pangofc-font.c

GTK+-2.0源码之pango-1.15.6.tar.gz

/* Pango
 * pangofc-font.c: Shared interfaces for fontconfig-based backends
 *
 * Copyright (C) 2003 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 "pangofc-font.h"
#include "pangofc-fontmap.h"
#include "pangofc-private.h"
#include "pango-layout.h"
#include "pango-modules.h"
#include "pango-impl-utils.h"

#include <fontconfig/fcfreetype.h>

#include FT_TRUETYPE_TABLES_H

enum {
  PROP_0,
  PROP_PATTERN
};

typedef struct _GUnicharToGlyphCacheEntry GUnicharToGlyphCacheEntry;

/* An entry in the fixed-size cache for the gunichar -> glyph mapping.
 * The cache is indexed by the lower N bits of the gunichar (see
 * GLYPH_CACHE_NUM_ENTRIES).  For scripts with few code points,
 * this should provide pretty much instant lookups.
 *
 * The "ch" field is zero if that cache entry is invalid.
 */
struct _GUnicharToGlyphCacheEntry
{
  gunichar   ch;
  PangoGlyph glyph;
};

typedef struct _PangoFcFontPrivate PangoFcFontPrivate;

struct _PangoFcFontPrivate
{
  PangoFcDecoder *decoder;
  gpointer context_key;
  GUnicharToGlyphCacheEntry *char_to_glyph_cache;
};

#define GLYPH_CACHE_NUM_ENTRIES 256 /* should be power of two */
#define GLYPH_CACHE_MASK (GLYPH_CACHE_NUM_ENTRIES - 1)

static gboolean pango_fc_font_real_has_char  (PangoFcFont *font,
					      gunichar     wc);
static guint    pango_fc_font_real_get_glyph (PangoFcFont *font,
					      gunichar     wc);

static void                  pango_fc_font_finalize     (GObject          *object);
static void                  pango_fc_font_set_property (GObject          *object,
							 guint             prop_id,
							 const GValue     *value,
							 GParamSpec       *pspec);
static PangoEngineShape *    pango_fc_font_find_shaper  (PangoFont        *font,
							 PangoLanguage    *language,
							 guint32           ch);
static PangoCoverage *       pango_fc_font_get_coverage (PangoFont        *font,
							 PangoLanguage    *language);
static PangoFontMetrics *    pango_fc_font_get_metrics  (PangoFont        *font,
							 PangoLanguage    *language);
static PangoFontMap *        pango_fc_font_get_font_map (PangoFont        *font);
static PangoFontDescription *pango_fc_font_describe     (PangoFont        *font);
static PangoFontDescription *pango_fc_font_describe_absolute (PangoFont        *font);


#define PANGO_FC_FONT_LOCK_FACE(font)	(PANGO_FC_FONT_GET_CLASS (font)->lock_face (font))
#define PANGO_FC_FONT_UNLOCK_FACE(font)	(PANGO_FC_FONT_GET_CLASS (font)->unlock_face (font))

G_DEFINE_TYPE (PangoFcFont, pango_fc_font, PANGO_TYPE_FONT)

static void
pango_fc_font_class_init (PangoFcFontClass *class)
{
  GObjectClass *object_class = G_OBJECT_CLASS (class);
  PangoFontClass *font_class = PANGO_FONT_CLASS (class);

  class->has_char = pango_fc_font_real_has_char;
  class->get_glyph = pango_fc_font_real_get_glyph;
  class->get_unknown_glyph = NULL;

  object_class->finalize = pango_fc_font_finalize;
  object_class->set_property = pango_fc_font_set_property;
  font_class->describe = pango_fc_font_describe;
  font_class->describe_absolute = pango_fc_font_describe_absolute;
  font_class->find_shaper = pango_fc_font_find_shaper;
  font_class->get_coverage = pango_fc_font_get_coverage;
  font_class->get_metrics = pango_fc_font_get_metrics;
  font_class->get_font_map = pango_fc_font_get_font_map;

  g_object_class_install_property (object_class, PROP_PATTERN,
				   g_param_spec_pointer ("pattern",
							 "Pattern",
							 "The fontconfig pattern for this font",
							 G_PARAM_WRITABLE | G_PARAM_CONSTRUCT_ONLY));

  g_type_class_add_private (object_class, sizeof (PangoFcFontPrivate));
}

static void
pango_fc_font_init (PangoFcFont *fcfont)
{
  fcfont->priv = G_TYPE_INSTANCE_GET_PRIVATE (fcfont,
					      PANGO_TYPE_FC_FONT,
					      PangoFcFontPrivate);
}

static void
free_metrics_info (PangoFcMetricsInfo *info)
{
  pango_font_metrics_unref (info->metrics);
  g_slice_free (PangoFcMetricsInfo, info);
}

static void
pango_fc_font_finalize (GObject *object)
{
  PangoFcFont *fcfont = PANGO_FC_FONT (object);
  PangoFcFontPrivate *priv = fcfont->priv;

  g_slist_foreach (fcfont->metrics_by_lang, (GFunc)free_metrics_info, NULL);
  g_slist_free (fcfont->metrics_by_lang);

  if (fcfont->fontmap)
    _pango_fc_font_map_remove (PANGO_FC_FONT_MAP (fcfont->fontmap), fcfont);

  FcPatternDestroy (fcfont->font_pattern);
  pango_font_description_free (fcfont->description);

  if (priv->decoder)
    _pango_fc_font_set_decoder (fcfont, NULL);

  g_free (priv->char_to_glyph_cache);

  G_OBJECT_CLASS (pango_fc_font_parent_class)->finalize (object);
}

static gboolean
pattern_is_hinted (FcPattern *pattern)
{
  FcBool hinting;

  if (FcPatternGetBool (pattern,
			FC_HINTING, 0, &hinting) != FcResultMatch)
    hinting = FcTrue;

  return hinting;
}

static gboolean
pattern_is_transformed (FcPattern *pattern)
{
  FcMatrix *fc_matrix;

  if (FcPatternGetMatrix (pattern, FC_MATRIX, 0, &fc_matrix) == FcResultMatch)
    {
      FT_Matrix ft_matrix;

      ft_matrix.xx = 0x10000L * fc_matrix->xx;
      ft_matrix.yy = 0x10000L * fc_matrix->yy;
      ft_matrix.xy = 0x10000L * fc_matrix->xy;
      ft_matrix.yx = 0x10000L * fc_matrix->yx;

      return ((ft_matrix.xy | ft_matrix.yx) != 0 ||
	      ft_matrix.xx != 0x10000L ||
	      ft_matrix.yy != 0x10000L);
    }
  else
    return FALSE;
}

static void
pango_fc_font_set_property (GObject       *object,
			    guint          prop_id,
			    const GValue  *value,
			    GParamSpec    *pspec)
{
  switch (prop_id)
    {
    case PROP_PATTERN:
      {
	PangoFcFont *fcfont = PANGO_FC_FONT (object);
	FcPattern *pattern = g_value_get_pointer (value);

	g_return_if_fail (pattern != NULL);
	g_return_if_fail (fcfont->font_pattern == NULL);

	FcPatternReference (pattern);
	fcfont->font_pattern = pattern;
	fcfont->description = pango_fc_font_description_from_pattern (pattern, TRUE);
	fcfont->is_hinted = pattern_is_hinted (pattern);
	fcfont->is_transformed = pattern_is_transformed (pattern);
      }
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
    }
}

static PangoFontDescription *
pango_fc_font_describe (PangoFont *font)
{
  PangoFcFont *fcfont = (PangoFcFont *)font;

  return pango_font_description_copy (fcfont->description);
}

static PangoFontDescription *
pango_fc_font_describe_absolute (PangoFont *font)
{
  PangoFcFont *fcfont = (PangoFcFont *)font;
  PangoFontDescription *desc = pango_font_description_copy (fcfont->description);
  double size;

  if (FcPatternGetDouble (fcfont->font_pattern, FC_PIXEL_SIZE, 0, &size) == FcResultMatch)
    pango_font_description_set_absolute_size (desc, size * PANGO_SCALE);

  return desc;
}

static PangoMap *
pango_fc_get_shaper_map (PangoLanguage *language)
{
  static guint engine_type_id = 0;
  static guint render_type_id = 0;

  if (engine_type_id == 0)
    {
      engine_type_id = g_quark_from_static_string (PANGO_ENGINE_TYPE_SHAPE);
      render_type_id = g_quark_from_static_string (PANGO_RENDER_TYPE_FC);
    }

  return pango_find_map (language, engine_type_id, render_type_id);
}

static PangoEngineShape *
pango_fc_font_find_shaper (PangoFont     *font,
			   PangoLanguage *language,
			   guint32        ch)
{
  PangoMap *shaper_map = NULL;
  PangoScript script;

  shaper_map = pango_fc_get_shaper_map (language);
  script = pango_script_for_unichar (ch);
  return (PangoEngineShape *)pango_map_get_engine (shaper_map, script);
}

static PangoCoverage *
pango_fc_font_get_coverage (PangoFont     *font,
			    PangoLanguage *language)
{
  PangoFcFont *fcfont = (PangoFcFont *)font;
  PangoFcFontPrivate *priv = fcfont->priv;
  FcCharSet *charset;

  if (priv->decoder)
    {
      charset = pango_fc_decoder_get_charset (priv->decoder, fcfont);
      return _pango_fc_font_map_fc_to_coverage (charset);
    }

  return _pango_fc_font_map_get_coverage (PANGO_FC_FONT_MAP (fcfont->fontmap),
					  fcfont);
}

/* For Xft, it would be slightly more efficient to simply to
 * call Xft, and also more robust against changes in Xft.
 * But for now, we simply use the same code for all backends.
 *
 * The code in this function is partly based on code from Xft,
 * Copyright 2000 Keith Packard
 */
static void
get_face_metrics (PangoFcFont      *fcfont,
		  PangoFontMetrics *metrics)
{
  FT_Face face = PANGO_FC_FONT_LOCK_FACE (fcfont);
  FcMatrix *fc_matrix;
  FT_Matrix ft_matrix;
  TT_OS2 *os2;
  gboolean have_transform = FALSE;

  if (!face)
    {
      metrics->descent = 0;
      metrics->ascent = PANGO_SCALE * PANGO_UNKNOWN_GLYPH_HEIGHT;
      metrics->underline_thickness = PANGO_SCALE;
      metrics->underline_position = - PANGO_SCALE;
      metrics->strikethrough_thickness = PANGO_SCALE;
      metrics->strikethrough_position = PANGO_SCALE * (PANGO_UNKNOWN_GLYPH_HEIGHT/2);
      return;
    }

  if  (FcPatternGetMatrix (fcfont->font_pattern,
			   FC_MATRIX, 0, &fc_matrix) == FcResultMatch)
    {
      ft_matrix.xx = 0x10000L * fc_matrix->xx;
      ft_matrix.yy = 0x10000L * fc_matrix->yy;
      ft_matrix.xy = 0x10000L * fc_matrix->xy;
      ft_matrix.yx = 0x10000L * fc_matrix->yx;

      have_transform = (ft_matrix.xx != 0x10000 || ft_matrix.xy != 0 ||
			ft_matrix.yx != 0 || ft_matrix.yy != 0x10000);
    }

  if (have_transform)
    {
      FT_Vector	vector;

      vector.x = 0;
      vector.y = face->size->metrics.descender;
      FT_Vector_Transform (&vector, &ft_matrix);
      metrics->descent = - PANGO_UNITS_26_6 (vector.y);

      vector.x = 0;
      vector.y = face->size->metrics.ascender;
      FT_Vector_Transform (&vector, &ft_matrix);
      metrics->ascent = PANGO_UNITS_26_6 (vector.y);
    }
  else if (fcfont->is_hinted ||
	   (face->face_flags & FT_FACE_FLAG_SCALABLE) == 0)
    {
      metrics->descent = - PANGO_UNITS_26_6 (face->size->metrics.descender);
      metrics->ascent = PANGO_UNITS_26_6 (face->size->metrics.ascender);
    }
  else
    {
      FT_Fixed ascender, descender;

      descender = FT_MulFix (face->descender, face->size->metrics.y_scale);
      metrics->descent = - PANGO_UNITS_26_6 (descender);

      ascender = FT_MulFix (face->ascender, face->size->metrics.y_scale);
      metrics->ascent = PANGO_UNITS_26_6 (ascender);
    }

  /* Versions of FreeType < 2.1.8 get underline thickness wrong
   * for Postscript fonts (always zero), so we need a fallback
   */
  if (face->underline_thickness == 0)
    {
      metrics->underline_thickness = (PANGO_SCALE * face->size->metrics.y_ppem) / 14;
      metrics->underline_position = - metrics->underline_thickness;
    }
  else
    {
      FT_Fixed ft_thickness, ft_position;

      ft_thickness = FT_MulFix (face->underline_thickness, face->size->metrics.y_scale);
      metrics->underline_thickness = PANGO_UNITS_26_6 (ft_thickness);

      ft_position = FT_MulFix (face->underline_position, face->size->metrics.y_scale);
      metrics->underline_position = PANGO_UNITS_26_6 (ft_position);
    }

  os2 = FT_Get_Sfnt_Table (face, ft_sfnt_os2);
  if (os2 && os2->version != 0xFFFF && os2->yStrikeoutSize != 0)
    {
      FT_Fixed ft_thickness, ft_position;

      ft_thickness = FT_MulFix (os2->yStrikeoutSize, face->size->metrics.y_scale);
      metrics->strikethrough_thickness = PANGO_UNITS_26_6 (ft_thickness);

      ft_position = FT_MulFix (os2->yStrikeoutPosition, face->size->metrics.y_scale);
      metrics->strikethrough_position = PANGO_UNITS_26_6 (ft_position);
    }
  else
    {
      metrics->strikethrough_thickness = metrics->underline_thickness;
      metrics->strikethrough_position = (PANGO_SCALE * face->size->metrics.y_ppem) / 4;
    }

  /* If hinting is on for this font, quantize the underline and strikethrough position
   * to integer values.
   */
  if (fcfont->is_hinted)
    {
      pango_quantize_line_geometry (&metrics->underline_thickness,
				    &metrics->underline_position);
      pango_quantize_line_geometry (&metrics->strikethrough_thickness,
				    &metrics->strikethrough_position);
    }

  PANGO_FC_FONT_UNLOCK_FACE (fcfont);
}

static int
max_glyph_width (PangoLayout *layout)
{
  int max_width = 0;
  GSList *l, *r;

  for (l = pango_layout_get_lines_readonly (layout); l; l = l->next)
    {
      PangoLayoutLine *line = l->data;

      for (r = line->runs; r; r = r->next)
	{
	  PangoGlyphString *glyphs = ((PangoGlyphItem *)r->data)->glyphs;
	  int i;

	  for (i = 0; i < glyphs->num_glyphs; i++)
	    if (glyphs->glyphs[i].geometry.width > max_width)
	      max_width = glyphs->glyphs[i].geometry.width;
	}
    }

  return max_width;
}

PangoFontMetrics *
pango_fc_font_create_metrics_for_context (PangoFcFont   *fcfont,
					  PangoContext  *context)
{
  PangoFontMetrics *metrics;
  PangoLayout *layout;
  PangoRectangle extents;
  PangoLanguage *language = pango_context_get_language (context);
  const char *sample_str = pango_language_get_sample_string (language);
  PangoFontDescription *desc = pango_font_describe_with_absolute_size (fcfont);

  metrics = pango_font_metrics_new ();

  get_face_metrics (fcfont, metrics);

  layout = pango_layout_new (context);
  pango_layout_set_font_description (layout, desc);
  pango_font_description_free (desc);

  pango_layout_set_text (layout, sample_str, -1);
  pango_layout_get_extents (layout, NULL, &extents);

  metrics->approximate_char_width =
    extents.width / g_utf8_strlen (sample_str, -1);

  pango_layout_set_text (layout, "0123456789", -1);
  metrics->approximate_digit_width = max_glyph_width (layout);

  g_object_unref (layout);