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 includes the relevant parts
of cairo_font_options_t (via pango_cairo_context_set_font_options)
as well as the dpi (via pango_cairo_font_map_set_resolution).

The default values we use match the default of the gsettings backing
our GtkSettings:

hint-metrics: off;
hint-style: slight;
antialias: on;
dpi: 96;

This will help with better font testing.

Parser test included.

demos/node-editor/node-format.md

@@ -322,12 +322,16 @@ stroke bounds of the path.
 
 ### text
 
-| property | syntax              | default             | printed     |
-| -------- | ------------------- | ------------------- | ----------- |
-| color    | `<color>`           | black               | non-default |
-| font     | `<string>` `<url>`? | "Cantarell 11"      | always      |
-| glyphs   | `<glyphs>`          | "Hello"             | always      |
-| offset   | `<point>`           | 0 0                 | non-default |
+| property     | syntax              | default             | printed     |
+| ------------ | ------------------- | ------------------- | ----------- |
+| color        | `<color>`           | black               | non-default |
+| font         | `<string>` `<url>`? | "Cantarell 11"      | always      |
+| glyphs       | `<glyphs>`          | "Hello"             | always      |
+| offset       | `<point>`           | 0 0                 | non-default |
+| hint-metrics | `<hint metrics>`    | off                 | non-default |
+| hint-style   | `<hint style>`      | slight              | non-default |
+| antialias    | `<antialias>`       | on                  | non-default |
+| dpi          | `<number>`          | 96                  | non-default |
 
 Creates a node like `gsk_text_node_new()` with the given properties.
 

gsk/gskrendernodeparser.c

@@ -46,7 +46,9 @@
 #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 +88,39 @@ 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,
@@ -887,6 +922,82 @@ font_from_string (PangoFontMap *fontmap,
   return font;
 }
 
+static double
+font_get_dpi (PangoFont *font)
+{
+#ifdef HAVE_PANGOFT
+  if (PANGO_IS_FC_FONT (font))
+    {
+      FcPattern *pattern;
+      double dpi;
+
+      pattern = pango_fc_font_get_pattern (PANGO_FC_FONT (font));
+      if (FcPatternGetDouble (pattern, FC_DPI, 0, &dpi) == FcResultMatch)
+        return dpi;
+    }
+#endif
+
+  /* FIXME, needs pango api */
+
+  return 96.0;
+}
+
+static PangoFont *
+recreate_font_with_options (PangoFont            *font,
+                            cairo_hint_metrics_t  hint_metrics,
+                            cairo_hint_style_t    hint_style,
+                            cairo_antialias_t     antialias,
+                            double                dpi)
+{
+  PangoFontMap *fontmap;
+  PangoFontDescription *desc;
+  PangoContext *ctx;
+  cairo_scaled_font_t *sf;
+  cairo_font_options_t *options;
+  PangoFont *new_font;
+  double old_dpi;
+
+  options = cairo_font_options_create ();
+
+  sf = pango_cairo_font_get_scaled_font (PANGO_CAIRO_FONT (font));
+  cairo_scaled_font_get_font_options (sf, options);
+
+  if (cairo_font_options_get_hint_metrics (options) == hint_metrics &&
+      cairo_font_options_get_hint_style (options) == hint_style &&
+      cairo_font_options_get_antialias (options) == antialias &&
+      font_get_dpi (font) == dpi)
+    {
+      cairo_font_options_destroy (options);
+
+      return font;
+    }
+
+  cairo_font_options_set_hint_metrics (options, hint_metrics);
+  cairo_font_options_set_hint_style (options, hint_style);
+  cairo_font_options_set_antialias (options, antialias);
+
+  desc = pango_font_describe (font);
+  fontmap = pango_font_get_font_map (font);
+
+  ctx = pango_font_map_create_context (fontmap);
+  pango_cairo_context_set_font_options (ctx, options);
+
+  old_dpi = pango_cairo_font_map_get_resolution (PANGO_CAIRO_FONT_MAP (fontmap));
+  pango_cairo_font_map_set_resolution (PANGO_CAIRO_FONT_MAP (fontmap), dpi);
+
+  new_font = pango_font_map_load_font (fontmap, ctx, desc);
+
+  pango_cairo_font_map_set_resolution (PANGO_CAIRO_FONT_MAP (fontmap), old_dpi);
+
+  g_object_unref (ctx);
+  pango_font_description_free (desc);
+  cairo_font_options_destroy (options);
+
+  g_object_unref (font);
+
+  return new_font;
+}
+
 #define MIN_ASCII_GLYPH 32
 #define MAX_ASCII_GLYPH 127 /* exclusive */
 #define N_ASCII_GLYPHS (MAX_ASCII_GLYPH - MIN_ASCII_GLYPH)
@@ -2217,6 +2328,61 @@ unpack_glyphs (PangoFont        *font,
   return TRUE;
 }
 
+static gboolean
+parse_hint_metrics (GtkCssParser *parser,
+                    Context      *context,
+                    gpointer      out)
+{
+  if (!parse_enum (parser, CAIRO_GOBJECT_TYPE_HINT_METRICS, out))
+    return FALSE;
+
+  if (*(cairo_hint_metrics_t *) out == CAIRO_HINT_METRICS_DEFAULT)
+    {
+      gtk_css_parser_error_value (parser, "Unsupported value for enum \"%s\"",
+                                  g_type_name (CAIRO_GOBJECT_TYPE_HINT_METRICS));
+      return FALSE;
+    }
+
+  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_DEFAULT)
+    {
+      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)
@@ -2225,11 +2391,19 @@ parse_text_node (GtkCssParser *parser,
   graphene_point_t offset = GRAPHENE_POINT_INIT (0, 0);
   GdkRGBA color = GDK_RGBA("000000");
   PangoGlyphString *glyphs = NULL;
+  cairo_hint_metrics_t hint_metrics = CAIRO_HINT_METRICS_OFF;
+  cairo_hint_style_t hint_style = CAIRO_HINT_STYLE_SLIGHT;
+  cairo_antialias_t antialias = CAIRO_ANTIALIAS_GRAY;
+  double dpi = 96.0;
   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-metrics", parse_hint_metrics, NULL, &hint_metrics },
+    { "hint-style", parse_hint_style, NULL, &hint_style },
+    { "antialias", parse_antialias, NULL, &antialias },
+    { "dpi", parse_positive_double, NULL, &dpi },
   };
   GskRenderNode *result;
 
@@ -2241,6 +2415,8 @@ parse_text_node (GtkCssParser *parser,
       g_assert (font);
     }
 
+  font = recreate_font_with_options (font, hint_metrics, hint_style, antialias, dpi);
+
   if (!glyphs)
     {
       const char *text = "Hello";
@@ -2429,39 +2605,6 @@ 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,
@@ -3248,6 +3391,33 @@ 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,
@@ -3515,6 +3685,43 @@ 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_metrics_t hint_metrics;
+  cairo_hint_style_t hint_style;
+  cairo_antialias_t antialias;
+
+  options = cairo_font_options_create ();
+  cairo_scaled_font_get_font_options (sf, options);
+  hint_metrics = cairo_font_options_get_hint_metrics (options);
+  hint_style = cairo_font_options_get_hint_style (options);
+  antialias = cairo_font_options_get_antialias (options);
+  cairo_font_options_destroy (options);
+
+  if (hint_metrics != CAIRO_HINT_METRICS_OFF && hint_metrics != CAIRO_HINT_METRICS_DEFAULT)
+    append_enum_param (p, "hint-metrics", CAIRO_GOBJECT_TYPE_HINT_METRICS, hint_metrics);
+
+  if (hint_style != CAIRO_HINT_STYLE_SLIGHT && hint_style != CAIRO_HINT_STYLE_DEFAULT)
+    append_enum_param (p, "hint-style", CAIRO_GOBJECT_TYPE_HINT_STYLE, hint_style);
+
+  if (antialias != CAIRO_ANTIALIAS_GRAY && antialias != CAIRO_ANTIALIAS_DEFAULT)
+    append_enum_param (p, "antialias", CAIRO_GOBJECT_TYPE_ANTIALIAS, antialias);
+}
+
+static void
+gsk_text_node_serialize_font_dpi (GskRenderNode *node,
+                                  Printer       *p)
+{
+  PangoFont *font = gsk_text_node_get_font (node);
+
+  append_float_param (p, "dpi", font_get_dpi (font), 96.f);
+}
+
 void
 gsk_text_node_serialize_glyphs (GskRenderNode *node,
                                 GString       *p)
@@ -3596,33 +3803,6 @@ 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,
@@ -4087,6 +4267,9 @@ 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);
+        gsk_text_node_serialize_font_dpi (node, p);
+
         end_node (p);
       }
       break;

testsuite/gsk/meson.build

@@ -400,6 +400,11 @@ 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 +1,5 @@
+<data>:7:17-24: error: GTK_CSS_PARSER_ERROR_UNKNOWN_VALUE
+<data>:8:15-22: error: GTK_CSS_PARSER_ERROR_UNKNOWN_VALUE
+<data>:9:14-21: error: GTK_CSS_PARSER_ERROR_UNKNOWN_VALUE
+<data>:10:8-10: error: GTK_CSS_PARSER_ERROR_SYNTAX
+<data>:17:14-22: error: GTK_CSS_PARSER_ERROR_UNKNOWN_VALUE

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

@@ -0,0 +1,18 @@
+
+text {
+  color: rgb(50,50,50);
+  font: "Cantarell 11";
+  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-metrics: default;
+  hint-style: default;
+  antialias: default;
+  dpi: -1;
+}
+text {
+  color: rgb(50,50,50);
+  font: "Cantarell 11";
+  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 +1,13 @@
+text {
+  color: rgb(50,50,50);
+  font: "Cantarell 11";
+  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 11";
+  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.node

@@ -0,0 +1,34 @@
+text {
+  color: rgb(50,50,50);
+  font: "Cantarell 11";
+  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-metrics: off;
+  hint-style: slight;
+  antialias: gray;
+  dpi: 96;
+}
+text {
+  color: rgb(50,50,50);
+  font: "Cantarell 11";
+  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-metrics: on;
+  hint-style: full;
+  antialias: none;
+  dpi: 111;
+}
+text {
+  color: rgb(50,50,50);
+  font: "Cantarell 11";
+  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: medium;
+}
+text {
+  color: rgb(50,50,50);
+  font: "Cantarell 11";
+  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;
+}

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

@@ -0,0 +1,30 @@
+text {
+  color: rgb(50,50,50);
+  font: "Cantarell 11";
+  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 10.9990234375";
+  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-metrics: on;
+  hint-style: full;
+  antialias: none;
+  dpi: 111;
+}
+text {
+  color: rgb(50,50,50);
+  font: "Cantarell 11";
+  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: medium;
+}
+text {
+  color: rgb(50,50,50);
+  font: "Cantarell 11";
+  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;
+}