pangocairo-fontmap.c

GTK+-2.0源码之pango-1.15.6.tar.gz

/* Pango
 * pangocairo-fontmap.c: Cairo font handling
 *
 * 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 "pangocairo.h"
#include "pangocairo-private.h"
#include "pango-impl-utils.h"

#if defined (HAVE_CAIRO_ATSUI)
#  include "pangocairo-atsui.h"
#elif defined (HAVE_CAIRO_WIN32)
#  include "pangocairo-win32.h"
#elif defined (HAVE_CAIRO_FREETYPE)
#  include "pangocairo-fc.h"
#endif

GType
pango_cairo_font_map_get_type (void)
{
  static GType cairo_font_map_type = 0;

  if (! cairo_font_map_type)
    {
      const GTypeInfo cairo_font_map_info =
      {
	sizeof (PangoCairoFontMapIface), /* class_size */
	NULL,           /* base_init */
	NULL,		/* base_finalize */
	NULL,
	NULL,		/* class_finalize */
	NULL,		/* class_data */
	0,
	0,
	NULL,
	NULL
      };

      cairo_font_map_type =
	g_type_register_static (G_TYPE_INTERFACE, I_("PangoCairoFontMap"),
				&cairo_font_map_info, 0);

      g_type_interface_add_prerequisite (cairo_font_map_type, PANGO_TYPE_FONT_MAP);
    }

  return cairo_font_map_type;
}

/**
 * pango_cairo_font_map_new:
 *
 * Creates a new #PangoCairoFontMap object; a fontmap is used
 * to cache information about available fonts, and holds
 * certain global parameters such as the resolution.
 * In most cases, you can use pango_cairo_font_map_get_default()
 * instead.
 *
 * Note that the type of the returned object will depend
 * on the particular font backend Cairo was compiled to use;
 * You generally should only use the #PangoFontMap and
 * #PangoCairoFontMap interfaces on the returned object.
 *
 * Return value: the newly allocated #PangoFontMap, which should
 *               be freed with g_object_unref().
 *
 * Since: 1.10
 **/
PangoFontMap *
pango_cairo_font_map_new (void)
{
  /* Make sure that the type system is initialized */
  g_type_init ();

#if defined(HAVE_CAIRO_ATSUI)
  return g_object_new (PANGO_TYPE_CAIRO_ATSUI_FONT_MAP, NULL);
#elif defined(HAVE_CAIRO_WIN32)
  return g_object_new (PANGO_TYPE_CAIRO_WIN32_FONT_MAP, NULL);
#elif defined(HAVE_CAIRO_FREETYPE)
  return g_object_new (PANGO_TYPE_CAIRO_FC_FONT_MAP, NULL);
#endif
}

/**
 * pango_cairo_font_map_get_default:
 *
 * Gets a default font map to use with Cairo.
 *
 * Return value: the default Cairo fontmap for #Pango. This
 *  object is owned by Pango and must not be freed.
 *
 * Since: 1.10
 **/
PangoFontMap *
pango_cairo_font_map_get_default (void)
{
  static PangoFontMap *default_font_map = NULL;

  if (!default_font_map)
    default_font_map = pango_cairo_font_map_new ();

  return default_font_map;
}

/**
 * pango_cairo_font_map_set_resolution:
 * @fontmap: a #PangoCairoFontMap
 * @dpi: the resolution in "dots per inch". (Physical inches aren't actually
 *   involved; the terminology is conventional.)
 *
 * Sets the resolution for the fontmap. This is a scale factor between
 * points specified in a #PangoFontDescription and Cairo units. The
 * default value is 96, meaning that a 10 point font will be 13
 * units high. (10 * 96. / 72. = 13.3).
 *
 * Since: 1.10
 **/
void
pango_cairo_font_map_set_resolution (PangoCairoFontMap *fontmap,
				     double             dpi)
{
  g_return_if_fail (PANGO_IS_CAIRO_FONT_MAP (fontmap));

  (* PANGO_CAIRO_FONT_MAP_GET_IFACE (fontmap)->set_resolution) (fontmap, dpi);
}

/**
 * pango_cairo_font_map_get_resolution:
 * @fontmap: a #PangoCairoFontMap
 *
 * Gets the resolution for the fontmap. See pango_cairo_font_map_set_resolution()
 *
 * Return value: the resolution in "dots per inch"
 *
 * Since: 1.10
 **/
double
pango_cairo_font_map_get_resolution (PangoCairoFontMap *fontmap)
{
  g_return_val_if_fail (PANGO_IS_CAIRO_FONT_MAP (fontmap), 96.);

  return (* PANGO_CAIRO_FONT_MAP_GET_IFACE (fontmap)->get_resolution) (fontmap);
}

/**
 * pango_cairo_font_map_create_context:
 * @fontmap: a #PangoCairoFontMap
 *
 * Create a #PangoContext for the given fontmap.
 *
 * Return value: the newly created context; free with g_object_unref().
 *
 * Since: 1.10
 **/
PangoContext *
pango_cairo_font_map_create_context (PangoCairoFontMap *fontmap)
{
  PangoContext *context;

  g_return_val_if_fail (PANGO_IS_CAIRO_FONT_MAP (fontmap), NULL);

  context = pango_context_new ();
  pango_context_set_font_map (context, PANGO_FONT_MAP (fontmap));

  return context;
}

/**
 * _pango_cairo_font_map_get_renderer:
 * @fontmap: a #PangoCairoFontmap
 *
 * Gets the singleton #PangoCairoRenderer for this fontmap.
 *
 * Return value: the singleton renderer
 **/
PangoRenderer *
_pango_cairo_font_map_get_renderer (PangoCairoFontMap *fontmap)
{
  g_return_val_if_fail (PANGO_IS_CAIRO_FONT_MAP (fontmap), NULL);

  return (* PANGO_CAIRO_FONT_MAP_GET_IFACE (fontmap)->get_renderer) (fontmap);
}

typedef struct _PangoCairoContextInfo PangoCairoContextInfo;

struct _PangoCairoContextInfo
{
  double dpi;

  cairo_font_options_t *set_options;
  cairo_font_options_t *surface_options;
  cairo_font_options_t *merged_options;
};

static void
free_context_info (PangoCairoContextInfo *info)
{
  if (info->set_options)
    cairo_font_options_destroy (info->set_options);
  if (info->surface_options)
    cairo_font_options_destroy (info->surface_options);
  if (info->merged_options)
    cairo_font_options_destroy (info->merged_options);

  g_slice_free (PangoCairoContextInfo, info);
}

static PangoCairoContextInfo *
get_context_info (PangoContext *context,
		  gboolean      create)
{
  static GQuark context_info_quark;
  PangoCairoContextInfo *info;

  if (G_UNLIKELY (!context_info_quark))
    context_info_quark = g_quark_from_static_string ("pango-cairo-context-info");

  info = g_object_get_qdata (G_OBJECT (context), context_info_quark);

  if (G_UNLIKELY (!info) && create)
    {
      info = g_slice_new (PangoCairoContextInfo);
      info->dpi = -1.0;
      info->set_options = NULL;
      info->surface_options = NULL;
      info->merged_options = NULL;

      g_object_set_qdata_full (G_OBJECT (context), context_info_quark,
			       info, (GDestroyNotify)free_context_info);
    }

  return info;
}

/**
 * pango_cairo_update_context:
 * @cr: a Cairo context
 * @context: a #PangoContext, from pango_cairo_font_map_create_context()
 *
 * Updates a #PangoContext previously created for use with Cairo to
 * match the current transformation and target surface of a Cairo
 * context. If any layouts have been created for the context,
 * it's necessary to call pango_layout_context_changed() on those
 * layouts.
 *
 * Since: 1.10
 **/
void
pango_cairo_update_context (cairo_t      *cr,
			    PangoContext *context)
{
  PangoCairoContextInfo *info;
  cairo_matrix_t cairo_matrix;
  cairo_surface_t *target;
  PangoMatrix pango_matrix;

  g_return_if_fail (cr != NULL);
  g_return_if_fail (PANGO_IS_CONTEXT (context));

  info = get_context_info (context, TRUE);

  cairo_get_matrix (cr, &cairo_matrix);
  pango_matrix.xx = cairo_matrix.xx;
  pango_matrix.yx = cairo_matrix.yx;
  pango_matrix.xy = cairo_matrix.xy;
  pango_matrix.yy = cairo_matrix.yy;
  pango_matrix.x0 = cairo_matrix.x0;
  pango_matrix.y0 = cairo_matrix.y0;

  pango_context_set_matrix (context, &pango_matrix);

  if (!info->surface_options)
    info->surface_options = cairo_font_options_create ();

  target = cairo_get_target (cr);
  cairo_surface_get_font_options (target, info->surface_options);

  if (info->merged_options)
    {
      cairo_font_options_destroy (info->merged_options);
      info->merged_options = NULL;
    }
}

/**
 * pango_cairo_context_set_resolution:
 * @context: a #PangoContext, from pango_cairo_font_map_create_context()
 * @dpi: the resolution in "dots per inch". (Physical inches aren't actually
 *   involved; the terminology is conventional.) A 0 or negative value
 *   means to use the resolution from the font map.
 *
 * Sets the resolution for the context. This is a scale factor between
 * points specified in a #PangoFontDescription and Cairo units. The
 * default value is 96, meaning that a 10 point font will be 13
 * units high. (10 * 96. / 72. = 13.3).
 *
 * Since: 1.10
 **/
void
pango_cairo_context_set_resolution (PangoContext *context,
				    double        dpi)
{
  PangoCairoContextInfo *info = get_context_info (context, TRUE);
  info->dpi = dpi;
}

/**
 * pango_cairo_context_get_resolution:
 * @context: a #PangoContext, from pango_cairo_font_map_create_context()
 *
 * Gets the resolution for the context. See pango_cairo_context_set_resolution()
 *
 * Return value: the resolution in "dots per inch". A negative value will
 *  be returned if no resolution has previously been set.
 *
 * Since: 1.10
 **/
double
pango_cairo_context_get_resolution (PangoContext *context)
{
  PangoCairoContextInfo *info = get_context_info (context, FALSE);

  if (info)
    return info->dpi;
  else
    return -1.0;
}

/**
 * pango_cairo_context_set_font_options:
 * @context: a #PangoContext, from pango_cairo_font_map_create_context()
 * @options: a #cairo_font_options_t, or %NULL to unset any previously set
 *           options. A copy is made.
 *
 * Sets the font options used when rendering text with this context.
 * These options override any options that pango_cairo_update_context()
 * derives from the target surface.
 */
void
pango_cairo_context_set_font_options (PangoContext               *context,
				      const cairo_font_options_t *options)
{
  PangoCairoContextInfo *info;

  g_return_if_fail (PANGO_IS_CONTEXT (context));

  info  = get_context_info (context, TRUE);

  if (info->set_options)
    cairo_font_options_destroy (info->set_options);

  if (options)
    info->set_options = cairo_font_options_copy (options);
  else
    info->set_options = NULL;

  if (info->merged_options)
    {
      cairo_font_options_destroy (info->merged_options);
      info->merged_options = NULL;
    }
}

/**
 * pango_cairo_context_get_font_options:
 * @context: a #PangoContext, from pango_cairo_font_map_create_context()
 *
 * Retrieves any font rendering options previously set with
 * pango_cairo_font_map_set_font_options(). This functions not report options
 * that are derived from the target surface by pango_cairo_update_context()
 *
 * Return value: the font options previously set on the context, or %NULL
 *   if no options have been set. This value is owned by the context
 *   and must not be modified or freed.
 **/
G_CONST_RETURN cairo_font_options_t *
pango_cairo_context_get_font_options (PangoContext *context)
{
  PangoCairoContextInfo *info;

  g_return_val_if_fail (PANGO_IS_CONTEXT (context), NULL);

  info = get_context_info (context, FALSE);

  if (info)
    return info->set_options;
  else
    return NULL;
}

/**
 * _pango_cairo_context_merge_font_options:
 * @context: a #PangoContext
 * @options: a #cairo_font_options_t
 *
 * Merge together options from the target surface and explicitly set
 * on the context.
 *
 * Return value: the combined set of font options. This value is owned
 * by the context and must not be modified or freed.
 **/
G_CONST_RETURN cairo_font_options_t *
_pango_cairo_context_get_merged_font_options (PangoContext *context)
{
  PangoCairoContextInfo *info = get_context_info (context, TRUE);

  if (!info->merged_options)
    {
      info->merged_options = cairo_font_options_create ();

      if (info->surface_options)
	cairo_font_options_merge (info->merged_options, info->surface_options);
      if (info->set_options)
	cairo_font_options_merge (info->merged_options, info->set_options);
    }

  return info->merged_options;
}

/**
 * pango_cairo_create_layout:
 * @cr: a Cairo context
 *
 * Creates a layout object set up to match the current transformation
 * and target surface of the Cairo context.  This layout can then be
 * used for text measurement with functions like
 * pango_layout_get_size() or drawing with functions like
 * pango_cairo_show_layout(). If you change the transformation
 * or target surface for @cr, you need to call pango_cairo_update_layout()
 *
 * This function is the most convenient way to use Cairo with Pango,
 * however it is slightly inefficient since it creates a separate
 * #PangoContext object for each layout. This might matter in an
 * application that was laying out large amounts of text.
 *
 * Return value: the newly created #PangoLayout. Free with
 *   g_object_unref().
 *
 * Since: 1.10
 **/
PangoLayout *
pango_cairo_create_layout  (cairo_t *cr)
{
  PangoFontMap *fontmap;
  PangoContext *context;
  PangoLayout *layout;

  g_return_val_if_fail (cr != NULL, NULL);

  fontmap = pango_cairo_font_map_get_default ();
  context = pango_cairo_font_map_create_context ((PangoCairoFontMap *) (fontmap));
  layout = pango_layout_new (context);

  pango_cairo_update_context (cr, context);
  g_object_unref (context);

  return layout;
}

/**
 * pango_cairo_update_layout:
 * @cr: a Cairo context
 * @layout: a #PangoLayout, from pango_cairo_create_layout()
 *
 * Updates the private #PangoContext of a #PangoLayout created with
 * pango_cairo_create_layout() to match the current transformation
 * and target surface of a Cairo context.
 *
 * Since: 1.10
 **/
void
pango_cairo_update_layout (cairo_t     *cr,
			   PangoLayout *layout)
{
  g_return_if_fail (cr != NULL);
  g_return_if_fail (PANGO_IS_LAYOUT (layout));

  pango_cairo_update_context (cr, pango_layout_get_context (layout));
  pango_layout_context_changed (layout);
}