css: Turn number values into a virtual type

GtkCssNumberValue is now a base class for numbers.

Actual numbers are now implemented in GtkCssDimensionValue. The name is
borrowed from the CSS spec, so there.

1 files changed, 293 insertions, 0 deletions

diff --git a/gtk/gtkcssdimensionvalue.c b/gtk/gtkcssdimensionvalue.c
new file mode 100644
index 0000000000..edf8a6fc75
--- /dev/null
+++ b/gtk/gtkcssdimensionvalue.c
@@ -0,0 +1,293 @@
+/* GTK - The GIMP Toolkit
+ * Copyright (C) 2011 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 "gtkcssdimensionvalueprivate.h"
+
+#include "gtkcssenumvalueprivate.h"
+#include "gtkstylepropertyprivate.h"
+
+#include "fallback-c89.c"
+
+struct _GtkCssValue {
+  GTK_CSS_VALUE_BASE
+  GtkCssUnit unit;
+  double value;
+};
+
+static void
+gtk_css_value_dimension_free (GtkCssValue *value)
+{
+  g_slice_free (GtkCssValue, value);
+}
+
+static double
+get_base_font_size (guint                    property_id,
+                    GtkStyleProviderPrivate *provider,
+                    GtkCssStyle             *style,
+                    GtkCssStyle             *parent_style)
+{
+  if (property_id == GTK_CSS_PROPERTY_FONT_SIZE)
+    {
+      if (parent_style)
+        return _gtk_css_number_value_get (gtk_css_style_get_value (parent_style, GTK_CSS_PROPERTY_FONT_SIZE), 100);
+      else
+        return _gtk_css_font_size_get_default (provider);
+    }
+
+  return _gtk_css_number_value_get (gtk_css_style_get_value (style, GTK_CSS_PROPERTY_FONT_SIZE), 100);
+}
+
+static double
+get_dpi (GtkCssStyle *style)
+{
+  return _gtk_css_number_value_get (gtk_css_style_get_value (style, GTK_CSS_PROPERTY_DPI), 96);
+}
+
+static GtkCssValue *
+gtk_css_value_dimension_compute (GtkCssValue             *number,
+                              guint                    property_id,
+                              GtkStyleProviderPrivate *provider,
+                              GtkCssStyle             *style,
+                              GtkCssStyle             *parent_style)
+{
+  GtkBorderStyle border_style;
+
+  /* special case according to http://dev.w3.org/csswg/css-backgrounds/#the-border-width */
+  switch (property_id)
+    {
+      case GTK_CSS_PROPERTY_BORDER_TOP_WIDTH:
+        border_style = _gtk_css_border_style_value_get(gtk_css_style_get_value (style, GTK_CSS_PROPERTY_BORDER_TOP_STYLE));
+        if (border_style == GTK_BORDER_STYLE_NONE || border_style == GTK_BORDER_STYLE_HIDDEN)
+          return gtk_css_dimension_value_new (0, GTK_CSS_NUMBER);
+        break;
+      case GTK_CSS_PROPERTY_BORDER_RIGHT_WIDTH:
+        border_style = _gtk_css_border_style_value_get(gtk_css_style_get_value (style, GTK_CSS_PROPERTY_BORDER_RIGHT_STYLE));
+        if (border_style == GTK_BORDER_STYLE_NONE || border_style == GTK_BORDER_STYLE_HIDDEN)
+          return gtk_css_dimension_value_new (0, GTK_CSS_NUMBER);
+        break;
+      case GTK_CSS_PROPERTY_BORDER_BOTTOM_WIDTH:
+        border_style = _gtk_css_border_style_value_get(gtk_css_style_get_value (style, GTK_CSS_PROPERTY_BORDER_BOTTOM_STYLE));
+        if (border_style == GTK_BORDER_STYLE_NONE || border_style == GTK_BORDER_STYLE_HIDDEN)
+          return gtk_css_dimension_value_new (0, GTK_CSS_NUMBER);
+        break;
+      case GTK_CSS_PROPERTY_BORDER_LEFT_WIDTH:
+        border_style = _gtk_css_border_style_value_get(gtk_css_style_get_value (style, GTK_CSS_PROPERTY_BORDER_LEFT_STYLE));
+        if (border_style == GTK_BORDER_STYLE_NONE || border_style == GTK_BORDER_STYLE_HIDDEN)
+          return gtk_css_dimension_value_new (0, GTK_CSS_NUMBER);
+        break;
+      case GTK_CSS_PROPERTY_OUTLINE_WIDTH:
+        border_style = _gtk_css_border_style_value_get(gtk_css_style_get_value (style, GTK_CSS_PROPERTY_OUTLINE_STYLE));
+        if (border_style == GTK_BORDER_STYLE_NONE || border_style == GTK_BORDER_STYLE_HIDDEN)
+          return gtk_css_dimension_value_new (0, GTK_CSS_NUMBER);
+        break;
+      default:
+        break;
+    }
+
+  switch (number->unit)
+    {
+    default:
+      g_assert_not_reached();
+      /* fall through */
+    case GTK_CSS_PERCENT:
+      /* percentages for font sizes are computed, other percentages aren't */
+      if (property_id == GTK_CSS_PROPERTY_FONT_SIZE)
+        return gtk_css_dimension_value_new (number->value / 100.0 * 
+                                            get_base_font_size (property_id, provider, style, parent_style),
+                                            GTK_CSS_PX);
+    case GTK_CSS_NUMBER:
+    case GTK_CSS_PX:
+    case GTK_CSS_DEG:
+    case GTK_CSS_S:
+      return _gtk_css_value_ref (number);
+    case GTK_CSS_PT:
+      return gtk_css_dimension_value_new (number->value * get_dpi (style) / 72.0,
+                                          GTK_CSS_PX);
+    case GTK_CSS_PC:
+      return gtk_css_dimension_value_new (number->value * get_dpi (style) / 72.0 * 12.0,
+                                          GTK_CSS_PX);
+    case GTK_CSS_IN:
+      return gtk_css_dimension_value_new (number->value * get_dpi (style),
+                                          GTK_CSS_PX);
+    case GTK_CSS_CM:
+      return gtk_css_dimension_value_new (number->value * get_dpi (style) * 0.39370078740157477,
+                                          GTK_CSS_PX);
+    case GTK_CSS_MM:
+      return gtk_css_dimension_value_new (number->value * get_dpi (style) * 0.039370078740157477,
+                                          GTK_CSS_PX);
+    case GTK_CSS_EM:
+      return gtk_css_dimension_value_new (number->value * get_dpi (style) / 72.0 *
+                                          get_base_font_size (property_id, provider, style, parent_style),
+                                          GTK_CSS_PX);
+    case GTK_CSS_EX:
+      /* for now we pretend ex is half of em */
+      return gtk_css_dimension_value_new (number->value * 0.5 * get_dpi (style) / 72.0 *
+                                          get_base_font_size (property_id, provider, style, parent_style),
+                                          GTK_CSS_PX);
+    case GTK_CSS_REM:
+      return gtk_css_dimension_value_new (number->value * get_dpi (style) / 72.0 *
+                                          _gtk_css_font_size_get_default (provider),
+                                          GTK_CSS_PX);
+    case GTK_CSS_RAD:
+      return gtk_css_dimension_value_new (number->value * 360.0 / (2 * G_PI),
+                                          GTK_CSS_DEG);
+    case GTK_CSS_GRAD:
+      return gtk_css_dimension_value_new (number->value * 360.0 / 400.0,
+                                          GTK_CSS_DEG);
+    case GTK_CSS_TURN:
+      return gtk_css_dimension_value_new (number->value * 360.0,
+                                          GTK_CSS_DEG);
+    case GTK_CSS_MS:
+      return gtk_css_dimension_value_new (number->value / 1000.0,
+                                          GTK_CSS_S);
+    }
+}
+
+static gboolean
+gtk_css_value_dimension_equal (const GtkCssValue *number1,
+                            const GtkCssValue *number2)
+{
+  return number1->unit == number2->unit &&
+         number1->value == number2->value;
+}
+
+static GtkCssValue *
+gtk_css_value_dimension_transition (GtkCssValue *start,
+                                 GtkCssValue *end,
+                                 guint        property_id,
+                                 double       progress)
+{
+  /* FIXME: This needs to be supported at least for percentages,
+   * but for that we kinda need to support calc(5px + 50%) */
+  if (start->unit != end->unit)
+    return NULL;
+
+  return gtk_css_dimension_value_new (start->value + (end->value - start->value) * progress,
+                                      start->unit);
+}
+
+static void
+gtk_css_value_dimension_print (const GtkCssValue *number,
+                            GString           *string)
+{
+  char buf[G_ASCII_DTOSTR_BUF_SIZE];
+
+  const char *names[] = {
+    /* [GTK_CSS_NUMBER] = */ "",
+    /* [GTK_CSS_PERCENT] = */ "%",
+    /* [GTK_CSS_PX] = */ "px",
+    /* [GTK_CSS_PT] = */ "pt",
+    /* [GTK_CSS_EM] = */ "em",
+    /* [GTK_CSS_EX] = */ "ex",
+    /* [GTK_CSS_REM] = */ "rem",
+    /* [GTK_CSS_PC] = */ "pc",
+    /* [GTK_CSS_IN] = */ "in",
+    /* [GTK_CSS_CM] = */ "cm",
+    /* [GTK_CSS_MM] = */ "mm",
+    /* [GTK_CSS_RAD] = */ "rad",
+    /* [GTK_CSS_DEG] = */ "deg",
+    /* [GTK_CSS_GRAD] = */ "grad",
+    /* [GTK_CSS_TURN] = */ "turn",
+    /* [GTK_CSS_S] = */ "s",
+    /* [GTK_CSS_MS] = */ "ms",
+  };
+
+  if (isinf (number->value))
+    g_string_append (string, "infinite");
+  else
+    {
+      g_ascii_dtostr (buf, sizeof (buf), number->value);
+      g_string_append (string, buf);
+      if (number->value != 0.0)
+        g_string_append (string, names[number->unit]);
+    }
+}
+
+static double
+gtk_css_value_dimension_get (const GtkCssValue *value,
+                             double             one_hundred_percent)
+{
+  if (value->unit == GTK_CSS_PERCENT)
+    return value->value * one_hundred_percent / 100;
+  else
+    return value->value;
+}
+
+static GtkCssDimension
+gtk_css_value_dimension_get_dimension (const GtkCssValue *value)
+{
+  return gtk_css_unit_get_dimension (value->unit);
+}
+
+static gboolean
+gtk_css_value_dimension_has_percent (const GtkCssValue *value)
+{
+  return gtk_css_unit_get_dimension (value->unit) == GTK_CSS_DIMENSION_PERCENTAGE;
+}
+
+static const GtkCssNumberValueClass GTK_CSS_VALUE_DIMENSION = {
+  {
+    gtk_css_value_dimension_free,
+    gtk_css_value_dimension_compute,
+    gtk_css_value_dimension_equal,
+    gtk_css_value_dimension_transition,
+    gtk_css_value_dimension_print
+  },
+  gtk_css_value_dimension_get,
+  gtk_css_value_dimension_get_dimension,
+  gtk_css_value_dimension_has_percent
+};
+
+GtkCssValue *
+gtk_css_dimension_value_new (double     value,
+                             GtkCssUnit unit)
+{
+  static GtkCssValue number_singletons[] = {
+    { &GTK_CSS_VALUE_DIMENSION.value_class, 1, GTK_CSS_NUMBER, 0 },
+    { &GTK_CSS_VALUE_DIMENSION.value_class, 1, GTK_CSS_NUMBER, 1 },
+  };
+  static GtkCssValue px_singletons[] = {
+    { &GTK_CSS_VALUE_DIMENSION.value_class, 1, GTK_CSS_PX, 0 },
+    { &GTK_CSS_VALUE_DIMENSION.value_class, 1, GTK_CSS_PX, 1 },
+    { &GTK_CSS_VALUE_DIMENSION.value_class, 1, GTK_CSS_PX, 2 },
+    { &GTK_CSS_VALUE_DIMENSION.value_class, 1, GTK_CSS_PX, 3 },
+    { &GTK_CSS_VALUE_DIMENSION.value_class, 1, GTK_CSS_PX, 4 },
+  };
+  GtkCssValue *result;
+
+  if (unit == GTK_CSS_NUMBER && (value == 0 || value == 1))
+    return _gtk_css_value_ref (&number_singletons[(int) value]);
+
+  if (unit == GTK_CSS_PX &&
+      (value == 0 ||
+       value == 1 ||
+       value == 2 ||
+       value == 3 ||
+       value == 4))
+    {
+      return _gtk_css_value_ref (&px_singletons[(int) value]);
+    }
+
+  result = _gtk_css_value_new (GtkCssValue, &GTK_CSS_VALUE_DIMENSION.value_class);
+  result->unit = unit;
+  result->value = value;
+
+  return result;
+}
+