pango_color_parse (&color, json_reader_get_string_value (reader));
+      attr = pango_attr_background_new (color.red, color.green, color.blue);
+      break;
+    case PANGO_ATTR_UNDERLINE:
+      attr = pango_attr_underline_new (get_enum_value (PANGO_TYPE_UNDERLINE, json_reader_get_string_value (reader), FALSE));
+      break;
+    case PANGO_ATTR_STRIKETHROUGH:
+      attr = pango_attr_strikethrough_new (json_reader_get_boolean_value (reader));
+      break;
+    case PANGO_ATTR_RISE:
+      attr = pango_attr_rise_new (json_reader_get_int_value (reader));
+      break;
+    case PANGO_ATTR_SHAPE:
+      /* FIXME */
+      attr = pango_attr_shape_new (&(PangoRectangle) { 0, 0, 0, 0}, &(PangoRectangle) { 0, 0, 0, 0});
+      break;
+    case PANGO_ATTR_SCALE:
+      attr = pango_attr_scale_new (json_reader_get_double_value (reader));
+      break;
+    case PANGO_ATTR_FALLBACK:
+      attr = pango_attr_fallback_new (json_reader_get_boolean_value (reader));
+      break;
+    case PANGO_ATTR_LETTER_SPACING:
+      attr = pango_attr_letter_spacing_new (json_reader_get_int_value (reader));
+      break;
+    case PANGO_ATTR_UNDERLINE_COLOR:
+      pango_color_parse (&color, json_reader_get_string_value (reader));
+      attr = pango_attr_underline_color_new (color.red, color.green, color.blue);
+      break;
+    case PANGO_ATTR_STRIKETHROUGH_COLOR:
+      pango_color_parse (&color, json_reader_get_string_value (reader));
+      attr = pango_attr_strikethrough_color_new (color.red, color.green, color.blue);
+      break;
+    case PANGO_ATTR_ABSOLUTE_SIZE:
+      attr = pango_attr_size_new_absolute (json_reader_get_int_value (reader));
+      break;
+    case PANGO_ATTR_GRAVITY:
+      attr = pango_attr_gravity_new (get_enum_value (PANGO_TYPE_GRAVITY, json_reader_get_string_value (reader), FALSE));
+      break;
+    case PANGO_ATTR_GRAVITY_HINT:
+      attr = pango_attr_gravity_hint_new (get_enum_value (PANGO_TYPE_GRAVITY_HINT, json_reader_get_string_value (reader), FALSE));
+      break;
+    case PANGO_ATTR_FONT_FEATURES:
+      attr = pango_attr_font_features_new (json_reader_get_string_value (reader));
+      break;
+    case PANGO_ATTR_FOREGROUND_ALPHA:
+      attr = pango_attr_foreground_alpha_new (json_reader_get_int_value (reader));
+      break;
+    case PANGO_ATTR_BACKGROUND_ALPHA:
+      attr = pango_attr_background_alpha_new (json_reader_get_int_value (reader));
+      break;
+    case PANGO_ATTR_ALLOW_BREAKS:
+      attr = pango_attr_allow_breaks_new (json_reader_get_boolean_value (reader));
+      break;
+    case PANGO_ATTR_SHOW:
+      attr = pango_attr_show_new (json_reader_get_int_value (reader));
+      break;
+    case PANGO_ATTR_INSERT_HYPHENS:
+      attr = pango_attr_insert_hyphens_new (json_reader_get_boolean_value (reader));
+      break;
+    case PANGO_ATTR_OVERLINE:
+      attr = pango_attr_overline_new (get_enum_value (PANGO_TYPE_OVERLINE, json_reader_get_string_value (reader), FALSE));
+      break;
+    case PANGO_ATTR_OVERLINE_COLOR:
+      pango_color_parse (&color, json_reader_get_string_value (reader));
+      attr = pango_attr_overline_color_new (color.red, color.green, color.blue);
+      break;
+    case PANGO_ATTR_LINE_HEIGHT:
+      attr = pango_attr_line_height_new (json_reader_get_double_value (reader));
+      break;
+    case PANGO_ATTR_ABSOLUTE_LINE_HEIGHT:
+      attr = pango_attr_line_height_new_absolute (json_reader_get_int_value (reader));
+      break;
+    case PANGO_ATTR_TEXT_TRANSFORM:
+      attr = pango_attr_text_transform_new (get_enum_value (PANGO_TYPE_TEXT_TRANSFORM, json_reader_get_string_value (reader), FALSE));
+      break;
+    case PANGO_ATTR_WORD:
+      attr = pango_attr_word_new ();
+      break;
+    case PANGO_ATTR_SENTENCE:
+      attr = pango_attr_sentence_new ();
+      break;
+    case PANGO_ATTR_BASELINE_SHIFT:
+      attr = pango_attr_baseline_shift_new (get_enum_value (PANGO_TYPE_BASELINE_SHIFT, json_reader_get_string_value (reader), TRUE));
+      break;
+    case PANGO_ATTR_FONT_SCALE:
+      attr = pango_attr_font_scale_new (get_enum_value (PANGO_TYPE_BASELINE_SHIFT, json_reader_get_string_value (reader), FALSE));
+      break;
+    }
+
+  attr->start_index = start;
+  attr->end_index = end;
+
+  json_reader_end_member (reader);
+
+  return attr;
+}
+
+static PangoAttrList *
+json_to_attr_list (JsonReader  *reader,
+                   GError     **error)
+{
+  PangoAttrList *attributes;
+
+  if (!json_reader_is_array (reader))
+    {
+      g_set_error (error,
+                   PANGO_LAYOUT_SERIALIZE_ERROR, PANGO_LAYOUT_SERIALIZE_INVALID_SYNTAX,
+                   "\"attributes\" must be a Json array");
+      goto fail;
+    }
+
+  attributes = pango_attr_list_new ();
+
+  for (int i = 0; i < json_reader_count_elements (reader); i++)
+    {
+      PangoAttribute *attr;
+      json_reader_read_element (reader, i);
+      attr = json_to_attribute (reader, error);
+      if (!attr)
+        goto fail;
+      pango_attr_list_insert (attributes, attr);
+      json_reader_end_element (reader);
+    }
+
+  return attributes;
+
+fail:
+  if (attributes)
+    pango_attr_list_unref (attributes);
+  return NULL;
+}
+
+static PangoTabArray *
+json_to_tab_array (JsonReader  *reader,
+                   GError     **error)
+{
+  PangoTabArray *tabs;
+  gboolean positions_in_pixels = FALSE;
+
+  if (json_reader_read_member (reader, "positions-in-pixels"))
+    positions_in_pixels = json_reader_get_boolean_value (reader);
+  json_reader_end_member (reader);
+
+  tabs = pango_tab_array_new (0, positions_in_pixels);
+
+  if (json_reader_read_member (reader, "positions"))
+    {
+      if (!json_reader_is_array (reader))
+        {
+          g_set_error (error,
+                       PANGO_LAYOUT_SERIALIZE_ERROR,
+                       PANGO_LAYOUT_SERIALIZE_INVALID_SYNTAX,
+                       "Tab \"positions\"  must be a Json array");
+          goto fail;
+        }
+
+      pango_tab_array_resize (tabs, json_reader_count_elements (reader));
+      for (int i = 0; i < json_reader_count_elements (reader); i++)
+        {
+          int pos;
+          json_reader_read_element (reader, i);
+          pos = json_reader_get_int_value (reader);
+          pango_tab_array_set_tab (tabs, i, PANGO_TAB_LEFT, pos);
+          json_reader_end_element (reader);
+        }
+    }
+  json_reader_end_member (reader);
+
+  return tabs;
+
+fail:
+  if (tabs)
+    pango_tab_array_free (tabs);
+  return NULL;
+}
+
+static PangoLayout *
+json_to_layout (PangoContext *context,
+                JsonNode     *node,
+                GError      **error)
+{
+  JsonReader *reader;
+  PangoLayout *layout;
+
+  layout = pango_layout_new (context);
+
+  reader = json_reader_new (node);
+  if (!json_reader_is_object (reader))
+    {
+      g_set_error (error,
+                   PANGO_LAYOUT_SERIALIZE_ERROR,
+                   PANGO_LAYOUT_SERIALIZE_INVALID_SYNTAX,
+                   "Layout must be a Json object");
+      goto fail;
+    }
+
+  if (json_reader_read_member (reader, "text"))
+    pango_layout_set_text (layout, json_reader_get_string_value (reader), -1);
+  json_reader_end_member (reader);
+
+  if (json_reader_read_member (reader, "attributes"))
+    {
+      PangoAttrList *attributes;
+
+      attributes = json_to_attr_list (reader, error);
+
+      if (!attributes)
+        goto fail;
+
+      pango_layout_set_attributes (layout, attributes);
+      pango_attr_list_unref (attributes);
+    }
+  json_reader_end_member (reader);
+
+  if (json_reader_read_member (reader, "font"))
+    {
+      PangoFontDescription *desc;
+
+      desc = pango_font_description_from_string ( json_reader_get_string_value (reader));
+      if (!desc)
+        {
+          g_set_error (error,
+                       PANGO_LAYOUT_SERIALIZE_ERROR,
+                       PANGO_LAYOUT_SERIALIZE_INVALID_VALUE,
+                       "Could not parse \"font\" value: %s",
+                       json_reader_get_string_value (reader));
+          goto fail;
+        }
+      pango_layout_set_font_description (layout, desc);
+      pango_font_description_free (desc);
+    }
+  json_reader_end_member (reader);
+
+  if (json_reader_read_member (reader, "tabs"))
+    {
+      PangoTabArray *tabs;
+
+      tabs = json_to_tab_array (reader, error);
+
+      if (!tabs)
+        goto fail;
+
+      pango_layout_set_tabs (layout, tabs);
+      pango_tab_array_free (tabs);
+    }
+  json_reader_end_member (reader);
+
+  if (json_reader_read_member (reader, "justify"))
+    pango_layout_set_justify (layout, json_reader_get_boolean_value (reader));
+  json_reader_end_member (reader);
+
+  if (json_reader_read_member (reader, "justify-last-line"))
+    pango_layout_set_justify_last_line (layout, json_reader_get_boolean_value (reader));
+  json_reader_end_member (reader);
+
+  if (json_reader_read_member (reader, "single-paragraph"))
+    pango_layout_set_single_paragraph_mode (layout, json_reader_get_boolean_value (reader));
+  json_reader_end_member (reader);
+
+  if (json_reader_read_member (reader, "auto-dir"))
+    pango_layout_set_auto_dir (layout, json_reader_get_boolean_value (reader));
+  json_reader_end_member (reader);
+
+  if (json_reader_read_member (reader, "alignment"))
+    {
+      PangoAlignment align = get_enum_value (PANGO_TYPE_ALIGNMENT,
+                                             json_reader_get_string_value (reader),
+                                             FALSE);
+      if (align == -1)
+        {
+          g_set_error (error,
+                       PANGO_LAYOUT_SERIALIZE_ERROR,
+                       PANGO_LAYOUT_SERIALIZE_INVALID_VALUE,
+                       "Could not parse \"alignment\" value: %s",
+                       json_reader_get_string_value (reader));
+          goto fail;
+        }
+
+      pango_layout_set_alignment (layout, align);
+    }
+
+  json_reader_end_member (reader);
+
+  if (json_reader_read_member (reader, "wrap"))
+    {
+      PangoWrapMode wrap = get_enum_value (PANGO_TYPE_WRAP_MODE,
+                                           json_reader_get_string_value (reader),
+                                           FALSE);
+
+      if (wrap == -1)
+        {
+          g_set_error (error,
+                       PANGO_LAYOUT_SERIALIZE_ERROR,
+                       PANGO_LAYOUT_SERIALIZE_INVALID_VALUE,
+                       "Could not parse \"wrap\" value: %s",
+                       json_reader_get_string_value (reader));
+          goto fail;
+        }
+
+      pango_layout_set_wrap (layout, wrap);
+    }
+
+  json_reader_end_member (reader);
+
+  if (json_reader_read_member (reader, "ellipsize"))
+    {
+      PangoEllipsizeMode ellipsize = get_enum_value (PANGO_TYPE_ELLIPSIZE_MODE,
+                                                     json_reader_get_string_value (reader),
+                                                     FALSE);
+
+      if (ellipsize == -1)
+        {
+          g_set_error (error,
+                       PANGO_LAYOUT_SERIALIZE_ERROR,
+                       PANGO_LAYOUT_SERIALIZE_INVALID_VALUE,
+                       "Could not parse \"ellipsize\" value: %s",
+                       json_reader_get_string_value (reader));
+          goto fail;
+        }
+
+      pango_layout_set_ellipsize (layout, ellipsize);
+    }
+
+  json_reader_end_member (reader);
+
+  if (json_reader_read_member (reader, "width"))
+    pango_layout_set_width (layout, json_reader_get_int_value (reader));
+  json_reader_end_member (reader);
+
+  if (json_reader_read_member (reader, "height"))
+    pango_layout_set_height (layout, json_reader_get_int_value (reader));
+  json_reader_end_member (reader);
+
+  if (json_reader_read_member (reader, "indent"))
+    pango_layout_set_indent (layout, json_reader_get_int_value (reader));
+  json_reader_end_member (reader);
+
+  if (json_reader_read_member (reader, "spacing"))
+    pango_layout_set_spacing (layout, json_reader_get_int_value (reader));
+  json_reader_end_member (reader);
+
+  if (json_reader_read_member (reader, "line-spacing"))
+    pango_layout_set_line_spacing (layout, json_reader_get_double_value (reader));
+  json_reader_end_member (reader);
+
+  g_object_unref (reader);
+
+  return layout;
+
+fail:
+  g_object_unref (reader);
+  g_object_unref (layout);
+  return NULL;
+}
+
+ /* }}} */
+ /* {{{ Public API */
+
+/**
+ * pango_layout_serialize:
+ * @layout: a `PangoLayout`
+ *
+ * Serializes the @layout for later deserialization via [method@Pango.Layout.deserialize].
+ *
+ * There are no guarantees about the format of the output accross different
+ * versions of Pango and [method@Pango.Layout.deserialize] will reject data
+ * that it cannot parse.
+ *
+ * The intended use of this function is testing, benchmarking and debugging.
+ * The format is not meant as a permanent storage format.
+ *
+ * Returns: a `GBytes` containing the serialized form of @layout
+ *
+ * Since: 1.50
+ */
+GBytes *
+pango_layout_serialize (PangoLayout *layout)
+{
+  JsonGenerator *generator;
+  JsonNode *node;
+  char *data;
+  gsize size;
+
+  node = layout_to_json (layout);
+
+  generator = json_generator_new ();
+  json_generator_set_pretty (generator, TRUE);
+  json_generator_set_indent (generator, 2);
+
+  json_generator_set_root (generator, node);
+  data = json_generator_to_data (generator, &size);
+
+  json_node_free (node);
+  g_object_unref (generator);
+
+  return g_bytes_new_take (data, size);
+}
+
+/**
+ * pango_layout_write_to_file:
+ * @layout: a `PangoLayout`
+ * @filename: (type filename): the file to save it to
+ * @error: Return location for a potential error
+ *
+ * This function is equivalent to calling [method@Pango.Layout.serialize]
+ * followed by g_file_set_contents().
+ *
+ * See those two functions for details on the arguments.
+ *
+ * It is mostly intended for use inside a debugger to quickly dump
+ * a layout to a file for later inspection.
+ *
+ * Returns: %TRUE if saving was successful
+ *
+ * Since: 1.50
+ */
+gboolean
+pango_layout_write_to_file (PangoLayout  *layout,
+                            const char   *filename,
+                            GError      **error)
+{
+  GBytes *bytes;
+  gboolean result;
+
+  g_return_val_if_fail (PANGO_IS_LAYOUT (layout), FALSE);
+  g_return_val_if_fail (filename != NULL, FALSE);
+  g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
+
+  bytes = pango_layout_serialize (layout);
+  result = g_file_set_contents (filename,
+                                g_bytes_get_data (bytes, NULL),
+                                g_bytes_get_size (bytes),
+                                error);
+  g_bytes_unref (bytes);
+
+  return result;
+
+}
+
+/**
+ * pango_layout_deserialize:
+ * @context: a `PangoContext`
+ * @bytes: the bytes containing the data
+ * @error: return location for an error
+ *
+ * Loads data previously created via [method@Pango.Layout.serialize].
+ *
+ * For a discussion of the supported format, see that function.
+ *
+ * Returns: (nullable) (transfer full): a new `PangoLayout`
+ *
+ * Since: 1.50
+ */
+PangoLayout *
+pango_layout_deserialize (PangoContext  *context,
+                          GBytes        *bytes,
+                          GError       **error)
+{
+  JsonParser *parser;
+  JsonNode *node;
+  PangoLayout *layout;
+
+  parser = json_parser_new_immutable ();
+  if (!json_parser_load_from_data (parser,
+                                   g_bytes_get_data (bytes, NULL),
+                                   g_bytes_get_size (bytes),
+                                   error))
+    {
+      g_object_unref (parser);
+      return NULL;
+    }
+
+  node = json_parser_get_root (parser);
+  layout = json_to_layout (context, node, error);
+
+  g_object_unref (parser);
+
+  return layout;
+}
+
+/* }}} */
+
+/* vim:set foldmethod=marker expandtab: */
diff --git a/subprojects/json-glib.wrap b/subprojects/json-glib.wrap
new file mode 100644
index 00000000..b88acd72
--- /dev/null
+++ b/subprojects/json-glib.wrap
@@ -0,0 +1,5 @@
+[wrap-git]
+directory=json-glib
+url=https://gitlab.gnome.org/GNOME/json-glib.git
+revision=master
+depth=1
diff --git a/tests/layouts/valid-1.layout b/tests/layouts/valid-1.layout
new file mode 100644
index 00000000..9289830b
--- /dev/null
+++ b/tests/layouts/valid-1.layout
@@ -0,0 +1,20 @@
+{
+  "text" : "This is a test of the automatic emergency brake!\n",
+  "attributes" : [
+    {
+      "start" : 22,
+      "end" : 41,
+      "type" : "foreground",
+      "value" : "#00000000ffff"
+    },
+    {
+      "start" : 22,
+      "end" : 41,
+      "type" : "underline",
+      "value" : "single"
+    }
+  ],
+  "font" : "Cantarell 11",
+  "ellipsize" : "end",
+  "width" : 225280
+}
diff --git a/tests/layouts/valid-1.markup b/tests/layouts/valid-1.markup
deleted file mode 100644
index 780e6831..00000000
--- a/tests/layouts/valid-1.markup
+++ /dev/null
@@ -1,2 +0,0 @@
-width=220,ellipsize=end
-This is a test of the <span foreground="#0000ff" underline="single">automatic emergency</span> brake!
diff --git a/tests/layouts/valid-10.layout b/tests/layouts/valid-10.layout
new file mode 100644
index 00000000..0d36a38d
--- /dev/null
+++ b/tests/layouts/valid-10.layout
@@ -0,0 +1,8 @@
+{
+  "text" : "Hello שלום Γειά σας\n",
+  "attributes" : [],
+  "font" : "Cantarell 11",
+  "justify" : true,
+  "ellipsize" : "end",
+  "width" : 102400
+}
diff --git a/tests/layouts/valid-10.markup b/tests/layouts/valid-10.markup
deleted file mode 100644
index 15bf693d..00000000
--- a/tests/layouts/valid-10.markup
+++ /dev/null
@@ -1,2 +0,0 @@
-width=100,justify=true,ellipsize=end
-Hello שלום Γειά σας
diff --git a/tests/layouts/valid-11.layout b/tests/layouts/valid-11.layout
new file mode 100644
index 00000000..a044cc53
--- /dev/null
+++ b/tests/layouts/valid-11.layout
@@ -0,0 +1,42 @@
+{
+  "text" : "double low error\n",
+  "attributes" : [
+    {
+      "end" : 6,
+      "type" : "underline",
+      "value" : "double"
+    },
+    {
+      "end" : 6,
+      "type" : "overline",
+      "value" : "single"
+    },
+    {
+      "start" : 7,
+      "end" : 10,
+      "type" : "underline",
+      "value" : "low"
+    },
+    {
+      "start" : 7,
+      "end" : 10,
+      "type" : "strikethrough",
+      "value" : true
+    },
+    {
+      "start" : 11,
+      "end" : 16,
+      "type" : "underline",
+      "value" : "error"
+    },
+    {
+      "start" : 11,
+      "end" : 16,
+      "type" : "rise",
+      "value" : 1024
+    }
+  ],
+  "font" : "Cantarell 11",
+  "wrap" : "char",
+  "width" : 225280
+}
diff --git a/tests/layouts/valid-11.markup b/tests/layouts/valid-11.markup
deleted file mode 100644
index fbf1abd2..00000000
--- a/tests/layouts/valid-11.markup
+++ /dev/null
@@ -1,2 +0,0 @@
-width=220,wrap=char
-<span underline='double' overline='single'>double</span> <span underline='low' strikethrough='true'>low</span> <span underline='error' rise='1024'>error</span>
diff --git a/tests/layouts/valid-12.layout b/tests/layouts/valid-12.layout
new file mode 100644
index 00000000..1c9fa227
--- /dev/null
+++ b/tests/layouts/valid-12.layout
@@ -0,0 +1,15 @@
+{
+  "text" : "a       b       c       d
e     f       g       h\n",
+  "attributes" : [],
+  "font" : "Cantarell 11",
+  "tabs" : {
+    "positions-in-pixels" : true,
+    "positions" : [
+      0,
+      50,
+      100,
+      150,
+      200
+    ]
+  }
+}
diff --git a/tests/layouts/valid-12.markup b/tests/layouts/valid-12.markup
deleted file mode 100644
index b7306cc6..00000000
--- a/tests/layouts/valid-12.markup
+++ /dev/null
@@ -1,2 +0,0 @@
-wrap=word,tabs=0 50 100 150 200
-a       b       c       d
e     f       g       h
diff --git a/tests/layouts/valid-13.layout b/tests/layouts/valid-13.layout
new file mode 100644
index 00000000..a9f10f86
--- /dev/null
+++ b/tests/layouts/valid-13.layout
@@ -0,0 +1,16 @@
+{
+  "text" : "a       b       c       d
e     f       g       h\n",
+  "attributes" : [],
+  "font" : "Cantarell 11",
+  "tabs" : {
+    "positions-in-pixels" : true,
+    "positions" : [
+      0,
+      50,
+      100,
+      150,
+      200
+    ]
+  },
+  "single-paragraph" : true
+}
diff --git a/tests/layouts/valid-13.markup b/tests/layouts/valid-13.markup
deleted file mode 100644
index be2345d1..00000000
--- a/tests/layouts/valid-13.markup
+++ /dev/null
@@ -1,2 +0,0 @@
-wrap=word,tabs=0 50 100 150 200,single_paragraph=true
-a       b       c       d
e     f       g       h
diff --git a/tests/layouts/valid-14.layout b/tests/layouts/valid-14.layout
new file mode 100644
index 00000000..116cc94f
--- /dev/null
+++ b/tests/layouts/valid-14.layout
@@ -0,0 +1,8 @@
+{
+  "text" : "你好 Hello שלום Γειά σας\n",
+  "attributes" : [],
+  "font" : "Cantarell 11",
+  "ellipsize" : "start",
+  "width" : 161792,
+  "line-spacing" : 1.5
+}
diff --git a/tests/layouts/valid-14.markup b/tests/layouts/valid-14.markup
deleted file mode 100644
index 1d556d26..00000000
--- a/tests/layouts/valid-14.markup
+++ /dev/null
@@ -1,2 +0,0 @@
-line_spacing=1.5,width=158,ellipsize=start
-你好 Hello שלום Γειά σας
diff --git a/tests/layouts/valid-15.layout b/tests/layouts/valid-15.layout
new file mode 100644
index 00000000..9f584ba6
--- /dev/null
+++ b/tests/layouts/valid-15.layout
@@ -0,0 +1,8 @@
+{
+  "text" : "Lets see if this text is long enough to wrap due to height limitations. It might, or it might not.\n",
+  "attributes" : [],
+  "font" : "Cantarell 11",
+  "ellipsize" : "end",
+  "width" : 153600,
+  "height" : 40960
+}
diff --git a/tests/layouts/valid-15.markup b/tests/layouts/valid-15.markup
deleted file mode 100644
index e3081c81..00000000
--- a/tests/layouts/valid-15.markup
+++ /dev/null
@@ -1,2 +0,0 @@
-ellipsize=end,height=40,width=150
-Lets see if this text is long enough to wrap due to height limitations. It might, or it might not.
diff --git a/tests/layouts/valid-16.layout b/tests/layouts/valid-16.layout
new file mode 100644
index 00000000..e2a82d96
--- /dev/null
+++ b/tests/layouts/valid-16.layout
@@ -0,0 +1,9 @@
+{
+  "text" : "Lets see if this text is long enough to wrap due to height limitations. It might, or it might not.\n",
+  "attributes" : [],
+  "font" : "Cantarell 11",
+  "wrap" : "word-char",
+  "ellipsize" : "end",
+  "width" : 153600,
+  "height" : -2
+}
diff --git a/tests/layouts/valid-16.markup b/tests/layouts/valid-16.markup
deleted file mode 100644
index 91a8ae37..00000000
--- a/tests/layouts/valid-16.markup
+++ /dev/null
@@ -1,2 +0,0 @@
-wrap=word-char,ellipsize=end,width=150,height=-2
-Lets see if this text is long enough to wrap due to height limitations. It might, or it might not.
diff --git a/tests/layouts/valid-17.layout b/tests/layouts/valid-17.layout
new file mode 100644
index 00000000..062cc241
--- /dev/null
+++ b/tests/layouts/valid-17.layout
@@ -0,0 +1,7 @@
+{
+  "text" : "some|bla|bla|bla\n",
+  "attributes" : [],
+  "font" : "Cantarell 11",
+  "justify" : true,
+  "width" : 102400
+}
diff --git a/tests/layouts/valid-17.markup b/tests/layouts/valid-17.markup
deleted file mode 100644
index d804c20a..00000000
--- a/tests/layouts/valid-17.markup
+++ /dev/null
@@ -1,2 +0,0 @@
-justify=true,width=100
-some|bla|bla|bla
diff --git a/tests/layouts/valid-18.layout b/tests/layouts/valid-18.layout
new file mode 100644
index 00000000..85e9a7d1
--- /dev/null
+++ b/tests/layouts/valid-18.layout
@@ -0,0 +1,11 @@
+{
+  "text" : "some line breaks
and mis­ce­llaneous ignora‌bles\n",
+  "attributes" : [
+    {
+      "end" : 57,
+      "type" : "show",
+      "value" : 7
+    }
+  ],
+  "font" : "Cantarell 11"
+}
diff --git a/tests/layouts/valid-18.markup b/tests/layouts/valid-18.markup
deleted file mode 100644
index ab5f5f35..00000000
--- a/tests/layouts/valid-18.markup
+++ /dev/null
@@ -1,2 +0,0 @@
-
-<span show="spaces|line-breaks|ignorables">some line breaks
and mis­ce­llaneous ignora‌bles</span>
diff --git a/tests/layouts/valid-19.layout b/tests/layouts/valid-19.layout
new file mode 100644
index 00000000..32ad1283
--- /dev/null
+++ b/tests/layouts/valid-19.layout
@@ -0,0 +1,5 @@
+{
+  "text" : " a⃠ 😊︎ 😊️ 🇩🇪 ✊ ✋🏾 0 # 🏴󠁵󠁳󠁣󠁡󠁿 ©\n",
+  "attributes" : [],
+  "font" : "Cantarell 11"
+}
diff --git a/tests/layouts/valid-19.markup b/tests/layouts/valid-19.markup
deleted file mode 100644
index e48c9f0e..00000000
--- a/tests/layouts/valid-19.markup
+++ /dev/null
@@ -1,2 +0,0 @@
-# various Emoji segmentation cases
- a⃠ 😊︎ 😊️ 🇩🇪 ✊ ✋🏾 0 # 🏴󠁵󠁳󠁣󠁡󠁿 ©
diff --git a/tests/layouts/valid-2.layout b/tests/layouts/valid-2.layout
new file mode 100644
index 00000000..303b2b67
--- /dev/null
+++ b/tests/layouts/valid-2.layout
@@ -0,0 +1,18 @@
+{
+  "text" : "test the blue drink after dinner\n",
+  "attributes" : [
+    {
+      "start" : 9,
+      "end" : 13,
+      "type" : "style",
+      "value" : "italic"
+    },
+    {
+      "start" : 20,
+      "end" : 25,
+      "type" : "underline",
+      "value" : "single"
+    }
+  ],
+  "font" : "Cantarell 11"
+}
diff --git a/tests/layouts/valid-2.markup b/tests/layouts/valid-2.markup
deleted file mode 100644
index 677f26f8..00000000
--- a/tests/layouts/valid-2.markup
+++ /dev/null
@@ -1,2 +0,0 @@
-
-test the <i>blue</i> drink <u>after</u> dinner
diff --git a/tests/layouts/valid-20.layout b/tests/layouts/valid-20.layout
new file mode 100644
index 00000000..bde84b6f
--- /dev/null
+++ b/tests/layouts/valid-20.layout
@@ -0,0 +1,22 @@
+{
+  "text" : "abcdef\n",
+  "attributes" : [
+    {
+      "end" : 3,
+      "type" : "gravity",
+      "value" : "east"
+    },
+    {
+      "end" : 3,
+      "type" : "gravity-hint",
+      "value" : "strong"
+    },
+    {
+      "start" : 3,
+      "end" : 6,
+      "type" : "gravity",
+      "value" : "south"
+    }
+  ],
+  "font" : "Cantarell 11"
+}
diff --git a/tests/layouts/valid-20.markup b/tests/layouts/valid-20.markup
deleted file mode 100644
index fe6480d7..00000000
--- a/tests/layouts/valid-20.markup
+++ /dev/null
@@ -1,2 +0,0 @@
-# exercise gravity handling
-<span gravity='east' gravity_hint='strong'>abc</span><span gravity='south'>def</span>
diff --git a/tests/layouts/valid-21.expected b/tests/layouts/valid-21.expected
deleted file mode 100644
index 5999056f..00000000
--- a/tests/layouts/valid-21.expected
+++ /dev/null
@@ -1,36 +0,0 @@
-有一位住在石室裏的詩人叫施氏，abc, 愛吃獅子，決心要吃十隻獅子。
-
---- parameters
-
-wrapped: 0
-ellipsized: 0
-lines: 2
-
---- attributes
-
-range 0 2147483647
-
---- directions
-
-0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 
-
---- cursor positions
-
-0(0) 3(0) 6(0) 9(0) 12(0) 15(0) 18(0) 21(0) 24(0) 27(0) 30(0) 33(0) 36(0) 39(0) 42(0) 45(0) 46(0) 47(0) 48(0) 49(0) 50(0) 53(0) 56(0) 59(0) 62(0) 65(0) 68(0) 71(0) 74(0) 77(0) 80(0) 83(0) 86(0) 89(0) 89(1) 93(0) 
-
---- lines
-
-i=1, index=0, paragraph-start=1, dir=ltr '有一位住在石室裏的詩人叫施氏，abc, 愛吃獅子，決心要吃十隻獅子。
-'
-i=2, index=93, paragraph-start=1, dir=ltr ''
-
---- runs
-
-i=1, index=0, chars=14, level=0, gravity=east, flags=1, font=OMITTED, script=han, language=xx, '有一位住在石室裏的詩人叫施氏'
-i=2, index=42, chars=1, level=0, gravity=east, flags=1, font=OMITTED, script=han, language=xx, '，'
-i=3, index=45, chars=5, level=0, gravity=south, flags=1, font=OMITTED, script=latin, language=en-us, 'abc, '
-i=4, index=50, chars=4, level=0, gravity=east, flags=1, font=OMITTED, script=han, language=xx, '愛吃獅子'
-i=5, index=62, chars=1, level=0, gravity=east, flags=1, font=OMITTED, script=han, language=xx, '，'
-i=6, index=65, chars=9, level=0, gravity=east, flags=1, font=OMITTED, script=han, language=xx, '決心要吃十隻獅子。'
-i=7, index=92, no run, line end
-i=8, index=93, no run, line end
diff --git a/tests/layouts/valid-21.markup b/tests/layouts/valid-21.markup
deleted file mode 100644
index 676a5e56..00000000
--- a/tests/layouts/valid-21.markup
+++ /dev/null
@@ -1,2 +0,0 @@
-gravity=east
-有一位住在石室裏的詩人叫施氏，abc, 愛吃獅子，決心要吃十隻獅子。
diff --git a/tests/layouts/valid-22.layout b/tests/layouts/valid-22.layout
new file mode 100644
index 00000000..be57d26a
--- /dev/null
+++ b/tests/layouts/valid-22.layout
@@ -0,0 +1,84 @@
+{
+  "text" : "e0 = ooo...\n",
+  "attributes" : [
+    {
+      "start" : 1,
+      "end" : 2,
+      "type" : "font-desc",
+      "value" : "Italic"
+    },
+    {
+      "start" : 1,
+      "end" : 2,
+      "type" : "font-scale",
+      "value" : "subscript"
+    },
+    {
+      "start" : 1,
+      "end" : 2,
+      "type" : "baseline-shift",
+      "value" : "subscript"
+    },
+    {
+      "start" : 6,
+      "end" : 11,
+      "type" : "font-scale",
+      "value" : "superscript"
+    },
+    {
+      "start" : 6,
+      "end" : 11,
+      "type" : "baseline-shift",
+      "value" : "superscript"
+    },
+    {
+      "start" : 7,
+      "end" : 11,
+      "type" : "font-scale",
+      "value" : "superscript"
+    },
+    {
+      "start" : 7,
+      "end" : 11,
+      "type" : "baseline-shift",
+      "value" : "superscript"
+    },
+    {
+      "start" : 8,
+      "end" : 11,
+      "type" : "font-scale",
+      "value" : "superscript"
+    },
+    {
+      "start" : 8,
+      "end" : 11,
+      "type" : "baseline-shift",
+      "value" : "superscript"
+    },
+    {
+      "start" : 9,
+      "end" : 11,
+      "type" : "font-scale",
+      "value" : "superscript"
+    },
+    {
+      "start" : 9,
+      "end" : 11,
+      "type" : "baseline-shift",
+      "value" : "superscript"
+    },
+    {
+      "start" : 10,
+      "end" : 11,
+      "type" : "font-scale",
+      "value" : "superscript"
+    },
+    {
+      "start" : 10,
+      "end" : 11,
+      "type" : "baseline-shift",
+      "value" : "superscript"
+    }
+  ],
+  "font" : "Cantarell 11"
+}
diff --git a/tests/layouts/valid-22.markup b/tests/layouts/valid-22.markup
deleted file mode 100644
index d761749a..00000000
--- a/tests/layouts/valid-22.markup
+++ /dev/null
@@ -1,2 +0,0 @@
-
-e<span font_desc="italic"><sub>0</sub></span> = o<sup>o<sup>o<sup>.<sup>.<sup>.</sup></sup></sup></sup></sup>
diff --git a/tests/layouts/valid-3.layout b/tests/layouts/valid-3.layout
new file mode 100644
index 00000000..ef1b1917
--- /dev/null
+++ b/tests/layouts/valid-3.layout
@@ -0,0 +1,5 @@
+{
+  "text" : "ABC😀️D\n",
+  "attributes" : [],
+  "font" : "Cantarell 11"
+}
diff --git a/tests/layouts/valid-3.markup b/tests/layouts/valid-3.markup
deleted file mode 100644
index 4e394a42..00000000
--- a/tests/layouts/valid-3.markup
+++ /dev/null
@@ -1,2 +0,0 @@
-
-ABC😀️D
diff --git a/tests/layouts/valid-4.layout b/tests/layouts/valid-4.layout
new file mode 100644
index 00000000..5504107d
--- /dev/null
+++ b/tests/layouts/valid-4.layout
@@ -0,0 +1,6 @@
+{
+  "text" : "This paragraph should ac­tual­ly have multiple lines, unlike all the other wannabe äöü pa­ra­graph tests in this ugh test-case. Grow some lines!\n",
+  "attributes" : [],
+  "font" : "Cantarell 11",
+  "width" : 198656
+}
diff --git a/tests/layouts/valid-4.markup b/tests/layouts/valid-4.markup
deleted file mode 100644
index d8890baf..00000000
--- a/tests/layouts/valid-4.markup
+++ /dev/null
@@ -1,2 +0,0 @@
-width=194
-This paragraph should ac­tual­ly have multiple lines, unlike all the other wannabe äöü pa­ra­graph tests in this ugh test-case. Grow some lines!
diff --git a/tests/layouts/valid-5.layout b/tests/layouts/valid-5.layout
new file mode 100644
index 00000000..e5e96b9a
--- /dev/null
+++ b/tests/layouts/valid-5.layout
@@ -0,0 +1,13 @@
+{
+  "text" : "A test with multiple paragraphs and with no-break attributes, which might trigger a crash.\nIf it doesn't the fix has worked.\n",
+  "attributes" : [
+    {
+      "start" : 21,
+      "end" : 31,
+      "type" : "font-features",
+      "value" : "tnum=1"
+    }
+  ],
+  "font" : "Cantarell 11",
+  "width" : 194560
+}
diff --git a/tests/layouts/valid-5.markup b/tests/layouts/valid-5.markup
deleted file mode 100644
index 2b2023ad..00000000
--- a/tests/layouts/valid-5.markup
+++ /dev/null
@@ -1,3 +0,0 @@
-width=190
-A test with multiple <span font_features="tnum=1">paragraphs</span> and with no-break attributes, which might trigger a crash.
-If it doesn't the fix has worked.
diff --git a/tests/layouts/valid-6.layout b/tests/layouts/valid-6.layout
new file mode 100644
index 00000000..4423d068
--- /dev/null
+++ b/tests/layouts/valid-6.layout
@@ -0,0 +1,5 @@
+{
+  "text" : " 0️⃣ Keycap Digit Zero\n",
+  "attributes" : [],
+  "font" : "Cantarell 11"
+}
diff --git a/tests/layouts/valid-6.markup b/tests/layouts/valid-6.markup
deleted file mode 100644
index 92c53e28..00000000
--- a/tests/layouts/valid-6.markup
+++ /dev/null
@@ -1,2 +0,0 @@
-
- 0️⃣ Keycap Digit Zero
diff --git a/tests/layouts/valid-7.layout b/tests/layouts/valid-7.layout
new file mode 100644
index 00000000..b49484c6
--- /dev/null
+++ b/tests/layouts/valid-7.layout
@@ -0,0 +1,21 @@
+{
+  "text" : "This is a test of the automatic emergency brake!\n",
+  "attributes" : [
+    {
+      "start" : 22,
+      "end" : 41,
+      "type" : "foreground",
+      "value" : "#00000000ffff"
+    },
+    {
+      "start" : 22,
+      "end" : 41,
+      "type" : "underline",
+      "value" : "single"
+    }
+  ],
+  "font" : "Cantarell 11",
+  "ellipsize" : "middle",
+  "width" : 204800,
+  "indent" : 51200
+}
diff --git a/tests/layouts/valid-7.markup b/tests/layouts/valid-7.markup
deleted file mode 100644
index d5f9821e..00000000
--- a/tests/layouts/valid-7.markup
+++ /dev/null
@@ -1,2 +0,0 @@
-width=200,indent=50,ellipsize=middle
-This is a test of the <span foreground="#0000ff" underline="single">automatic emergency</span> brake!
diff --git a/tests/layouts/valid-8.layout b/tests/layouts/valid-8.layout
new file mode 100644
index 00000000..063ec370
--- /dev/null
+++ b/tests/layouts/valid-8.layout
@@ -0,0 +1,8 @@
+{
+  "text" : "Hello שלום Γειά σας\n",
+  "attributes" : [],
+  "font" : "Cantarell 11",
+  "auto-dir" : false,
+  "alignment" : "center",
+  "spacing" : 51200
+}
diff --git a/tests/layouts/valid-8.markup b/tests/layouts/valid-8.markup
deleted file mode 100644
index 3272ea2b..00000000
--- a/tests/layouts/valid-8.markup
+++ /dev/null
@@ -1,2 +0,0 @@
-spacing=50,auto_dir=false,alignment=center
-Hello שלום Γειά σας
diff --git a/tests/layouts/valid-9.layout b/tests/layouts/valid-9.layout
new file mode 100644
index 00000000..e3dfa57b
--- /dev/null
+++ b/tests/layouts/valid-9.layout
@@ -0,0 +1,12 @@
+{
+  "text" : "Hello שלום Γειά σας\n",
+  "attributes" : [
+    {
+      "end" : 30,
+      "type" : "letter-spacing",
+      "value" : 8888
+    }
+  ],
+  "font" : "Cantarell 11",
+  "width" : 102400
+}
diff --git a/tests/layouts/valid-9.markup b/tests/layouts/valid-9.markup
deleted file mode 100644
index ced8f8e5..00000000
--- a/tests/layouts/valid-9.markup
+++ /dev/null
@@ -1,2 +0,0 @@
-width=100
-<span letter_spacing="8888">Hello שלום Γειά σας</span>
diff --git a/tests/test-layout.c b/tests/test-layout.c
index cd60450e..7415efe7 100644
--- a/tests/test-layout.c
+++ b/tests/test-layout.c
@@ -219,176 +219,14 @@ dump_cursor_positions (PangoLayout *layout, GString *string)
   g_string_append (string, "\n");
 }
 
-typedef struct {
-  int width;
-  int height;
-  int indent;
-  int spacing;
-  float line_spacing;
-  PangoEllipsizeMode ellipsize;
-  PangoWrapMode wrap;
-  PangoAlignment alignment;
-  gboolean justify;
-  gboolean auto_dir;
-  gboolean single_paragraph;
-  PangoTabArray *tabs;
-  PangoGravity gravity;
-} LayoutParams;
-
-static void
-init_params (LayoutParams *params)
-{
-  params->width = -1;
-  params->height = -1;
-  params->indent = 0;
-  params->spacing = 0;
-  params->line_spacing = 0.0;
-  params->ellipsize = PANGO_ELLIPSIZE_NONE;
-  params->wrap = PANGO_WRAP_WORD;
-  params->alignment = PANGO_ALIGN_LEFT;
-  params->justify = FALSE;
-  params->auto_dir = TRUE;
-  params->single_paragraph = FALSE;
-  params->tabs = NULL;
-  params->gravity = PANGO_GRAVITY_AUTO;
-}
-
-static void
-parse_params (const char   *str,
-              LayoutParams *params)
-{
-  char **strings;
-  int i;
-  GEnumClass *eclass;
-  GEnumValue *ev;
-
-  strings = g_strsplit (str, ",", -1);
-  for (i = 0; strings[i]; i++)
-    {
-      char **str2 = g_strsplit (strings[i], "=", -1);
-      if (strcmp (str2[0], "width") == 0)
-        {
-          params->width = (int) g_ascii_strtoll (str2[1], NULL, 10);
-        }
-      else if (strcmp (str2[0], "height") == 0)
-        {
-          params->height = (int) g_ascii_strtoll (str2[1], NULL, 10);
-        }
-      else if (strcmp (str2[0], "indent") == 0)
-        {
-          params->indent = (int) g_ascii_strtoll (str2[1], NULL, 10);
-        }
-      else if (strcmp (str2[0], "spacing") == 0)
-        {
-          params->spacing = (int) g_ascii_strtoll (str2[1], NULL, 10);
-        }
-      else if (strcmp (str2[0], "line_spacing") == 0)
-        {
-          params->line_spacing = (float) g_ascii_strtod (str2[1], NULL);
-        }
-      else if (strcmp (str2[0], "ellipsize") == 0)
-        {
-          eclass = g_type_class_ref (PANGO_TYPE_ELLIPSIZE_MODE);
-          ev = g_enum_get_value_by_name (eclass, str2[1]);
-          if (!ev)
-            ev = g_enum_get_value_by_nick (eclass, str2[1]);
-          if (ev)
-            params->ellipsize = ev->value;
-          g_type_class_unref (eclass);
-        }
-      else if (strcmp (str2[0], "wrap") == 0)
-        {
-          eclass = g_type_class_ref (PANGO_TYPE_WRAP_MODE);
-          ev = g_enum_get_value_by_name (eclass, str2[1]);
-          if (!ev)
-            ev = g_enum_get_value_by_nick (eclass, str2[1]);
-          if (ev)
-            params->wrap = ev->value;
-          g_type_class_unref (eclass);
-        }
-      else if (strcmp (str2[0], "alignment") == 0)
-        {
-          eclass = g_type_class_ref (PANGO_TYPE_ALIGNMENT);
-          ev = g_enum_get_value_by_name (eclass, str2[1]);
-          if (!ev)
-            ev = g_enum_get_value_by_nick (eclass, str2[1]);
-          if (ev)
-            params->alignment = ev->value;
-          g_type_class_unref (eclass);
-        }
-      else if (strcmp (str2[0], "justify") == 0)
-        {
-          params->justify = g_str_equal (str2[1], "true");
-        }
-      else if (strcmp (str2[0], "auto_dir") == 0)
-        {
-          params->auto_dir = g_str_equal (str2[1], "true");
-        }
-      else if (strcmp (str2[0], "single_paragraph") == 0)
-        {
-          params->single_paragraph = g_str_equal (str2[1], "true");
-        }
-      else if (strcmp (str2[0], "tabs") == 0)
-        {
-          char **str3 = g_strsplit (strings[i], " ", -1);
-          params->tabs = pango_tab_array_new (g_strv_length (str3), TRUE);
-          for (int j = 0; str3[j]; j++)
-            {
-              int tab = (int) g_ascii_strtoll (str3[j], NULL, 10);
-              pango_tab_array_set_tab (params->tabs, j, PANGO_TAB_LEFT, tab);
-            }
-          g_strfreev (str3);
-        }
-      else if (strcmp (str2[0], "gravity") == 0)
-        {
-          eclass = g_type_class_ref (PANGO_TYPE_GRAVITY);
-          ev = g_enum_get_value_by_name (eclass, str2[1]);
-          if (!ev)
-            ev = g_enum_get_value_by_nick (eclass, str2[1]);
-          if (ev)
-            params->gravity = ev->value;
-          g_type_class_unref (eclass);
-        }
-
-      g_strfreev (str2);
-    }
-  g_strfreev (strings);
-}
-
-#define assert_layout_changed(layout) \
-  g_assert_cmpuint (pango_layout_get_serial (layout), !=, serial); \
-  serial = pango_layout_get_serial (layout);
-
-#define assert_rectangle_equal(r1, r2) \
-  g_assert_true((r1)->x == (r2)->x && \
-                (r1)->y == (r2)->y && \
-                (r1)->width == (r2)->width && \
-                (r1)->height == (r2)->height)
-
-#define assert_rectangle_contained(r1, r2) \
-  g_assert_true ((r1)->x >= (r2)->x && \
-                 (r1)->y >= (r2)->y && \
-                 (r1)->x + (r1)->width <= (r2)->x + (r2)->width && \
-                 (r1)->y + (r1)->height <= (r2)->y + (r2)->height)
-
-#define assert_rectangle_size_contained(r1, r2) \
-  g_assert_true ((r1)->width <= (r2)->width && \
-                 (r1)->height <= (r2)->height)
-
 static void
 test_file (const char *filename, GString *string)
 {
   char *contents;
-  char *markup;
   gsize  length;
+  GBytes *bytes;
   GError *error = NULL;
   PangoLayout *layout;
-  char *p;
-  LayoutParams params;
-  PangoFontDescription *desc;
-  const PangoFontDescription *desc2;
-  guint serial;
-  PangoTabArray *tabs;
 
   if (context == NULL)
     context = pango_font_map_create_context (pango_cairo_font_map_get_default ());
@@ -396,85 +234,12 @@ test_file (const char *filename, GString *string)
   g_file_get_contents (filename, &contents, &length, &error);
   g_assert_no_error (error);
 
-  p = strchr (contents, '\n');
-  g_assert (p);
-  markup = p + 1;
-  *p = '\0';
-  length = strlen (markup);
-
-  init_params (&params);
-
-  layout = pango_layout_new (context);
-
-  serial = pango_layout_get_serial (layout);
-  g_assert_cmpuint (serial, !=, 0);
-
-  /* Check initial values */
-  g_assert_cmpint (pango_layout_get_width (layout), ==, params.width);
-  g_assert_cmpint (pango_layout_get_height (layout), ==, params.height);
-  g_assert_cmpint (pango_layout_get_indent (layout), ==, params.indent);
-  g_assert_cmpint (pango_layout_get_spacing (layout), ==, params.spacing);
-  g_assert_cmpfloat (pango_layout_get_line_spacing (layout), ==, params.line_spacing);
-  g_assert_cmpint (pango_layout_get_ellipsize (layout), ==, params.ellipsize);
-  g_assert_cmpint (pango_layout_get_wrap (layout), ==, params.wrap);
-  g_assert_cmpint (pango_layout_get_alignment (layout), ==, params.alignment);
-  g_assert_cmpint (pango_layout_get_justify (layout), ==, params.justify);
-  g_assert_cmpint (pango_layout_get_auto_dir (layout), ==, params.auto_dir);
-  g_assert_cmpint (pango_layout_get_single_paragraph_mode (layout), ==, params.single_paragraph);
-
-  g_assert_cmpstr (pango_layout_get_text (layout), ==, "");
-  g_assert_null (pango_layout_get_attributes (layout));
-  g_assert_null (pango_layout_get_tabs (layout));
-  g_assert_null (pango_layout_get_font_description (layout));
-  g_assert_cmpint (pango_layout_is_ellipsized (layout), ==, FALSE);
-  g_assert_cmpint (pango_layout_is_wrapped (layout), ==, FALSE);
-
-  desc = pango_font_description_from_string ("Cantarell 11");
-  pango_layout_set_font_description (layout, desc);
-  desc2 = pango_layout_get_font_description (layout);
-  g_assert_true (pango_font_description_equal (desc, desc2));
-  pango_font_description_free (desc);
-  assert_layout_changed (layout);
-
-  pango_layout_set_markup (layout, markup, length);
-  assert_layout_changed (layout);
-
-  parse_params (contents, &params);
-
-  pango_context_set_base_gravity (context, params.gravity);
-
-  pango_layout_set_width (layout, params.width > 0 ? params.width * PANGO_SCALE : -1);
-  pango_layout_set_height (layout, params.height > 0 ? params.height * PANGO_SCALE : params.height);
-  pango_layout_set_indent (layout, params.indent * PANGO_SCALE);
-  pango_layout_set_spacing (layout, params.spacing * PANGO_SCALE);
-  pango_layout_set_line_spacing (layout, params.line_spacing);
-  pango_layout_set_ellipsize (layout, params.ellipsize);
-  pango_layout_set_wrap (layout, params.wrap);
-  pango_layout_set_alignment (layout, params.alignment);
-  pango_layout_set_justify (layout, params.justify);
-  pango_layout_set_auto_dir (layout, params.auto_dir);
-  pango_layout_set_single_paragraph_mode (layout, params.single_paragraph);
-  pango_layout_set_tabs (layout, params.tabs);
-
-  /* Check the values we set */
-  g_assert_cmpint (pango_layout_get_width (layout), ==, params.width > 0 ? params.width * PANGO_SCALE : -1);
-  g_assert_cmpint (pango_layout_get_height (layout), ==, params.height > 0 ? params.height * PANGO_SCALE : params.height);
-  g_assert_cmpint (pango_layout_get_indent (layout), ==, params.indent * PANGO_SCALE);
-  g_assert_cmpint (pango_layout_get_spacing (layout), ==, params.spacing * PANGO_SCALE);
-  g_assert_cmpfloat (pango_layout_get_line_spacing (layout), ==, params.line_spacing);
-  g_assert_cmpint (pango_layout_get_ellipsize (layout), ==, params.ellipsize);
-  g_assert_cmpint (pango_layout_get_wrap (layout), ==, params.wrap);
-  g_assert_cmpint (pango_layout_get_alignment (layout), ==, params.alignment);
-  g_assert_cmpint (pango_layout_get_justify (layout), ==, params.justify);
-  g_assert_cmpint (pango_layout_get_auto_dir (layout), ==, params.auto_dir);
-  g_assert_cmpint (pango_layout_get_single_paragraph_mode (layout), ==, params.single_paragraph);
-
-  tabs = pango_layout_get_tabs (layout);
-  g_assert_true ((tabs == NULL) == (params.tabs == NULL));
-  if (tabs)
-    pango_tab_array_free (tabs);
-
-  g_assert_cmpint (pango_layout_get_character_count (layout), ==, g_utf8_strlen (pango_layout_get_text (layout), -1));
+  bytes = g_bytes_new_take (contents, length);
+
+  layout = pango_layout_deserialize (context, bytes, &error);
+  g_assert_no_error (error);
+
+  g_bytes_unref (bytes);
 
   /* generate the dumps */
   g_string_append (string, pango_layout_get_text (layout));
@@ -484,13 +249,11 @@ test_file (const char *filename, GString *string)
   g_string_append_printf (string, "wrapped: %d\n", pango_layout_is_wrapped (layout));
   g_string_append_printf (string, "ellipsized: %d\n", pango_layout_is_ellipsized (layout));
   g_string_append_printf (string, "lines: %d\n", pango_layout_get_line_count (layout));
-  if (params.width > 0)
+  if (pango_layout_get_width (layout) > 0)
     g_string_append_printf (string, "width: %d\n", pango_layout_get_width (layout));
-
-  if (params.height > 0)
+  if (pango_layout_get_height (layout) > 0)
     g_string_append_printf (string, "height: %d\n", pango_layout_get_height (layout));
-
-  if (params.indent != 0)
+  if (pango_layout_get_indent (layout) != 0)
     g_string_append_printf (string, "indent: %d\n", pango_layout_get_indent (layout));
 
   g_string_append (string, "\n--- attributes\n\n");
@@ -509,19 +272,15 @@ test_file (const char *filename, GString *string)
   dump_runs (layout, string);
 
   g_object_unref (layout);
-  g_free (contents);
-
-  if (params.tabs)
-    pango_tab_array_free (params.tabs);
 }
 
 static gchar *
-get_expected_filename (const gchar *filename)
+get_expected_filename (const char *filename)
 {
-  gchar *f, *p, *expected;
+  char *f, *p, *expected;
 
   f = g_strdup (filename);
-  p = strstr (f, ".markup");
+  p = strstr (f, ".layout");
   if (p)
     *p = 0;
   expected = g_strconcat (f, ".expected", NULL);
@@ -534,11 +293,11 @@ get_expected_filename (const gchar *filename)
 static void
 test_layout (gconstpointer d)
 {
-  const gchar *filename = d;
-  gchar *expected_file;
+  const char *filename = d;
+  char *expected_file;
   GError *error = NULL;
   GString *dump;
-  gchar *diff;
+  char *diff;
   PangoFontFamily **families;
   int n_families;
   gboolean found_cantarell;
@@ -616,7 +375,7 @@ main (int argc, char *argv[])
   GDir *dir;
   GError *error = NULL;
   const gchar *name;
-  gchar *path;
+  char *path;
   GOptionContext *option_context;
   GOptionEntry entries[] = {
     { "show-fonts", '0', 0, G_OPTION_ARG_NONE, &opt_show_font, "Print font names in dumps", NULL },
@@ -659,7 +418,7 @@ main (int argc, char *argv[])
   g_assert_no_error (error);
   while ((name = g_dir_read_name (dir)) != NULL)
     {
-      if (!strstr (name, "markup"))
+      if (!g_str_has_suffix (name, ".layout"))
         continue;
 
       path = g_strdup_printf ("/layout/%s", name);
diff --git a/tests/testserialize.c b/tests/testserialize.c
index cc6c67bc..5fb7543a 100644
--- a/tests/testserialize.c
+++ b/tests/testserialize.c
@@ -21,6 +21,7 @@
 #include "config.h"
 #include <glib.h>
 #include <pango/pangocairo.h>
+#include <gio/gio.h>
 
 static void
 test_serialize_attr_list (void)
@@ -122,6 +123,191 @@ test_serialize_tab_array (void)
     }
 }
 
+static void
+test_serialize_layout_minimal (void)
+{
+  const char *test =
+    "{\n"
+    "  \"text\" : \"Almost nothing\"\n"
+    "}";
+
+  PangoContext *context;
+  GBytes *bytes;
+  PangoLayout *layout;
+  GError *error = NULL;
+  GBytes *out_bytes;
+  const char *str;
+
+  context = pango_font_map_create_context (pango_cairo_font_map_get_default ());
+
+  bytes = g_bytes_new_static (test, -1);
+
+  layout = pango_layout_deserialize (context, bytes, &error);
+  g_assert_no_error (error);
+  g_assert_true (PANGO_IS_LAYOUT (layout));
+  g_assert_cmpstr (pango_layout_get_text (layout), ==, "Almost nothing");
+  g_assert_null (pango_layout_get_attributes (layout));
+  g_assert_null (pango_layout_get_tabs (layout));
+  g_assert_null (pango_layout_get_font_description (layout));
+  g_assert_cmpint (pango_layout_get_alignment (layout), ==, PANGO_ALIGN_LEFT);
+  g_assert_cmpint (pango_layout_get_width (layout), ==, -1);
+
+  out_bytes = pango_layout_serialize (layout);
+  str = g_bytes_get_data (out_bytes, NULL);
+
+  g_assert_cmpstr (str, ==, test);
+
+  g_bytes_unref (out_bytes);
+
+  g_object_unref (layout);
+  g_bytes_unref (bytes);
+  g_object_unref (context);
+}
+
+static void
+test_serialize_layout_valid (void)
+{
+  const char *test =
+    "{\n"
+    "  \"text\" : \"Some fun with layouts!\",\n"
+    "  \"attributes\" : [\n"
+    "    {\n"
+    "      \"end\" : 4,\n"
+    "      \"type\" : \"foreground\",\n"
+    "      \"value\" : \"#ffff00000000\"\n"
+    "    },\n"
+    "    {\n"
+    "      \"start\" : 5,\n"
+    "      \"end\" : 8,\n"
+    "      \"type\" : \"foreground\",\n"
+    "      \"value\" : \"#000080800000\"\n"
+    "    },\n"
+    "    {\n"
+    "      \"start\" : 14,\n"
+    "      \"type\" : \"foreground\",\n"
+    "      \"value\" : \"#ffff0000ffff\"\n"
+    "    }\n"
+    "  ],\n"
+    "  \"font\" : \"Sans Bold 32\",\n"
+    "  \"tabs\" : {\n"
+    "    \"positions-in-pixels\" : true,\n"
+    "    \"positions\" : [\n"
+    "      0,\n"
+    "      50,\n"
+    "      100\n"
+    "    ]\n"
+    "  },\n"
+    "  \"alignment\" : \"center\",\n"
+    "  \"width\" : 350000,\n"
+    "  \"line-spacing\" : 1.5\n"
+    "}";
+
+  PangoContext *context;
+  GBytes *bytes;
+  PangoLayout *layout;
+  PangoTabArray *tabs;
+  GError *error = NULL;
+  GBytes *out_bytes;
+  const char *str;
+  char *s;
+
+  context = pango_font_map_create_context (pango_cairo_font_map_get_default ());
+
+  bytes = g_bytes_new_static (test, -1);
+
+  layout = pango_layout_deserialize (context, bytes, &error);
+  g_assert_no_error (error);
+  g_assert_true (PANGO_IS_LAYOUT (layout));
+  g_assert_cmpstr (pango_layout_get_text (layout), ==, "Some fun with layouts!");
+  g_assert_nonnull (pango_layout_get_attributes (layout));
+  tabs = pango_layout_get_tabs (layout);
+  g_assert_nonnull (tabs);
+  pango_tab_array_free (tabs);
+  s = pango_font_description_to_string (pango_layout_get_font_description (layout));
+  g_assert_cmpstr (s, ==, "Sans Bold 32");
+  g_free (s);
+  g_assert_cmpint (pango_layout_get_alignment (layout), ==, PANGO_ALIGN_CENTER);
+  g_assert_cmpint (pango_layout_get_width (layout), ==, 350000);
+  g_assert_cmpfloat_with_epsilon (pango_layout_get_line_spacing (layout), 1.5, 0.0001);
+
+  out_bytes = pango_layout_serialize (layout);
+  str = g_bytes_get_data (out_bytes, NULL);
+
+  g_assert_cmpstr (str, ==, test);
+
+  g_bytes_unref (out_bytes);
+
+  g_object_unref (layout);
+  g_bytes_unref (bytes);
+  g_object_unref (context);
+}
+
+static void
+test_serialize_layout_invalid (void)
+{
+  struct {
+    const char *json;
+    int expected_error;
+  } test[] = {
+    {
+      "{\n"
+      "  \"attributes\" : [\n"
+      "    {\n"
+      "      \"type\" : \"caramba\"\n"
+      "    }\n"
+      "  ]\n"
+      "}",
+      PANGO_LAYOUT_SERIALIZE_INVALID_VALUE
+    },
+    {
+      "{\n"
+      "  \"attributes\" : [\n"
+      "    {\n"
+      "      \"type\" : \"weight\"\n"
+      "    }\n"
+      "  ]\n"
+      "}",
+      PANGO_LAYOUT_SERIALIZE_MISSING_VALUE
+    },
+    {
+      "{\n"
+      "  \"attributes\" : [\n"
+      "    {\n"
+      "      \"type\" : \"alignment\",\n"
+      "      \"value\" : \"nonsense\"\n"
+      "    }\n"
+      "  ]\n"
+      "}",
+      PANGO_LAYOUT_SERIALIZE_INVALID_VALUE
+    },
+    {
+      "{\n"
+      "  \"alignment\" : \"nonsense\"\n"
+      "}",
+      PANGO_LAYOUT_SERIALIZE_INVALID_VALUE
+    }
+  };
+
+  PangoContext *context;
+
+  context = pango_font_map_create_context (pango_cairo_font_map_get_default ());
+
+  for (int i = 0; i < G_N_ELEMENTS (test); i++)
+    {
+      GBytes *bytes;
+      PangoLayout *layout;
+      GError *error = NULL;
+
+       bytes = g_bytes_new_static (test[i].json, -1);
+       layout = pango_layout_deserialize (context, bytes, &error);
+       g_assert_null (layout);
+       g_assert_error (error, PANGO_LAYOUT_SERIALIZE_ERROR, test[i].expected_error);
+       g_bytes_unref (bytes);
+       g_clear_error (&error);
+    }
+
+  g_object_unref (context);
+}
 int
 main (int argc, char *argv[])
 {
@@ -129,6 +315,9 @@ main (int argc, char *argv[])
 
   g_test_add_func ("/serialize/attr-list", test_serialize_attr_list);
   g_test_add_func ("/serialize/tab-array", test_serialize_tab_array);
+  g_test_add_func ("/serialize/layout/minimal", test_serialize_layout_minimal);
+  g_test_add_func ("/serialize/layout/valid", test_serialize_layout_valid);
+  g_test_add_func ("/serialize/layout/invalid", test_serialize_layout_invalid);
 
   return g_test_run ();
 }