/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8; coding: utf-8 -*- *
 * gtksourceprintcompositor.c
 * This file is part of GtkSourceView
 *
 * Copyright (C) 2000, 2001 Chema Celorio  
 * Copyright (C) 2003  Gustavo Giráldez
 * Copyright (C) 2004  Red Hat, Inc.
 * Copyright (C) 2001-2007  Paolo Maggi
 * Copyright (C) 2008  Paolo Maggi, Paolo Borelli and Yevgen Muntyan
 *
 * GtkSourceView is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * GtkSourceView 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
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
 
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <string.h>
#include <time.h>

#include "gtksourceview-i18n.h" 
#include "gtksourceprintcompositor.h"

/**
 * SECTION:printcompositor
 * @Short_description: Compose a #GtkSourceBuffer for printing
 * @Title: GtkSourcePrintCompositor
 *
 * The #GtkSourcePrintCompositor object is used to compose a #GtkSourceBuffer
 * for printing. You can set various configuration options to customize the
 * printed output. #GtkSourcePrintCompositor is designed to be used with the
 * high-level printing API of gtk+, i.e. #GtkPrintOperation.
 *
 * The margins specified in this object are the layout margins: they define the
 * blank space bordering the printed area of the pages. They must not be
 * confused with the "print margins", i.e. the parts of the page that the
 * printer cannot print on, defined in the #GtkPageSetup objects. If the
 * specified layout margins are smaller than the "print margins", the latter
 * ones are used as a fallback by the #GtkSourcePrintCompositor object, so that
 * the printed area is not clipped.
 */

/*
#define ENABLE_DEBUG
#define ENABLE_PROFILE
*/

#undef ENABLE_DEBUG
#undef ENABLE_PROFILE

#ifdef ENABLE_DEBUG
#define DEBUG(x) (x)
#else
#define DEBUG(x)
#endif

#ifdef ENABLE_PROFILE
#define PROFILE(x) (x)
static GTimer *pagination_timer = NULL;
#else
#define PROFILE(x)
#endif

#define DEFAULT_TAB_WIDTH 		8
#define MAX_TAB_WIDTH			32

#define DEFAULT_FONT_NAME   "Monospace 10"

/* 5 mm */
#define NUMBERS_TEXT_SEPARATION convert_from_mm (5, GTK_UNIT_POINTS)

#define HEADER_FOOTER_SIZE_FACTOR 2.2
#define SEPARATOR_SPACING_FACTOR  0.4
#define SEPARATOR_LINE_WIDTH      0.7

/* Number of pages paginated on each invocation of the paginate() method. */
#define PAGINATION_CHUNK_SIZE 3

typedef enum 
{
	/* Initial state: properties can be changed only when the paginator
	   is in the INIT state */
	INIT,
	
	/* Paginating state: paginator goes in this state when the paginate
	   function is called for the first time */
	PAGINATING,
	
	/* Done state: paginator goes in this state when the entire document
	   has been paginated */
	DONE
} PaginatorState;

struct _GtkSourcePrintCompositorPrivate
{
	GtkSourceBuffer         *buffer;

	/* Properties */
	guint			 tab_width;
	GtkWrapMode		 wrap_mode;
	gboolean                 highlight_syntax;
	guint                    print_line_numbers;
	
	PangoFontDescription    *body_font;
	PangoFontDescription    *line_numbers_font;
	PangoFontDescription    *header_font;
	PangoFontDescription    *footer_font;

	/* Paper size, stored in points */
	gdouble                  paper_width;
	gdouble                  paper_height;

	/* These are stored in mm */
	gdouble                  margin_top;
	gdouble                  margin_bottom;
	gdouble                  margin_left;
	gdouble                  margin_right;

	gboolean                 print_header;
	gboolean                 print_footer;

	gchar                   *header_format_left;
	gchar                   *header_format_center;
	gchar                   *header_format_right;
	gboolean                 header_separator;
	gchar                   *footer_format_left;
	gchar                   *footer_format_center;
	gchar                   *footer_format_right;
	gboolean                 footer_separator;	

	/* State */
	PaginatorState           state;
	
	GArray                  *pages; /* pages[i] contains the begin offset
	                                   of i-th  */

	guint                    paginated_lines;
	gint                     n_pages;
	gint                     current_page;

	/* Stored in points */
	gdouble                  header_height;
	gdouble                  footer_height;
	gdouble                  line_numbers_width;
	gdouble                  line_numbers_height;

	gdouble                  footer_font_descent;
	
	/* layout objects */
	PangoLayout             *layout;
	PangoLayout             *line_numbers_layout;
	PangoLayout             *header_layout;
	PangoLayout             *footer_layout;	

	gdouble                  real_margin_top;
	gdouble                  real_margin_bottom;
	gdouble                  real_margin_left;
	gdouble                  real_margin_right;
	
	gdouble                  page_margin_top;
	gdouble                  page_margin_left;	
	
	PangoLanguage           *language; /* must not be freed */
	
	GtkTextMark             *pagination_mark;
};

enum
{
	PROP_0,
	PROP_BUFFER,
	PROP_TAB_WIDTH,
	PROP_WRAP_MODE,
	PROP_HIGHLIGHT_SYNTAX,
	PROP_PRINT_LINE_NUMBERS,
	PROP_PRINT_HEADER,
	PROP_PRINT_FOOTER,
	PROP_BODY_FONT_NAME,
	PROP_LINE_NUMBERS_FONT_NAME,
	PROP_HEADER_FONT_NAME,
	PROP_FOOTER_FONT_NAME,
	PROP_N_PAGES
};

G_DEFINE_TYPE (GtkSourcePrintCompositor, gtk_source_print_compositor, G_TYPE_OBJECT)

#define MM_PER_INCH 25.4
#define POINTS_PER_INCH 72

static gdouble
convert_to_mm (gdouble len, GtkUnit unit)
{
	switch (unit)
	{
		case GTK_UNIT_MM:
			return len;

		case GTK_UNIT_INCH:
			return len * MM_PER_INCH;
		
		default:
		case GTK_UNIT_PIXEL:
			g_warning ("Unsupported unit");
			/* Fall through */

		case GTK_UNIT_POINTS:
			return len * (MM_PER_INCH / POINTS_PER_INCH);
    	}
}

static gdouble
convert_from_mm (gdouble len, GtkUnit unit)
{
	switch (unit)
	{
		case GTK_UNIT_MM:
			return len;
		
		case GTK_UNIT_INCH:
			return len / MM_PER_INCH;
			
		default:
		case GTK_UNIT_PIXEL:
			g_warning ("Unsupported unit");
			/* Fall through */

		case GTK_UNIT_POINTS:
			return len / (MM_PER_INCH / POINTS_PER_INCH);
	}
}

static void 
gtk_source_print_compositor_get_property (GObject    *object,
					  guint       prop_id,
					  GValue     *value,
					  GParamSpec *pspec)
{
	GtkSourcePrintCompositor *compositor = GTK_SOURCE_PRINT_COMPOSITOR (object);

	switch (prop_id)
	{			
		case PROP_BUFFER:
			g_value_set_object (value, compositor->priv->buffer);
			break;
		case PROP_TAB_WIDTH:
			g_value_set_uint (value,
					  gtk_source_print_compositor_get_tab_width (compositor));
			break;
		case PROP_WRAP_MODE:
			g_value_set_enum (value,
					  gtk_source_print_compositor_get_wrap_mode (compositor));
			break;
		case PROP_HIGHLIGHT_SYNTAX:
			g_value_set_boolean (value,
					     gtk_source_print_compositor_get_highlight_syntax (compositor));
			break;
		case PROP_PRINT_LINE_NUMBERS:
			g_value_set_uint (value,
					  gtk_source_print_compositor_get_print_line_numbers (compositor));
			break;
		case PROP_PRINT_HEADER:
			g_value_set_boolean (value,
					     gtk_source_print_compositor_get_print_header (compositor));
			break;			
		case PROP_PRINT_FOOTER:
			g_value_set_boolean (value,
					     gtk_source_print_compositor_get_print_footer (compositor));			
			break;			
		case PROP_BODY_FONT_NAME:
			g_value_set_string (value,
					    gtk_source_print_compositor_get_body_font_name (compositor));
			break;
		case PROP_LINE_NUMBERS_FONT_NAME:
			g_value_set_string (value,
					    gtk_source_print_compositor_get_line_numbers_font_name (compositor));
			break;
		case PROP_HEADER_FONT_NAME:
			g_value_set_string (value,
					    gtk_source_print_compositor_get_header_font_name (compositor));
			break;
		case PROP_FOOTER_FONT_NAME:
			g_value_set_string (value,
					    gtk_source_print_compositor_get_footer_font_name (compositor));
			break;
		case PROP_N_PAGES:
			g_value_set_int (value,
					 gtk_source_print_compositor_get_n_pages (compositor));
			break;
		default:
			G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
			break;
	}
}

static void 
gtk_source_print_compositor_set_property (GObject      *object,
					  guint         prop_id,
					  const GValue *value,
					  GParamSpec   *pspec)
{
	GtkSourcePrintCompositor *compositor = GTK_SOURCE_PRINT_COMPOSITOR (object);
	
	switch (prop_id)
	{
		case PROP_BUFFER:
			compositor->priv->buffer = GTK_SOURCE_BUFFER (g_value_dup_object (value));
			break;
		case PROP_TAB_WIDTH:
			gtk_source_print_compositor_set_tab_width (compositor,
								   g_value_get_uint (value));
			break;
		case PROP_WRAP_MODE:
			gtk_source_print_compositor_set_wrap_mode (compositor,
								   g_value_get_enum (value));
			break;
		case PROP_HIGHLIGHT_SYNTAX:
			gtk_source_print_compositor_set_highlight_syntax (compositor,
									  g_value_get_boolean (value));
			break;
		case PROP_PRINT_LINE_NUMBERS:
			gtk_source_print_compositor_set_print_line_numbers (compositor,
									    g_value_get_uint (value));
			break;
		case PROP_PRINT_HEADER:
			gtk_source_print_compositor_set_print_header (compositor, g_value_get_boolean (value));
			break;

		case PROP_PRINT_FOOTER:
			gtk_source_print_compositor_set_print_footer (compositor, g_value_get_boolean (value));
			break;						
		case PROP_BODY_FONT_NAME:
			gtk_source_print_compositor_set_body_font_name (compositor,
									g_value_get_string (value));
			break;
		case PROP_LINE_NUMBERS_FONT_NAME:
			gtk_source_print_compositor_set_line_numbers_font_name (compositor,
										g_value_get_string (value));
			break;
		case PROP_HEADER_FONT_NAME:
			gtk_source_print_compositor_set_header_font_name (compositor,
									g_value_get_string (value));
			break;
		case PROP_FOOTER_FONT_NAME:
			gtk_source_print_compositor_set_footer_font_name (compositor,
									g_value_get_string (value));
			break;			
		default:
			G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
			break;
	}
}

static void
gtk_source_print_compositor_finalize (GObject *object)
{
	GtkSourcePrintCompositor *compositor;

	compositor = GTK_SOURCE_PRINT_COMPOSITOR (object);

	if (compositor->priv->pages != NULL)
		g_array_free (compositor->priv->pages, TRUE);
		
	if (compositor->priv->layout != NULL)
		g_object_unref (compositor->priv->layout);

	if (compositor->priv->line_numbers_layout != NULL)
		g_object_unref (compositor->priv->line_numbers_layout);

	if (compositor->priv->header_layout != NULL)
		g_object_unref (compositor->priv->header_layout);

	if (compositor->priv->footer_layout != NULL)
		g_object_unref (compositor->priv->footer_layout);

	pango_font_description_free (compositor->priv->body_font);

	if (compositor->priv->line_numbers_font != NULL)
		pango_font_description_free (compositor->priv->line_numbers_font);

	if (compositor->priv->header_font != NULL)
		pango_font_description_free (compositor->priv->header_font);

	if (compositor->priv->footer_font != NULL)
		pango_font_description_free (compositor->priv->footer_font);

	g_free (compositor->priv->header_format_left);
	g_free (compositor->priv->header_format_right);
	g_free (compositor->priv->header_format_center);
	g_free (compositor->priv->footer_format_left);
	g_free (compositor->priv->footer_format_right);
	g_free (compositor->priv->footer_format_center);

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

static void
gtk_source_print_compositor_dispose (GObject *object)
{
	GtkSourcePrintCompositor *compositor;

	compositor = GTK_SOURCE_PRINT_COMPOSITOR (object);

	if (compositor->priv->buffer != NULL) {
		g_object_unref (compositor->priv->buffer);
		compositor->priv->buffer = NULL;
	}

	G_OBJECT_CLASS (gtk_source_print_compositor_parent_class)->dispose (object);
}

static void						 
gtk_source_print_compositor_class_init (GtkSourcePrintCompositorClass *klass)
{
	GObjectClass *object_class;
	
	object_class = G_OBJECT_CLASS (klass);

	object_class->get_property = gtk_source_print_compositor_get_property;
	object_class->set_property = gtk_source_print_compositor_set_property;
	object_class->finalize = gtk_source_print_compositor_finalize;
	object_class->dispose = gtk_source_print_compositor_dispose;

	/**
	 * GtkSourcePrintCompositor:buffer:
	 *
	 * The GtkSourceBuffer object to print.
	 *
	 * Since: 2.2
	 */
	g_object_class_install_property (object_class,
					 PROP_BUFFER,
					 g_param_spec_object ("buffer",
							      _("Source Buffer"),
							      _("The GtkSourceBuffer object to print"),
							      GTK_SOURCE_TYPE_BUFFER,
							      G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY));

	/**
	 * GtkSourcePrintCompositor:tab-width:
	 *
	 * Width of a tab character expressed in spaces.
	 *
	 * The value of this property cannot be changed anymore after the first 
	 * call to the gtk_source_print_compositor_paginate() function. 	 
	 *
	 * Since: 2.2
	 */
	g_object_class_install_property (object_class,
					 PROP_TAB_WIDTH,
					 g_param_spec_uint ("tab-width",
							    _("Tab Width"),
							    _("Width of a tab character expressed in spaces"),
							    1,
							    MAX_TAB_WIDTH,
							    DEFAULT_TAB_WIDTH,
							    G_PARAM_READWRITE));


	/**
	 * GtkSourcePrintCompositor:wrap-mode:
	 *
	 * Whether to wrap lines never, at word boundaries, or at character boundaries.
	 *
 	 * The value of this property cannot be changed anymore after the first 
	 * call to the gtk_source_print_compositor_paginate() function. 
	 *
	 * Since: 2.2
	 */
	g_object_class_install_property (object_class,
					 PROP_WRAP_MODE,
					 g_param_spec_enum ("wrap-mode",
							    _("Wrap Mode"),
							    _("Whether to wrap lines never, "
							      "at word boundaries, or at "
							      "character boundaries."),
							    GTK_TYPE_WRAP_MODE,
							    GTK_WRAP_NONE,
							    G_PARAM_READWRITE));

	/**
	 * GtkSourcePrintCompositor:highlight-syntax:
	 *
	 * Whether to print the document with highlighted syntax.
	 *	 
 	 * The value of this property cannot be changed anymore after the first 
	 * call to the gtk_source_print_compositor_paginate() function. 
	 *
	 * Since: 2.2
	 */
	g_object_class_install_property (object_class,
					 PROP_HIGHLIGHT_SYNTAX,
					 g_param_spec_boolean ("highlight-syntax",
							       _("Highlight Syntax"),
							       _("Whether to print the "
								 "document with highlighted "
								 "syntax"),
							       TRUE,
							       G_PARAM_READWRITE));

	/**
	 * GtkSourcePrintCompositor:print-line-numbers:
	 *
	 * Interval of printed line numbers. If this property is set to 0 no
	 * numbers will be printed.  If greater than 0, a number will be
 	 * printed every "print-line-numbers" lines (i.e. 1 will print all line numbers).
	 *
	 * The value of this property cannot be changed anymore after the first 
	 * call to the gtk_source_print_compositor_paginate() function. 
	 *	 
	 * Since: 2.2
	 */
	g_object_class_install_property (object_class,
					 PROP_PRINT_LINE_NUMBERS,
					 g_param_spec_uint ("print-line-numbers",
							    _("Print Line Numbers"),
							    _("Interval of printed line numbers "
							      "(0 means no numbers)"),
							    0, 100, 1,
							    G_PARAM_READWRITE));
	
	/**
	 * GtkSourcePrintCompositor:print-header:
	 * 
	 * Whether to print a header in each page.
	 *
	 * Note that by default the header format is unspecified, and if it is
	 * unspecified the header will not be printed, regardless of the value of 
	 * this property.
	 *
	 * The value of this property cannot be changed anymore after the first 
	 * call to the gtk_source_print_compositor_paginate() function. 
	 *
	 * Since: 2.2
	 */
	g_object_class_install_property (object_class,
					 PROP_PRINT_HEADER,
					 g_param_spec_boolean ("print-header",
							       _("Print Header"),
							       _("Whether to print a header "
								 "in each page"),
							       FALSE,
							       G_PARAM_READWRITE));

	/**
	 * GtkSourcePrintCompositor:print-footer:
	 * 
	 * Whether to print a footer in each page.
	 *
	 * Note that by default the footer format is unspecified, and if it is
	 * unspecified the footer will not be printed, regardless of the value of 
	 * this property.
	 *
	 * The value of this property cannot be changed anymore after the first 
	 * call to the gtk_source_print_compositor_paginate() function. 
	 *
	 * Since: 2.2
	 */
	g_object_class_install_property (object_class,
					 PROP_PRINT_FOOTER,
					 g_param_spec_boolean ("print-footer",
							       _("Print Footer"),
							       _("Whether to print a footer "
								 "in each page"),
							       FALSE,
							       G_PARAM_READWRITE));

	/**
	 * GtkSourcePrintCompositor:body-font-name:
	 *
	 * Name of the font used for the text body. 
	 *
	 * Accepted values are strings representing a font description Pango can understand.
	 * (e.g. &quot;Monospace 10&quot;). See pango_font_description_from_string()
	 * for a description of the format of the string representation. 
	 *
	 * The value of this property cannot be changed anymore after the first 
	 * call to the gtk_source_print_compositor_paginate() function. 
	 *
	 * Since: 2.2
	 */	 
	g_object_class_install_property (object_class,
					 PROP_BODY_FONT_NAME,
					 g_param_spec_string ("body-font-name",
							      _("Body Font Name"),
							      _("Name of the font to use for the text body "
							        "(e.g. \"Monospace 10\")"),
							      NULL,
							      G_PARAM_READWRITE));

	/**
	 * GtkSourcePrintCompositor:line-numbers-font-name:
	 *
	 * Name of the font used to print line numbers on the left margin.  
	 * If this property is unspecified, the text body font is used.
	 *
	 * Accepted values are strings representing a font description Pango can understand.
	 * (e.g. &quot;Monospace 10&quot;). See pango_font_description_from_string()
	 * for a description of the format of the string representation. 
	 *
	 * The value of this property cannot be changed anymore after the first 
	 * call to the gtk_source_print_compositor_paginate() function. 
	 *
	 * Since: 2.2
	 */
	g_object_class_install_property (object_class,
					 PROP_LINE_NUMBERS_FONT_NAME,
					 g_param_spec_string ("line-numbers-font-name",
							      _("Line Numbers Font Name"),
							      _("Name of the font to use for the line numbers "
							        "(e.g. \"Monospace 10\")"),							      
							      NULL,
							      G_PARAM_READWRITE));

	/**
	 * GtkSourcePrintCompositor:header-font-name:
	 *
	 * Name of the font used to print page header.  
	 * If this property is unspecified, the text body font is used.
	 *
	 * Accepted values are strings representing a font description Pango can understand.
	 * (e.g. &quot;Monospace 10&quot;). See pango_font_description_from_string()
	 * for a description of the format of the string representation. 
	 *
	 * The value of this property cannot be changed anymore after the first 
	 * call to the gtk_source_print_compositor_paginate() function. 
	 *
	 * Since: 2.2
	 */
	g_object_class_install_property (object_class,
					 PROP_HEADER_FONT_NAME,
					 g_param_spec_string ("header-font-name",
							      _("Header Font Name"),
							      _("Name of the font to use for the page header "
							        "(e.g. \"Monospace 10\")"),							      
							      NULL,
							      G_PARAM_READWRITE));

	/**
	 * GtkSourcePrintCompositor:footer-font-name:
	 *
	 * Name of the font used to print page footer.  
	 * If this property is unspecified, the text body font is used.
	 *
	 * Accepted values are strings representing a font description Pango can understand.
	 * (e.g. &quot;Monospace 10&quot;). See pango_font_description_from_string()
	 * for a description of the format of the string representation. 
	 *
	 * The value of this property cannot be changed anymore after the first 
	 * call to the gtk_source_print_compositor_paginate() function. 
	 *
	 * Since: 2.2
	 */
	g_object_class_install_property (object_class,
					 PROP_FOOTER_FONT_NAME,
					 g_param_spec_string ("footer-font-name",
							      _("Footer Font Name"),
							      _("Name of the font to use for the page footer "
							        "(e.g. \"Monospace 10\")"),							      
							      NULL,
							      G_PARAM_READWRITE));

	/**
	 * GtkSourcePrintCompositor:n-pages:
	 *
	 * The number of pages in the document or <code>-1</code> if the 
 	 * document has not been completely paginated.
 	 *
 	 * Since: 2.2
 	 */
	g_object_class_install_property (object_class,
					 PROP_N_PAGES,
					 g_param_spec_int ("n-pages",
							   _("Number of pages"),
							   _("The number of pages in the document "
							     "(-1 means the document has not been "
							     "completely paginated)."),
							   -1, G_MAXINT, -1,
							   G_PARAM_READABLE));

	g_type_class_add_private (object_class, sizeof(GtkSourcePrintCompositorPrivate));	
}

static void
gtk_source_print_compositor_init (GtkSourcePrintCompositor *compositor)
{
	GtkSourcePrintCompositorPrivate *priv;
	
	priv = G_TYPE_INSTANCE_GET_PRIVATE (compositor, 
					    GTK_SOURCE_TYPE_PRINT_COMPOSITOR,
					    GtkSourcePrintCompositorPrivate);

	compositor->priv = priv;
	
	priv->buffer = NULL;
	
	priv->tab_width = DEFAULT_TAB_WIDTH;
	priv->wrap_mode = GTK_WRAP_NONE;
	priv->highlight_syntax = TRUE;
	priv->print_line_numbers = 0;

	priv->body_font = pango_font_description_from_string (DEFAULT_FONT_NAME);
	priv->line_numbers_font = NULL;
	priv->header_font = NULL;
	priv->footer_font = NULL;

	priv->paper_width = 0.0;
	priv->paper_height = 0.0;

	priv->margin_top = 0.0;
	priv->margin_bottom = 0.0;
	priv->margin_left = 0.0;
	priv->margin_right = 0.0;

	priv->print_header = FALSE;
	priv->print_footer = FALSE;

	priv->header_format_left = NULL;
	priv->header_format_center = NULL;
	priv->header_format_right = NULL;
	priv->header_separator = FALSE;
	
	priv->footer_format_left = NULL;
	priv->footer_format_center = NULL;
	priv->footer_format_right = NULL;
	priv->footer_separator = FALSE;
	
	priv->state = INIT;
	
	priv->pages = NULL;
	
	priv->paginated_lines = 0;
	priv->n_pages = -1;
	priv->current_page = -1;
	
	priv->layout = NULL;
	priv->line_numbers_layout = NULL;

	priv->language = gtk_get_default_language ();

	/* Negative values mean uninitialized */
	priv->header_height = -1.0; 
	priv->footer_height = -1.0;
	priv->line_numbers_width = -1.0;
	priv->line_numbers_height = -1.0;
}

/**
 * gtk_source_print_compositor_new:
 * @buffer: the #GtkSourceBuffer to print.
 * 
 * Creates a new print compositor that can be used to print @buffer.
 * 
 * Return value: a new print compositor object.
 *
 * Since: 2.2
 **/
GtkSourcePrintCompositor *
gtk_source_print_compositor_new (GtkSourceBuffer *buffer)
{
	g_return_val_if_fail (GTK_SOURCE_IS_BUFFER (buffer), NULL);
	
	return g_object_new (GTK_SOURCE_TYPE_PRINT_COMPOSITOR,
			     "buffer", buffer,
			     NULL);
}

/**
 * gtk_source_print_compositor_new_from_view:
 * @view: a #GtkSourceView to get configuration from.
 * 
 * Creates a new print compositor that can be used to print the buffer
 * associated with @view.
 * This constructor sets some configuration properties to make the 
 * printed output match @view as much as possible.  The properties set are
 * #GtkSourcePrintCompositor:tab-width, #GtkSourcePrintCompositor:highlight-syntax, 
 * #GtkSourcePrintCompositor:wrap-mode, #GtkSourcePrintCompositor:body-font-name and
 * #GtkSourcePrintCompositor:print-line-numbers.
 *
 * Return value: a new print compositor object.
 *
 * Since: 2.2
 **/
GtkSourcePrintCompositor *
gtk_source_print_compositor_new_from_view (GtkSourceView *view)
{
	GtkSourceBuffer *buffer = NULL;
	PangoContext *pango_context;
	PangoFontDescription* font_desc;
	GtkSourcePrintCompositor *compositor;
	
	g_return_val_if_fail (GTK_SOURCE_IS_VIEW (view), NULL);
	g_return_val_if_fail (GTK_SOURCE_IS_BUFFER (gtk_text_view_get_buffer (GTK_TEXT_VIEW (view))), NULL);	

	buffer = GTK_SOURCE_BUFFER (gtk_text_view_get_buffer (GTK_TEXT_VIEW (view)));
	
	compositor = GTK_SOURCE_PRINT_COMPOSITOR (
			g_object_new (GTK_SOURCE_TYPE_PRINT_COMPOSITOR,
				     "buffer", buffer,
				     "tab-width", gtk_source_view_get_tab_width (view),
				     "highlight-syntax", gtk_source_buffer_get_highlight_syntax (buffer) != FALSE,
				     "wrap-mode", gtk_text_view_get_wrap_mode (GTK_TEXT_VIEW (view)),
				     "print-line-numbers", (gtk_source_view_get_show_line_numbers (view) == FALSE) ? 0 : 1,
				     NULL));

	/* Set the body font directly since the property get a name while body_font is a PangoFontDescription */
	pango_context = gtk_widget_get_pango_context (GTK_WIDGET (view));
	
	font_desc = pango_context_get_font_description (pango_context);
	
	compositor->priv->body_font = pango_font_description_copy (font_desc);
	g_object_notify (G_OBJECT (compositor), "body-font-name"); // FIXME: is this needed?
	
	return compositor;
}

/**
 * gtk_source_print_compositor_get_buffer:
 * @compositor: a #GtkSourcePrintCompositor.
 * 
 * Gets the #GtkSourceBuffer associated with the compositor. The returned
 * object reference is owned by the compositor object and
 * should not be unreferenced.
 * 
 * Return value: (transfer none): the #GtkSourceBuffer associated with the compositor.
 *
 * Since: 2.2
 **/
GtkSourceBuffer *
gtk_source_print_compositor_get_buffer (GtkSourcePrintCompositor *compositor)
{
	g_return_val_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor), NULL);
	
	return compositor->priv->buffer;
}

/**
 * gtk_source_print_compositor_set_tab_width:
 * @compositor: a #GtkSourcePrintCompositor.
 * @width: width of tab in characters.
 *
 * Sets the width of tabulation in characters for printed text. 
 *
 * This function cannot be called anymore after the first call to the 
 * gtk_source_print_compositor_paginate() function.
 *
 * Since: 2.2
 */
void
gtk_source_print_compositor_set_tab_width (GtkSourcePrintCompositor *compositor,
					   guint                     width)
{
	g_return_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor));
	g_return_if_fail (width > 0 && width <= MAX_TAB_WIDTH);
	g_return_if_fail (compositor->priv->state == INIT);
	
	if (width == compositor->priv->tab_width)
		return;
	
	compositor->priv->tab_width = width;

	g_object_notify (G_OBJECT (compositor), "tab-width");
}

/**
 * gtk_source_print_compositor_get_tab_width:
 * @compositor: a #GtkSourcePrintCompositor.
 *
 * Returns the width of tabulation in characters for printed text.
 *
 * Return value: width of tab.
 *
 * Since: 2.2
 */
guint
gtk_source_print_compositor_get_tab_width (GtkSourcePrintCompositor *compositor)
{
	g_return_val_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor), DEFAULT_TAB_WIDTH);

	return compositor->priv->tab_width;
}

/**
 * gtk_source_print_compositor_set_wrap_mode:
 * @compositor: a #GtkSourcePrintCompositor.
 * @wrap_mode: a #GtkWrapMode.
 *
 * Sets the line wrapping mode for the printed text.
 *
 * This function cannot be called anymore after the first call to the 
 * gtk_source_print_compositor_paginate() function.  
 *
 * Since: 2.2
 */
void
gtk_source_print_compositor_set_wrap_mode (GtkSourcePrintCompositor *compositor,
					   GtkWrapMode               wrap_mode)
{
	g_return_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor));
	g_return_if_fail (compositor->priv->state == INIT);

	if (wrap_mode == compositor->priv->wrap_mode)
		return;
	
	compositor->priv->wrap_mode = wrap_mode;

	g_object_notify (G_OBJECT (compositor), "wrap-mode");
}

/**
 * gtk_source_print_compositor_get_wrap_mode:
 * @compositor: a #GtkSourcePrintCompositor.
 *
 * Gets the line wrapping mode for the printed text.
 *
 * Return value: the line wrap mode.
 *
 * Since: 2.2
 */
GtkWrapMode
gtk_source_print_compositor_get_wrap_mode (GtkSourcePrintCompositor *compositor)
{
	g_return_val_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor), GTK_WRAP_NONE);
	
	return compositor->priv->wrap_mode;
}

/**
 * gtk_source_print_compositor_set_highlight_syntax:
 * @compositor: a #GtkSourcePrintCompositor.
 * @highlight: whether syntax should be highlighted.
 * 
 * Sets whether the printed text will be highlighted according to the
 * buffer rules.  Both color and font style are applied.
 *
 * This function cannot be called anymore after the first call to the 
 * gtk_source_print_compositor_paginate() function.   
 *
 * Since: 2.2
 **/
void
gtk_source_print_compositor_set_highlight_syntax (GtkSourcePrintCompositor *compositor,
						  gboolean                  highlight)
{
	g_return_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor));
	g_return_if_fail (compositor->priv->state == INIT);

	highlight = (highlight != FALSE);
	
	if (highlight == compositor->priv->highlight_syntax)
		return;

	compositor->priv->highlight_syntax = highlight;

	g_object_notify (G_OBJECT (compositor), "highlight-syntax");
}

/**
 * gtk_source_print_compositor_get_highlight_syntax:
 * @compositor: a #GtkSourcePrintCompositor.
 *
 * Determines whether the printed text will be highlighted according to the
 * buffer rules.  Note that highlighting will happen
 * only if the buffer to print has highlighting activated.
 * 
 * Return value: %TRUE if the printed output will be highlighted.
 *
 * Since: 2.2
 **/
gboolean
gtk_source_print_compositor_get_highlight_syntax (GtkSourcePrintCompositor *compositor)
{
	g_return_val_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor), FALSE);

	return compositor->priv->highlight_syntax;
}

/**
 * gtk_source_print_compositor_set_print_line_numbers:
 * @compositor: a #GtkSourcePrintCompositor.
 * @interval: interval for printed line numbers.
 * 
 * Sets the interval for printed line numbers.  If @interval is 0 no
 * numbers will be printed.  If greater than 0, a number will be
 * printed every @interval lines (i.e. 1 will print all line numbers).
 *
 * Maximum accepted value for @interval is 100.
 * 
 * This function cannot be called anymore after the first call to the 
 * gtk_source_print_compositor_paginate() function.   
 *
 * Since: 2.2
 **/
void
gtk_source_print_compositor_set_print_line_numbers (GtkSourcePrintCompositor *compositor,
						    guint                     interval)
{
	g_return_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor));
	g_return_if_fail (compositor->priv->state == INIT);
	g_return_if_fail (interval <= 100);
	
	if (interval == compositor->priv->print_line_numbers)
		return;
	
	compositor->priv->print_line_numbers = interval;

	g_object_notify (G_OBJECT (compositor), "print-line-numbers");
}

/**
 * gtk_source_print_compositor_set_print_header:
 * @compositor: a #GtkSourcePrintCompositor.
 * @print: %TRUE if you want the header to be printed.
 * 
 * Sets whether you want to print a header in each page.  The 
 * header consists of three pieces of text and an optional line
 * separator, configurable with
 * gtk_source_print_compositor_set_header_format().
 *
 * Note that by default the header format is unspecified, and if it's
 * empty it will not be printed, regardless of this setting.
 *
 * This function cannot be called anymore after the first call to the 
 * gtk_source_print_compositor_paginate() function.    
 *
 * Since: 2.2
 **/
void
gtk_source_print_compositor_set_print_header (GtkSourcePrintCompositor *compositor,
					      gboolean                  print)
{
	g_return_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor));
	g_return_if_fail (compositor->priv->state == INIT);
	
	print = (print != FALSE);
	
	if (print == compositor->priv->print_header)
		return;
	
	compositor->priv->print_header = print;

	g_object_notify (G_OBJECT (compositor), "print-header");	
}

/**
 * gtk_source_print_compositor_get_print_header:
 * @compositor: a #GtkSourcePrintCompositor.
 * 
 * Determines if a header is set to be printed for each page.  A
 * header will be printed if this function returns %TRUE
 * <emphasis>and</emphasis> some format strings have been specified
 * with gtk_source_print_compositor_set_header_format().
 * 
 * Return value: %TRUE if the header is set to be printed.
 *
 * Since: 2.2
 **/
gboolean
gtk_source_print_compositor_get_print_header (GtkSourcePrintCompositor *compositor)
{
	g_return_val_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor), FALSE);

	return compositor->priv->print_header;
}

/**
 * gtk_source_print_compositor_set_print_footer:
 * @compositor: a #GtkSourcePrintCompositor.
 * @print: %TRUE if you want the footer to be printed.
 * 
 * Sets whether you want to print a footer in each page.  The 
 * footer consists of three pieces of text and an optional line
 * separator, configurable with
 * gtk_source_print_compositor_set_footer_format().
 *
 * Note that by default the footer format is unspecified, and if it's
 * empty it will not be printed, regardless of this setting.
 *
 * This function cannot be called anymore after the first call to the 
 * gtk_source_print_compositor_paginate() function.    
 *
 * Since: 2.2
 **/
void
gtk_source_print_compositor_set_print_footer (GtkSourcePrintCompositor *compositor,
					      gboolean                  print)
{
	g_return_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor));
	g_return_if_fail (compositor->priv->state == INIT);
	
	print = (print != FALSE);
	
	if (print == compositor->priv->print_footer)
		return;
	
	compositor->priv->print_footer = print;

	g_object_notify (G_OBJECT (compositor), "print-footer");	
}

/**
 * gtk_source_print_compositor_get_print_footer:
 * @compositor: a #GtkSourcePrintCompositor.
 * 
 * Determines if a footer is set to be printed for each page.  A
 * footer will be printed if this function returns %TRUE
 * <emphasis>and</emphasis> some format strings have been specified
 * with gtk_source_print_compositor_set_footer_format().
 * 
 * Return value: %TRUE if the footer is set to be printed.
 *
 * Since: 2.2
 **/
gboolean
gtk_source_print_compositor_get_print_footer (GtkSourcePrintCompositor *compositor)
{
	g_return_val_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor), FALSE);

	return compositor->priv->print_footer;
}

/**
 * gtk_source_print_compositor_set_header_format:
 * @compositor: a #GtkSourcePrintCompositor.
 * @separator: %TRUE if you want a separator line to be printed.
 * @left: (allow-none): a format string to print on the left of the header.
 * @center: (allow-none): a format string to print on the center of the header.
 * @right: (allow-none): a format string to print on the right of the header.
 * 
 * Sets strftime like header format strings, to be printed on the
 * left, center and right of the top of each page.  The strings may
 * include strftime(3) codes which will be expanded at print time.
 * All strftime() codes are accepted, with the addition of %N for the
 * page number and %Q for the page count.
 *
 * @separator specifies if a solid line should be drawn to separate
 * the header from the document text.
 *
 * If %NULL is given for any of the three arguments, that particular
 * string will not be printed.
 * 
 * For the header to be printed, in
 * addition to specifying format strings, you need to enable header
 * printing with gtk_source_print_compositor_set_print_header().
 *
 * This function cannot be called anymore after the first call to the 
 * gtk_source_print_compositor_paginate() function.    
 *
 * Since: 2.2
 **/
void 
gtk_source_print_compositor_set_header_format (GtkSourcePrintCompositor *compositor,
					       gboolean                  separator,
					       const gchar              *left,
					       const gchar              *center,
					       const gchar              *right)
{
	g_return_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor));
	g_return_if_fail (compositor->priv->state == INIT);
	
	/* FIXME: validate given strings? */
	g_free (compositor->priv->header_format_left);
	g_free (compositor->priv->header_format_center);
	g_free (compositor->priv->header_format_right);
	
	compositor->priv->header_separator = separator;

	compositor->priv->header_format_left = g_strdup (left);
	compositor->priv->header_format_center = g_strdup (center);
	compositor->priv->header_format_right = g_strdup (right);		
}

/**
 * gtk_source_print_compositor_set_footer_format:
 * @compositor: a #GtkSourcePrintCompositor.
 * @separator: %TRUE if you want a separator line to be printed.
 * @left: (allow-none): a format string to print on the left of the footer.
 * @center: (allow-none): a format string to print on the center of the footer.
 * @right: (allow-none): a format string to print on the right of the footer.
 * 
 * Sets strftime like header format strings, to be printed on the
 * left, center and right of the bottom of each page. The strings may
 * include strftime(3) codes which will be expanded at print time.
 * All strftime() codes are accepted, with the addition of %N for the
 * page number and %Q for the page count.
 *
 * @separator specifies if a solid line should be drawn to separate
 * the footer from the document text.
 *
 * If %NULL is given for any of the three arguments, that particular
 * string will not be printed.
 *
 * For the footer to be printed, in
 * addition to specifying format strings, you need to enable footer
 * printing with gtk_source_print_compositor_set_print_footer().
 *
 * This function cannot be called anymore after the first call to the 
 * gtk_source_print_compositor_paginate() function.    
 *
 * Since: 2.2
 **/
void 
gtk_source_print_compositor_set_footer_format (GtkSourcePrintCompositor *compositor,
					       gboolean                  separator,
					       const gchar              *left,
					       const gchar              *center,
					       const gchar              *right)
{
	g_return_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor));
	g_return_if_fail (compositor->priv->state == INIT);

	/* FIXME: validate given strings? */
	g_free (compositor->priv->footer_format_left);
	g_free (compositor->priv->footer_format_center);
	g_free (compositor->priv->footer_format_right);
	
	compositor->priv->footer_separator = separator;
		
	compositor->priv->footer_format_left = g_strdup (left);
	compositor->priv->footer_format_center = g_strdup (center);
	compositor->priv->footer_format_right = g_strdup (right);
}

/**
 * gtk_source_print_compositor_get_print_line_numbers:
 * @compositor: a #GtkSourcePrintCompositor.
 *
 * Returns the interval used for line number printing.  If the
 * value is 0, no line numbers will be printed.  The default value is
 * 1 (i.e. numbers printed in all lines).
 * 
 * Return value: the interval of printed line numbers.
 *
 * Since: 2.2
 **/
guint
gtk_source_print_compositor_get_print_line_numbers (GtkSourcePrintCompositor *compositor)
{
	g_return_val_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor), 0);

	return compositor->priv->print_line_numbers;
}

static gboolean
set_font_description_from_name (GtkSourcePrintCompositor  *compositor,
				PangoFontDescription     **font,
				const gchar               *font_name)
{
	PangoFontDescription *new;

	if (font_name != NULL)	
		new = pango_font_description_from_string (font_name);
	else
	{
		g_return_val_if_fail (compositor->priv->body_font != NULL, FALSE);
		new = pango_font_description_copy (compositor->priv->body_font);
	}	

	if (*font == NULL || !pango_font_description_equal (*font, new))
	{
		if (*font != NULL)
			pango_font_description_free (*font);
		*font = new;

		return TRUE;
	}
	else
	{
		pango_font_description_free (new);

		return FALSE;
	}
}

/**
 * gtk_source_print_compositor_set_body_font_name:
 * @compositor: a #GtkSourcePrintCompositor.
 * @font_name: the name of the default font for the body text.
 *
 * Sets the default font for the printed text. 
 *
 * @font_name should be a
 * string representation of a font description Pango can understand.
 * (e.g. &quot;Monospace 10&quot;). See pango_font_description_from_string()
 * for a description of the format of the string representation. 
 * 
 * This function cannot be called anymore after the first call to the 
 * gtk_source_print_compositor_paginate() function.   
 *
 * Since: 2.2
 */
void
gtk_source_print_compositor_set_body_font_name (GtkSourcePrintCompositor *compositor,
						const gchar              *font_name)
{
	g_return_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor));
	g_return_if_fail (font_name != NULL);
	g_return_if_fail (compositor->priv->state == INIT);	

	if (set_font_description_from_name (compositor,
					    &compositor->priv->body_font,
					    font_name))
	{
		g_object_notify (G_OBJECT (compositor), "body-font-name");
	}
}

/**
 * gtk_source_print_compositor_get_body_font_name:
 * @compositor: a #GtkSourcePrintCompositor.
 *
 * Returns the name of the font used to print the text body. The returned string
 * must be freed with g_free().
 *
 * Return value: a new string containing the name of the font used to print the 
 * text body.
 *
 * Since: 2.2
 */
gchar *
gtk_source_print_compositor_get_body_font_name (GtkSourcePrintCompositor *compositor)
{
	g_return_val_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor), NULL);

	return pango_font_description_to_string (compositor->priv->body_font);
}

/**
 * gtk_source_print_compositor_set_line_numbers_font_name:
 * @compositor: a #GtkSourcePrintCompositor.
 * @font_name: (allow-none): the name of the font for line numbers, or %NULL.
 *
 * Sets the font for printing line numbers on the left margin.  If
 * %NULL is supplied, the default font (i.e. the one being used for the
 * text) will be used instead.  
 *
 * @font_name should be a
 * string representation of a font description Pango can understand.
 * (e.g. &quot;Monospace 10&quot;). See pango_font_description_from_string()
 * for a description of the format of the string representation. 
 *
 * This function cannot be called anymore after the first call to the 
 * gtk_source_print_compositor_paginate() function.    
 *
 * Since: 2.2
 */
void
gtk_source_print_compositor_set_line_numbers_font_name (GtkSourcePrintCompositor *compositor,
							const gchar              *font_name)
{
	g_return_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor));
	g_return_if_fail (font_name != NULL);
	g_return_if_fail (compositor->priv->state == INIT);	

	if (set_font_description_from_name (compositor,
					    &compositor->priv->line_numbers_font,	
					    font_name))
	{
		g_object_notify (G_OBJECT (compositor), "line-numbers-font-name");
	}
}

/**
 * gtk_source_print_compositor_get_line_numbers_font_name:
 * @compositor: a #GtkSourcePrintCompositor.
 *
 * Returns the name of the font used to print line numbers on the left margin. 
 * The returned string must be freed with g_free().
 *
 * Return value: a new string containing the name of the font used to print 
 * line numbers on the left margin.
 *
 * Since: 2.2
 */
gchar *
gtk_source_print_compositor_get_line_numbers_font_name (GtkSourcePrintCompositor *compositor)
{
	g_return_val_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor), NULL);

	if (compositor->priv->line_numbers_font == NULL)
	{
		g_return_val_if_fail (compositor->priv->body_font != NULL, NULL);
		compositor->priv->line_numbers_font = pango_font_description_copy (compositor->priv->body_font);
	}
	
	return pango_font_description_to_string (compositor->priv->line_numbers_font);
}

/**
 * gtk_source_print_compositor_set_header_font_name:
 * @compositor: a #GtkSourcePrintCompositor.
 * @font_name: (allow-none): the name of the font for header text, or %NULL.
 *
 * Sets the font for printing the page header. If
 * %NULL is supplied, the default font (i.e. the one being used for the
 * text) will be used instead.  
 *
 * @font_name should be a
 * string representation of a font description Pango can understand.
 * (e.g. &quot;Monospace 10&quot;). See pango_font_description_from_string()
 * for a description of the format of the string representation. 
 *
 * This function cannot be called anymore after the first call to the 
 * gtk_source_print_compositor_paginate() function.    
 *
 * Since: 2.2
 */
void
gtk_source_print_compositor_set_header_font_name (GtkSourcePrintCompositor *compositor,
							const gchar              *font_name)
{
	g_return_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor));
	g_return_if_fail (font_name != NULL);
	g_return_if_fail (compositor->priv->state == INIT);	

	if (set_font_description_from_name (compositor,
					    &compositor->priv->header_font,	
					    font_name))

	{
		g_object_notify (G_OBJECT (compositor), "header-font-name");
	}
}

/**
 * gtk_source_print_compositor_get_header_font_name:
 * @compositor: a #GtkSourcePrintCompositor.
 *
 * Returns the name of the font used to print the page header. 
 * The returned string must be freed with g_free().
 *
 * Return value: a new string containing the name of the font used to print 
 * the page header.
 *
 * Since: 2.2
 */
gchar *
gtk_source_print_compositor_get_header_font_name (GtkSourcePrintCompositor *compositor)
{
	g_return_val_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor), NULL);

	if (compositor->priv->header_font == NULL)
	{
		g_return_val_if_fail (compositor->priv->body_font != NULL, NULL);
		compositor->priv->header_font = pango_font_description_copy (compositor->priv->body_font);
	}

	return pango_font_description_to_string (compositor->priv->header_font);
}

/**
 * gtk_source_print_compositor_set_footer_font_name:
 * @compositor: a #GtkSourcePrintCompositor.
 * @font_name: (allow-none): the name of the font for the footer text, or %NULL.
 *
 * Sets the font for printing the page footer. If
 * %NULL is supplied, the default font (i.e. the one being used for the
 * text) will be used instead.  
 *
 * @font_name should be a
 * string representation of a font description Pango can understand.
 * (e.g. &quot;Monospace 10&quot;). See pango_font_description_from_string()
 * for a description of the format of the string representation. 
 *
 * This function cannot be called anymore after the first call to the 
 * gtk_source_print_compositor_paginate() function.    
 *
 * Since: 2.2
 */
void
gtk_source_print_compositor_set_footer_font_name (GtkSourcePrintCompositor *compositor,
						  const gchar              *font_name)
{
	g_return_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor));
	g_return_if_fail (font_name != NULL);
	g_return_if_fail (compositor->priv->state == INIT);	

	if (set_font_description_from_name (compositor,
					    &compositor->priv->footer_font,	
					    font_name))

	{
		g_object_notify (G_OBJECT (compositor), "footer-font-name");
	}
}

/**
 * gtk_source_print_compositor_get_footer_font_name:
 * @compositor: a #GtkSourcePrintCompositor.
 *
 * Returns the name of the font used to print the page footer. 
 * The returned string must be freed with g_free().
 *
 * Return value: a new string containing the name of the font used to print 
 * the page footer.
 *
 * Since: 2.2
 */
gchar *
gtk_source_print_compositor_get_footer_font_name (GtkSourcePrintCompositor *compositor)
{
	g_return_val_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor), NULL);

	if (compositor->priv->footer_font == NULL)
	{
		g_return_val_if_fail (compositor->priv->body_font != NULL, NULL);
		compositor->priv->footer_font = pango_font_description_copy (compositor->priv->body_font);
	}

	return pango_font_description_to_string (compositor->priv->footer_font);
}

/**
 * gtk_source_print_compositor_set_top_margin:
 * @compositor: a #GtkSourcePrintCompositor.
 * @margin: the new top margin in units of @unit
 * @unit: the units for @margin
 * 
 * Sets the top margin used by @compositor.
 *
 * Since: 2.2
 */
void
gtk_source_print_compositor_set_top_margin (GtkSourcePrintCompositor *compositor,
					    gdouble                   margin,
					    GtkUnit                   unit)
{
	g_return_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor));

	compositor->priv->margin_top = convert_to_mm (margin, unit);
}

/**
 * gtk_source_print_compositor_get_top_margin:
 * @compositor: a #GtkSourcePrintCompositor.
 * @unit: the unit for the return value.
 * 
 * Gets the top margin in units of @unit.
 * 
 * Return value: the top margin.
 *
 * Since: 2.2
 */
gdouble
gtk_source_print_compositor_get_top_margin (GtkSourcePrintCompositor *compositor,
					    GtkUnit                   unit)
{
	g_return_val_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor), 0);

	return convert_from_mm (compositor->priv->margin_top, unit);
}

/**
 * gtk_source_print_compositor_set_bottom_margin:
 * @compositor: a #GtkSourcePrintCompositor.
 * @margin: the new bottom margin in units of @unit.
 * @unit: the units for @margin.
 * 
 * Sets the bottom margin used by @compositor.
 *
 * Since: 2.2
 */
void
gtk_source_print_compositor_set_bottom_margin (GtkSourcePrintCompositor *compositor,
					       gdouble                   margin,
					       GtkUnit                   unit)
{
	g_return_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor));

	compositor->priv->margin_bottom = convert_to_mm (margin, unit);
}

/**
 * gtk_source_print_compositor_get_bottom_margin:
 * @compositor: a #GtkSourcePrintCompositor.
 * @unit: the unit for the return value.
 * 
 * Gets the bottom margin in units of @unit.
 * 
 * Return value: the bottom margin.
 *
 * Since: 2.2
 */
gdouble
gtk_source_print_compositor_get_bottom_margin (GtkSourcePrintCompositor *compositor,
					       GtkUnit                   unit)
{
	g_return_val_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor), 0);

	return convert_from_mm (compositor->priv->margin_bottom, unit);
}

/**
 * gtk_source_print_compositor_set_left_margin:
 * @compositor: a #GtkSourcePrintCompositor.
 * @margin: the new left margin in units of @unit.
 * @unit: the units for @margin.
 * 
 * Sets the left margin used by @compositor.
 *
 * Since: 2.2
 */
void
gtk_source_print_compositor_set_left_margin (GtkSourcePrintCompositor *compositor,
					     gdouble                   margin,
					     GtkUnit                   unit)
{
	g_return_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor));

	compositor->priv->margin_left = convert_to_mm (margin, unit);
}

/**
 * gtk_source_print_compositor_get_left_margin:
 * @compositor: a #GtkSourcePrintCompositor.
 * @unit: the unit for the return value.
 * 
 * Gets the left margin in units of @unit.
 * 
 * Return value: the left margin
 *
 * Since: 2.2
 */
gdouble
gtk_source_print_compositor_get_left_margin (GtkSourcePrintCompositor *compositor,
					     GtkUnit                   unit)
{
	g_return_val_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor), 0);

	return convert_from_mm (compositor->priv->margin_left, unit);
}

/**
 * gtk_source_print_compositor_set_right_margin:
 * @compositor: a #GtkSourcePrintCompositor.
 * @margin: the new right margin in units of @unit.
 * @unit: the units for @margin.
 * 
 * Sets the right margin used by @compositor.
 *
 * Since: 2.2
 */
void
gtk_source_print_compositor_set_right_margin (GtkSourcePrintCompositor *compositor,
					      gdouble                   margin,
					      GtkUnit                   unit)
{
	g_return_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor));

	compositor->priv->margin_right = convert_to_mm (margin, unit);
}

/**
 * gtk_source_print_compositor_get_right_margin:
 * @compositor: a #GtkSourcePrintCompositor.
 * @unit: the unit for the return value.
 * 
 * Gets the right margin in units of @unit.
 * 
 * Return value: the right margin.
 *
 * Since: 2.2
 */
gdouble
gtk_source_print_compositor_get_right_margin (GtkSourcePrintCompositor *compositor,
					      GtkUnit                   unit)
{
	g_return_val_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor), 0);

	return convert_from_mm (compositor->priv->margin_right, unit);
}

/**
 * gtk_source_print_compositor_get_n_pages:
 * @compositor: a #GtkSourcePrintCompositor.
 * 
 * Returns the number of pages in the document or <code>-1</code> if the 
 * document has not been completely paginated.
 *
 * Return value: the number of pages in the document or <code>-1</code> if the 
 * document has not been completely paginated.
 *
 * Since: 2.2
 */
gint
gtk_source_print_compositor_get_n_pages	(GtkSourcePrintCompositor *compositor)
{
	g_return_val_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor), -1);

	if (compositor->priv->state != DONE)
		return -1;

	return compositor->priv->n_pages;
}

/* utility functions to deal with coordinates (returns) */

static gdouble
get_text_x (GtkSourcePrintCompositor *compositor)
{
	gdouble x;

	x = compositor->priv->real_margin_left;

	if (compositor->priv->print_line_numbers)
	     x += compositor->priv->line_numbers_width + NUMBERS_TEXT_SEPARATION;

	return x;
}

static gdouble
get_text_y (GtkSourcePrintCompositor *compositor)
{
	gdouble y;

	y = compositor->priv->real_margin_top + compositor->priv->header_height;

	return y;
}

static gdouble
get_line_numbers_x (GtkSourcePrintCompositor *compositor)
{
	gdouble x;

	x = compositor->priv->real_margin_left;

	return x;
}

static gdouble
get_text_width (GtkSourcePrintCompositor *compositor)
{
	gdouble w;
	
	w = compositor->priv->paper_width -
	    compositor->priv->real_margin_left -
	    compositor->priv->real_margin_right;

	if (compositor->priv->print_line_numbers)
		w -= (compositor->priv->line_numbers_width + NUMBERS_TEXT_SEPARATION);

	if (w < convert_from_mm (50, GTK_UNIT_POINTS)) {
		g_warning ("Printable page width too little.");
		return convert_from_mm (50, GTK_UNIT_POINTS);
	}
	
	return w;
}

static gdouble
get_text_height (GtkSourcePrintCompositor *compositor)
{
	double h;

	h = compositor->priv->paper_height -
	    compositor->priv->real_margin_top -
	    compositor->priv->real_margin_bottom -
	    compositor->priv->header_height -
	    compositor->priv->footer_height;

	if (h < convert_from_mm (50, GTK_UNIT_POINTS)) {
		g_warning ("Printable page height too little.");
		return convert_from_mm (50, GTK_UNIT_POINTS);
	}

	return h;
}

static gboolean
is_header_to_print (GtkSourcePrintCompositor *compositor)
{
	return (compositor->priv->print_header && 
	       ((compositor->priv->header_format_left != NULL) ||
	        (compositor->priv->header_format_center != NULL) ||
	        (compositor->priv->header_format_right != NULL)));
}

static gboolean
is_footer_to_print (GtkSourcePrintCompositor *compositor)
{
	return (compositor->priv->print_footer && 
	       ((compositor->priv->footer_format_left != NULL) ||
	        (compositor->priv->footer_format_center != NULL) ||
	        (compositor->priv->footer_format_right != NULL)));
}

static void
set_layout_tab_width (GtkSourcePrintCompositor *compositor,
		      PangoLayout              *layout)
{
	gchar *str;
	gint tab_width = 0;

	str = g_strnfill (compositor->priv->tab_width, ' ');
	pango_layout_set_text (layout, str, -1);
	g_free (str);

	pango_layout_get_size (layout, &tab_width, NULL);

	if (tab_width > 0)
	{
		PangoTabArray *tab_array;

		tab_array = pango_tab_array_new (1, FALSE);

		pango_tab_array_set_tab (tab_array,
					 0,
					 PANGO_TAB_LEFT,
					 tab_width);
		pango_layout_set_tabs (layout, tab_array);

		pango_tab_array_free (tab_array);
	}
}

static void
setup_pango_layouts (GtkSourcePrintCompositor *compositor,
		     GtkPrintContext          *context)
{
	PangoLayout *layout;

	/* Layout for the text */
	layout = gtk_print_context_create_pango_layout (context);
	pango_layout_set_font_description (layout, compositor->priv->body_font);

	switch (compositor->priv->wrap_mode)
	{
		case GTK_WRAP_CHAR:
			pango_layout_set_wrap (layout, PANGO_WRAP_CHAR);
			break;
		case GTK_WRAP_WORD:
			pango_layout_set_wrap (layout, PANGO_WRAP_WORD);
			break;
		case GTK_WRAP_WORD_CHAR:
			pango_layout_set_wrap (layout, PANGO_WRAP_WORD_CHAR);
			break;
		case GTK_WRAP_NONE:
			/* FIXME: hack 
			 * Ellipsize the paragraph when text wrapping is disabled.
			 * Another possibility would be to set the width so the text 
			 * breaks into multiple lines, and paginate/render just the 
			 * first one.
			 * See also Comment #23 by Owen on bug #143874.
			 */
			pango_layout_set_ellipsize (layout, PANGO_ELLIPSIZE_END);
			break;
	}

	set_layout_tab_width (compositor, layout);

	g_return_if_fail (compositor->priv->layout == NULL);
	compositor->priv->layout = layout;

	/* Layout for line numbers */
	if (compositor->priv->print_line_numbers > 0)
	{
		layout = gtk_print_context_create_pango_layout (context);

		if (compositor->priv->line_numbers_font == NULL)
			compositor->priv->line_numbers_font = pango_font_description_copy_static (compositor->priv->body_font);
		pango_layout_set_font_description (layout, compositor->priv->line_numbers_font);
		pango_layout_set_alignment (layout, PANGO_ALIGN_RIGHT);

		g_return_if_fail (compositor->priv->line_numbers_layout == NULL);
		compositor->priv->line_numbers_layout = layout;
	}

	/* Layout for header */
	if (is_header_to_print (compositor))
	{
		layout = gtk_print_context_create_pango_layout (context);

		if (compositor->priv->header_font == NULL)
			compositor->priv->header_font = pango_font_description_copy_static (compositor->priv->body_font);

		pango_layout_set_font_description (layout, compositor->priv->header_font);

		g_return_if_fail (compositor->priv->header_layout == NULL);
		compositor->priv->header_layout = layout;
	}
	
	/* Layout for footer */
	if (is_footer_to_print (compositor))
	{
		layout = gtk_print_context_create_pango_layout (context);

		if (compositor->priv->footer_font == NULL)
			compositor->priv->footer_font = pango_font_description_copy_static (compositor->priv->body_font);

		pango_layout_set_font_description (layout, compositor->priv->footer_font);

		g_return_if_fail (compositor->priv->footer_layout == NULL);
		compositor->priv->footer_layout = layout;
	}	
}

/* ---- Header and footer ---- */

/* Most of this code taken from GLib's g_date_strftime() in gdate.c
 * GLIB - Library of useful routines for C programming
 * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald */

static gchar *
strdup_strftime (const gchar *format, const struct tm *tm)
{
	gsize locale_format_len = 0;
	gchar *locale_format;
	gsize tmplen;
	gchar *tmpbuf;
	gsize tmpbufsize;
	gchar *convbuf;
	gsize convlen = 0;
	GError *error = NULL;

	g_return_val_if_fail (format != NULL, NULL);
	g_return_val_if_fail (tm != NULL, NULL);

	locale_format = g_locale_from_utf8 (format, -1, NULL, &locale_format_len, &error);

	if (error)
	{
		g_warning (G_STRLOC "Error converting format to locale encoding: %s",
			   error->message);
		g_error_free (error);
		
		return NULL;
	}

	tmpbufsize = MAX (128, locale_format_len * 2);
	while (TRUE)
	{
		tmpbuf = g_malloc (tmpbufsize);
		
		/* Set the first byte to something other than '\0', to be able to
		 * recognize whether strftime actually failed or just returned "".
		 */
		tmpbuf[0] = '\1';
		tmplen = strftime (tmpbuf, tmpbufsize, locale_format, tm);
		
		if (tmplen == 0 && tmpbuf[0] != '\0')
		{
			g_free (tmpbuf);
			tmpbufsize *= 2;
			
			if (tmpbufsize > 65536)
			{
				g_warning (G_STRLOC "Maximum buffer size for strdup_strftime "
					   "exceeded: giving up");
				g_free (locale_format);
				return NULL;
			}
		}
		else
			break;
	}
	g_free (locale_format);

	convbuf = g_locale_to_utf8 (tmpbuf, tmplen, NULL, &convlen, &error);
	g_free (tmpbuf);

	if (error)
	{
		g_warning (G_STRLOC "Error converting results of strftime to UTF-8: %s",
			   error->message);
		g_error_free (error);
		
		return NULL;
	}

	return convbuf;
}

static gchar *
evaluate_format_string (GtkSourcePrintCompositor *compositor,
			const gchar              *format)
{
	GString *eval;
	gchar *eval_str, *retval;
	const struct tm *tm;
	time_t now;
	gunichar ch;
	
	/* get time */
	time (&now);
	tm = localtime (&now);

	/* analyze format string and replace the codes we know */
	eval = g_string_new_len (NULL, strlen (format));
	ch = g_utf8_get_char (format);
	while (ch != 0)
	{
		if (ch == '%')
		{
			format = g_utf8_next_char (format);
			ch = g_utf8_get_char (format);
			if (ch == 'N')
				g_string_append_printf (eval, "%d", compositor->priv->current_page + 1);
			else if (ch == 'Q')
				g_string_append_printf (eval, "%d", compositor->priv->n_pages);
			else
			{
				g_string_append_c (eval, '%');
				g_string_append_unichar (eval, ch);
			}
		}
		else
		{
			g_string_append_unichar (eval, ch);
		}

		format = g_utf8_next_char (format);
		ch = g_utf8_get_char (format);
	}

	eval_str = g_string_free (eval, FALSE);
	retval = strdup_strftime (eval_str, tm);
	g_free (eval_str);

	return retval;
}

static void
get_layout_size (PangoLayout *layout,
                 double      *width,
                 double      *height)
{
	PangoRectangle rect;

	pango_layout_get_extents (layout, NULL, &rect);

	if (width)
		*width = (double) rect.width / (double) PANGO_SCALE;

	if (height)
		*height = (double) rect.height / (double) PANGO_SCALE;
}

static gsize
get_n_digits (guint n)
{
	gsize d = 1;

	while (n /= 10)
		d++;

	return d;
}

static void
calculate_line_numbers_layout_size (GtkSourcePrintCompositor *compositor,
				    GtkPrintContext          *context)
{
	gint line_count;
	gint n_digits;
	gchar *str;

	if (compositor->priv->print_line_numbers == 0)
	{
		compositor->priv->line_numbers_width = 0.0;
		compositor->priv->line_numbers_height = 0.0;	

		DEBUG ({
			g_debug ("line_numbers_width: %f points (%f mm)", 
				 compositor->priv->line_numbers_width, 
				 convert_to_mm (compositor->priv->line_numbers_width, GTK_UNIT_POINTS));
			g_debug ("line_numbers_height: %f points (%f mm)", 
				 compositor->priv->line_numbers_height,
				 convert_to_mm (compositor->priv->line_numbers_height, GTK_UNIT_POINTS));
		});
		
		return;
	}

	line_count = gtk_text_buffer_get_line_count (GTK_TEXT_BUFFER (compositor->priv->buffer));
	n_digits = get_n_digits (line_count);
	str = g_strnfill (n_digits, '9');	
	pango_layout_set_text (compositor->priv->line_numbers_layout, str, -1);
	g_free (str);

	get_layout_size (compositor->priv->line_numbers_layout,
			 &compositor->priv->line_numbers_width,
			 &compositor->priv->line_numbers_height);

	DEBUG ({
		g_debug ("line_numbers_width: %f points (%f mm)", 
			 compositor->priv->line_numbers_width,
			 convert_to_mm (compositor->priv->line_numbers_width, GTK_UNIT_POINTS));
		g_debug ("line_numbers_height: %f points (%f mm)",
			 compositor->priv->line_numbers_height,
			 convert_to_mm (compositor->priv->line_numbers_height, GTK_UNIT_POINTS));
	});
}

static gdouble
calculate_header_footer_height (GtkSourcePrintCompositor *compositor,
		                GtkPrintContext          *context,
		                PangoFontDescription     *font,
		                gdouble                  *d)
{
	PangoContext *pango_context;
	PangoFontMetrics* font_metrics;
	gdouble ascent;
	gdouble descent;
	
	pango_context = gtk_print_context_create_pango_context (context);
	pango_context_set_font_description (pango_context, font);
	
	font_metrics = pango_context_get_metrics (pango_context,
						  font,
						  compositor->priv->language);

	ascent = (gdouble) pango_font_metrics_get_ascent (font_metrics) / PANGO_SCALE;
	descent = (gdouble) pango_font_metrics_get_descent (font_metrics) / PANGO_SCALE;

	pango_font_metrics_unref (font_metrics);
	g_object_unref (pango_context);
	
	if (d != NULL)
		*d = descent;
		
	return HEADER_FOOTER_SIZE_FACTOR * (ascent + descent);
}

static void
calculate_header_height (GtkSourcePrintCompositor *compositor,
		         GtkPrintContext          *context)
{
	if (!is_header_to_print(compositor))
	{
		compositor->priv->header_height = 0.0;
	
		DEBUG ({
			g_debug ("header_height: %f points (%f mm)", 
				 compositor->priv->header_height,
				 convert_to_mm (compositor->priv->header_height, GTK_UNIT_POINTS));
		});
		
		return;
	}
	
	g_return_if_fail (compositor->priv->header_font != NULL);
	
	compositor->priv->header_height = calculate_header_footer_height (compositor,
									  context,
									  compositor->priv->header_font,
									  NULL);

	DEBUG ({
		g_debug ("header_height: %f points (%f mm)", 
			 compositor->priv->header_height,
			 convert_to_mm (compositor->priv->header_height, GTK_UNIT_POINTS));
	});									  
}
			         
static void
calculate_footer_height (GtkSourcePrintCompositor *compositor,
		         GtkPrintContext          *context)
{
	if (!is_footer_to_print (compositor))
	{
		compositor->priv->footer_height = 0.0;

		DEBUG ({
			g_debug ("footer_height: %f points (%f mm)", 
				 compositor->priv->footer_height,
				 convert_to_mm (compositor->priv->footer_height, GTK_UNIT_POINTS));
		});
		
		
		return;
	}

	if (compositor->priv->footer_font == NULL)
		compositor->priv->footer_font = pango_font_description_copy_static (compositor->priv->body_font);
	
	compositor->priv->footer_height = calculate_header_footer_height (compositor,
									  context,
									  compositor->priv->footer_font,
									  &compositor->priv->footer_font_descent);
												  
	DEBUG ({
		g_debug ("footer_height: %f points (%f mm)", 
			 compositor->priv->footer_height,
			 convert_to_mm (compositor->priv->footer_height, GTK_UNIT_POINTS));
	});
}

static void
calculate_page_size_and_margins (GtkSourcePrintCompositor *compositor,
			         GtkPrintContext          *context)
{
	GtkPageSetup *page_setup;

	/* calculate_line_numbers_layout_size and calculate_header_footer_height 
	   functions must be called before calculate_page_size_and_margins */	
	g_return_if_fail (compositor->priv->line_numbers_width >= 0.0);
	g_return_if_fail (compositor->priv->header_height >= 0.0);
	g_return_if_fail (compositor->priv->footer_height >= 0.0);			
	
	page_setup = gtk_print_context_get_page_setup (context);

	compositor->priv->page_margin_top = gtk_page_setup_get_top_margin (page_setup, GTK_UNIT_POINTS);
	compositor->priv->page_margin_left = gtk_page_setup_get_left_margin (page_setup, GTK_UNIT_POINTS);
		
	/* Calculate real margins: the margins specified in the GtkPageSetup object are the "print margins".
	   they are used to determine the minimal size for the layout margins. */
	compositor->priv->real_margin_top = MAX (compositor->priv->page_margin_top,
						 convert_from_mm (compositor->priv->margin_top, GTK_UNIT_POINTS));
	compositor->priv->real_margin_bottom = MAX (gtk_page_setup_get_bottom_margin (page_setup, GTK_UNIT_POINTS),
						    convert_from_mm (compositor->priv->margin_bottom, GTK_UNIT_POINTS));
	compositor->priv->real_margin_left = MAX (compositor->priv->page_margin_left,
						  convert_from_mm (compositor->priv->margin_left, GTK_UNIT_POINTS));
	compositor->priv->real_margin_right = MAX (gtk_page_setup_get_right_margin (page_setup, GTK_UNIT_POINTS),
						   convert_from_mm (compositor->priv->margin_right, GTK_UNIT_POINTS));

	DEBUG ({
		g_debug ("real_margin_top: %f points (%f mm)", 
			 compositor->priv->real_margin_top,
			 convert_to_mm (compositor->priv->real_margin_top, GTK_UNIT_POINTS));
		g_debug ("real_margin_bottom: %f points (%f mm)",
			 compositor->priv->real_margin_bottom,
			 convert_to_mm (compositor->priv->real_margin_bottom, GTK_UNIT_POINTS));
		g_debug ("real_margin_left: %f points (%f mm)",
			 compositor->priv->real_margin_left,
			 convert_to_mm (compositor->priv->real_margin_left, GTK_UNIT_POINTS));
		g_debug ("real_margin_righ: %f points (%f mm)",
			 compositor->priv->real_margin_right,
			 convert_to_mm (compositor->priv->real_margin_right, GTK_UNIT_POINTS));
	});

	compositor->priv->paper_width = gtk_page_setup_get_paper_width (page_setup, GTK_UNIT_POINTS);
	compositor->priv->paper_height = gtk_page_setup_get_paper_height (page_setup, GTK_UNIT_POINTS);
	
	DEBUG ({
		gdouble text_width;
		gdouble text_height;
		g_debug ("paper_width: %f points (%f mm)", 
			 compositor->priv->paper_width,
			 convert_to_mm (compositor->priv->paper_width, GTK_UNIT_POINTS));
		g_debug ("paper_heigth: %f points (%f mm)",
			 compositor->priv->paper_height,
			 convert_to_mm (compositor->priv->paper_height, GTK_UNIT_POINTS));
		text_width = get_text_width (compositor);
		text_height = get_text_height (compositor);
		g_debug ("text_width: %f points (%f mm)", text_width, convert_to_mm (text_width, GTK_UNIT_POINTS));
		g_debug ("text_height: %f points (%f mm)", text_height, convert_to_mm (text_height, GTK_UNIT_POINTS));		
		
	});						 
}

/* TODO: maybe we should have a public api to set
 * which tags need to be printed and which should not.
 * For now we special case bracket matches.
 */
static gboolean
ignore_tag (GtkSourcePrintCompositor *compositor,
            GtkTextTag               *tag)
{
	GtkTextTag *bm_tag;

	bm_tag = _gtk_source_buffer_get_bracket_match_tag (compositor->priv->buffer);
	if ((bm_tag != NULL) && (tag == bm_tag))
		return TRUE;

	return FALSE;
}

static GSList *
get_iter_attrs (GtkSourcePrintCompositor *compositor,
		GtkTextIter              *iter,
		GtkTextIter              *limit)
{
	GSList *attrs = NULL;
	GSList *tags;
	PangoAttribute *bg = NULL, *fg = NULL, *style = NULL, *ul = NULL;
	PangoAttribute *weight = NULL, *st = NULL;

	tags = gtk_text_iter_get_tags (iter);
	gtk_text_iter_forward_to_tag_toggle (iter, NULL);

	if (gtk_text_iter_compare (iter, limit) > 0)
		*iter = *limit;

	while (tags)
	{
		GtkTextTag *tag;
		gboolean bg_set, fg_set, style_set, ul_set, weight_set, st_set;

		tag = tags->data;
		tags = g_slist_delete_link (tags, tags);

		if (ignore_tag (compositor, tag))
			continue;

		g_object_get (tag,
			     "background-set", &bg_set,
			     "foreground-set", &fg_set,
			     "style-set", &style_set,
			     "underline-set", &ul_set,
			     "weight-set", &weight_set,
			     "strikethrough-set", &st_set,
			     NULL);

		if (bg_set)
		{
			GdkColor *color = NULL;
			if (bg) pango_attribute_destroy (bg);
			g_object_get (tag, "background-gdk", &color, NULL);
			bg = pango_attr_background_new (color->red, color->green, color->blue);
			gdk_color_free (color);
		}

		if (fg_set)
		{
			GdkColor *color = NULL;
			if (fg) pango_attribute_destroy (fg);
			g_object_get (tag, "foreground-gdk", &color, NULL);
			fg = pango_attr_foreground_new (color->red, color->green, color->blue);
			gdk_color_free (color);
		}

		if (style_set)
		{
			PangoStyle style_value;
			if (style) pango_attribute_destroy (style);
			g_object_get (tag, "style", &style_value, NULL);
			style = pango_attr_style_new (style_value);
		}

		if (ul_set)
		{
			PangoUnderline underline;
			if (ul) pango_attribute_destroy (ul);
			g_object_get (tag, "underline", &underline, NULL);
			ul = pango_attr_underline_new (underline);
		}

		if (weight_set)
		{
			PangoWeight weight_value;
			if (weight) pango_attribute_destroy (weight);
			g_object_get (tag, "weight", &weight_value, NULL);
			weight = pango_attr_weight_new (weight_value);
		}

		if (st_set)
		{
			gboolean strikethrough;
			if (st) pango_attribute_destroy (st);
			g_object_get (tag, "strikethrough", &strikethrough, NULL);
			st = pango_attr_strikethrough_new (strikethrough);
		}
	}

	if (bg)
		attrs = g_slist_prepend (attrs, bg);
	if (fg)
		attrs = g_slist_prepend (attrs, fg);
	if (style)
		attrs = g_slist_prepend (attrs, style);
	if (ul)
		attrs = g_slist_prepend (attrs, ul);
	if (weight)
		attrs = g_slist_prepend (attrs, weight);
	if (st)
		attrs = g_slist_prepend (attrs, st);

	return attrs;
}

static gboolean
is_empty_line (const gchar *text)
{
	if (*text != '\0')
	{
		const gchar *p;

		for (p = text; p != NULL; p = g_utf8_next_char (p))
		{
			if (!g_unichar_isspace (*p))
			{
				return FALSE;
			}
		}
	}

	return TRUE;
}

static void
layout_paragraph (GtkSourcePrintCompositor *compositor,
		  GtkTextIter              *start,
		  GtkTextIter              *end)
{
	gchar *text;

	text = gtk_text_iter_get_slice (start, end);

	/* If it is an empty line (or it just contains tabs) pango has problems:
	 * see for instance comment #22 and #23 on bug #143874 and bug #457990.
	 * We just hack around it by inserting a space... not elegant but
	 * works :-) */
	if (gtk_text_iter_ends_line (start) ||
	    is_empty_line (text))
	{
		pango_layout_set_text (compositor->priv->layout, " ", 1);
		g_free (text);
		return;
	}

	pango_layout_set_text (compositor->priv->layout, text, -1);
	g_free (text);

	if (compositor->priv->highlight_syntax)
	{
		PangoAttrList *attr_list = NULL;
		GtkTextIter segm_start, segm_end;
		int start_index;

		/* Make sure it is highlighted even if it was not shown yet */
		gtk_source_buffer_ensure_highlight (compositor->priv->buffer,
						    start,
						    end);

		segm_start = *start;
		start_index = gtk_text_iter_get_line_index (start);

		while (gtk_text_iter_compare (&segm_start, end) < 0)
		{
			GSList *attrs;
			int si, ei;

			segm_end = segm_start;
			attrs = get_iter_attrs (compositor, &segm_end, end);
			if (attrs)
			{
				si = gtk_text_iter_get_line_index (&segm_start) - start_index;
				ei = gtk_text_iter_get_line_index (&segm_end) - start_index;
			}

			while (attrs)
			{
				PangoAttribute *a = attrs->data;

				a->start_index = si;
				a->end_index = ei;

				if (!attr_list)
					attr_list = pango_attr_list_new ();

				pango_attr_list_insert (attr_list, a);

				attrs = g_slist_delete_link (attrs, attrs);
			}

			segm_start = segm_end;
		}

		pango_layout_set_attributes (compositor->priv->layout,
					     attr_list);

		if (attr_list)
			pango_attr_list_unref (attr_list);
	}
}

static gboolean
line_is_numbered (GtkSourcePrintCompositor *compositor,
		  gint                      line_number)
{
	return (compositor->priv->print_line_numbers > 0) &&
	       ((line_number + 1) % compositor->priv->print_line_numbers == 0);
}

static void
set_pango_layouts_width (GtkSourcePrintCompositor *compositor)
{
	g_return_if_fail (compositor->priv->layout != NULL);
	pango_layout_set_width (compositor->priv->layout,
				get_text_width (compositor) * PANGO_SCALE);

	if (compositor->priv->print_line_numbers)
	{
		g_return_if_fail (compositor->priv->line_numbers_layout != NULL);
		pango_layout_set_width (compositor->priv->line_numbers_layout,
					compositor->priv->line_numbers_width * PANGO_SCALE);
	}
}

/* If you want
   to use the ::paginate signal to perform pagination in async way, it is suggested to
   ensure the buffer is not modified until pagination terminates. */

/**
 * gtk_source_print_compositor_paginate:
 * @compositor: a #GtkSourcePrintCompositor.
 * @context: the #GtkPrintContext whose parameters (e.g. paper size, print margins, etc.) 
 * are used by the the @compositor to paginate the document.
 *
 * Paginate the document associated with the @compositor.
 *
 * In order to support non-blocking pagination, document is paginated in small chunks.
 * Each time gtk_source_print_compositor_paginate() is invoked, a chunk of the document 
 * is paginated. To paginate the entire document, gtk_source_print_compositor_paginate() 
 * must be invoked multiple times.
 * It returns %TRUE if the document has been completely paginated, otherwise it returns %FALSE.
 *
 * This method has been designed to be invoked in the handler of the #GtkPrintOperation::paginate signal,
 * as shown in the following example:
 *
 * <informalexample><programlisting>
 * // Signal handler for the GtkPrintOperation::paginate signal
 * 
 * static gboolean
 * paginate (GtkPrintOperation *operation,
 *           GtkPrintContext   *context,
 *           gpointer           user_data)
 * {
 *     GtkSourcePrintCompositor *compositor;
 *
 *     compositor = GTK_SOURCE_PRINT_COMPOSITOR (user_data);
 *
 *     if (gtk_source_print_compositor_paginate (compositor, context))
 *     {
 *         gint n_pages;
 *         
 *         n_pages = gtk_source_print_compositor_get_n_pages (compositor);
 *         gtk_print_operation_set_n_pages (operation, n_pages);
 *
 *         return TRUE;
 *     }
 *      
 *     return FALSE;
 * }
 * </programlisting></informalexample>
 *
 * If you don't need to do pagination in chunks, you can simply do it all in the 
 * #GtkPrintOperation::begin-print handler, and set the number of pages from there, like
 * in the following example:
 *
 * <informalexample><programlisting>
 * // Signal handler for the GtkPrintOperation::begin-print signal
 * 
 * static void
 * begin_print (GtkPrintOperation *operation,
 *              GtkPrintContext   *context,
 *              gpointer           user_data)
 * {
 *     GtkSourcePrintCompositor *compositor;
 *     gint n_pages;
 *
 *     compositor = GTK_SOURCE_PRINT_COMPOSITOR (user_data);
 *
 *     while (!gtk_source_print_compositor_paginate (compositor, context));
 * 
 *     n_pages = gtk_source_print_compositor_get_n_pages (compositor);
 *     gtk_print_operation_set_n_pages (operation, n_pages);
 * }
 * </programlisting></informalexample>
 *
 * Return value: %TRUE if the document has been completely paginated, %FALSE otherwise.
 *
 * Since: 2.2
 */
gboolean
gtk_source_print_compositor_paginate (GtkSourcePrintCompositor *compositor,
				      GtkPrintContext          *context)
{	
	GtkTextIter start, end;
	gint page_start_offset;
	double text_height;
	double cur_height;
	
	gboolean done;
	gint pages_count;

	g_return_val_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor), TRUE);
	g_return_val_if_fail (GTK_IS_PRINT_CONTEXT (context), TRUE);
	
	if (compositor->priv->state == DONE)
		return TRUE;

	if (compositor->priv->state == INIT)
	{
		PROFILE ({
			if (pagination_timer != NULL)
				g_timer_destroy (pagination_timer);
				
			pagination_timer = g_timer_new ();
		});
		
		g_return_val_if_fail (compositor->priv->pages == NULL, TRUE);

		compositor->priv->pages = g_array_new (FALSE, FALSE, sizeof (gint));

		setup_pango_layouts (compositor, context);

		calculate_line_numbers_layout_size (compositor, context);
		calculate_footer_height (compositor, context);
		calculate_header_height (compositor, context);
		calculate_page_size_and_margins (compositor, context);

		/* Set layouts width otherwise "aligh right" does not work as expected */
		/* Cannot be done when setting up layouts since we need the width */
		set_pango_layouts_width (compositor);		
		
		compositor->priv->state = PAGINATING;
	}

	g_return_val_if_fail (compositor->priv->state == PAGINATING, FALSE);
	g_return_val_if_fail (compositor->priv->layout != NULL, FALSE);

	if (compositor->priv->pagination_mark == NULL)
	{
		gtk_text_buffer_get_start_iter (GTK_TEXT_BUFFER (compositor->priv->buffer), &start);
		
		compositor->priv->pagination_mark = gtk_text_buffer_create_mark (GTK_TEXT_BUFFER (compositor->priv->buffer),
										 NULL,
										 &start,
										 TRUE);
										 
		/* add the first page start */
		page_start_offset = gtk_text_iter_get_offset (&start);
		g_array_append_val (compositor->priv->pages, page_start_offset);
	}
	else
	{
		gtk_text_buffer_get_iter_at_mark (GTK_TEXT_BUFFER (compositor->priv->buffer),
						  &start,
						  compositor->priv->pagination_mark);
	}
	
	DEBUG ({
		g_debug ("Start paginating at %d", gtk_text_iter_get_offset (&start));
	});
		
	gtk_text_buffer_get_end_iter (GTK_TEXT_BUFFER (compositor->priv->buffer), &end);

	cur_height = 0;
	text_height = get_text_height (compositor);

	done = gtk_text_iter_compare (&start, &end) >= 0;
	pages_count = 0;
	
	while (!done && (pages_count < PAGINATION_CHUNK_SIZE))
	{
		gint line_number;
		GtkTextIter line_end;
		gdouble line_height;
		
		line_number = gtk_text_iter_get_line (&start);

		line_end = start;
		if (!gtk_text_iter_ends_line (&line_end))
			gtk_text_iter_forward_to_line_end (&line_end);

		layout_paragraph (compositor, &start, &line_end);

		get_layout_size (compositor->priv->layout, NULL, &line_height);

		if (line_is_numbered (compositor, line_number))
		{
			g_assert (compositor->priv->line_numbers_height > 0);

			line_height = MAX (line_height,
					   compositor->priv->line_numbers_height);
		}

#define EPS (.1)
		if (cur_height + line_height > text_height + EPS)
		{
			/* if we have multiline paragraphs, see how much of
			 * it we can fit in the current page */
			if (compositor->priv->wrap_mode != GTK_WRAP_NONE &&
			    pango_layout_get_line_count (compositor->priv->layout) > 1)
			{
				PangoLayoutIter *layout_iter;
				PangoRectangle logical_rect;
				gboolean is_first_line = TRUE;
				double part_height = 0;
				gint idx;

				layout_iter = pango_layout_get_iter (compositor->priv->layout);

				do
				{
					double layout_line_height;

					pango_layout_iter_get_line_extents (layout_iter, NULL, &logical_rect);
					layout_line_height = logical_rect.height / PANGO_SCALE;

					if (is_first_line &&
					    line_is_numbered (compositor, line_number))
					{
						layout_line_height = MAX (compositor->priv->line_numbers_height,
									  layout_line_height);
					}

					if (cur_height + part_height + layout_line_height > text_height + EPS)
						break;

					part_height += layout_line_height;
					is_first_line = FALSE;
				}
				while (pango_layout_iter_next_line (layout_iter));

				/* move our start iter to the page break:
				 * note that text_iter_set_index mesures from
				 * the start of the line, while our layout
				 * may start in the middle of a line, so we have
				 * to add.
				 */
				idx = gtk_text_iter_get_line_index (&start);
				idx += pango_layout_iter_get_index (layout_iter);
				gtk_text_iter_set_line_index (&start, idx);

				pango_layout_iter_free (layout_iter);

				page_start_offset = gtk_text_iter_get_offset (&start);

				gtk_text_buffer_move_mark (GTK_TEXT_BUFFER (compositor->priv->buffer),
							   compositor->priv->pagination_mark,
							   &start);

				/* if the remainder fits on the next page, go
				 * on to the next line, otherwise restart pagination
				 * from the page break we found */
				if (line_height - part_height > text_height + EPS)
				{
					cur_height = 0;
				}
				else
				{
					/* reset cur_height for the next page */
					cur_height = line_height - part_height;
					gtk_text_iter_forward_line (&start);
				}
			}
			else
			{
				page_start_offset = gtk_text_iter_get_offset (&start);
   
				gtk_text_buffer_move_mark (GTK_TEXT_BUFFER (compositor->priv->buffer),
							   compositor->priv->pagination_mark,
							   &start);

				/* reset cur_height for the next page */
				cur_height = line_height;
				gtk_text_iter_forward_line (&start);
			}

			/* store the start of the new page */
			g_array_append_val (compositor->priv->pages,
					    page_start_offset);
	      
			++pages_count;
		}
		else
		{
			cur_height += line_height;
			gtk_text_iter_forward_line (&start);
		}
		
		done = gtk_text_iter_compare (&start, &end) >= 0;
	}
#undef EPS

	if (done) 
	{
		PROFILE ({	
			g_debug ("Paginated in %f seconds:\n", g_timer_elapsed (pagination_timer, NULL));

			g_timer_destroy (pagination_timer);
			pagination_timer = NULL;
		});
	
		DEBUG ({
			int i;

			for (i = 0; i < compositor->priv->pages->len; i += 1)
			{
				gint offset;
				GtkTextIter iter;

				offset = g_array_index (compositor->priv->pages, int, i);
				gtk_text_buffer_get_iter_at_offset (GTK_TEXT_BUFFER (compositor->priv->buffer), &iter, offset);

				g_debug ("  page %d starts at line %d (offset %d)\n", i, gtk_text_iter_get_line (&iter), offset); 
			}
		});

		compositor->priv->state = DONE;

		compositor->priv->n_pages = compositor->priv->pages->len;
		
		/* Remove the pagination mark */
		gtk_text_buffer_delete_mark (GTK_TEXT_BUFFER (compositor->priv->buffer),
					     compositor->priv->pagination_mark);
		compositor->priv->pagination_mark = NULL;
	}
	
	return (done != FALSE);
}

/**
 * gtk_source_print_compositor_get_pagination_progress:
 * @compositor: a #GtkSourcePrintCompositor.
 *
 * Returns the current fraction of the document pagination that has been completed.
 *
 * Return value: a fraction from 0.0 to 1.0 inclusive.
 *
 * Since: 2.2
 */
gdouble
gtk_source_print_compositor_get_pagination_progress (GtkSourcePrintCompositor *compositor)
{
	GtkTextIter current;
	gint char_count;

	g_return_val_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor), 0.0);

	if (compositor->priv->state == INIT)
		return 0.0;

	if (compositor->priv->state == DONE)
		return 1.0;

	char_count = gtk_text_buffer_get_char_count (GTK_TEXT_BUFFER (compositor->priv->buffer));
	if (char_count == 0)
		return 1.0;

	g_return_val_if_fail (compositor->priv->pagination_mark != NULL, 0.0);
	
	gtk_text_buffer_get_iter_at_mark (GTK_TEXT_BUFFER (compositor->priv->buffer),
					  &current,
					  compositor->priv->pagination_mark);

	return (gdouble) gtk_text_iter_get_offset (&current) / (gdouble) char_count;
}

static void
print_header_string (GtkSourcePrintCompositor *compositor,
		     cairo_t                  *cr,		
		     PangoAlignment            alignment,
		     const gchar              *format)
{
	gchar *text;
			
	text = evaluate_format_string (compositor, format);
	if (text != NULL)
	{		
		PangoLayoutLine* line;		
		gdouble	baseline;
		PangoLayoutIter *iter;
		
		gdouble layout_width;
		gdouble layout_height;		
		gdouble header_width;
		gdouble x;
		
		header_width = compositor->priv->paper_width - 
			       compositor->priv->real_margin_left -
			       compositor->priv->real_margin_right;
						
		pango_layout_set_text (compositor->priv->header_layout, text, -1);
		
		/* Print only the first line */
		iter = pango_layout_get_iter (compositor->priv->header_layout);
		baseline = (gdouble) pango_layout_iter_get_baseline (iter) / (gdouble) PANGO_SCALE;
		
		get_layout_size (compositor->priv->header_layout, &layout_width, &layout_height);

		switch (alignment)
		{
			case PANGO_ALIGN_RIGHT:
				x = compositor->priv->real_margin_left + header_width - layout_width;
				break;
				
			case PANGO_ALIGN_CENTER:
				x = compositor->priv->real_margin_left + header_width / 2 - layout_width / 2;
				break;
				
			case PANGO_ALIGN_LEFT:
			default:
				x = compositor->priv->real_margin_left;
				break;
		}	
				
		DEBUG ({
			cairo_save (cr);

			cairo_set_line_width (cr, 1.);
			cairo_set_source_rgb (cr, 0., 0., 1.);
			cairo_rectangle (cr,
					 x,
					 compositor->priv->real_margin_top,
					 layout_width,
					 layout_height);
			cairo_stroke (cr);

			cairo_restore (cr);
		});

		line = pango_layout_iter_get_line_readonly (iter);

		cairo_move_to (cr,
			       x, 
			       compositor->priv->real_margin_top + baseline);
		
		pango_cairo_show_layout_line (cr, line);

		pango_layout_iter_free (iter);		
		g_free (text);
	}
}

static void 
print_header (GtkSourcePrintCompositor *compositor,
	      cairo_t                  *cr)
{
	pango_cairo_update_layout (cr, compositor->priv->header_layout);
	
	/* left format */
	if (compositor->priv->header_format_left != NULL)
		print_header_string (compositor, 
				     cr,					    
				     PANGO_ALIGN_LEFT,
				     compositor->priv->header_format_left);
	
	/* right format */
	if (compositor->priv->header_format_right != NULL)
		print_header_string (compositor, 
				     cr,					    
				     PANGO_ALIGN_RIGHT,
				     compositor->priv->header_format_right);

	/* center format */
	if (compositor->priv->header_format_center != NULL) 
		print_header_string (compositor, 
				     cr,					    
				     PANGO_ALIGN_CENTER,
				     compositor->priv->header_format_center);
	
	/* separator */
	if (compositor->priv->header_separator)
	{
		gdouble y = compositor->priv->real_margin_top + 
			    (1 - SEPARATOR_SPACING_FACTOR) * compositor->priv->header_height;

		cairo_save (cr);
	
		cairo_move_to (cr, compositor->priv->real_margin_left, y);
		cairo_set_line_width (cr, SEPARATOR_LINE_WIDTH);
		cairo_line_to (cr, compositor->priv->paper_width - compositor->priv->real_margin_right, y);
		cairo_stroke (cr);

		cairo_restore (cr);
	}
}

static void
print_footer_string (GtkSourcePrintCompositor *compositor,
		     cairo_t                  *cr,		
		     PangoAlignment            alignment,
		     const gchar              *format)
{
	gchar *text;
			
	text = evaluate_format_string (compositor, format);
	if (text != NULL)
	{		
		PangoLayoutLine* line;		
		
		gdouble layout_width;
		gdouble layout_height;		
		gdouble footer_width;
		gdouble x;
		
		footer_width = compositor->priv->paper_width - 
			       compositor->priv->real_margin_left -
			       compositor->priv->real_margin_right;
			       		
		pango_layout_set_text (compositor->priv->footer_layout, text, -1);

		get_layout_size (compositor->priv->footer_layout, &layout_width, &layout_height);

		switch (alignment)
		{
			case PANGO_ALIGN_RIGHT:
				x = compositor->priv->real_margin_left + footer_width - layout_width;
				break;
				
			case PANGO_ALIGN_CENTER:
				x = compositor->priv->real_margin_left + footer_width / 2 - layout_width / 2;
				break;
				
			case PANGO_ALIGN_LEFT:
			default:
				x = compositor->priv->real_margin_left;
				break;
		}	
		/* Print only the first line */
		line = pango_layout_get_line (compositor->priv->footer_layout, 0);

		DEBUG ({
			gdouble w;
			gdouble h;
			
			get_layout_size (compositor->priv->footer_layout, &w, &h);
			
			cairo_save (cr);
			cairo_set_line_width (cr, 1.);
			cairo_set_source_rgb (cr, 0., 0., 1.);
			cairo_rectangle (cr,
					 x,
					 compositor->priv->paper_height - compositor->priv->real_margin_bottom - h,
					 layout_width,
					 layout_height);
			cairo_stroke (cr);
			cairo_restore (cr);
		});
					
		cairo_move_to (cr,
			       x, 
			       compositor->priv->paper_height - 
			       	compositor->priv->real_margin_bottom - compositor->priv->footer_font_descent);
		
		pango_cairo_show_layout_line (cr, line);
	
		g_free (text);
	}
}

static void 
print_footer (GtkSourcePrintCompositor *compositor,
	      cairo_t                  *cr)
{
	pango_cairo_update_layout (cr, compositor->priv->footer_layout);
	
	/* left format */
	if (compositor->priv->footer_format_left != NULL)
		print_footer_string (compositor, 
				     cr,					    
				     PANGO_ALIGN_LEFT,
				     compositor->priv->footer_format_left);
	
	/* right format */
	if (compositor->priv->footer_format_right != NULL)
		print_footer_string (compositor, 
				     cr,					    
				     PANGO_ALIGN_RIGHT,
				     compositor->priv->footer_format_right);

	/* center format */
	if (compositor->priv->footer_format_center != NULL) 
		print_footer_string (compositor, 
				     cr,					    
				     PANGO_ALIGN_CENTER,
				     compositor->priv->footer_format_center);
	
	/* separator */
	if (compositor->priv->footer_separator)
	{
		gdouble y = compositor->priv->paper_height - 
			    compositor->priv->real_margin_bottom -
			    (1 - SEPARATOR_SPACING_FACTOR) * compositor->priv->footer_height;

		cairo_save (cr);

		cairo_move_to (cr, compositor->priv->real_margin_left, y);
		cairo_set_line_width (cr, SEPARATOR_LINE_WIDTH);
		cairo_line_to (cr, compositor->priv->paper_width - compositor->priv->real_margin_right, y);
		cairo_stroke (cr);

		cairo_restore (cr);
	}
}

/**
 * gtk_source_print_compositor_draw_page:
 * @compositor: a #GtkSourcePrintCompositor.
 * @context: the #GtkPrintContext encapsulating the context information that is required when 
 *           drawing the page for printing.
 * @page_nr: the number of the page to print.
 *
 * Draw page @page_nr for printing on the the Cairo context encapsuled in @context.
 *
 * This method has been designed to be called in the handler of the #GtkPrintOperation::draw_page signal
 * as shown in the following example:
 *
 * <informalexample><programlisting>
 * // Signal handler for the GtkPrintOperation::draw_page signal
 * 
 * static void
 * draw_page (GtkPrintOperation *operation,
 *            GtkPrintContext   *context,
 *            gint               page_nr,
 *            gpointer           user_data)
 * {
 *     GtkSourcePrintCompositor *compositor;
 *
 *     compositor = GTK_SOURCE_PRINT_COMPOSITOR (user_data);
 *
 *     gtk_source_print_compositor_draw_page (compositor, 
 *                                            context,
 *                                            page_nr);
 * }
 * </programlisting></informalexample>
 */ 
void
gtk_source_print_compositor_draw_page (GtkSourcePrintCompositor *compositor,
				       GtkPrintContext          *context,
				       gint                      page_nr)
{
	cairo_t *cr;
	GtkTextIter start, end;
	gint offset;
	double x, y, ln_x;

	g_return_if_fail (GTK_SOURCE_IS_PRINT_COMPOSITOR (compositor));
	g_return_if_fail (GTK_IS_PRINT_CONTEXT (context));
	g_return_if_fail (page_nr >= 0);

	compositor->priv->current_page = page_nr;

	cr = gtk_print_context_get_cairo_context (context);
	cairo_set_source_rgb (cr, 0, 0, 0);
	cairo_translate (cr, 
			 -1 * compositor->priv->page_margin_left,
			 -1 * compositor->priv->page_margin_top);

	if (is_header_to_print (compositor))
	{
		print_header (compositor, cr);
	}

	if (is_footer_to_print (compositor))
	{
		print_footer (compositor, cr);
	}

	x = get_text_x (compositor);
	y = get_text_y (compositor);
	ln_x = get_line_numbers_x (compositor);

	DEBUG ({
		cairo_save (cr);
		
		cairo_set_line_width (cr, 1.);
		cairo_set_source_rgb (cr, 0., 0., 1.);
		cairo_rectangle (cr,
				 compositor->priv->real_margin_left, 
				 compositor->priv->real_margin_top,
				 compositor->priv->paper_width - 
				 	compositor->priv->real_margin_left - compositor->priv->real_margin_right,
				 compositor->priv->paper_height - 
				 	compositor->priv->real_margin_top - compositor->priv->real_margin_bottom);
		cairo_stroke (cr);
		
		cairo_set_source_rgb (cr, 1., 0., 0.);
		cairo_rectangle (cr,
				 ln_x, y,
				 compositor->priv->line_numbers_width,
				 get_text_height (compositor));
		cairo_stroke (cr);
		
		cairo_set_source_rgb (cr, 0., 1., 0.);
		cairo_rectangle (cr,
				 x, y,
				 get_text_width (compositor),
				 get_text_height (compositor));
		cairo_stroke (cr);

		cairo_set_source_rgb (cr, 1., 0., 0.);
		cairo_rectangle (cr,
				 0, 0,
				 compositor->priv->paper_width,
				 compositor->priv->paper_height);
		cairo_stroke (cr);
		
		cairo_restore (cr);
	});

	g_return_if_fail (compositor->priv->layout != NULL);
	pango_cairo_update_layout (cr, compositor->priv->layout);
	
	if (compositor->priv->print_line_numbers) 
	{
		g_return_if_fail (compositor->priv->line_numbers_layout != NULL);	
		pango_cairo_update_layout (cr, compositor->priv->line_numbers_layout);
	}

	g_return_if_fail (compositor->priv->buffer != NULL);
	g_return_if_fail (compositor->priv->pages != NULL);
	g_return_if_fail ((guint) page_nr < compositor->priv->pages->len);

	offset = g_array_index (compositor->priv->pages, int, page_nr);
	gtk_text_buffer_get_iter_at_offset (GTK_TEXT_BUFFER (compositor->priv->buffer),
					    &start, offset);

	if ((guint) page_nr + 1 < compositor->priv->pages->len)
	{
		offset = g_array_index (compositor->priv->pages, int, page_nr + 1);
		gtk_text_buffer_get_iter_at_offset (GTK_TEXT_BUFFER (compositor->priv->buffer),
						    &end, offset);
	}
	else
	{
		gtk_text_buffer_get_end_iter (GTK_TEXT_BUFFER (compositor->priv->buffer),
					      &end);
	}

	while (gtk_text_iter_compare (&start, &end) < 0)
	{
		GtkTextIter line_end;
		gint line_number;
		double line_height;
		double baseline_offset;

		line_end = start;
		if (!gtk_text_iter_ends_line (&line_end))
			gtk_text_iter_forward_to_line_end (&line_end);
		if (gtk_text_iter_compare (&line_end, &end) > 0)
			line_end = end;

		if (gtk_text_iter_starts_line (&start)) 
		{
			line_number = gtk_text_iter_get_line (&start);
		}
		else
		{
			/* This happens only if the first line of the page 
			 * is the continuation of the last line of the previous page.
			 * In this case the line numbers must not be print
			 */
			line_number = -1;
		}

		layout_paragraph (compositor, &start, &line_end);

		get_layout_size (compositor->priv->layout, NULL, &line_height);

		baseline_offset = 0;

		/* print the line number if needed */
		if ((line_number >= 0) && line_is_numbered (compositor, line_number))
		{
			PangoLayoutIter *iter;
			double baseline;
			double ln_baseline;
			double ln_baseline_offset;
			gchar *str;

			str = g_strdup_printf ("%d", line_number + 1);	
			pango_layout_set_text (compositor->priv->line_numbers_layout, str, -1);
			g_free (str);

			/* Adjust the baseline */
			iter = pango_layout_get_iter (compositor->priv->layout);
			baseline = (double) pango_layout_iter_get_baseline (iter) / (double) PANGO_SCALE;
			pango_layout_iter_free (iter);

			iter = pango_layout_get_iter (compositor->priv->line_numbers_layout);
			ln_baseline = (double) pango_layout_iter_get_baseline (iter) / (double) PANGO_SCALE;
			pango_layout_iter_free (iter);

			ln_baseline_offset = baseline - ln_baseline;

			if (ln_baseline_offset < 0)
			{
				baseline_offset = -ln_baseline_offset;
				ln_baseline_offset =  0;
			}

			cairo_move_to (cr, ln_x, y + ln_baseline_offset);
			
			g_return_if_fail (compositor->priv->line_numbers_layout != NULL);
			pango_cairo_show_layout (cr, compositor->priv->line_numbers_layout);
		}

		cairo_move_to (cr, x, y + baseline_offset);
		pango_cairo_show_layout (cr, compositor->priv->layout);

		line_height = MAX (line_height,
				   compositor->priv->line_numbers_height);

		y += line_height;
		gtk_text_iter_forward_line (&start);
	}
}

