css: Add line-height property

This adds the plumbing to parse the line-height
property from CSS. Widgets are not picking it
up yet.

gtk/gtkcssanimatedstyle.c

@@ -204,6 +204,10 @@ gtk_css_animated_style_set_animated_value (GtkCssAnimatedStyle *animated,
       unshare_font (animated);
       gtk_css_take_value (&style->font->letter_spacing, value);
       break;
+    case GTK_CSS_PROPERTY_LINE_HEIGHT:
+      unshare_font (animated);
+      gtk_css_take_value (&style->font->line_height, value);
+      break;
     case GTK_CSS_PROPERTY_TEXT_DECORATION_LINE:
       unshare_font_variant (animated);
       gtk_css_take_value (&style->font_variant->text_decoration_line, value);

gtk/gtkcsslineheightvalue.c

@@ -0,0 +1,184 @@
+/* GTK - The GIMP Toolkit
+ * 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 Lesser 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include "gtkcsslineheightvalueprivate.h"
+#include "gtkcssnumbervalueprivate.h"
+#include "gtkcssstyleprivate.h"
+
+struct _GtkCssValue {
+  GTK_CSS_VALUE_BASE
+  GtkCssValue *height;
+};
+
+static GtkCssValue *default_line_height;
+
+static GtkCssValue *gtk_css_value_line_height_new_empty (void);
+static GtkCssValue *gtk_css_value_line_height_new       (GtkCssValue *height);
+
+static void
+gtk_css_value_line_height_free (GtkCssValue *value)
+{
+  _gtk_css_value_unref (value->height);
+  g_slice_free (GtkCssValue, value);
+}
+
+static GtkCssValue *
+gtk_css_value_line_height_compute (GtkCssValue      *value,
+                                   guint             property_id,
+                                   GtkStyleProvider *provider,
+                                   GtkCssStyle      *style,
+                                   GtkCssStyle      *parent_style)
+{
+  GtkCssValue *height;
+
+  height = _gtk_css_value_compute (value->height, property_id, provider, style, parent_style);
+
+  if (gtk_css_number_value_get_dimension (height) == GTK_CSS_DIMENSION_PERCENTAGE)
+    {
+      double factor;
+      GtkCssValue *val;
+      GtkCssValue *computed;
+
+      factor =  _gtk_css_number_value_get (height, 1);
+      val = gtk_css_dimension_value_new (factor, GTK_CSS_EM);
+
+      computed = _gtk_css_value_compute (val,
+                                         GTK_CSS_PROPERTY_FONT_SIZE,
+                                         provider,
+                                         style,
+                                         parent_style);
+
+      _gtk_css_value_unref (val);
+      _gtk_css_value_unref (height);
+
+      return computed;
+    }
+  else
+    {
+      return height;
+    }
+}
+
+static gboolean
+gtk_css_value_line_height_equal (const GtkCssValue *value1,
+                                 const GtkCssValue *value2)
+{
+  if (value1->height == NULL || value2->height == NULL)
+    return FALSE;
+
+  return _gtk_css_value_equal (value1->height, value2->height);
+}
+
+static GtkCssValue *
+gtk_css_value_line_height_transition (GtkCssValue *start,
+                                      GtkCssValue *end,
+                                      guint        property_id,
+                                      double       progress)
+{
+  GtkCssValue *height;
+
+  if (start->height == NULL || end->height == NULL)
+    return NULL;
+
+  height = _gtk_css_value_transition (start->height, end->height, property_id, progress);
+  if (height == NULL)
+    return NULL;
+
+  return gtk_css_value_line_height_new (height);
+}
+
+static void
+gtk_css_value_line_height_print (const GtkCssValue *value,
+                                 GString           *string)
+{
+  if (value->height == NULL)
+    g_string_append (string, "normal");
+  else
+    _gtk_css_value_print (value->height, string);
+}
+
+static const GtkCssValueClass GTK_CSS_VALUE_LINE_HEIGHT = {
+  "GtkCssLineHeightValue",
+  gtk_css_value_line_height_free,
+  gtk_css_value_line_height_compute,
+  gtk_css_value_line_height_equal,
+  gtk_css_value_line_height_transition,
+  NULL,
+  NULL,
+  gtk_css_value_line_height_print
+};
+
+static GtkCssValue *
+gtk_css_value_line_height_new_empty (void)
+{
+  GtkCssValue *result;
+
+  result = _gtk_css_value_new (GtkCssValue, &GTK_CSS_VALUE_LINE_HEIGHT);
+  result->height = NULL;
+  result->is_computed = TRUE;
+
+  return result;
+}
+
+static GtkCssValue *
+gtk_css_value_line_height_new (GtkCssValue *height)
+{
+  GtkCssValue *result;
+
+  result = _gtk_css_value_new (GtkCssValue, &GTK_CSS_VALUE_LINE_HEIGHT);
+  result->height = height;
+
+  return result;
+}
+
+GtkCssValue *
+gtk_css_line_height_value_get_default (void)
+{
+  if (default_line_height == NULL)
+    default_line_height = gtk_css_value_line_height_new_empty ();
+
+  return default_line_height;
+}
+
+GtkCssValue *
+gtk_css_line_height_value_parse (GtkCssParser *parser)
+{
+  GtkCssValue *height;
+
+  if (gtk_css_parser_try_ident (parser, "normal"))
+    return _gtk_css_value_ref (gtk_css_line_height_value_get_default ());
+
+  height = _gtk_css_number_value_parse (parser, GTK_CSS_PARSE_NUMBER |
+                                                GTK_CSS_PARSE_PERCENT |
+                                                GTK_CSS_PARSE_LENGTH |
+                                                GTK_CSS_POSITIVE_ONLY);
+  if (!height)
+    return NULL;
+
+  return gtk_css_value_line_height_new (height);
+}
+
+double
+gtk_css_line_height_value_get (const GtkCssValue *value)
+{
+  if (value->class == &GTK_CSS_VALUE_LINE_HEIGHT)
+    return 0.0;
+
+  return _gtk_css_number_value_get (value, 1);
+}

gtk/gtkcsslineheightvalueprivate.h

@@ -0,0 +1,37 @@
+/*
+ * Copyright © 2021 Red Hat Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Matthias Clasen <mclasen@redhat.com>
+ */
+
+#ifndef __GTK_CSS_LINE_HEIGHT_VALUE_PRIVATE_H__
+#define __GTK_CSS_LINE_HEIGHT_VALUE_PRIVATE_H__
+
+#include <gtk/css/gtkcss.h>
+#include "gtk/css/gtkcsstokenizerprivate.h"
+#include "gtk/css/gtkcssparserprivate.h"
+#include "gtkcssvalueprivate.h"
+
+G_BEGIN_DECLS
+
+GtkCssValue * gtk_css_line_height_value_get_default (void);
+GtkCssValue * gtk_css_line_height_value_parse       (GtkCssParser      *parser);
+
+double        gtk_css_line_height_value_get         (const GtkCssValue *value);
+
+G_END_DECLS
+
+#endif /* __GTK_CSS_LINE_HEIGHT_VALUE_PRIVATE_H__ */

gtk/gtkcssstaticstyle.c

@@ -107,11 +107,12 @@ static const int font_props[] = {
   GTK_CSS_PROPERTY_FONT_WEIGHT,
   GTK_CSS_PROPERTY_FONT_STRETCH,
   GTK_CSS_PROPERTY_LETTER_SPACING,
-  GTK_CSS_PROPERTY_TEXT_SHADOW,  
+  GTK_CSS_PROPERTY_TEXT_SHADOW,
   GTK_CSS_PROPERTY_CARET_COLOR,
   GTK_CSS_PROPERTY_SECONDARY_CARET_COLOR,
   GTK_CSS_PROPERTY_FONT_FEATURE_SETTINGS,
   GTK_CSS_PROPERTY_FONT_VARIATION_SETTINGS,
+  GTK_CSS_PROPERTY_LINE_HEIGHT,
 };
 static const int font_variant_props[] = {
   GTK_CSS_PROPERTY_TEXT_DECORATION_LINE,
@@ -417,6 +418,9 @@ gtk_css_static_style_set_value (GtkCssStaticStyle *sstyle,
     case GTK_CSS_PROPERTY_LETTER_SPACING:
       gtk_css_take_value (&style->font->letter_spacing, value);
       break;
+    case GTK_CSS_PROPERTY_LINE_HEIGHT:
+      gtk_css_take_value (&style->font->line_height, value);
+      break;
     case GTK_CSS_PROPERTY_TEXT_DECORATION_LINE:
       gtk_css_take_value (&style->font_variant->text_decoration_line, value);
       break;

gtk/gtkcssstyle.c

@@ -117,6 +117,8 @@ gtk_css_style_get_value (GtkCssStyle *style,
       return style->font->font_stretch;
     case GTK_CSS_PROPERTY_LETTER_SPACING:
       return style->font->letter_spacing;
+    case GTK_CSS_PROPERTY_LINE_HEIGHT:
+      return style->font->line_height;
     case GTK_CSS_PROPERTY_TEXT_DECORATION_LINE:
       return style->font_variant->text_decoration_line;
     case GTK_CSS_PROPERTY_TEXT_DECORATION_COLOR:

gtk/gtkcssstyleprivate.h

@@ -151,6 +151,7 @@ struct _GtkCssFontValues {
   GtkCssValue *secondary_caret_color; // NULL if currentColor
   GtkCssValue *font_feature_settings;
   GtkCssValue *font_variation_settings;
+  GtkCssValue *line_height;
 };
 
 struct _GtkCssFontVariantValues {

gtk/gtkcssstylepropertyimpl.c

@@ -52,6 +52,7 @@
 #include "gtkcssstringvalueprivate.h"
 #include "gtkcsstransformvalueprivate.h"
 #include "gtkcssfontvariationsvalueprivate.h"
+#include "gtkcsslineheightvalueprivate.h"
 #include "gtktypebuiltins.h"
 
 /*** REGISTRATION ***/
@@ -812,6 +813,13 @@ transform_origin_parse (GtkCssStyleProperty *property,
   return _gtk_css_position_value_parse (parser);
 }
 
+static GtkCssValue *
+parse_line_height (GtkCssStyleProperty *property,
+                   GtkCssParser        *parser)
+{
+  return gtk_css_line_height_value_parse (parser);
+}
+
 /*** REGISTRATION ***/
 
 G_STATIC_ASSERT (GTK_CSS_PROPERTY_COLOR == 0);
@@ -1401,4 +1409,10 @@ _gtk_css_style_property_init_properties (void)
                                           GTK_CSS_AFFECTS_TEXT_ATTRS | GTK_CSS_AFFECTS_TEXT_SIZE,
                                           parse_font_variation_settings,
                                           gtk_css_font_variations_value_new_default ());
+  gtk_css_style_property_register        ("line-height",
+                                          GTK_CSS_PROPERTY_LINE_HEIGHT,
+                                          GTK_STYLE_PROPERTY_INHERIT | GTK_STYLE_PROPERTY_ANIMATED,
+                                          GTK_CSS_AFFECTS_TEXT_ATTRS | GTK_CSS_AFFECTS_TEXT_SIZE,
+                                          parse_line_height,
+                                          _gtk_css_value_ref (gtk_css_line_height_value_get_default ()));
 }

gtk/gtkcsstypesprivate.h

@@ -275,6 +275,7 @@ enum { /*< skip >*/
   GTK_CSS_PROPERTY_SECONDARY_CARET_COLOR,
   GTK_CSS_PROPERTY_FONT_FEATURE_SETTINGS,
   GTK_CSS_PROPERTY_FONT_VARIATION_SETTINGS,
+  GTK_CSS_PROPERTY_LINE_HEIGHT,
   /* add more */
   GTK_CSS_PROPERTY_N_PROPERTIES
 };

gtk/meson.build

@@ -78,6 +78,7 @@ gtk_private_sources = files([
   'gtkcssinheritvalue.c',
   'gtkcssinitialvalue.c',
   'gtkcsskeyframes.c',
+  'gtkcsslineheightvalue.c',
   'gtkcsslookup.c',
   'gtkcssnode.c',
   'gtkcssnodedeclaration.c',