basic-x.c

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

/* Pango
 * basic.c:
 *
 * Copyright (C) 1999 Red Hat Software
 *
 * 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 <glib.h>
#include <string.h>
#include "pango-engine.h"
#include "pango-utils.h"

#undef PANGO_DISABLE_DEPRECATED
#include "pangox.h"

/* No extra fields needed */
typedef PangoEngineShape      BasicEngineX;
typedef PangoEngineShapeClass BasicEngineXClass ;

typedef struct _CharRange CharRange;
typedef struct _Charset Charset;
typedef struct _CharsetOrdering CharsetOrdering;
typedef struct _CharCache CharCache;
typedef struct _CharCachePointer CharCachePointer;
typedef struct _MaskTable MaskTable;

typedef PangoGlyph (*ConvFunc) (CharCache   *cache,
				GIConv       cd,
				const gchar *input);

#define MAX_CHARSETS 32

#define SCRIPT_ENGINE_NAME "BasicScriptEngineX"

struct _Charset
{
  int   index;
  const char *id;
  const char *x_charset;
  ConvFunc conv_func;
};

struct _CharsetOrdering
{
  const char *langs;
  char charsets[MAX_CHARSETS];
};

struct _CharRange
{
  guint16 start;
  guint16 end;
  guint16 charsets;
};

struct _MaskTable
{
  int n_subfonts;

  PangoXSubfont *subfonts;
  Charset **charsets;
};

struct _CharCache
{
  guint ref_count;
  CharsetOrdering *ordering;
  MaskTable *mask_tables[256];
  GIConv converters[MAX_CHARSETS];
  PangoCoverage *coverage;
};

struct _CharCachePointer
{
  PangoLanguage *lang;
  CharCache *cache;
};

static PangoGlyph conv_8bit (CharCache  *cache,
			     GIConv      cd,
			     const char *input);
static PangoGlyph conv_eucjp (CharCache  *cache,
			      GIConv      cd,
			      const char *input);
static PangoGlyph conv_16bit (CharCache  *cache,
			      GIConv      cd,
			      const char *input);
static PangoGlyph conv_ucs4 (CharCache  *cache,
			     GIConv      cd,
			     const char *input);
static PangoGlyph conv_16bit_MSB_on (CharCache  *cache,
			      GIConv      cd,
			      const char *input);
static PangoGlyph conv_gb18030_1 (CharCache  *cache,
			      GIConv      cd,
			      const char *input);
static PangoGlyph conv_euctw (CharCache  *cache,
			      GIConv      cd,
			      const char *input);

#include "tables-big.i"

static PangoEngineScriptInfo basic_scripts[] = {
  { PANGO_SCRIPT_COMMON,  "" },
};

static PangoEngineInfo script_engines[] = {
  {
    SCRIPT_ENGINE_NAME,
    PANGO_ENGINE_TYPE_SHAPE,
    PANGO_RENDER_TYPE_X,
    basic_scripts, G_N_ELEMENTS(basic_scripts)
  }
};

/*
 * X window system script engine portion
 */

/* Structure of our cache:
 *
 * PangoFont => CharCachePointer  ===\
 *                    |               \
 *              CharCachePointer  ======> CharCache => CharsetOrdering
 *                    |                       |======> MaskTable[0]    => {subfonts,charset}[n_subfonts],
 *                    |                       |======> MaskTable[1]    => {subfonts,charset}[n_subfonts],
 *                    |                       \======> MaskTable[...]  => {subfonts,charset}[n_subfonts]
 *                    |
 *              CharCachePointer  ======> CharCache => CharsetOrdering
 *                                            |======> MaskTable[0]    => {subfonts,charset}[n_subfonts],
 *                                            |======> MaskTable[1]    => {subfonts,charset}[n_subfonts],
 *                                            \======> MaskTable[...]  => {subfonts,charset}[n_subfonts]
 *
 * A CharCache structure caches the lookup of what subfonts can be used for what characters for a pair of a Font
 * and CharsetOrdering. Multiple language tags can share the same CharsetOrdering - the list of CharCachePointer
 * structures that is attached to the font as object data provides lookups from language tag to charcache.
 */
static CharCache *
char_cache_new (CharsetOrdering *ordering)
{
  CharCache *result;
  int i;

  result = g_new0 (CharCache, 1);

  result->ref_count = 1;
  result->ordering = ordering;
  for (i=0; i<MAX_CHARSETS; i++)
    result->converters[i] = (GIConv)-1;

  return result;
}

static void
char_cache_free (CharCache *cache)
{
  int i;

  for (i=0; i<256; i++)
    if (cache->mask_tables[i])
      {
	g_free (cache->mask_tables[i]->subfonts);
	g_free (cache->mask_tables[i]->charsets);

	g_free (cache->mask_tables[i]);
      }

  for (i=0; i<MAX_CHARSETS; i++)
    if (cache->converters[i] != (GIConv)-1)
      g_iconv_close (cache->converters[i]);

  g_free (cache);
}

static PangoGlyph
find_char (CharCache *cache, PangoFont *font, gunichar wc, const char *input)
{
  int mask_index;
  MaskTable *mask_table;
  int i;

  switch (wc)
    {
    case '\n':
    case '\r':
    case 0x2028: /* Line separator */
    case 0x2029: /* Paragraph separator */
      return PANGO_GET_UNKNOWN_GLYPH (wc);
      break;
    }

  if (wc >= G_N_ELEMENTS (char_masks))
    mask_index = 0;
  else
    mask_index = char_masks[wc];

  if (cache->mask_tables[mask_index])
    mask_table = cache->mask_tables[mask_index];
  else
    {
      const char *charset_names[G_N_ELEMENTS(charsets)];
      Charset *charsets_map[G_N_ELEMENTS(charsets)];
      guint mask;
      int n_charsets = 0;
      int *subfont_charsets;

      mask_table = g_new (MaskTable, 1);

      mask = char_mask_map[mask_index] | ENC_ISO_10646;

      /* Find the character sets that are included in this mask
       */

      for (i=0; i<(int)G_N_ELEMENTS(charsets); i++)
	{
	  int charset_index = cache->ordering->charsets[i];

	  if (mask & (1 << charset_index))
	    {
	      charset_names[n_charsets] = charsets[charset_index].x_charset;
	      charsets_map[n_charsets] = &charsets[charset_index];

	      n_charsets++;
	    }
	}

      mask_table->n_subfonts = pango_x_list_subfonts (font, (char**)charset_names, n_charsets, &mask_table->subfonts, &subfont_charsets);

      mask_table->charsets = g_new (Charset *, mask_table->n_subfonts);
      for (i=0; i<mask_table->n_subfonts; i++)
	mask_table->charsets[i] = charsets_map[subfont_charsets[i]];

      g_free (subfont_charsets);

      cache->mask_tables[mask_index] = mask_table;
    }

  for (i=0; i < mask_table->n_subfonts; i++)
    {
      PangoGlyph index;
      PangoGlyph glyph;
      Charset *charset;

      charset = mask_table->charsets[i];
      if (charset)
	{
	  GIConv cd = cache->converters[charset->index];

	  if (charset->id && cd == (GIConv)-1)
	    {
	      cd = g_iconv_open (charset->id, "UTF-8");
	      if (cd == (GIConv)-1)
		{
		  g_warning ("Could not load converter from %s to UTF-8", charset->id);
		  mask_table->charsets[i] = NULL;
		  continue;
		}

	      cache->converters[charset->index] = cd;
	    }

	  index = (*charset->conv_func) (cache, cd, input);
	  glyph = PANGO_X_MAKE_GLYPH (mask_table->subfonts[i], index);

	  if (pango_x_has_glyph (font, glyph))
	    return glyph;
	}
    }

  return 0;
}

static void
set_glyph (PangoFont *font, PangoGlyphString *glyphs, int i, int offset, PangoGlyph glyph)
{
  PangoRectangle logical_rect;

  glyphs->glyphs[i].glyph = glyph;

  glyphs->glyphs[i].geometry.x_offset = 0;
  glyphs->glyphs[i].geometry.y_offset = 0;

  glyphs->log_clusters[i] = offset;

  pango_font_get_glyph_extents (font, glyphs->glyphs[i].glyph, NULL, &logical_rect);
  glyphs->glyphs[i].geometry.width = logical_rect.width;
}

static PangoGlyph
conv_8bit (CharCache  *cache,
	   GIConv      cd,
	   const char *input)
{
  char outbuf;

  const char *inptr = input;
  size_t inbytesleft;
  char *outptr = &outbuf;
  size_t outbytesleft = 1;

  inbytesleft = g_utf8_next_char (input) - input;

  g_iconv (cd, (char **)&inptr, &inbytesleft, &outptr, &outbytesleft);

  return (guchar)outbuf;
}

static PangoGlyph
conv_eucjp (CharCache  *cache,
	    GIConv      cd,
	    const char *input)
{
  char outbuf[4];

  const char *inptr = input;
  size_t inbytesleft;
  char *outptr = outbuf;
  size_t outbytesleft = 4;

  inbytesleft = g_utf8_next_char (input) - input;

  g_iconv (cd, (char **)&inptr, &inbytesleft, &outptr, &outbytesleft);

  if ((guchar)outbuf[0] < 128)
    return outbuf[0];
  else if ((guchar)outbuf[0] == 0x8e && outbytesleft == 2)
    return ((guchar)outbuf[1]);
  else if ((guchar)outbuf[0] == 0x8f && outbytesleft == 1)
    return ((guchar)outbuf[1] & 0x7f) * 256 + ((guchar)outbuf[2] & 0x7f);
  else
    return ((guchar)outbuf[0] & 0x7f) * 256 + ((guchar)outbuf[1] & 0x7f);
}

static PangoGlyph
conv_16bit (CharCache  *cache,
	    GIConv      cd,
	    const char *input)
{
  char outbuf[2];

  const char *inptr = input;
  size_t inbytesleft;
  char *outptr = outbuf;
  size_t outbytesleft = 2;

  inbytesleft = g_utf8_next_char (input) - input;