Pango X Hebrew Engine.

2 files changed, 554 insertions, 0 deletions

diff --git a/modules/hebrew/Makefile.am b/modules/hebrew/Makefile.am
new file mode 100644
index 00000000..ce925aec
--- /dev/null
+++ b/modules/hebrew/Makefile.am
@@ -0,0 +1,23 @@
+## Process this file with automake to create Makefile.in.
+
+sources = hebrew-x.c
+
+if HAVE_X
+if INCLUDE_HEBREW_X
+noinst_LTLIBRARIES = libpango-hebrew-x.la
+moddefine = -DX_MODULE_PREFIX
+else
+moduledir = $(libdir)/pango/modules
+module_LTLIBRARIES = pango-hebrew-x.la
+moduleflags=-rpath $(libdir)
+endif
+endif
+
+INCLUDES = -I$(top_srcdir) -I$(top_srcdir)/pango/ $(moddefine) $(X_CFLAGS)
+
+pango_hebrew_x_la_LDFLAGS = $(moduleflags) -export-dynamic -avoid-version -module
+pango_hebrew_x_la_LIBADD =
+pango_hebrew_x_la_SOURCES = $(sources)
+
+libpango_hebrew_x_la_SOURCES = $(sources)
+
diff --git a/modules/hebrew/hebrew-x.c b/modules/hebrew/hebrew-x.c
new file mode 100644
index 00000000..bb521661
--- /dev/null
+++ b/modules/hebrew/hebrew-x.c
@@ -0,0 +1,531 @@
+/* Pango
+ * hebrew-x.c:
+ *
+ * Copyright (C) 1999 Red Hat Software
+ * Author: Owen Taylor <otaylor@redhat.com>
+ *
+ * Copyright (c) 1996-2000 by Sun Microsystems, Inc.
+ * Author: Chookij Vanatham <Chookij.Vanatham@Eng.Sun.COM>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+
+#include <string.h>
+
+#include <glib.h>
+#include <string.h>
+#include "pangox.h"
+#include "pango-engine.h"
+
+#define ucs2iso8859_8(wc)		(unsigned int)((unsigned int)(wc) - 0x0590 + 0x10)
+#define iso8859_8_2uni(c)		((gunichar)(c) - 0x10 + 0x0590)
+
+#define MAX_CLUSTER_CHRS	256
+#define MAX_GLYPHS		256
+
+/* Define Hebrew character classes */
+#define _ND			0
+#define _SP			1
+#define _NS			(1<<1)
+
+#define NormalLetter		_SP
+#define	PointPunc		_NS
+
+#define is_char_type(wc, mask)	(char_type_table[ucs2iso8859_8 ((wc))] & (mask))
+#define	is_composible(cur_wc, nxt_wc)	(compose_table[char_type_table[ucs2iso8859_8 (cur_wc)]]\
+						      [char_type_table[ucs2iso8859_8 (nxt_wc)]])
+
+#define SCRIPT_ENGINE_NAME "HebrewScriptEngineX"
+
+/* We handle the range U+0591 to U+05f4 exactly
+ */
+static PangoEngineRange hebrew_ranges[] = {
+  { 0x0591, 0x05f4, "*" },  /* Hebrew */
+};
+
+static PangoEngineInfo script_engines[] = {
+  {
+    SCRIPT_ENGINE_NAME,
+    PANGO_ENGINE_TYPE_SHAPE,
+    PANGO_RENDER_TYPE_X,
+    hebrew_ranges, G_N_ELEMENTS(hebrew_ranges)
+  }
+};
+
+/*
+ * X window system script engine portion
+ */
+
+typedef struct _HebrewFontInfo HebrewFontInfo;
+
+/* The type of encoding that we will use
+ */
+typedef enum {
+  HEBREW_FONT_NONE,
+  HEBREW_FONT_ISO8859_8,
+  HEBREW_FONT_ISO10646,
+} HebrewFontType;
+
+struct _HebrewFontInfo
+{
+  PangoFont   *font;
+  HebrewFontType type;
+  PangoXSubfont subfont;
+};
+
+static const gint char_type_table[128] = {
+  /*       0,   1,   2,   3,   4,   5,   6,   7 */
+
+  /*00*/ _ND, _ND, _ND, _ND, _ND, _ND, _ND, _ND,
+         _ND, _ND, _ND, _ND, _ND, _ND, _ND, _ND,
+		
+  /*10*/ _ND, _NS, _NS, _NS, _NS, _NS, _NS, _NS,
+         _NS, _NS, _NS, _NS, _NS, _NS, _NS, _NS,
+  /*20*/ _NS, _NS, _ND, _NS, _NS, _NS, _NS, _NS,
+         _NS, _NS, _NS, _NS, _NS, _NS, _NS, _NS,
+  /*30*/ _NS, _NS, _NS, _NS, _NS, _NS, _NS, _NS,
+         _NS, _NS, _ND, _NS, _NS, _NS, _SP, _NS,
+  /*40*/ _SP, _NS, _NS, _SP, _NS, _ND, _ND, _ND,
+         _ND, _ND, _ND, _ND, _ND, _ND, _ND, _ND,
+  /*50*/ _SP, _SP, _SP, _SP, _SP, _SP, _SP, _SP,
+         _SP, _SP, _SP, _SP, _SP, _SP, _SP, _SP,
+  /*60*/ _SP, _SP, _SP, _SP, _SP, _SP, _SP, _SP,
+         _SP, _SP, _SP, _ND, _ND, _ND, _ND, _ND,
+  /*70*/ _SP, _SP, _SP, _SP, _SP, _ND, _ND, _ND,
+	 _ND, _ND, _ND, _ND, _ND, _ND, _ND, _ND,
+};
+
+static const gboolean compose_table[3][3] = {
+      /* Cn */ /*     0,     1,     2 */
+/* Cn-1 00 */	{ FALSE, FALSE, FALSE },
+  /* 10 */      { FALSE, FALSE,  TRUE },
+  /* 20 */      { FALSE, FALSE, FALSE },
+};
+
+/* Sun Hebrew Font Layout
+ */
+static const gint Sun_shape_table[128] = {
+  0x00, 0x00, 0x00, 0x00,  0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00,  0x00, 0x00, 0x00, 0x00,
+
+  0x00, 0x00, 0x00, 0x00,  0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00,  0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00,  0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00,  0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00,  0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00,  0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00,  0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00,  0x00, 0x00, 0x00, 0x00,
+
+  0xE0, 0xE1, 0xE2, 0xE3,  0xE4, 0xE5, 0xE6, 0xE7,
+  0xE8, 0xE9, 0xEA, 0xEB,  0xEC, 0xED, 0xEE, 0xEF,
+  0xF0, 0xF1, 0xF2, 0xF3,  0xF4, 0xF5, 0xF6, 0xF7,
+  0xF8, 0xF9, 0xFA, 0x00,  0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00,  0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00,  0x00, 0x00, 0x00, 0x00,
+};
+
+/* Unicode Hebrew Font Layout
+ */
+static const gint Unicode_shape_table[128] = {
+  0x00, 0x00, 0x00, 0x00,  0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00,  0x00, 0x00, 0x00, 0x00,
+
+  0x0000, 0x0591, 0x0592, 0x0593, 0x0594, 0x0595, 0x0596, 0x0597,
+  0x0598, 0x0599, 0x059A, 0x059B, 0x059C, 0x059D, 0x059E, 0x059F,
+  0x05A0, 0x05A1, 0x0000, 0x05A3, 0x05A4, 0x05A5, 0x05A6, 0x05A7,
+  0x05A8, 0x05A9, 0x05AA, 0x05AB, 0x05AC, 0x05AD, 0x05AE, 0x05AF,
+  0x05B0, 0x05B1, 0x05B2, 0x05B3, 0x05B4, 0x05B5, 0x05B6, 0x05B7,
+  0x05B8, 0x05B9, 0x0000, 0x05BB, 0x05BC, 0x05BD, 0x05BE, 0x05BF,
+  0x05C0, 0x05C1, 0x05C2, 0x05C3, 0x05C4, 0x0000, 0x0000, 0x0000,
+  0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
+
+  0x05D0, 0x05D1, 0x05D2, 0x05D3, 0x05D4, 0x05D5, 0x05D6, 0x05D7,
+  0x05D8, 0x05D9, 0x05DA, 0x05DB, 0x05DC, 0x05DD, 0x05DE, 0x05DF,
+  0x05E0, 0x05E1, 0x05E2, 0x05E3, 0x05E4, 0x05E5, 0x05E6, 0x05E7,
+  0x05E8, 0x05E9, 0x05EA, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
+  0x05F0, 0x05F1, 0x05F2, 0x05F3, 0x05F4, 0x0000, 0x0000, 0x0000,
+  0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
+};
+
+/* Returns a structure with information we will use to rendering given the
+ * #PangoFont. This is computed once per font and cached for later retrieval.
+ */
+static HebrewFontInfo *
+get_font_info (PangoFont *font)
+{
+  static const char *charsets[] = {
+    "iso8859-8",
+    "iso10646-1",
+  };
+
+  static const int charset_types[] = {
+    HEBREW_FONT_ISO8859_8,
+    HEBREW_FONT_ISO10646,
+  };
+  
+  HebrewFontInfo *font_info;
+  GQuark info_id = g_quark_from_string ("hebrew-font-info");
+  
+  font_info = g_object_get_qdata (G_OBJECT (font), info_id);
+
+  if (!font_info)
+    {
+      /* No cached information not found, so we need to compute it
+       * from scratch
+       */
+      PangoXSubfont *subfont_ids;
+      gint *subfont_charsets;
+      gint n_subfonts, i;
+
+      font_info = g_new (HebrewFontInfo, 1);
+      font_info->font = font;
+      font_info->type = HEBREW_FONT_NONE;
+      
+      g_object_set_qdata_full (G_OBJECT (font), info_id, font_info, (GDestroyNotify)g_free);
+      
+      n_subfonts = pango_x_list_subfonts (font, (char **)charsets, G_N_ELEMENTS (charsets),
+					  &subfont_ids, &subfont_charsets);
+
+      for (i=0; i < n_subfonts; i++)
+	{
+	  HebrewFontType font_type = charset_types[subfont_charsets[i]];
+	  
+	  if (font_type == HEBREW_FONT_ISO10646 &&
+	      pango_x_has_glyph (font, PANGO_X_MAKE_GLYPH (subfont_ids[i], 0x05D0)))
+	    {
+	      font_info->type = font_type;
+	      font_info->subfont = subfont_ids[i];
+	      
+	      break;
+	    }
+	  else if (font_type == HEBREW_FONT_ISO8859_8 &&
+		   pango_x_has_glyph (font, PANGO_X_MAKE_GLYPH (subfont_ids[i], 0xE0)))
+	    {
+	      font_info->type = font_type;
+	      font_info->subfont = subfont_ids[i];
+	      
+	      break;
+	    }
+	}
+
+      g_free (subfont_ids);
+      g_free (subfont_charsets);
+    }
+
+  return font_info;
+}
+
+static void
+add_glyph (HebrewFontInfo   *font_info, 
+	   PangoGlyphString *glyphs, 
+	   gint              cluster_start, 
+	   PangoGlyph        glyph,
+	   gboolean          combining)
+{
+  PangoRectangle ink_rect, logical_rect;
+  gint index = glyphs->num_glyphs;
+
+  pango_glyph_string_set_size (glyphs, index + 1);
+  
+  glyphs->glyphs[index].glyph = glyph;
+  glyphs->glyphs[index].attr.is_cluster_start = combining ? 0 : 1;
+  
+  glyphs->log_clusters[index] = cluster_start;
+
+  pango_font_get_glyph_extents (font_info->font,
+				glyphs->glyphs[index].glyph, &ink_rect, &logical_rect);
+
+  if (combining)
+    {
+      if (font_info->type == HEBREW_FONT_ISO8859_8)
+	{
+          glyphs->glyphs[index].geometry.width =
+		logical_rect.width + glyphs->glyphs[index - 1].geometry.width;
+          if (logical_rect.width > 0)
+	      glyphs->glyphs[index].geometry.x_offset = glyphs->glyphs[index - 1].geometry.width;
+          else
+	      glyphs->glyphs[index].geometry.x_offset = glyphs->glyphs[index].geometry.width;
+	  glyphs->glyphs[index - 1].geometry.width = 0;
+	}
+      else
+        {
+	  glyphs->glyphs[index].geometry.width =
+		MAX (logical_rect.width, glyphs->glyphs[index -1].geometry.width);
+	  glyphs->glyphs[index - 1].geometry.width = 0;
+	  glyphs->glyphs[index].geometry.x_offset = 0;
+        }
+    }
+  else
+    {
+      glyphs->glyphs[index].geometry.x_offset = 0;
+      glyphs->glyphs[index].geometry.width = logical_rect.width;
+    }
+  
+  glyphs->glyphs[index].geometry.y_offset = 0;
+}
+
+static gint
+get_adjusted_glyphs_list (HebrewFontInfo *font_info,
+			  gunichar *cluster,
+			  gint num_chrs,
+			  PangoGlyph *glyph_lists,
+			  const gint *shaping_table)
+{
+  gint i = 0;
+
+  if ((num_chrs == 1) &&
+      is_char_type (cluster[0], PointPunc))
+    {
+      if (font_info->type == HEBREW_FONT_ISO8859_8)
+	{
+	  glyph_lists[0] = PANGO_X_MAKE_GLYPH (font_info->subfont, 0x20);
+	  glyph_lists[1] = PANGO_X_MAKE_GLYPH (font_info->subfont,
+			shaping_table[ucs2iso8859_8 (cluster[0])]);
+	  return 2;
+	}
+      else
+	{
+	  glyph_lists[0] = PANGO_X_MAKE_GLYPH (font_info->subfont,
+			shaping_table[ucs2iso8859_8 (cluster[0])]);
+	  return 1;
+	}
+    }
+  else
+    {
+      while (i < num_chrs) {
+	glyph_lists[i] = PANGO_X_MAKE_GLYPH (font_info->subfont,
+				shaping_table[ucs2iso8859_8 (cluster[i])]);
+	i++;
+      }
+      return num_chrs;
+    }
+}
+
+static gint
+get_glyphs_list (HebrewFontInfo	*font_info,
+		 gunichar	*cluster,
+		 gint		num_chrs,
+		 PangoGlyph	*glyph_lists)
+{
+  gint i;
+
+  switch (font_info->type)
+    {
+      case HEBREW_FONT_NONE:
+        for (i=0; i < num_chrs; i++)
+	  glyph_lists[i] = pango_x_get_unknown_glyph (font_info->font);
+        return num_chrs;
+
+      case HEBREW_FONT_ISO8859_8:
+        return get_adjusted_glyphs_list (font_info, cluster,
+			num_chrs, glyph_lists, Sun_shape_table);
+      
+      case HEBREW_FONT_ISO10646:
+        return get_adjusted_glyphs_list (font_info, cluster,
+			num_chrs, glyph_lists, Unicode_shape_table);
+    }
+  return 0;
+}
+
+static void
+add_cluster (HebrewFontInfo	*font_info,
+	     PangoGlyphString	*glyphs,
+	     gint		cluster_start,
+	     gunichar		*cluster,
+	     gint		num_chrs)
+	     
+{
+  PangoGlyph glyphs_list[MAX_GLYPHS];
+  gint num_glyphs;
+  gint i;
+  
+  num_glyphs = get_glyphs_list(font_info, cluster, num_chrs, glyphs_list);
+  for (i=0; i<num_glyphs; i++)
+       add_glyph (font_info, glyphs, cluster_start, glyphs_list[i],
+	    		i == 0 ? FALSE : TRUE);
+}
+
+static const char *
+get_next_cluster(const char	*text,
+		 gint		length,
+		 gunichar       *cluster,
+		 gint		*num_chrs)
+{  
+  const char *p;
+  gint n_chars = 0;
+  
+  p = text;
+  while (p < text + length && n_chars < 3)  
+    {
+      gunichar current = g_utf8_get_char (p);
+      
+      if (n_chars == 0 ||
+	  is_composible ((gunichar)(cluster[n_chars - 1]), current))
+	{
+	  cluster[n_chars++] = current;
+	  p = g_utf8_next_char (p);
+	}
+      else
+	break;
+    }
+
+  *num_chrs = n_chars;
+  return p;
+}
+
+static void
+swap_range (PangoGlyphString *glyphs, int start, int end)
+{
+  int i, j;
+
+  for (i = start, j = end - 1; i < j; i++, j--)
+    {
+      PangoGlyphInfo glyph_info;
+      gint log_cluster;
+
+      glyph_info = glyphs->glyphs[i];
+      glyphs->glyphs[i] = glyphs->glyphs[j];
+      glyphs->glyphs[j] = glyph_info;
+
+      log_cluster = glyphs->log_clusters[i];
+      glyphs->log_clusters[i] = glyphs->log_clusters[j];
+      glyphs->log_clusters[j] = log_cluster;
+    }
+}
+
+static void 
+hebrew_engine_shape (PangoFont      *font,
+		   const char       *text,
+		   gint              length,
+		   PangoAnalysis    *analysis,
+		   PangoGlyphString *glyphs)
+{
+  HebrewFontInfo *font_info;
+  const char *p;
+  const char *log_cluster;
+  gunichar cluster[MAX_CLUSTER_CHRS];
+  gint num_chrs;
+
+  pango_glyph_string_set_size (glyphs, 0);
+
+  font_info = get_font_info (font);
+
+  p = text;
+  while (p < text + length)
+    {
+	log_cluster = p;
+	p = get_next_cluster (p, text + length - p, cluster, &num_chrs);
+	add_cluster (font_info, glyphs, log_cluster - text, cluster, num_chrs);
+    }
+
+  /* Simple bidi support */
+  if (analysis->level % 2)
+    {
+      int start, end;
+
+      /* Swap all glyphs */
+      swap_range (glyphs, 0, glyphs->num_glyphs);
+
+      /* Now reorder glyphs within each cluster back to LTR */
+      for (start=0; start<glyphs->num_glyphs;)
+  	{
+	  end = start;
+	  while (end < glyphs->num_glyphs &&
+		 glyphs->log_clusters[end] == glyphs->log_clusters[start])
+	    end++;
+
+	  if (end > start + 1)
+	    swap_range (glyphs, start, end);
+	  start = end;
+  	}
+    }
+}
+
+static PangoCoverage *
+hebrew_engine_get_coverage (PangoFont *font,
+			   const char *lang)
+{
+  PangoCoverage *result = pango_coverage_new ();
+  
+  HebrewFontInfo *font_info = get_font_info (font);
+  
+  if (font_info->type != HEBREW_FONT_NONE)
+    {
+      gunichar wc;
+      
+      for (wc = 0x590; wc <= 0x5f4; wc++)
+	pango_coverage_set (result, wc, PANGO_COVERAGE_EXACT);
+    }
+
+  return result;
+}
+
+static PangoEngine *
+hebrew_engine_x_new ()
+{
+  PangoEngineShape *result;
+  
+  result = g_new (PangoEngineShape, 1);
+
+  result->engine.id = SCRIPT_ENGINE_NAME;
+  result->engine.type = PANGO_ENGINE_TYPE_SHAPE;
+  result->engine.length = sizeof (result);
+  result->script_shape = hebrew_engine_shape;
+  result->get_coverage = hebrew_engine_get_coverage;
+
+  return (PangoEngine *)result;
+}
+
+/* The following three functions provide the public module API for
+ * Pango. If we are compiling it is a module, then we name the
+ * entry points script_engine_list, etc. But if we are compiling
+ * it for inclusion directly in Pango, then we need them to
+ * to have distinct names for this module, so we prepend
+ * _pango_hebrew_x_
+ */
+#ifdef X_MODULE_PREFIX
+#define MODULE_ENTRY(func) _pango_hebrew_x_##func
+#else
+#define MODULE_ENTRY(func) func
+#endif
+
+/* List the engines contained within this module
+ */
+void 
+MODULE_ENTRY(script_engine_list) (PangoEngineInfo **engines, gint *n_engines)
+{
+  *engines = script_engines;
+  *n_engines = G_N_ELEMENTS (script_engines);
+}
+
+/* Load a particular engine given the ID for the engine
+ */
+PangoEngine *
+MODULE_ENTRY(script_engine_load) (const char *id)
+{
+  if (!strcmp (id, SCRIPT_ENGINE_NAME))
+    return hebrew_engine_x_new ();
+  else
+    return NULL;
+}
+
+void 
+MODULE_ENTRY(script_engine_unload) (PangoEngine *engine)
+{
+}
+