gsk: Accept font options in node files

The goal is to fix all the context that influences the rendering
of text nodes in the node file. This will help with better font
testing.

The newly accepted properties are

hint-style: none/slight/full
antialias: none/gray

We are omitting font options and values that aren't supported
in GSK or have no influence on the rendering.

Note that these settings will get incorporated in the PangoFont
that gets set on the resulting text node.

Parser tests included.

demos/node-editor/node-format.md

@@ -322,12 +322,14 @@ stroke bounds of the path.
 
 ### text
 
-| property | syntax              | default             | printed     |
-| -------- | ------------------- | ------------------- | ----------- |
-| color    | `<color>`           | black               | non-default |
-| font     | `<string>` `<url>`? | "Cantarell 15px"    | always      |
-| glyphs   | `<glyphs>`          | "Hello"             | always      |
-| offset   | `<point>`           | 0 0                 | non-default |
+| property     | syntax              | default             | printed     |
+| ------------ | ------------------- | ------------------- | ----------- |
+| color        | `<color>`           | black               | non-default |
+| font         | `<string>` `<url>`? | "Cantarell 15px"    | always      |
+| glyphs       | `<glyphs>`          | "Hello"             | always      |
+| offset       | `<point>`           | 0 0                 | non-default |
+| hint-style   | `<hint style>`      | slight              | non-default |
+| antialias    | `<antialias>`       | gray                | non-default |
 
 Creates a node like `gsk_text_node_new()` with the given properties.
 
@@ -342,6 +344,9 @@ be specified as well, like this: 40 10 0 0 color.
 If the given font does not exist or the given glyphs are invalid for the given
 font, an error node will be returned.
 
+Possible values for hint-style are none, slight or full.
+Possible value for antialias are none or gray.
+
 ### texture
 
 | property | syntax              | default                | printed     |

gsk/gskrendernodeparser.c

@@ -30,6 +30,7 @@
 #include "gskstroke.h"
 #include "gsktransformprivate.h"
 #include "gskenumtypes.h"
+#include "gskprivate.h"
 
 #include "gdk/gdkrgbaprivate.h"
 #include "gdk/gdktextureprivate.h"
@@ -46,7 +47,9 @@
 #include <cairo-script-interpreter.h>
 #endif
 
+#include <cairo-gobject.h>
 #include <pango/pangocairo.h>
+
 #ifdef HAVE_PANGOFT
 #include <pango/pangofc-fontmap.h>
 #endif
@@ -86,6 +89,39 @@ context_finish (Context *context)
   g_clear_object (&context->fontmap);
 }
 
+static gboolean
+parse_enum (GtkCssParser *parser,
+            GType         type,
+            gpointer      out_value)
+{
+  GEnumClass *class;
+  GEnumValue *v;
+  char *enum_name;
+
+  enum_name = gtk_css_parser_consume_ident (parser);
+  if (enum_name == NULL)
+    return FALSE;
+
+  class = g_type_class_ref (type);
+
+  v = g_enum_get_value_by_nick (class, enum_name);
+  if (v == NULL)
+    {
+      gtk_css_parser_error_value (parser, "Unknown value \"%s\" for enum \"%s\"",
+                                  enum_name, g_type_name (type));
+      g_free (enum_name);
+      g_type_class_unref (class);
+      return FALSE;
+    }
+
+  *(int*)out_value = v->value;
+
+  g_free (enum_name);
+  g_type_class_unref (class);
+
+  return TRUE;
+}
+
 static gboolean
 parse_rect (GtkCssParser    *parser,
             Context         *context,
@@ -2241,6 +2277,45 @@ unpack_glyphs (PangoFont        *font,
   return TRUE;
 }
 
+static gboolean
+parse_hint_style (GtkCssParser *parser,
+                  Context      *context,
+                  gpointer      out)
+{
+  if (!parse_enum (parser, CAIRO_GOBJECT_TYPE_HINT_STYLE, out))
+    return FALSE;
+
+  if (*(cairo_hint_style_t *) out != CAIRO_HINT_STYLE_NONE &&
+      *(cairo_hint_style_t *) out != CAIRO_HINT_STYLE_SLIGHT &&
+      *(cairo_hint_style_t *) out != CAIRO_HINT_STYLE_FULL)
+    {
+      gtk_css_parser_error_value (parser, "Unsupported value for enum \"%s\"",
+                                  g_type_name (CAIRO_GOBJECT_TYPE_HINT_STYLE));
+      return FALSE;
+    }
+
+  return TRUE;
+}
+
+static gboolean
+parse_antialias (GtkCssParser *parser,
+                 Context      *context,
+                 gpointer      out)
+{
+  if (!parse_enum (parser, CAIRO_GOBJECT_TYPE_ANTIALIAS, out))
+    return FALSE;
+
+  if (*(cairo_antialias_t *) out != CAIRO_ANTIALIAS_NONE &&
+      *(cairo_antialias_t *) out != CAIRO_ANTIALIAS_GRAY)
+    {
+      gtk_css_parser_error_value (parser, "Unsupported value for enum \"%s\"",
+                                  g_type_name (CAIRO_GOBJECT_TYPE_ANTIALIAS));
+      return FALSE;
+    }
+
+  return TRUE;
+}
+
 static GskRenderNode *
 parse_text_node (GtkCssParser *parser,
                  Context      *context)
@@ -2249,11 +2324,16 @@ parse_text_node (GtkCssParser *parser,
   graphene_point_t offset = GRAPHENE_POINT_INIT (0, 0);
   GdkRGBA color = GDK_RGBA("000000");
   PangoGlyphString *glyphs = NULL;
+  cairo_hint_style_t hint_style = CAIRO_HINT_STYLE_SLIGHT;
+  cairo_antialias_t antialias = CAIRO_ANTIALIAS_GRAY;
+  PangoFont *hinted;
   const Declaration declarations[] = {
     { "font", parse_font, clear_font, &font },
     { "offset", parse_point, NULL, &offset },
     { "color", parse_color, NULL, &color },
-    { "glyphs", parse_glyphs, clear_glyphs, &glyphs }
+    { "glyphs", parse_glyphs, clear_glyphs, &glyphs },
+    { "hint-style", parse_hint_style, NULL, &hint_style },
+    { "antialias", parse_antialias, NULL, &antialias },
   };
   GskRenderNode *result;
 
@@ -2265,6 +2345,10 @@ parse_text_node (GtkCssParser *parser,
       g_assert (font);
     }
 
+  hinted = gsk_get_hinted_font (font, hint_style, antialias);
+  g_object_unref (font);
+  font = hinted;
+
   if (!glyphs)
     {
       const char *text = "Hello";
@@ -2454,39 +2538,6 @@ clear_dash (gpointer inout_array)
   g_clear_pointer ((GArray **) inout_array, g_array_unref);
 }
 
-static gboolean
-parse_enum (GtkCssParser *parser,
-            GType         type,
-            gpointer      out_value)
-{
-  GEnumClass *class;
-  GEnumValue *v;
-  char *enum_name;
-
-  enum_name = gtk_css_parser_consume_ident (parser);
-  if (enum_name == NULL)
-    return FALSE;
-
-  class = g_type_class_ref (type);
-
-  v = g_enum_get_value_by_nick (class, enum_name);
-  if (v == NULL)
-    {
-      gtk_css_parser_error_value (parser, "Unknown value \"%s\" for enum \"%s\"",
-                                  enum_name, g_type_name (type));
-      g_free (enum_name);
-      g_type_class_unref (class);
-      return FALSE;
-    }
-
-  *(int*)out_value = v->value;
-
-  g_free (enum_name);
-  g_type_class_unref (class);
-
-  return TRUE;
-}
-
 static gboolean
 parse_fill_rule (GtkCssParser *parser,
                  Context      *context,
@@ -3273,6 +3324,33 @@ append_string_param (Printer    *p,
   g_string_append_c (p->str, '\n');
 }
 
+static const char *
+enum_to_nick (GType type,
+              int   value)
+{
+  GEnumClass *class;
+  GEnumValue *v;
+
+  class = g_type_class_ref (type);
+  v = g_enum_get_value (class, value);
+  g_type_class_unref (class);
+
+  return v->value_nick;
+}
+
+static void
+append_enum_param (Printer    *p,
+                   const char *param_name,
+                   GType       type,
+                   int         value)
+{
+  _indent (p);
+  g_string_append_printf (p->str, "%s: ", param_name);
+  g_string_append (p->str, enum_to_nick (type, value));
+  g_string_append_c (p->str, ';');
+  g_string_append_c (p->str, '\n');
+}
+
 static void
 append_vec4_param (Printer               *p,
                    const char            *param_name,
@@ -3540,6 +3618,37 @@ gsk_text_node_serialize_font (GskRenderNode *node,
 #endif
 }
 
+static void
+gsk_text_node_serialize_font_options (GskRenderNode *node,
+                                      Printer       *p)
+{
+  PangoFont *font = gsk_text_node_get_font (node);
+  cairo_scaled_font_t *sf = pango_cairo_font_get_scaled_font (PANGO_CAIRO_FONT (font));
+  cairo_font_options_t *options;
+  cairo_hint_style_t hint_style;
+  cairo_antialias_t antialias;
+
+  options = cairo_font_options_create ();
+  cairo_scaled_font_get_font_options (sf, options);
+  hint_style = cairo_font_options_get_hint_style (options);
+  antialias = cairo_font_options_get_antialias (options);
+  cairo_font_options_destroy (options);
+
+  /* medium and full are identical in the absence of subpixel modes */
+  if (hint_style == CAIRO_HINT_STYLE_MEDIUM)
+    hint_style = CAIRO_HINT_STYLE_FULL;
+
+  if (hint_style == CAIRO_HINT_STYLE_NONE ||
+      hint_style == CAIRO_HINT_STYLE_FULL)
+    append_enum_param (p, "hint-style", CAIRO_GOBJECT_TYPE_HINT_STYLE, hint_style);
+
+  /* CAIRO_ANTIALIAS_NONE is the only value we ever emit here, since gray is the default,
+   * and we don't accept any other values.
+   */
+  if (antialias == CAIRO_ANTIALIAS_NONE)
+    append_enum_param (p, "antialias", CAIRO_GOBJECT_TYPE_ANTIALIAS, antialias);
+}
+
 void
 gsk_text_node_serialize_glyphs (GskRenderNode *node,
                                 GString       *p)
@@ -3621,33 +3730,6 @@ gsk_text_node_serialize_glyphs (GskRenderNode *node,
     pango_glyph_string_free (ascii);
 }
 
-static const char *
-enum_to_nick (GType type,
-              int   value)
-{
-  GEnumClass *class;
-  GEnumValue *v;
-
-  class = g_type_class_ref (type);
-  v = g_enum_get_value (class, value);
-  g_type_class_unref (class);
-
-  return v->value_nick;
-}
-
-static void
-append_enum_param (Printer    *p,
-                   const char *param_name,
-                   GType       type,
-                   int         value)
-{
-  _indent (p);
-  g_string_append_printf (p->str, "%s: ", param_name);
-  g_string_append (p->str, enum_to_nick (type, value));
-  g_string_append_c (p->str, ';');
-  g_string_append_c (p->str, '\n');
-}
-
 static void
 append_path_param (Printer    *p,
                    const char *param_name,
@@ -4112,6 +4194,8 @@ render_node_print (Printer       *p,
         if (!graphene_point_equal (offset, graphene_point_zero ()))
           append_point_param (p, "offset", offset);
 
+        gsk_text_node_serialize_font_options (node, p);
+
         end_node (p);
       }
       break;

testsuite/gsk/meson.build

@@ -383,6 +383,11 @@ node_parser_tests = [
   'text-font-errors.node',
   'text-font-errors.ref.node',
   'text-font-errors.errors',
+  'text-font-options.node',
+  'text-font-options.ref.node',
+  'text-font-options-error.node',
+  'text-font-options-error.ref.node',
+  'text-font-options-error.ref.errors',
   'text-no-color.node',
   'texture-fail.node',
   'texture-fail.ref.node',

testsuite/gsk/nodeparser/text-font-options-error.errors

@@ -0,0 +1,3 @@
+<data>:7:15-22: error: GTK_CSS_PARSER_ERROR_UNKNOWN_VALUE
+<data>:8:14-19: error: GTK_CSS_PARSER_ERROR_UNKNOWN_VALUE
+<data>:15:14-22: error: GTK_CSS_PARSER_ERROR_UNKNOWN_VALUE

testsuite/gsk/nodeparser/text-font-options-error.node

@@ -0,0 +1,16 @@
+
+text {
+  color: rgb(50,50,50);
+  font: "Cantarell 15px";
+  glyphs: "N", 430 5, 406 8, 417 7, 772 4, 783 5, 783 5, 793 6 0 0 same-cluster;
+  offset: 0 32.0186;
+  hint-style: garbage;
+  antialias: trash;
+}
+text {
+  color: rgb(50,50,50);
+  font: "Cantarell 15px";
+  glyphs: "N", 430 5, 406 8, 417 7, 772 4, 783 5, 783 5, 793 6 0 0 same-cluster;
+  offset: 0 32.0186;
+  antialias: subpixel;
+}

testsuite/gsk/nodeparser/text-font-options-error.ref.node

@@ -0,0 +1,12 @@
+text {
+  color: rgb(50,50,50);
+  font: "Cantarell 15px";
+  glyphs: "N", 430 5, 406 8, 417 7, 772 4, 783 5, 783 5, 793 6 0 0 same-cluster;
+  offset: 0 32.0186;
+}
+text {
+  color: rgb(50,50,50);
+  font: "Cantarell 15px";
+  glyphs: "N", 430 5, 406 8, 417 7, 772 4, 783 5, 783 5, 793 6 0 0 same-cluster;
+  offset: 0 32.0186;
+}

testsuite/gsk/nodeparser/text-font-options.node

@@ -0,0 +1,23 @@
+text {
+  color: rgb(50,50,50);
+  font: "Cantarell 15px";
+  glyphs: "N", 430 5, 406 8, 417 7, 772 4, 783 5, 783 5, 793 6 0 0 same-cluster;
+  offset: 0 32.0186;
+  hint-style: none;
+  antialias: none;
+}
+text {
+  color: rgb(50,50,50);
+  font: "Cantarell 15px";
+  glyphs: "N", 430 5, 406 8, 417 7, 772 4, 783 5, 783 5, 793 6 0 0 same-cluster;
+  offset: 0 32.0186;
+  hint-style: slight;
+  antialias: gray;
+}
+text {
+  color: rgb(50,50,50);
+  font: "Cantarell 15px";
+  glyphs: "N", 430 5, 406 8, 417 7, 772 4, 783 5, 783 5, 793 6 0 0 same-cluster;
+  offset: 0 32.0186;
+  hint-style: full;
+}

testsuite/gsk/nodeparser/text-font-options.ref.node

@@ -0,0 +1,21 @@
+text {
+  color: rgb(50,50,50);
+  font: "Cantarell 15px";
+  glyphs: "N", 430 5, 406 8, 417 7, 772 4, 783 5, 783 5, 793 6 0 0 same-cluster;
+  offset: 0 32.0186;
+  hint-style: none;
+  antialias: none;
+}
+text {
+  color: rgb(50,50,50);
+  font: "Cantarell 15px";
+  glyphs: "N", 430 5, 406 8, 417 7, 772 4, 783 5, 783 5, 793 6 0 0 same-cluster;
+  offset: 0 32.0186;
+}
+text {
+  color: rgb(50,50,50);
+  font: "Cantarell 15px";
+  glyphs: "N", 430 5, 406 8, 417 7, 772 4, 783 5, 783 5, 793 6 0 0 same-cluster;
+  offset: 0 32.0186;
+  hint-style: full;
+}

testsuite/gsk/nodeparser/text.ref.node

@@ -1,6 +1,6 @@
 text {
   color: rgb(50,50,50);
   font: "Cantarell 14px";
-  glyphs: "N", 430 5, 406 7, 417 7, 772 4, 783 5, 783 5, 793 6 0 0 same-cluster;
+  glyphs: "N", 430 4.2002, 406 6.10352, 417 7, 772 4, 783 5, 783 5, 793 6 0 0 same-cluster;
   offset: 0 32.0186;
 }