Add functions to convert font descriptions to and from human-readable

Mon Feb 28 19:46:35 2000  Owen Taylor  <otaylor@redhat.com>

	* libpango/fonts.c libpango/pango-fonts.h: Add functions
	to convert font descriptions to and from human-readable
	strings.

	* examples/viewer.c: Use functions from libpango instead
	of rolling our own font-description conversion functions.

1 files changed, 253 insertions, 0 deletions

diff --git a/pango/fonts.c b/pango/fonts.c
index 45f1dcac..c6e4cbd8 100644
--- a/pango/fonts.c
+++ b/pango/fonts.c
@@ -19,6 +19,9 @@
  * Boston, MA 02111-1307, USA.
  */
 
+#include <stdlib.h>
+#include <ctype.h>
+
 #include "pango.h"
 
 /**
@@ -108,6 +111,256 @@ pango_font_descriptions_free (PangoFontDescription **descs,
     }
 }
 
+typedef struct
+{
+  int value;
+  const char *str;
+} FieldMap;
+
+FieldMap style_map[] = {
+  { PANGO_STYLE_NORMAL, NULL },
+  { PANGO_STYLE_OBLIQUE, "Oblique" },
+  { PANGO_STYLE_ITALIC, "Italic" }
+};
+
+FieldMap variant_map[] = {
+  { PANGO_VARIANT_NORMAL, NULL },
+  { PANGO_VARIANT_SMALL_CAPS, "Small-Caps" }
+};
+
+FieldMap weight_map[] = {
+  { 300, "Light" },
+  { PANGO_WEIGHT_NORMAL, NULL },
+  { 500, "Medium" },
+  { 600, "Semi-Bold" },
+  { PANGO_WEIGHT_BOLD, "Bold" }
+};
+
+FieldMap stretch_map[] = {
+  { PANGO_STRETCH_ULTRA_CONDENSED, "Ultra-Condensed" },
+  { PANGO_STRETCH_EXTRA_CONDENSED, "Extra-Condensed" },
+  { PANGO_STRETCH_CONDENSED,       "Condensed" },
+  { PANGO_STRETCH_SEMI_CONDENSED,  "Semi-Condensed" },
+  { PANGO_STRETCH_NORMAL,          NULL },
+  { PANGO_STRETCH_SEMI_EXPANDED,   "Semi-Expanded" },
+  { PANGO_STRETCH_EXPANDED,        "Expanded" },
+  { PANGO_STRETCH_EXTRA_EXPANDED,  "Extra-Expanded" },
+  { PANGO_STRETCH_ULTRA_EXPANDED,  "Ultra-Expanded" }
+};
+
+static gboolean
+find_field (FieldMap *map, int n_elements, const char *str, int len, int *val)
+{
+  int i;
+  
+  for (i=0; i<n_elements; i++)
+    {
+      if (map[i].str && g_strncasecmp (map[i].str, str, len) == 0)
+	{
+	  if (val)
+	    *val = map[i].value;
+	  return TRUE;
+	}
+    }
+
+  return FALSE;
+}
+
+static gboolean
+find_field_any (const char *str, int len, PangoFontDescription *desc)
+{
+  return (g_strcasecmp (str, "Normal") == 0 ||
+	  find_field (style_map, G_N_ELEMENTS (style_map), str, len,
+		      desc ? (int *)&desc->style : NULL) ||
+	  find_field (variant_map, G_N_ELEMENTS (variant_map), str, len,
+		      desc ? (int *)&desc->variant : NULL) ||
+	  find_field (weight_map, G_N_ELEMENTS (weight_map), str, len,
+		      desc ? (int *)&desc->weight : NULL) || 
+	  find_field (stretch_map, G_N_ELEMENTS (stretch_map), str, len,
+		      desc ? (int *)&desc->stretch : NULL));
+}
+
+static const char *
+getword (const char *str, const char *last, size_t *wordlen)
+{
+  const char *result;
+  
+  while (last > str && isspace (*(last - 1)))
+    last--;
+
+  result = last;
+  while (result > str && !isspace (*(result - 1)))
+    result--;
+
+  *wordlen = last - result;
+  
+  return result;
+}
+
+/**
+ * pango_font_description_from_string:
+ * @str: string reprentation of a font description.
+ * 
+ * Create a new font description from a string representation in the
+ * form "[FAMILY-LIST] [STYLE-OPTIONS] [SIZE]", where FAMILY-LIST is a
+ * comma separated list of families optionally terminated by a comma,
+ * STYLE_OPTIONS is a whitespace separated list of words where each
+ * WORD describes one of style, variant, weight, or stretch, and SIZE
+ * is an decimal number (size in points). Any one of the options may
+ * be absent.  If FAMILY-LIST is absent, then the family_name field of
+ * the resulting font description will be initialized to NULL.  If
+ * STYLE-OPTIONS is missing, then all style options will be set to the
+ * default values. If SIZE is missing, the size in the resulting font
+ * description will be set to 0.
+ * 
+ * Return value: a new #PangoFontDescription, or %NULL if the 
+ * string could not be parsed. 
+ **/
+PangoFontDescription *
+pango_font_description_from_string (const char *str)
+{
+  PangoFontDescription *desc;
+  const char *p, *last;
+  size_t len, wordlen;
+
+  g_return_val_if_fail (str != NULL, NULL);
+
+  desc = g_new (PangoFontDescription, 1);
+  
+  desc->family_name = NULL;
+  desc->style = PANGO_STYLE_NORMAL;
+  desc->weight = PANGO_WEIGHT_NORMAL;
+  desc->variant = PANGO_VARIANT_NORMAL;
+  desc->stretch = PANGO_STRETCH_NORMAL;
+  
+  desc->size = 0;
+
+  len = strlen (str);
+  last = str + len;
+  p = getword (str, last, &wordlen);
+
+  /* Look for a size at the end of the string
+   */
+  if (wordlen != 0)
+    {
+      char *end;
+      double size = strtod (p, &end);
+      if (end - p == wordlen) /* word is a valid float */
+	{
+	  desc->size = (int)(size * 1000 + 0.5);
+	  last = p;
+	}
+    }
+
+  /* Now parse style words
+   */
+  p = getword (str, last, &wordlen);
+  while (wordlen != 0)
+    {
+      if (!find_field_any (p, wordlen, desc))
+	break;
+      else
+	{
+	  last = p;
+	  p = getword (str, last, &wordlen);
+	}
+    }
+
+  /* Remainder (str => p) is family list. Trim off trailing commas and leading and trailing white space
+   */
+
+  while (last > str && isspace (*(last - 1)))
+    last--;
+
+  if (last > str && *(last - 1) == ',')
+    last--;
+
+  while (last > str && isspace (*(last - 1)))
+    last--;
+
+  while (isspace (*str))
+    str++;
+
+  if (str != last)
+    desc->family_name = g_strndup (str, last - str);
+
+  return desc;
+}
+
+static void
+append_field (GString *str, FieldMap *map, int n_elements, int val)
+{
+  int i;
+  for (i=0; i<n_elements; i++)
+    {
+      if (map[i].value == val)
+	{
+	  if (map[i].str)
+	    {
+	      if (str->len != 0)
+		g_string_append_c (str, ' ');
+	      g_string_append (str, map[i].str);
+	    }
+	  return;
+	}
+    }
+  
+  if (str->len != 0)
+    g_string_append_c (str, ' ');
+  g_string_sprintfa (str, "%d", val);
+}
+
+/**
+ * pango_font_description_to_string:
+ * @desc: a #PangoFontDescription
+ * 
+ * Create a string representation of a font description. See
+ * pango_font_description_from_string() for a description of the
+ * format of the string representation. The family list in the
+ * string description will only have a terminating comma if the
+ * last word of the list is a valid style option.
+ * 
+ * Return value: a new string that must be freed with g_free().
+ **/
+char *
+pango_font_description_to_string (const PangoFontDescription  *desc)
+{
+  GString *result = g_string_new (NULL);
+  char *str;
+
+  if (desc->family_name)
+    {
+      const char *p;
+      size_t wordlen;
+
+      g_string_append (result, desc->family_name);
+      
+      p = getword (desc->family_name, desc->family_name + strlen(desc->family_name), &wordlen);
+      if (wordlen != 0 && find_field_any (p, wordlen, NULL))
+	g_string_append_c (result, ',');
+    }
+
+  append_field (result, weight_map, G_N_ELEMENTS (weight_map), desc->weight);
+  append_field (result, style_map, G_N_ELEMENTS (style_map), desc->style);
+  append_field (result, stretch_map, G_N_ELEMENTS (stretch_map), desc->stretch);
+  append_field (result, variant_map, G_N_ELEMENTS (variant_map), desc->variant);
+
+  if (result->len == 0)
+    g_string_append (result, "Normal");
+
+  if (desc->size > 0)
+    {
+      if (result->len == 0)
+	g_string_append_c (result, ' ');
+
+      g_string_sprintfa (result, "%f", desc->size / 1000.);
+    }
+  
+  str = result->str;
+  g_string_free (result, FALSE);
+  return str;
+}
+
 /**
  * pango_font_init:
  * @font:    a #PangoFont