thai-shaper.c

Pango is a library for layout and rendering of text, with an emphasis on internationalization. Pang

/* Pango
 * thai-shaper.c:
 *
 * Copyright (C) 1999 Red Hat Software
 * Author: Owen Taylor <[e-mail]>
 *
 * Copyright (C) 2005 Theppitak Karoonboonyanan
 * Copyright (C) 2002 Software and Language Engineering Laboratory, NECTEC
 * Author: Theppitak Karoonboonyanan <[e-mail]>
 *
 * Copyright (c) 1996-2000 by Sun Microsystems, Inc.
 * Author: Chookij Vanatham <[e-mail]>
 *
 * 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 <config.h>
#include <string.h>

#include <glib.h>
#include "pango-engine.h"
#include "thai-charprop.h"
#include "thai-shaper.h"

#define MAX_CLUSTER_CHRS	256
#define MAX_GLYPHS		256


typedef struct {
  guchar Start_TONE_AD, Start_AV, Start_BV_BD, Start_TailCutCons;

  guchar ShiftDown_TONE_AD[8];
  guchar ShiftDownLeft_TONE_AD[8];
  guchar ShiftLeft_TONE_AD[8];
  guchar ShiftLeft_AV[7];
  guchar ShiftDown_BV_BD[3];
  guchar TailCutCons[4];

  guchar AmComp[2];  /* Sara Am components */
} ThaiShapeTable;

#define shiftdown_tone_ad(c,tbl) \
	((tbl)->ShiftDown_TONE_AD[(c)-(tbl)->Start_TONE_AD])
#define shiftdownleft_tone_ad(c,tbl) \
	((tbl)->ShiftDownLeft_TONE_AD[(c)-(tbl)->Start_TONE_AD])
#define shiftleft_tone_ad(c,tbl) \
	((tbl)->ShiftLeft_TONE_AD[(c)-(tbl)->Start_TONE_AD])
#define shiftleft_av(c,tbl) \
	((tbl)->ShiftLeft_AV[(c)-(tbl)->Start_AV])
#define shiftdown_bv_bd(c,tbl) \
	((tbl)->ShiftDown_BV_BD[(c)-(tbl)->Start_BV_BD])
#define tailcutcons(c,tbl) \
	((tbl)->TailCutCons[(c)-(tbl)->Start_TailCutCons])

/* No adjusted vowel/tonemark glyphs (tis620-0)
 */
static const ThaiShapeTable tis620_0_shape_table = {
    0xE7, 0xD1, 0xD8, 0xAD,
    { 0xE7, 0xE8, 0xE9, 0xEA, 0xEB, 0xEC, 0xED, 0xEE },
    { 0xE7, 0xE8, 0xE9, 0xEA, 0xEB, 0xEC, 0xED, 0xEE },
    { 0xE7, 0xE8, 0xE9, 0xEA, 0xEB, 0xEC, 0xED, 0xEE },
    { 0xD1, 0x00, 0x00, 0xD4, 0xD5, 0xD6, 0xD7 },
    { 0xD8, 0xD9, 0xDA },
    { 0xAD, 0x00, 0x00, 0xB0 },
    { 0xED, 0xD2 }
};

/* Macintosh
 */
static const ThaiShapeTable Mac_shape_table = {
  0xE7, 0xD1, 0xD8, 0xAD,
  { 0xE7, 0x88, 0x89, 0x8A, 0x8B, 0x8C, 0xED, 0xEE },
  { 0x93, 0x83, 0x84, 0x85, 0x86, 0x87, 0x8F, 0xEE },
  { 0x93, 0x98, 0x99, 0x9A, 0x9B, 0x9C, 0x8F, 0xEE },
  { 0x92, 0x00, 0x00, 0x94, 0x95, 0x96, 0x97 },
  { 0xFC, 0xFD, 0xFE },
  { 0x90, 0x00, 0x00, 0x80 },
  { 0xED, 0xD2 }
};

/* Microsoft Window
 */
static const ThaiShapeTable Win_shape_table = {
    0xE7, 0xD1, 0xD8, 0xAD,
    { 0xE7, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F, 0xED, 0xEE },
    { 0x9A, 0x86, 0x87, 0x88, 0x89, 0x8A, 0x99, 0xEE },
    { 0x9A, 0x9B, 0x9C, 0x9D, 0x9E, 0x9F, 0x99, 0xEE },
    { 0x98, 0x00, 0x00, 0x81, 0x82, 0x83, 0x84 },
    { 0xFC, 0xFD, 0xFE },
    { 0x90, 0x00, 0x00, 0x80 },
    { 0xED, 0xD2 }
};

static const ThaiShapeTable Lao_shape_table = {
  0x67, 0x51, 0x58, 0x2D,
  { 0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E },
  { 0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E },
  { 0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E },
  { 0x51, 0x00, 0x00, 0x54, 0x55, 0x56, 0x57 },
  { 0x58, 0x59, 0x00 },
  { 0x2D, 0x00, 0x00, 0x30 },
  { 0x6D, 0x52 }
};

static void
add_glyph (ThaiFontInfo     *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 || logical_rect.width > 0)
    {
      glyphs->glyphs[index].geometry.x_offset = 0;
      glyphs->glyphs[index].geometry.width = logical_rect.width;
    }
  else
    {
      glyphs->glyphs[index].geometry.x_offset = ink_rect.width;
      glyphs->glyphs[index].geometry.width = ink_rect.width;
    }
  glyphs->glyphs[index].geometry.y_offset = 0;
}

static PangoGlyph
get_null_base_glyph (ThaiFontInfo *font_info)
{
  return thai_get_glyph_uni (font_info, 0x25cc);
}

static gint
get_adjusted_glyphs_list (ThaiFontInfo *font_info,
			  gunichar *cluster,
			  gint num_chrs,
			  PangoGlyph *glyph_lists,
			  const ThaiShapeTable *shaping_table)
{
  switch (num_chrs)
    {
      case 1:
	if (is_char_type (cluster[0],
			  BelowVowel|BelowDiac|AboveVowel|AboveDiac|Tone|SaraAm))
	  {
	    gint n;
	    glyph_lists[0] = get_null_base_glyph (font_info);
	    n = glyph_lists[0] ? 1 : 0;
	    glyph_lists[n++] =
		thai_make_glyph_tis (font_info, ucs2tis (cluster[0]));
	    return n;
	  }
	else
	  {
	    glyph_lists[0] =
		thai_make_glyph_tis (font_info, ucs2tis (cluster[0]));
	    return 1;
	  }
	break;

      case 2:
	if (is_char_type (cluster[0], NoTailCons|BotTailCons|SpltTailCons) &&
	    is_char_type (cluster[1], SaraAm))
	  {
	    glyph_lists[0] =
		thai_make_glyph_tis (font_info, ucs2tis (cluster[0]));
	    glyph_lists[1] = thai_make_glyph_tis (font_info, shaping_table->AmComp[0]);
	    glyph_lists[2] = thai_make_glyph_tis (font_info, shaping_table->AmComp[1]);
	    return 3;
	  }
	else if (is_char_type (cluster[0], UpTailCons) &&
		 is_char_type (cluster[1], SaraAm))
	  {
	    glyph_lists[0] =
		thai_make_glyph_tis (font_info, ucs2tis (cluster[0]));
	    glyph_lists[1] = thai_make_glyph_tis (font_info,
					shiftleft_tone_ad (shaping_table->AmComp[0], shaping_table));
	    glyph_lists[2] = thai_make_glyph_tis (font_info, shaping_table->AmComp[1]);
	    return 3;
	  }
	else if (is_char_type (cluster[0], NoTailCons|BotTailCons|SpltTailCons) &&
		 is_char_type (cluster[1], AboveVowel))
	  {
	    glyph_lists[0] =
		thai_make_glyph_tis (font_info, ucs2tis (cluster[0]));
	    glyph_lists[1] =
		thai_make_glyph_tis (font_info, ucs2tis (cluster[1]));
	    return 2;
	  }
	else if (is_char_type (cluster[0], NoTailCons|BotTailCons|SpltTailCons) &&
		 is_char_type (cluster[1], AboveDiac|Tone))
	  {
	    glyph_lists[0] =
		thai_make_glyph_tis (font_info, ucs2tis (cluster[0]));
	    glyph_lists[1] = thai_make_glyph_tis (font_info,
			shiftdown_tone_ad (ucs2tis (cluster[1]), shaping_table));
	    return 2;
	  }
	else if (is_char_type (cluster[0], UpTailCons) &&
		 is_char_type (cluster[1], AboveVowel))
	  {
	    glyph_lists[0] =
		thai_make_glyph_tis (font_info, ucs2tis (cluster[0]));
	    glyph_lists[1] = thai_make_glyph_tis (font_info,
			shiftleft_av (ucs2tis (cluster[1]), shaping_table));
	    return 2;
	  }
	else if (is_char_type (cluster[0], UpTailCons) &&
		 is_char_type (cluster[1], AboveDiac|Tone))
	  {
	    glyph_lists[0] =
		thai_make_glyph_tis (font_info, ucs2tis (cluster[0]));
	    glyph_lists[1] = thai_make_glyph_tis (font_info,
			shiftdownleft_tone_ad (ucs2tis (cluster[1]), shaping_table));
	    return 2;
	  }
	else if (is_char_type (cluster[0], NoTailCons|UpTailCons) &&
		 is_char_type (cluster[1], BelowVowel|BelowDiac))
	  {
	    glyph_lists[0] =
		thai_make_glyph_tis (font_info, ucs2tis (cluster[0]));
	    glyph_lists[1] =
		thai_make_glyph_tis (font_info, ucs2tis (cluster[1]));
	    return 2;
	  }
	else if (is_char_type (cluster[0], BotTailCons) &&
		 is_char_type (cluster[1], BelowVowel|BelowDiac))
	  {
	    glyph_lists[0] =
		thai_make_glyph_tis (font_info, ucs2tis (cluster[0]));
	    glyph_lists[1] =
		thai_make_glyph_tis (font_info,
			shiftdown_bv_bd (ucs2tis (cluster[1]), shaping_table));
	    return 2;
	  }
	else if (is_char_type (cluster[0], SpltTailCons) &&
		 is_char_type (cluster[1], BelowVowel|BelowDiac))
	  {
	    glyph_lists[0] = thai_make_glyph_tis (font_info,
			       tailcutcons (ucs2tis (cluster[0]), shaping_table));
	    glyph_lists[1] =
		thai_make_glyph_tis (font_info, ucs2tis (cluster[1]));
	    return 2;
	  }
	else
	  {
	    gint n;
	    glyph_lists[0] = get_null_base_glyph (font_info);
	    n = glyph_lists[0] ? 1 : 0;
	    glyph_lists[n++] =
		thai_make_glyph_tis (font_info, ucs2tis (cluster[0]));
	    glyph_lists[n++] =