pangocairo-fcfont.c

GTK+-2.0源码之pango-1.15.6.tar.gz

/* Pango
 * pangocairofc-font.c: Cairo font handling, fontconfig backend
 *
 * Copyright (C) 2000-2005 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 <math.h>
#include <stdlib.h>

#include <cairo-ft.h>

#include "pango-fontmap.h"
#include "pangocairo-private.h"
#include "pangocairo-fc.h"
#include "pangofc-private.h"
#include "pango-impl-utils.h"

#define PANGO_TYPE_CAIRO_FC_FONT           (pango_cairo_fc_font_get_type ())
#define PANGO_CAIRO_FC_FONT(object)        (G_TYPE_CHECK_INSTANCE_CAST ((object), PANGO_TYPE_CAIRO_FC_FONT, PangoCairoFcFont))
#define PANGO_CAIRO_FC_FONT_CLASS(klass)   (G_TYPE_CHECK_CLASS_CAST ((klass), PANGO_TYPE_CAIRO_FC_FONT, PangoCairoFcFontClass))
#define PANGO_CAIRO_IS_FONT_CLASS(klass)   (G_TYPE_CHECK_CLASS_TYPE ((klass), PANGO_TYPE_CAIRO_FC_FONT))
#define PANGO_CAIRO_FC_FONT_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS ((obj), PANGO_TYPE_CAIRO_FC_FONT, PangoCairoFcFontClass))

typedef struct _PangoCairoFcFont      PangoCairoFcFont;
typedef struct _PangoCairoFcFontClass PangoCairoFcFontClass;

typedef struct _GlyphExtentsCacheEntry    GlyphExtentsCacheEntry;

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

/* An entry in the fixed-size cache for the glyph -> ink_rect mapping.
 * The cache is indexed by the lower N bits of the glyph (see
 * GLYPH_CACHE_NUM_ENTRIES).  For scripts with few glyphs,
 * this should provide pretty much instant lookups.
 */
struct _GlyphExtentsCacheEntry
{
  PangoGlyph     glyph;
  int            width;
  PangoRectangle ink_rect;
};

struct _PangoCairoFcFont
{
  PangoFcFont font;

  cairo_font_face_t *font_face;
  cairo_scaled_font_t *scaled_font;
  cairo_matrix_t font_matrix;
  cairo_matrix_t ctm;
  cairo_font_options_t *options;
  PangoGravity gravity;

  PangoRectangle font_extents;
  GlyphExtentsCacheEntry    *glyph_extents_cache;
};

struct _PangoCairoFcFontClass
{
  PangoFcFontClass  parent_class;
};

GType pango_cairo_fc_font_get_type (void);

static cairo_font_face_t *pango_cairo_fc_font_get_font_face (PangoCairoFont *font);

/*******************************
 *       Utility functions     *
 *******************************/

static cairo_font_face_t *
pango_cairo_fc_font_get_font_face (PangoCairoFont *font)
{
  PangoCairoFcFont *cffont = (PangoCairoFcFont *) (font);
  PangoFcFont *fcfont = (PangoFcFont *) (cffont);

  if (!cffont->font_face)
    {
      cffont->font_face = cairo_ft_font_face_create_for_pattern (fcfont->font_pattern);

      /* Unable to create FT2 cairo scaled font.
       * This means out of memory or a cairo/fontconfig/FreeType bug,
       */
      if (!cffont->font_face)
	return NULL;
    }

  return cffont->font_face;
}

static cairo_scaled_font_t *
pango_cairo_fc_font_get_scaled_font (PangoCairoFont *font)
{
  PangoCairoFcFont *cffont = (PangoCairoFcFont *)font;

  if (!cffont->scaled_font)
    {
      cairo_font_face_t *font_face;

      font_face = pango_cairo_fc_font_get_font_face (font);

      if (!font_face)
	return NULL;

      cffont->scaled_font = cairo_scaled_font_create (font_face,
						      &cffont->font_matrix,
						      &cffont->ctm,
						      cffont->options);

      /* Unable to create FT2 cairo scaled font.
       * This means out of memory or a cairo/fontconfig/FreeType bug,
       * or a missing font...
       */
      if (!cffont->scaled_font)
	return NULL;
    }

  return cffont->scaled_font;
}

/********************************
 *    Method implementations    *
 ********************************/

static gboolean
pango_cairo_fc_font_install (PangoCairoFont *font,
			     cairo_t        *cr)
{
  PangoCairoFcFont *cffont = (PangoCairoFcFont *) (font);

  cairo_set_font_face (cr,
		       pango_cairo_fc_font_get_font_face (font));
  cairo_set_font_matrix (cr, &cffont->font_matrix);
  cairo_set_font_options (cr, cffont->options);

  return TRUE;
}

static void
cairo_font_iface_init (PangoCairoFontIface *iface)
{
  iface->install = pango_cairo_fc_font_install;
  iface->get_font_face = pango_cairo_fc_font_get_font_face;
  iface->get_scaled_font = pango_cairo_fc_font_get_scaled_font;
}

G_DEFINE_TYPE_WITH_CODE (PangoCairoFcFont, pango_cairo_fc_font, PANGO_TYPE_FC_FONT,
    { G_IMPLEMENT_INTERFACE (PANGO_TYPE_CAIRO_FONT, cairo_font_iface_init) })

static void
pango_cairo_fc_font_finalize (GObject *object)
{
  PangoCairoFcFont *cffont = (PangoCairoFcFont *) (object);

  if (cffont->font_face)
    cairo_font_face_destroy (cffont->font_face);
  if (cffont->scaled_font)
    cairo_scaled_font_destroy (cffont->scaled_font);
  if (cffont->options)
    cairo_font_options_destroy (cffont->options);


  if (cffont->glyph_extents_cache)
    {
      g_free (cffont->glyph_extents_cache);
    }

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

/* This function is cut-and-pasted from pangocairo-fcfont.c - it might be
 * better to add a virtual fcfont->create_context (font).
 */
static PangoFontMetrics *
pango_cairo_fc_font_get_metrics (PangoFont     *font,
				 PangoLanguage *language)
{
  PangoFcFont *fcfont = (PangoFcFont *) (font);
  PangoCairoFcFont *cffont = (PangoCairoFcFont *) (font);
  PangoFcMetricsInfo *info = NULL; /* Quiet gcc */
  GSList *tmp_list;

  const char *sample_str = pango_language_get_sample_string (language);

  tmp_list = fcfont->metrics_by_lang;
  while (tmp_list)
    {
      info = tmp_list->data;

      if (info->sample_str == sample_str)    /* We _don't_ need strcmp */
	break;

      tmp_list = tmp_list->next;
    }

  if (!tmp_list)
    {
      PangoContext *context;
      int height, shift;

      if (!fcfont->fontmap)
	return pango_font_metrics_new ();

      info = g_slice_new0 (PangoFcMetricsInfo);

      fcfont->metrics_by_lang = g_slist_prepend (fcfont->metrics_by_lang, info);

      info->sample_str = sample_str;

      context = pango_fc_font_map_create_context (PANGO_FC_FONT_MAP (fcfont->fontmap));
      pango_context_set_language (context, language);
      pango_cairo_context_set_font_options (context, cffont->options);

      info->metrics = pango_fc_font_create_metrics_for_context (fcfont, context);
      /* We may actually reuse ascent/descent we got from cairo here.  that's
       * in cffont->font_extents.
       */
      height = info->metrics->ascent + info->metrics->descent;
      switch (cffont->gravity)
	{
	  default:
	  case PANGO_GRAVITY_AUTO:
	  case PANGO_GRAVITY_SOUTH:
	    break;
	  case PANGO_GRAVITY_NORTH:
	    info->metrics->ascent = info->metrics->descent;
	    break;
	  case PANGO_GRAVITY_EAST:
	  case PANGO_GRAVITY_WEST:
	    info->metrics->ascent = height / 2;
	}
      shift = (height - info->metrics->ascent) - info->metrics->descent;
      if (fcfont->is_hinted)
	shift &= ~(PANGO_SCALE - 1);
      info->metrics->descent += shift;
      info->metrics->underline_position -= shift;
      info->metrics->strikethrough_position -= shift;
      info->metrics->ascent = height - info->metrics->descent;

      g_object_unref (context);
    }

  return pango_font_metrics_ref (info->metrics);
}

static FT_Face
pango_cairo_fc_font_lock_face (PangoFcFont *font)
{
  PangoCairoFont *cfont = (PangoCairoFont *)font;
  cairo_scaled_font_t *scaled_font = pango_cairo_fc_font_get_scaled_font (cfont);
  if (G_UNLIKELY (!scaled_font))
    return NULL;

  return cairo_ft_scaled_font_lock_face (scaled_font);
}

static void
pango_cairo_fc_font_unlock_face (PangoFcFont *font)
{