/*
 * Copyright (C) 2003,2008 Red Hat, Inc.
 *
 * This library 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.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * 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 Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include "config.h"

#include <math.h>
#include <stdlib.h>
#include <string.h>
#include <sys/param.h> /* howmany() */

#include <glib.h>
#include <gtk/gtk.h>

#include "vtedraw.hh"
#include "vtedefines.hh"
#include "debug.h"

#include <pango/pangocairo.h>

/* Have a space between letters to make sure ligatures aren't used when caching the glyphs: bug 793391. */
#define VTE_DRAW_SINGLE_WIDE_CHARACTERS	\
					"  ! \" # $ % & ' ( ) * + , - . / " \
					"0 1 2 3 4 5 6 7 8 9 " \
					": ; < = > ? @ " \
					"A B C D E F G H I J K L M N O P Q R S T U V W X Y Z " \
					"[ \\ ] ^ _ ` " \
					"a b c d e f g h i j k l m n o p q r s t u v w x y z " \
					"{ | } ~ " \
					""

static inline bool
_vte_double_equal(double a,
                  double b)
{
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wfloat-equal"
        return a == b;
#pragma GCC diagnostic pop
}

/* Overview:
 *
 *
 * This file implements vte rendering using pangocairo.  Note that this does
 * NOT implement any kind of complex text rendering.  That's not currently a
 * goal.
 *
 * The aim is to be super-fast and avoid unneeded work as much as possible.
 * Here is an overview of how that is accomplished:
 *
 *   - We attach a font_info to the draw.  A font_info has all the information
 *     to quickly draw text.
 *
 *   - A font_info keeps uses unistr_font_info structs that represent all
 *     information needed to quickly draw a single vteunistr.  The font_info
 *     creates those unistr_font_info structs on demand and caches them
 *     indefinitely.  It uses a direct array for the ASCII range and a hash
 *     table for the rest.
 *
 *
 * Fast rendering of unistrs:
 *
 * A unistr_font_info (uinfo) calls Pango to set text for the unistr upon
 * initialization and then caches information needed to draw the results
 * later.  It uses three different internal representations and respectively
 * three drawing paths:
 *
 *   - COVERAGE_USE_CAIRO_GLYPH:
 *     Keeping a single glyph index and a cairo scaled-font.  This is the
 *     fastest way to draw text as it bypasses Pango completely and allows
 *     for stuffing multiple glyphs into a single cairo_show_glyphs() request
 *     (if scaled-fonts match).  This method is used if the glyphs used for
 *     the vteunistr as determined by Pango consists of a single regular glyph
 *     positioned at 0,0 using a regular font.  This method is used for more
 *     than 99% of the cases.  Only exceptional cases fall through to the
 *     other two methods.
 *
 *   - COVERAGE_USE_PANGO_GLYPH_STRING:
 *     Keeping a pango glyphstring and a pango font.  This is slightly slower
 *     than the previous case as drawing each glyph goes through pango
 *     separately and causes a separate cairo_show_glyphs() call.  This method
 *     is used when the previous method cannot be used but the glyphs for the
 *     character all use a single font.  This is the method used for hexboxes
 *     and "empty" characters like U+200C ZERO WIDTH NON-JOINER for example.
 *
 *   - COVERAGE_USE_PANGO_LAYOUT_LINE:
 *     Keeping a pango layout line.  This method is used only in the very
 *     weird and exceptional case that a single vteunistr uses more than one
 *     font to be drawn.  This happens for example if some diacretics is not
 *     available in the font chosen for the base character.
 *
 *
 * Caching of font infos:
 *
 * To avoid recreating font info structs for the same font again and again we
 * do the following:
 *
 *   - Use a global cache to share font info structs across different widgets.
 *     We use pango language, cairo font options, resolution, and font description
 *     as the key for our hash table.
 *
 *   - When a font info struct is no longer used by any widget, we delay
 *     destroying it for a while (FONT_CACHE_TIMEOUT seconds).  This is
 *     supposed to serve two purposes:
 *
 *       * Destroying a terminal widget and creating it again right after will
 *         reuse the font info struct from the previous widget.
 *
 *       * Zooming in and out a terminal reuses the font info structs.
 *
 *
 * Pre-caching ASCII letters:
 *
 * When initializing a font info struct we measure a string consisting of all
 * ASCII letters and some other ASCII characters.  Since we have a shaped pango
 * layout at hand, we walk over it and cache unistr font info for the ASCII
 * letters if we can do that easily using COVERAGE_USE_CAIRO_GLYPH.  This
 * means that we precache all ASCII letters without any extra pango shaping
 * involved.
 */



#define FONT_CACHE_TIMEOUT (30) /* seconds */


/* All shared data structures are implicitly protected by GDK mutex, because
 * that's how vte.c works and we only get called from there. */


/* cairo_show_glyphs accepts runs up to 102 glyphs before it allocates a
 * temporary array.
 *
 * Setting this to a large value can cause dramatic slow-downs for some
 * xservers (notably fglrx), see bug #410534.
 */
#define MAX_RUN_LENGTH 100


enum unistr_coverage {
	/* in increasing order of speed */
	COVERAGE_UNKNOWN = 0,		/* we don't know about the character yet */
	COVERAGE_USE_PANGO_LAYOUT_LINE,	/* use a PangoLayoutLine for the character */
	COVERAGE_USE_PANGO_GLYPH_STRING,	/* use a PangoGlyphString for the character */
	COVERAGE_USE_CAIRO_GLYPH	/* use a cairo_glyph_t for the character */
};

union unistr_font_info {
	/* COVERAGE_USE_PANGO_LAYOUT_LINE */
	struct {
		PangoLayoutLine *line;
	} using_pango_layout_line;
	/* COVERAGE_USE_PANGO_GLYPH_STRING */
	struct {
		PangoFont *font;
		PangoGlyphString *glyph_string;
	} using_pango_glyph_string;
	/* COVERAGE_USE_CAIRO_GLYPH */
	struct {
		cairo_scaled_font_t *scaled_font;
		unsigned int glyph_index;
	} using_cairo_glyph;
};

struct unistr_info {
	guchar coverage;
	guchar has_unknown_chars;
	guint16 width;
	union unistr_font_info ufi;
};

static struct unistr_info *
unistr_info_create (void)
{
	return g_slice_new0 (struct unistr_info);
}

static void
unistr_info_finish (struct unistr_info *uinfo)
{
	union unistr_font_info *ufi = &uinfo->ufi;

	switch (uinfo->coverage) {
	default:
	case COVERAGE_UNKNOWN:
		break;
	case COVERAGE_USE_PANGO_LAYOUT_LINE:
		/* we hold a manual reference on layout */
		g_object_unref (ufi->using_pango_layout_line.line->layout);
		ufi->using_pango_layout_line.line->layout = NULL;
		pango_layout_line_unref (ufi->using_pango_layout_line.line);
		ufi->using_pango_layout_line.line = NULL;
		break;
	case COVERAGE_USE_PANGO_GLYPH_STRING:
		if (ufi->using_pango_glyph_string.font)
			g_object_unref (ufi->using_pango_glyph_string.font);
		ufi->using_pango_glyph_string.font = NULL;
		pango_glyph_string_free (ufi->using_pango_glyph_string.glyph_string);
		ufi->using_pango_glyph_string.glyph_string = NULL;
		break;
	case COVERAGE_USE_CAIRO_GLYPH:
		cairo_scaled_font_destroy (ufi->using_cairo_glyph.scaled_font);
		ufi->using_cairo_glyph.scaled_font = NULL;
		break;
	}
}

static void
unistr_info_destroy (struct unistr_info *uinfo)
{
	unistr_info_finish (uinfo);
	g_slice_free (struct unistr_info, uinfo);
}

struct font_info {
	/* lifecycle */
	int ref_count;
	guint destroy_timeout; /* only used when ref_count == 0 */

	/* reusable layout set with font and everything set */
	PangoLayout *layout;

	/* cache of character info */
	struct unistr_info ascii_unistr_info[128];
	GHashTable *other_unistr_info;

        /* cell metrics as taken from the font, not yet scaled by cell_{width,height}_scale */
	gint width, height, ascent;

	/* reusable string for UTF-8 conversion */
	GString *string;

#ifdef VTE_DEBUG
	/* profiling info */
	int coverage_count[4];
#endif
};


static struct unistr_info *
font_info_find_unistr_info (struct font_info    *info,
			    vteunistr            c)
{
	struct unistr_info *uinfo;

	if (G_LIKELY (c < G_N_ELEMENTS (info->ascii_unistr_info)))
		return &info->ascii_unistr_info[c];

	if (G_UNLIKELY (info->other_unistr_info == NULL))
		info->other_unistr_info = g_hash_table_new_full (NULL, NULL, NULL, (GDestroyNotify) unistr_info_destroy);

	uinfo = (struct unistr_info *)g_hash_table_lookup (info->other_unistr_info, GINT_TO_POINTER (c));
	if (G_LIKELY (uinfo))
		return uinfo;

	uinfo = unistr_info_create ();
	g_hash_table_insert (info->other_unistr_info, GINT_TO_POINTER (c), uinfo);
	return uinfo;
}


static void
font_info_cache_ascii (struct font_info *info)
{
	PangoLayoutLine *line;
	PangoGlyphItemIter iter;
	PangoGlyphItem *glyph_item;
	PangoGlyphString *glyph_string;
	PangoFont *pango_font;
	cairo_scaled_font_t *scaled_font;
	const char *text;
	gboolean more;
	PangoLanguage *language;
	gboolean latin_uses_default_language;
	
	/* We have info->layout holding most ASCII characters.  We want to
	 * cache as much info as we can about the ASCII letters so we don't
	 * have to look them up again later */

	/* Don't cache if unknown glyphs found in layout */
	if (pango_layout_get_unknown_glyphs_count (info->layout) != 0)
		return;

	language = pango_context_get_language (pango_layout_get_context (info->layout));
	if (language == NULL)
		language = pango_language_get_default ();
	latin_uses_default_language = pango_language_includes_script (language, PANGO_SCRIPT_LATIN);

	text = pango_layout_get_text (info->layout);

	line = pango_layout_get_line_readonly (info->layout, 0);

	/* Don't cache if more than one font used for the line */
	if (G_UNLIKELY (!line || !line->runs || line->runs->next))
		return;

	glyph_item = (PangoGlyphItem *)line->runs->data;
	glyph_string = glyph_item->glyphs;
	pango_font = glyph_item->item->analysis.font;
	if (!pango_font)
		return;
	scaled_font = pango_cairo_font_get_scaled_font ((PangoCairoFont *) pango_font);
	if (!scaled_font)
		return;

	for (more = pango_glyph_item_iter_init_start (&iter, glyph_item, text);
	     more;
	     more = pango_glyph_item_iter_next_cluster (&iter))
	{
		struct unistr_info *uinfo;
		union unistr_font_info *ufi;
	 	PangoGlyphGeometry *geometry;
		PangoGlyph glyph;
		vteunistr c;

		/* Only cache simple clusters */
		if (iter.start_char +1 != iter.end_char  ||
		    iter.start_index+1 != iter.end_index ||
		    iter.start_glyph+1 != iter.end_glyph)
			continue;

		c = text[iter.start_index];
		glyph = glyph_string->glyphs[iter.start_glyph].glyph;
		geometry = &glyph_string->glyphs[iter.start_glyph].geometry;

		/* If not using the default locale language, only cache non-common
		 * characters as common characters get their font from their neighbors
		 * and we don't want to force Latin on them. */
		if (!latin_uses_default_language &&
		    pango_script_for_unichar (c) <= PANGO_SCRIPT_INHERITED)
			continue;

		/* Only cache simple glyphs */
		if (!(glyph <= 0xFFFF) || (geometry->x_offset | geometry->y_offset) != 0)
			continue;

		uinfo = font_info_find_unistr_info (info, c);
		if (G_UNLIKELY (uinfo->coverage != COVERAGE_UNKNOWN))
			continue;

		ufi = &uinfo->ufi;

		uinfo->width = PANGO_PIXELS_CEIL (geometry->width);
		uinfo->has_unknown_chars = FALSE;

		uinfo->coverage = COVERAGE_USE_CAIRO_GLYPH;

		ufi->using_cairo_glyph.scaled_font = cairo_scaled_font_reference (scaled_font);
		ufi->using_cairo_glyph.glyph_index = glyph;

#ifdef VTE_DEBUG
		info->coverage_count[0]++;
		info->coverage_count[uinfo->coverage]++;
#endif
	}

#ifdef VTE_DEBUG
	_vte_debug_print (VTE_DEBUG_PANGOCAIRO,
			  "vtepangocairo: %p cached %d ASCII letters\n",
			  info, info->coverage_count[0]);
#endif
}

static void
font_info_measure_font (struct font_info *info)
{
	PangoRectangle logical;

	/* Estimate for ASCII characters. */
	pango_layout_set_text (info->layout, VTE_DRAW_SINGLE_WIDE_CHARACTERS, -1);
	pango_layout_get_extents (info->layout, NULL, &logical);
	/* We don't do CEIL for width since we are averaging;
	 * rounding is more accurate */
	info->width  = PANGO_PIXELS (howmany (logical.width, strlen(VTE_DRAW_SINGLE_WIDE_CHARACTERS)));
        /* Guard against pathological font since width=0 causes a FPE later on */
	info->width = MAX (info->width, 1);

	info->height = PANGO_PIXELS_CEIL (logical.height);
	info->ascent = PANGO_PIXELS_CEIL (pango_layout_get_baseline (info->layout));

	/* Now that we shaped the entire ASCII character string, cache glyph
	 * info for them */
	font_info_cache_ascii (info);

	if (info->height == 0) {
		info->height = PANGO_PIXELS_CEIL (logical.height);
	}
	if (info->ascent == 0) {
		info->ascent = PANGO_PIXELS_CEIL (pango_layout_get_baseline (info->layout));
	}

	_vte_debug_print (VTE_DEBUG_MISC,
			  "vtepangocairo: %p font metrics = %dx%d (%d)\n",
			  info, info->width, info->height, info->ascent);
}

static struct font_info *
font_info_allocate (PangoContext *context)
{
	struct font_info *info;
	PangoTabArray *tabs;

	info = g_slice_new0 (struct font_info);

	_vte_debug_print (VTE_DEBUG_PANGOCAIRO,
			  "vtepangocairo: %p allocating font_info\n",
			  info);

	info->layout = pango_layout_new (context);
	tabs = pango_tab_array_new_with_positions (1, FALSE, PANGO_TAB_LEFT, 1);
	pango_layout_set_tabs (info->layout, tabs);
	pango_tab_array_free (tabs);

	info->string = g_string_sized_new (VTE_UTF8_BPC+1);

	font_info_measure_font (info);

	return info;
}

static void
font_info_free (struct font_info *info)
{
	vteunistr i;

#ifdef VTE_DEBUG
	_vte_debug_print (VTE_DEBUG_PANGOCAIRO,
			  "vtepangocairo: %p freeing font_info.  coverages %d = %d + %d + %d\n",
			  info,
			  info->coverage_count[0],
			  info->coverage_count[1],
			  info->coverage_count[2],
			  info->coverage_count[3]);
#endif

	g_string_free (info->string, TRUE);
	g_object_unref (info->layout);

	for (i = 0; i < G_N_ELEMENTS (info->ascii_unistr_info); i++)
		unistr_info_finish (&info->ascii_unistr_info[i]);
		
	if (info->other_unistr_info) {
		g_hash_table_destroy (info->other_unistr_info);
	}

	g_slice_free (struct font_info, info);
}


static GHashTable *font_info_for_context;

static struct font_info *
font_info_register (struct font_info *info)
{
	g_hash_table_insert (font_info_for_context,
			     pango_layout_get_context (info->layout),
			     info);

	return info;
}

static void
font_info_unregister (struct font_info *info)
{
	g_hash_table_remove (font_info_for_context,
			     pango_layout_get_context (info->layout));
}


static struct font_info *
font_info_reference (struct font_info *info)
{
	if (!info)
		return info;

	g_return_val_if_fail (info->ref_count >= 0, info);

	if (info->destroy_timeout) {
		g_source_remove (info->destroy_timeout);
		info->destroy_timeout = 0;
	}

	info->ref_count++;

	return info;
}

static gboolean
font_info_destroy_delayed (struct font_info *info)
{
	info->destroy_timeout = 0;

	font_info_unregister (info);
	font_info_free (info);

	return FALSE;
}

static void
font_info_destroy (struct font_info *info)
{
	if (!info)
		return;

	g_return_if_fail (info->ref_count > 0);

	info->ref_count--;
	if (info->ref_count)
		return;

	/* Delay destruction by a few seconds, in case we need it again */
	info->destroy_timeout = gdk_threads_add_timeout_seconds (FONT_CACHE_TIMEOUT,
								 (GSourceFunc) font_info_destroy_delayed,
								 info);
}

static GQuark
fontconfig_timestamp_quark (void)
{
	static GQuark quark;

	if (G_UNLIKELY (!quark))
		quark = g_quark_from_static_string ("vte-fontconfig-timestamp");

	return quark;
}

static void
vte_pango_context_set_fontconfig_timestamp (PangoContext *context,
					    guint         fontconfig_timestamp)
{
	g_object_set_qdata ((GObject *) context,
			    fontconfig_timestamp_quark (),
			    GUINT_TO_POINTER (fontconfig_timestamp));
}

static guint
vte_pango_context_get_fontconfig_timestamp (PangoContext *context)
{
	return GPOINTER_TO_UINT (g_object_get_qdata ((GObject *) context,
						     fontconfig_timestamp_quark ()));
}

static guint
context_hash (PangoContext *context)
{
	return pango_units_from_double (pango_cairo_context_get_resolution (context))
	     ^ pango_font_description_hash (pango_context_get_font_description (context))
	     ^ cairo_font_options_hash (pango_cairo_context_get_font_options (context))
	     ^ GPOINTER_TO_UINT (pango_context_get_language (context))
	     ^ vte_pango_context_get_fontconfig_timestamp (context);
}

static gboolean
context_equal (PangoContext *a,
	       PangoContext *b)
{
	return _vte_double_equal(pango_cairo_context_get_resolution(a), pango_cairo_context_get_resolution (b))
	    && pango_font_description_equal (pango_context_get_font_description (a), pango_context_get_font_description (b))
	    && cairo_font_options_equal (pango_cairo_context_get_font_options (a), pango_cairo_context_get_font_options (b))
	    && pango_context_get_language (a) == pango_context_get_language (b)
	    && vte_pango_context_get_fontconfig_timestamp (a) == vte_pango_context_get_fontconfig_timestamp (b);
}

static struct font_info *
font_info_find_for_context (PangoContext *context)
{
	struct font_info *info;

	if (G_UNLIKELY (font_info_for_context == NULL))
		font_info_for_context = g_hash_table_new ((GHashFunc) context_hash, (GEqualFunc) context_equal);

	info = (struct font_info *)g_hash_table_lookup (font_info_for_context, context);
	if (G_LIKELY (info)) {
		_vte_debug_print (VTE_DEBUG_PANGOCAIRO,
				  "vtepangocairo: %p found font_info in cache\n",
				  info);
		info = font_info_reference (info);
	} else {
		info = font_info_allocate (context);
		info->ref_count = 1;
		font_info_register (info);
	}

	g_object_unref (context);

	return info;
}

/* assumes ownership/reference of context */
static struct font_info *
font_info_create_for_context (PangoContext               *context,
			      const PangoFontDescription *desc,
			      PangoLanguage              *language,
			      guint                       fontconfig_timestamp)
{
	if (!PANGO_IS_CAIRO_FONT_MAP (pango_context_get_font_map (context))) {
		/* Ouch, Gtk+ switched over to some drawing system?
		 * Lets just create one from the default font map.
		 */
		g_object_unref (context);
		context = pango_font_map_create_context (pango_cairo_font_map_get_default ());
	}

	vte_pango_context_set_fontconfig_timestamp (context, fontconfig_timestamp);

	pango_context_set_base_dir (context, PANGO_DIRECTION_LTR);

	if (desc)
		pango_context_set_font_description (context, desc);

	pango_context_set_language (context, language);

        /* Make sure our contexts have a font_options set.  We use
          * this invariant in our context hash and equal functions.
          */
        if (!pango_cairo_context_get_font_options (context)) {
                cairo_font_options_t *font_options;

                font_options = cairo_font_options_create ();
                pango_cairo_context_set_font_options (context, font_options);
                cairo_font_options_destroy (font_options);
        }

	return font_info_find_for_context (context);
}

static struct font_info *
font_info_create_for_screen (GdkScreen                  *screen,
			     const PangoFontDescription *desc,
			     PangoLanguage              *language)
{
	GtkSettings *settings = gtk_settings_get_for_screen (screen);
	int fontconfig_timestamp;
	g_object_get (settings, "gtk-fontconfig-timestamp", &fontconfig_timestamp, nullptr);
	return font_info_create_for_context (gdk_pango_context_get_for_screen (screen),
					     desc, language, fontconfig_timestamp);
}

static struct font_info *
font_info_create_for_widget (GtkWidget                  *widget,
			     const PangoFontDescription *desc)
{
	GdkScreen *screen = gtk_widget_get_screen (widget);
	PangoLanguage *language = pango_context_get_language (gtk_widget_get_pango_context (widget));

	return font_info_create_for_screen (screen, desc, language);
}

static struct unistr_info *
font_info_get_unistr_info (struct font_info *info,
			   vteunistr c)
{
	struct unistr_info *uinfo;
	union unistr_font_info *ufi;
	PangoRectangle logical;
	PangoLayoutLine *line;

	uinfo = font_info_find_unistr_info (info, c);
	if (G_LIKELY (uinfo->coverage != COVERAGE_UNKNOWN))
		return uinfo;

	ufi = &uinfo->ufi;

	g_string_set_size (info->string, 0);
	_vte_unistr_append_to_string (c, info->string);
	pango_layout_set_text (info->layout, info->string->str, info->string->len);
	pango_layout_get_extents (info->layout, NULL, &logical);

	uinfo->width = PANGO_PIXELS_CEIL (logical.width);

	line = pango_layout_get_line_readonly (info->layout, 0);

	uinfo->has_unknown_chars = pango_layout_get_unknown_glyphs_count (info->layout) != 0;
	/* we use PangoLayoutRun rendering unless there is exactly one run in the line. */
	if (G_UNLIKELY (!line || !line->runs || line->runs->next))
	{
		uinfo->coverage = COVERAGE_USE_PANGO_LAYOUT_LINE;

		ufi->using_pango_layout_line.line = pango_layout_line_ref (line);
		/* we hold a manual reference on layout.  pango currently
		 * doesn't work if line->layout is NULL.  ugh! */
		pango_layout_set_text (info->layout, "", -1); /* make layout disassociate from the line */
		ufi->using_pango_layout_line.line->layout = (PangoLayout *)g_object_ref (info->layout);

	} else {
		PangoGlyphItem *glyph_item = (PangoGlyphItem *)line->runs->data;
		PangoFont *pango_font = glyph_item->item->analysis.font;
		PangoGlyphString *glyph_string = glyph_item->glyphs;

		/* we use fast cairo path if glyph string has only one real
		 * glyph and at origin */
		if (!uinfo->has_unknown_chars &&
		    glyph_string->num_glyphs == 1 && glyph_string->glyphs[0].glyph <= 0xFFFF &&
		    (glyph_string->glyphs[0].geometry.x_offset |
		     glyph_string->glyphs[0].geometry.y_offset) == 0)
		{
			cairo_scaled_font_t *scaled_font = pango_cairo_font_get_scaled_font ((PangoCairoFont *) pango_font);

			if (scaled_font) {
				uinfo->coverage = COVERAGE_USE_CAIRO_GLYPH;

				ufi->using_cairo_glyph.scaled_font = cairo_scaled_font_reference (scaled_font);
				ufi->using_cairo_glyph.glyph_index = glyph_string->glyphs[0].glyph;
			}
		}

		/* use pango fast path otherwise */
		if (G_UNLIKELY (uinfo->coverage == COVERAGE_UNKNOWN)) {
			uinfo->coverage = COVERAGE_USE_PANGO_GLYPH_STRING;

			ufi->using_pango_glyph_string.font = pango_font ? (PangoFont *)g_object_ref (pango_font) : NULL;
			ufi->using_pango_glyph_string.glyph_string = pango_glyph_string_copy (glyph_string);
		}
	}

	/* release internal layout resources */
	pango_layout_set_text (info->layout, "", -1);

#ifdef VTE_DEBUG
	info->coverage_count[0]++;
	info->coverage_count[uinfo->coverage]++;
#endif

	return uinfo;
}

guint _vte_draw_get_style(gboolean bold, gboolean italic) {
	guint style = 0;
	if (bold)
		style |= VTE_DRAW_BOLD;
	if (italic)
		style |= VTE_DRAW_ITALIC;
	return style;
}

struct _vte_draw {
	struct font_info *fonts[4];
        /* cell metrics, already adjusted by cell_{width,height}_scale */
        int cell_width, cell_height;
        GtkBorder char_spacing;

	cairo_t *cr;

        /* Cache the undercurl's rendered look. */
        cairo_surface_t *undercurl_surface;
};

struct _vte_draw *
_vte_draw_new (void)
{
	struct _vte_draw *draw;

	/* Create the structure. */
	draw = g_slice_new0 (struct _vte_draw);

	_vte_debug_print (VTE_DEBUG_DRAW, "draw_new\n");

	return draw;
}

void
_vte_draw_free (struct _vte_draw *draw)
{
	gint style;
	_vte_debug_print (VTE_DEBUG_DRAW, "draw_free\n");

	/* Free all fonts (make sure to destroy every font only once)*/
	for (style = 3; style >= 0; style--) {
		if (draw->fonts[style] != NULL &&
			(style == 0 || draw->fonts[style] != draw->fonts[style-1])) {
			font_info_destroy (draw->fonts[style]);
			draw->fonts[style] = NULL;
		}
	}

        if (draw->undercurl_surface != NULL) {
                cairo_surface_destroy (draw->undercurl_surface);
                draw->undercurl_surface = NULL;
        }

	g_slice_free (struct _vte_draw, draw);
}

void
_vte_draw_set_cairo (struct _vte_draw *draw,
                     cairo_t *cr)
{
        _vte_debug_print (VTE_DEBUG_DRAW, "%s cairo context\n", cr ? "Settings" : "Unsetting");

        if (cr) {
                g_assert (draw->cr == NULL);
                draw->cr = cr;
        } else {
                g_assert (draw->cr != NULL);
                draw->cr = NULL;
        }
}

static void
_vte_draw_set_source_color_alpha (struct _vte_draw *draw,
                                  vte::color::rgb const* color,
                                  double alpha)
{
        g_assert(draw->cr);
	cairo_set_source_rgba (draw->cr,
			      color->red / 65535.,
			      color->green / 65535.,
			      color->blue / 65535.,
			      alpha);
}

void
_vte_draw_clear (struct _vte_draw *draw, gint x, gint y, gint width, gint height,
                 vte::color::rgb const* color, double alpha)
{
	_vte_debug_print (VTE_DEBUG_DRAW, "draw_clear (%d, %d, %d, %d)\n",
			  x,y,width, height);

        g_assert(draw->cr);
	cairo_rectangle (draw->cr, x, y, width, height);
	cairo_set_operator (draw->cr, CAIRO_OPERATOR_SOURCE);
	_vte_draw_set_source_color_alpha(draw, color, alpha);
	cairo_fill (draw->cr);
}

void
_vte_draw_set_text_font (struct _vte_draw *draw,
                         GtkWidget *widget,
                         const PangoFontDescription *fontdesc,
                         double cell_width_scale,
                         double cell_height_scale)
{
	PangoFontDescription *bolddesc   = NULL;
	PangoFontDescription *italicdesc = NULL;
	PangoFontDescription *bolditalicdesc = NULL;
	gint style, normal, bold, ratio;

	_vte_debug_print (VTE_DEBUG_DRAW, "draw_set_text_font\n");

	/* Free all fonts (make sure to destroy every font only once)*/
	for (style = 3; style >= 0; style--) {
		if (draw->fonts[style] != NULL &&
			(style == 0 || draw->fonts[style] != draw->fonts[style-1])) {
			font_info_destroy (draw->fonts[style]);
			draw->fonts[style] = NULL;
		}
	}

	/* calculate bold font desc */
	bolddesc = pango_font_description_copy (fontdesc);
	pango_font_description_set_weight (bolddesc, PANGO_WEIGHT_BOLD);

	/* calculate italic font desc */
	italicdesc = pango_font_description_copy (fontdesc);
	pango_font_description_set_style (italicdesc, PANGO_STYLE_ITALIC);

	/* calculate bold italic font desc */
	bolditalicdesc = pango_font_description_copy (bolddesc);
	pango_font_description_set_style (bolditalicdesc, PANGO_STYLE_ITALIC);

	draw->fonts[VTE_DRAW_NORMAL]  = font_info_create_for_widget (widget, fontdesc);
	draw->fonts[VTE_DRAW_BOLD]    = font_info_create_for_widget (widget, bolddesc);
	draw->fonts[VTE_DRAW_ITALIC]  = font_info_create_for_widget (widget, italicdesc);
	draw->fonts[VTE_DRAW_ITALIC | VTE_DRAW_BOLD] =
                font_info_create_for_widget (widget, bolditalicdesc);
	pango_font_description_free (bolddesc);
	pango_font_description_free (italicdesc);
	pango_font_description_free (bolditalicdesc);

	/* Decide if we should keep this bold font face, per bug 54926:
	 *  - reject bold font if it is not within 10% of normal font width
	 */
	normal = VTE_DRAW_NORMAL;
	bold   = normal | VTE_DRAW_BOLD;
	ratio = draw->fonts[bold]->width * 100 / draw->fonts[normal]->width;
	if (abs(ratio - 100) > 10) {
		_vte_debug_print (VTE_DEBUG_DRAW,
			"Rejecting bold font (%i%%).\n", ratio);
		font_info_destroy (draw->fonts[bold]);
		draw->fonts[bold] = draw->fonts[normal];
	}
	normal = VTE_DRAW_ITALIC;
	bold   = normal | VTE_DRAW_BOLD;
	ratio = draw->fonts[bold]->width * 100 / draw->fonts[normal]->width;
	if (abs(ratio - 100) > 10) {
		_vte_debug_print (VTE_DEBUG_DRAW,
			"Rejecting italic bold font (%i%%).\n", ratio);
		font_info_destroy (draw->fonts[bold]);
		draw->fonts[bold] = draw->fonts[normal];
	}

        /* Apply letter spacing and line spacing. */
        draw->cell_width = draw->fonts[VTE_DRAW_NORMAL]->width * cell_width_scale;
        draw->char_spacing.left = (draw->cell_width - draw->fonts[VTE_DRAW_NORMAL]->width) / 2;
        draw->char_spacing.right = (draw->cell_width - draw->fonts[VTE_DRAW_NORMAL]->width + 1) / 2;
        draw->cell_height = draw->fonts[VTE_DRAW_NORMAL]->height * cell_height_scale;
        draw->char_spacing.top = (draw->cell_height - draw->fonts[VTE_DRAW_NORMAL]->height + 1) / 2;
        draw->char_spacing.bottom = (draw->cell_height - draw->fonts[VTE_DRAW_NORMAL]->height) / 2;

        /* Drop the undercurl's cached look. Will recache on demand. */
        if (draw->undercurl_surface != NULL) {
                cairo_surface_destroy (draw->undercurl_surface);
                draw->undercurl_surface = NULL;
        }
}

void
_vte_draw_get_text_metrics(struct _vte_draw *draw,
                           int *cell_width, int *cell_height,
                           int *char_ascent, int *char_descent,
                           GtkBorder *char_spacing)
{
	g_return_if_fail (draw->fonts[VTE_DRAW_NORMAL] != NULL);

        if (cell_width)
                *cell_width = draw->cell_width;
        if (cell_height)
                *cell_height = draw->cell_height;
        if (char_ascent)
                *char_ascent = draw->fonts[VTE_DRAW_NORMAL]->ascent;
        if (char_descent)
                *char_descent = draw->fonts[VTE_DRAW_NORMAL]->height - draw->fonts[VTE_DRAW_NORMAL]->ascent;
        if (char_spacing)
                *char_spacing = draw->char_spacing;
}


/* Stores the left and right edges of the given glyph, relative to the cell's left edge. */
void
_vte_draw_get_char_edges (struct _vte_draw *draw, vteunistr c, int columns, guint style,
                          int *left, int *right)
{
        int l, w, normal_width, fits_width;

        if (G_UNLIKELY (draw->fonts[VTE_DRAW_NORMAL] == NULL)) {
                if (left)
                        *left = 0;
                if (right)
                        *right = 0;
                return;
        }

        w = font_info_get_unistr_info (draw->fonts[style], c)->width;
        normal_width = draw->fonts[VTE_DRAW_NORMAL]->width * columns;
        fits_width = draw->cell_width * columns;

        if (G_LIKELY (w <= normal_width)) {
                /* The regular case: The glyph is not wider than one (CJK: two) regular character(s).
                 * Align to the left, after applying half (CJK: one) letter spacing. */
                l = draw->char_spacing.left + (columns == 2 ? draw->char_spacing.right : 0);
        } else if (G_UNLIKELY (w <= fits_width)) {
                /* Slightly wider glyph, but still fits in the cell (spacing included). This case can
                 * only happen with nonzero letter spacing. Center the glyph in the cell(s). */
                l = (fits_width - w) / 2;
        } else {
                /* Even wider glyph: doesn't fit in the cell. Align at left and overflow on the right. */
                l = 0;
        }

        if (left)
                *left = l;
        if (right)
                *right = l + w;
}

/* Check if a unicode character is actually a graphic character we draw
 * ourselves to handle cases where fonts don't have glyphs for them. */
static gboolean
_vte_draw_unichar_is_local_graphic(vteunistr c)
{
        /* Box Drawing & Block Elements */
        return (c >= 0x2500) && (c <= 0x259f);
}

#include "box_drawing.h"

/* Draw the graphic representation of a line-drawing or special graphics
 * character. */
static void
_vte_draw_terminal_draw_graphic(struct _vte_draw *draw, vteunistr c, vte::color::rgb const* fg,
                                gint x, gint y,
                                gint font_width, gint columns, gint font_height)
{
        gint width, height, xcenter, xright, ycenter, ybottom;
        int upper_half, lower_half, left_half, right_half;
        int light_line_width, heavy_line_width;
        double adjust;
        cairo_t *cr = draw->cr;

        cairo_save (cr);

        width = draw->cell_width * columns;
        height = draw->cell_height;
        upper_half = height / 2;
        lower_half = height - upper_half;
        left_half = width / 2;
        right_half = width - left_half;

        /* Note that the upper/left halves above are the same as 4 eights */
        /* FIXME: this could be smarter for very small n (< 8 resp. < 4) */
#define EIGHTS(n, k) \
        ({ int k_eights = (n) * (k) / 8; \
           k_eights = MAX(k_eights, 1); \
           k_eights; \
        })

        /* Exclude the spacing for line width computation. */
        light_line_width = font_width / 5;
        light_line_width = MAX (light_line_width, 1);

        if (c >= 0x2550 && c <= 0x256c) {
                heavy_line_width = 3 * light_line_width;
        } else {
                heavy_line_width = light_line_width + 2;
        }

        xcenter = x + left_half;
        ycenter = y + upper_half;
        xright = x + width;
        ybottom = y + height;

        switch (c) {

        /* Box Drawing */
        case 0x2500: /* box drawings light horizontal */
        case 0x2501: /* box drawings heavy horizontal */
        case 0x2502: /* box drawings light vertical */
        case 0x2503: /* box drawings heavy vertical */
        case 0x250c: /* box drawings light down and right */
        case 0x250d: /* box drawings down light and right heavy */
        case 0x250e: /* box drawings down heavy and right light */
        case 0x250f: /* box drawings heavy down and right */
        case 0x2510: /* box drawings light down and left */
        case 0x2511: /* box drawings down light and left heavy */
        case 0x2512: /* box drawings down heavy and left light */
        case 0x2513: /* box drawings heavy down and left */
        case 0x2514: /* box drawings light up and right */
        case 0x2515: /* box drawings up light and right heavy */
        case 0x2516: /* box drawings up heavy and right light */
        case 0x2517: /* box drawings heavy up and right */
        case 0x2518: /* box drawings light up and left */
        case 0x2519: /* box drawings up light and left heavy */
        case 0x251a: /* box drawings up heavy and left light */
        case 0x251b: /* box drawings heavy up and left */
        case 0x251c: /* box drawings light vertical and right */
        case 0x251d: /* box drawings vertical light and right heavy */
        case 0x251e: /* box drawings up heavy and right down light */
        case 0x251f: /* box drawings down heavy and right up light */
        case 0x2520: /* box drawings vertical heavy and right light */
        case 0x2521: /* box drawings down light and right up heavy */
        case 0x2522: /* box drawings up light and right down heavy */
        case 0x2523: /* box drawings heavy vertical and right */
        case 0x2524: /* box drawings light vertical and left */
        case 0x2525: /* box drawings vertical light and left heavy */
        case 0x2526: /* box drawings up heavy and left down light */
        case 0x2527: /* box drawings down heavy and left up light */
        case 0x2528: /* box drawings vertical heavy and left light */
        case 0x2529: /* box drawings down light and left up heavy */
        case 0x252a: /* box drawings up light and left down heavy */
        case 0x252b: /* box drawings heavy vertical and left */
        case 0x252c: /* box drawings light down and horizontal */
        case 0x252d: /* box drawings left heavy and right down light */
        case 0x252e: /* box drawings right heavy and left down light */
        case 0x252f: /* box drawings down light and horizontal heavy */
        case 0x2530: /* box drawings down heavy and horizontal light */
        case 0x2531: /* box drawings right light and left down heavy */
        case 0x2532: /* box drawings left light and right down heavy */
        case 0x2533: /* box drawings heavy down and horizontal */
        case 0x2534: /* box drawings light up and horizontal */
        case 0x2535: /* box drawings left heavy and right up light */
        case 0x2536: /* box drawings right heavy and left up light */
        case 0x2537: /* box drawings up light and horizontal heavy */
        case 0x2538: /* box drawings up heavy and horizontal light */
        case 0x2539: /* box drawings right light and left up heavy */
        case 0x253a: /* box drawings left light and right up heavy */
        case 0x253b: /* box drawings heavy up and horizontal */
        case 0x253c: /* box drawings light vertical and horizontal */
        case 0x253d: /* box drawings left heavy and right vertical light */
        case 0x253e: /* box drawings right heavy and left vertical light */
        case 0x253f: /* box drawings vertical light and horizontal heavy */
        case 0x2540: /* box drawings up heavy and down horizontal light */
        case 0x2541: /* box drawings down heavy and up horizontal light */
        case 0x2542: /* box drawings vertical heavy and horizontal light */
        case 0x2543: /* box drawings left up heavy and right down light */
        case 0x2544: /* box drawings right up heavy and left down light */
        case 0x2545: /* box drawings left down heavy and right up light */
        case 0x2546: /* box drawings right down heavy and left up light */
        case 0x2547: /* box drawings down light and up horizontal heavy */
        case 0x2548: /* box drawings up light and down horizontal heavy */
        case 0x2549: /* box drawings right light and left vertical heavy */
        case 0x254a: /* box drawings left light and right vertical heavy */
        case 0x254b: /* box drawings heavy vertical and horizontal */
        case 0x2550: /* box drawings double horizontal */
        case 0x2551: /* box drawings double vertical */
        case 0x2552: /* box drawings down single and right double */
        case 0x2553: /* box drawings down double and right single */
        case 0x2554: /* box drawings double down and right */
        case 0x2555: /* box drawings down single and left double */
        case 0x2556: /* box drawings down double and left single */
        case 0x2557: /* box drawings double down and left */
        case 0x2558: /* box drawings up single and right double */
        case 0x2559: /* box drawings up double and right single */
        case 0x255a: /* box drawings double up and right */
        case 0x255b: /* box drawings up single and left double */
        case 0x255c: /* box drawings up double and left single */
        case 0x255d: /* box drawings double up and left */
        case 0x255e: /* box drawings vertical single and right double */
        case 0x255f: /* box drawings vertical double and right single */
        case 0x2560: /* box drawings double vertical and right */
        case 0x2561: /* box drawings vertical single and left double */
        case 0x2562: /* box drawings vertical double and left single */
        case 0x2563: /* box drawings double vertical and left */
        case 0x2564: /* box drawings down single and horizontal double */
        case 0x2565: /* box drawings down double and horizontal single */
        case 0x2566: /* box drawings double down and horizontal */
        case 0x2567: /* box drawings up single and horizontal double */
        case 0x2568: /* box drawings up double and horizontal single */
        case 0x2569: /* box drawings double up and horizontal */
        case 0x256a: /* box drawings vertical single and horizontal double */
        case 0x256b: /* box drawings vertical double and horizontal single */
        case 0x256c: /* box drawings double vertical and horizontal */
        case 0x2574: /* box drawings light left */
        case 0x2575: /* box drawings light up */
        case 0x2576: /* box drawings light right */
        case 0x2577: /* box drawings light down */
        case 0x2578: /* box drawings heavy left */
        case 0x2579: /* box drawings heavy up */
        case 0x257a: /* box drawings heavy right */
        case 0x257b: /* box drawings heavy down */
        case 0x257c: /* box drawings light left and heavy right */
        case 0x257d: /* box drawings light up and heavy down */
        case 0x257e: /* box drawings heavy left and light right */
        case 0x257f: /* box drawings heavy up and light down */
        {
                guint32 bitmap = _vte_draw_box_drawing_bitmaps[c - 0x2500];
                int xboundaries[6] = { 0,
                                       left_half - heavy_line_width / 2,
                                       left_half - light_line_width / 2,
                                       left_half - light_line_width / 2 + light_line_width,
                                       left_half - heavy_line_width / 2 + heavy_line_width,
                                       width};
                int yboundaries[6] = { 0,
                                       upper_half - heavy_line_width / 2,
                                       upper_half - light_line_width / 2,
                                       upper_half - light_line_width / 2 + light_line_width,
                                       upper_half - heavy_line_width / 2 + heavy_line_width,
                                       height};
                int xi, yi;
                cairo_set_line_width(cr, 0);
                for (yi = 4; yi >= 0; yi--) {
                        for (xi = 4; xi >= 0; xi--) {
                                if (bitmap & 1) {
                                        cairo_rectangle(cr,
                                                        x + xboundaries[xi],
                                                        y + yboundaries[yi],
                                                        xboundaries[xi + 1] - xboundaries[xi],
                                                        yboundaries[yi + 1] - yboundaries[yi]);
                                        cairo_fill(cr);
                                }
                                bitmap >>= 1;
                        }
                }
                break;
        }

        case 0x2504: /* box drawings light triple dash horizontal */
        case 0x2505: /* box drawings heavy triple dash horizontal */
        case 0x2506: /* box drawings light triple dash vertical */
        case 0x2507: /* box drawings heavy triple dash vertical */
        case 0x2508: /* box drawings light quadruple dash horizontal */
        case 0x2509: /* box drawings heavy quadruple dash horizontal */
        case 0x250a: /* box drawings light quadruple dash vertical */
        case 0x250b: /* box drawings heavy quadruple dash vertical */
        case 0x254c: /* box drawings light double dash horizontal */
        case 0x254d: /* box drawings heavy double dash horizontal */
        case 0x254e: /* box drawings light double dash vertical */
        case 0x254f: /* box drawings heavy double dash vertical */
        {
                const guint v = c - 0x2500;
                int size, line_width;

                size = (v & 2) ? height : width;

                switch (v >> 2) {
                case 1: /* triple dash */
                {
                        double segment = size / 8.;
                        double dashes[2] = { segment * 2., segment };
                        cairo_set_dash(cr, dashes, G_N_ELEMENTS(dashes), 0.);
                        break;
                }
                case 2: /* quadruple dash */
                {
                        double segment = size / 11.;
                        double dashes[2] = { segment * 2., segment };
                        cairo_set_dash(cr, dashes, G_N_ELEMENTS(dashes), 0.);
                        break;
                }
                case 19: /* double dash */
                {
                        double segment = size / 5.;
                        double dashes[2] = { segment * 2., segment };
                        cairo_set_dash(cr, dashes, G_N_ELEMENTS(dashes), 0.);
                        break;
                }
                }

                line_width = (v & 1) ? heavy_line_width : light_line_width;
                adjust = (line_width & 1) ? .5 : 0.;

                cairo_set_line_width(cr, line_width);
                cairo_set_line_cap(cr, CAIRO_LINE_CAP_BUTT);
                if (v & 2) {
                        cairo_move_to(cr, xcenter + adjust, y);
                        cairo_line_to(cr, xcenter + adjust, y + height);
                } else {
                        cairo_move_to(cr, x, ycenter + adjust);
                        cairo_line_to(cr, x + width, ycenter + adjust);
                }
                cairo_stroke(cr);
                break;
        }

        case 0x256d: /* box drawings light arc down and right */
        case 0x256e: /* box drawings light arc down and left */
        case 0x256f: /* box drawings light arc up and left */
        case 0x2570: /* box drawings light arc up and right */
        {
                const guint v = c - 0x256d;
                int line_width;
                int radius;

                cairo_set_line_cap(cr, CAIRO_LINE_CAP_BUTT);

                line_width = light_line_width;
                adjust = (line_width & 1) ? .5 : 0.;
                cairo_set_line_width(cr, line_width);

                radius = (font_width + 2) / 3;
                radius = MAX(radius, heavy_line_width);

                if (v & 2) {
                        cairo_move_to(cr, xcenter + adjust, y);
                        cairo_line_to(cr, xcenter + adjust, ycenter - radius + 2 * adjust);
                } else {
                        cairo_move_to(cr, xcenter + adjust, ybottom);
                        cairo_line_to(cr, xcenter + adjust, ycenter + radius);
                }
                cairo_stroke(cr);

                cairo_arc(cr,
                          (v == 1 || v == 2) ? xcenter - radius + 2 * adjust
                                             : xcenter + radius,
                          (v & 2) ? ycenter - radius + 2 * adjust
                                  : ycenter + radius,
                          radius - adjust,
                          (v + 2) * M_PI / 2.0, (v + 3) * M_PI / 2.0);
                cairo_stroke(cr);

                if (v == 1 || v == 2) {
                        cairo_move_to(cr, xcenter - radius + 2 * adjust, ycenter + adjust);
                        cairo_line_to(cr, x, ycenter + adjust);
                } else {
                        cairo_move_to(cr, xcenter + radius, ycenter + adjust);
                        cairo_line_to(cr, xright, ycenter + adjust);
                }

                cairo_stroke(cr);
                break;
        }

        case 0x2571: /* box drawings light diagonal upper right to lower left */
        case 0x2572: /* box drawings light diagonal upper left to lower right */
        case 0x2573: /* box drawings light diagonal cross */
        {
                cairo_set_line_cap(cr, CAIRO_LINE_CAP_ROUND);
                cairo_set_line_width(cr, light_line_width);
                adjust = light_line_width / 2.;
                if (c != 0x2571) {
                        cairo_move_to(cr, x + adjust, y + adjust);
                        cairo_line_to(cr, xright - adjust, ybottom - adjust);
                        cairo_stroke(cr);
                }
                if (c != 0x2572) {
                        cairo_move_to(cr, xright - adjust, y + adjust);
                        cairo_line_to(cr, x + adjust, ybottom - adjust);
                        cairo_stroke(cr);
                }
                break;
        }

        /* Block Elements */
        case 0x2580: /* upper half block */
                cairo_rectangle(cr, x, y, width, upper_half);
                cairo_fill (cr);
                break;

        case 0x2581: /* lower one eighth block */
        case 0x2582: /* lower one quarter block */
        case 0x2583: /* lower three eighths block */
        case 0x2584: /* lower half block */
        case 0x2585: /* lower five eighths block */
        case 0x2586: /* lower three quarters block */
        case 0x2587: /* lower seven eighths block */
        {
                const guint v = c - 0x2580;
                /* Use the number of eights from the top, so that
                 * U+2584 aligns with U+2596..U+259f.
                 */
                const int h = EIGHTS (height, 8 - v);

                cairo_rectangle(cr, x, y + h, width, height - h);
                cairo_fill (cr);
                break;
        }

        case 0x2588: /* full block */
        case 0x2589: /* left seven eighths block */
        case 0x258a: /* left three quarters block */
        case 0x258b: /* left five eighths block */
        case 0x258c: /* left half block */
        case 0x258d: /* left three eighths block */
        case 0x258e: /* left one quarter block */
        case 0x258f: /* left one eighth block */
        {
                const guint v = c - 0x2588;
                /* Use the number of eights from the top, so that
                 * U+258c aligns with U+2596..U+259f.
                 */
                const int w = EIGHTS (width, 8 - v);

                cairo_rectangle(cr, x, y, w, height);
                cairo_fill (cr);
                break;
        }

        case 0x2590: /* right half block */
                cairo_rectangle(cr, x + left_half, y, right_half, height);
                cairo_fill (cr);
                break;

        case 0x2591: /* light shade */
        case 0x2592: /* medium shade */
        case 0x2593: /* dark shade */
                cairo_set_source_rgba (cr,
                                       fg->red / 65535.,
                                       fg->green / 65535.,
                                       fg->blue / 65535.,
                                       (c - 0x2590) / 4.);
                cairo_rectangle(cr, x, y, width, height);
                cairo_fill (cr);
                break;

        case 0x2594: /* upper one eighth block */
        {
                const int h = EIGHTS (height, 1); /* Align with U+2587 */
                cairo_rectangle(cr, x, y, width, h);
                cairo_fill (cr);
                break;
        }

        case 0x2595: /* right one eighth block */
        {
                const int w = EIGHTS (width, 7);  /* Align with U+2589 */
                cairo_rectangle(cr, x + w, y, width - w, height);
                cairo_fill (cr);
                break;
        }

        case 0x2596: /* quadrant lower left */
                cairo_rectangle(cr, x, y + upper_half, left_half, lower_half);
                cairo_fill (cr);
                break;

        case 0x2597: /* quadrant lower right */
                cairo_rectangle(cr, x + left_half, y + upper_half, right_half, lower_half);
                cairo_fill (cr);
                break;

        case 0x2598: /* quadrant upper left */
                cairo_rectangle(cr, x, y, left_half, upper_half);
                cairo_fill (cr);
                break;

        case 0x2599: /* quadrant upper left and lower left and lower right */
                cairo_rectangle(cr, x, y, left_half, upper_half);
                cairo_rectangle(cr, x, y + upper_half, left_half, lower_half);
                cairo_rectangle(cr, x + left_half, y + upper_half, right_half, lower_half);
                cairo_fill (cr);
                break;

        case 0x259a: /* quadrant upper left and lower right */
                cairo_rectangle(cr, x, y, left_half, upper_half);
                cairo_rectangle(cr, x + left_half, y + upper_half, right_half, lower_half);
                cairo_fill (cr);
                break;

        case 0x259b: /* quadrant upper left and upper right and lower left */
                cairo_rectangle(cr, x, y, left_half, upper_half);
                cairo_rectangle(cr, x + left_half, y, right_half, upper_half);
                cairo_rectangle(cr, x, y + upper_half, left_half, lower_half);
                cairo_fill (cr);
                break;

        case 0x259c: /* quadrant upper left and upper right and lower right */
                cairo_rectangle(cr, x, y, left_half, upper_half);
                cairo_rectangle(cr, x + left_half, y, right_half, upper_half);
                cairo_rectangle(cr, x + left_half, y + upper_half, right_half, lower_half);
                cairo_fill (cr);
                break;

        case 0x259d: /* quadrant upper right */
                cairo_rectangle(cr, x + left_half, y, right_half, upper_half);
                cairo_fill (cr);
                break;

        case 0x259e: /* quadrant upper right and lower left */
                cairo_rectangle(cr, x + left_half, y, right_half, upper_half);
                cairo_rectangle(cr, x, y + upper_half, left_half, lower_half);
                cairo_fill (cr);
                break;

        case 0x259f: /* quadrant upper right and lower left and lower right */
                cairo_rectangle(cr, x + left_half, y, right_half, upper_half);
                cairo_rectangle(cr, x, y + upper_half, left_half, lower_half);
                cairo_rectangle(cr, x + left_half, y + upper_half, right_half, lower_half);
                cairo_fill (cr);
                break;

        default:
                g_assert_not_reached();
        }

#undef EIGHTS

        cairo_restore(cr);
}

static void
_vte_draw_text_internal (struct _vte_draw *draw,
			 struct _vte_draw_text_request *requests, gsize n_requests,
			 vte::color::rgb const* color, double alpha, guint style)
{
	gsize i;
	cairo_scaled_font_t *last_scaled_font = NULL;
	int n_cr_glyphs = 0;
	cairo_glyph_t cr_glyphs[MAX_RUN_LENGTH];
	struct font_info *font = draw->fonts[style];

	g_return_if_fail (font != NULL);

        g_assert(draw->cr);
	_vte_draw_set_source_color_alpha (draw, color, alpha);
	cairo_set_operator (draw->cr, CAIRO_OPERATOR_OVER);

	for (i = 0; i < n_requests; i++) {
		vteunistr c = requests[i].c;
		struct unistr_info *uinfo = font_info_get_unistr_info (font, c);
		union unistr_font_info *ufi = &uinfo->ufi;
                int x, y;

                _vte_draw_get_char_edges(draw, c, requests[i].columns, style, &x, NULL);
                x += requests[i].x;
                y = requests[i].y + draw->char_spacing.top + font->ascent;

                if (_vte_draw_unichar_is_local_graphic(c)) {
                        _vte_draw_terminal_draw_graphic(draw, c, color,
                                                        requests[i].x, requests[i].y,
                                                        font->width, requests[i].columns, font->height);
                        continue;
                }

		switch (uinfo->coverage) {
		default:
		case COVERAGE_UNKNOWN:
			g_assert_not_reached ();
			break;
		case COVERAGE_USE_PANGO_LAYOUT_LINE:
			cairo_move_to (draw->cr, x, y);
			pango_cairo_show_layout_line (draw->cr,
						      ufi->using_pango_layout_line.line);
			break;
		case COVERAGE_USE_PANGO_GLYPH_STRING:
			cairo_move_to (draw->cr, x, y);
			pango_cairo_show_glyph_string (draw->cr,
						       ufi->using_pango_glyph_string.font,
						       ufi->using_pango_glyph_string.glyph_string);
			break;
		case COVERAGE_USE_CAIRO_GLYPH:
			if (last_scaled_font != ufi->using_cairo_glyph.scaled_font || n_cr_glyphs == MAX_RUN_LENGTH) {
				if (n_cr_glyphs) {
					cairo_set_scaled_font (draw->cr, last_scaled_font);
					cairo_show_glyphs (draw->cr,
							   cr_glyphs,
							   n_cr_glyphs);
					n_cr_glyphs = 0;
				}
				last_scaled_font = ufi->using_cairo_glyph.scaled_font;
			}
			cr_glyphs[n_cr_glyphs].index = ufi->using_cairo_glyph.glyph_index;
			cr_glyphs[n_cr_glyphs].x = x;
			cr_glyphs[n_cr_glyphs].y = y;
			n_cr_glyphs++;
			break;
		}
	}
	if (n_cr_glyphs) {
		cairo_set_scaled_font (draw->cr, last_scaled_font);
		cairo_show_glyphs (draw->cr,
				   cr_glyphs,
				   n_cr_glyphs);
		n_cr_glyphs = 0;
	}
}

void
_vte_draw_text (struct _vte_draw *draw,
	       struct _vte_draw_text_request *requests, gsize n_requests,
	       vte::color::rgb const* color, double alpha, guint style)
{
        g_assert(draw->cr);

	if (_vte_debug_on (VTE_DEBUG_DRAW)) {
		GString *string = g_string_new ("");
		gchar *str;
		gsize n;
		for (n = 0; n < n_requests; n++) {
			g_string_append_unichar (string, requests[n].c);
		}
		str = g_string_free (string, FALSE);
		g_printerr ("draw_text (\"%s\", len=%" G_GSIZE_FORMAT ", color=(%d,%d,%d,%.3f), %s - %s)\n",
				str, n_requests, color->red, color->green, color->blue, alpha,
				(style & VTE_DRAW_BOLD)   ? "bold"   : "normal",
				(style & VTE_DRAW_ITALIC) ? "italic" : "regular");
		g_free (str);
	}

	_vte_draw_text_internal (draw, requests, n_requests, color, alpha, style);
}

/* The following two functions are unused since commit 154abade902850afb44115cccf8fcac51fc082f0,
 * but let's keep them for now since they may become used again.
 */
gboolean
_vte_draw_has_char (struct _vte_draw *draw, vteunistr c, guint style)
{
	struct unistr_info *uinfo;

	_vte_debug_print (VTE_DEBUG_DRAW, "draw_has_char ('0x%04X', %s - %s)\n", c,
				(style & VTE_DRAW_BOLD)   ? "bold"   : "normal",
				(style & VTE_DRAW_ITALIC) ? "italic" : "regular");

	g_return_val_if_fail (draw->fonts[VTE_DRAW_NORMAL] != NULL, FALSE);

	uinfo = font_info_get_unistr_info (draw->fonts[style], c);
	return !uinfo->has_unknown_chars;
}

gboolean
_vte_draw_char (struct _vte_draw *draw,
	       struct _vte_draw_text_request *request,
	       vte::color::rgb const* color, double alpha, guint style)
{
	gboolean has_char;

	_vte_debug_print (VTE_DEBUG_DRAW,
			"draw_char ('%c', color=(%d,%d,%d,%.3f), %s, %s)\n",
			request->c,
			color->red, color->green, color->blue,
			alpha,
			(style & VTE_DRAW_BOLD)   ? "bold"   : "normal",
			(style & VTE_DRAW_ITALIC) ? "italic" : "regular");

	has_char =_vte_draw_has_char (draw, request->c, style);
	if (has_char)
		_vte_draw_text (draw, request, 1, color, alpha, style);

	return has_char;
}

void
_vte_draw_draw_rectangle (struct _vte_draw *draw,
			 gint x, gint y, gint width, gint height,
			 vte::color::rgb const* color, double alpha)
{
        g_assert(draw->cr);

	_vte_debug_print (VTE_DEBUG_DRAW,
			"draw_rectangle (%d, %d, %d, %d, color=(%d,%d,%d,%.3f))\n",
			x,y,width,height,
			color->red, color->green, color->blue,
			alpha);

	cairo_set_operator (draw->cr, CAIRO_OPERATOR_OVER);
	cairo_rectangle (draw->cr, x+VTE_LINE_WIDTH/2., y+VTE_LINE_WIDTH/2., width-VTE_LINE_WIDTH, height-VTE_LINE_WIDTH);
	_vte_draw_set_source_color_alpha (draw, color, alpha);
	cairo_set_line_width (draw->cr, VTE_LINE_WIDTH);
	cairo_stroke (draw->cr);
}

void
_vte_draw_fill_rectangle (struct _vte_draw *draw,
			 gint x, gint y, gint width, gint height,
			 vte::color::rgb const* color, double alpha)
{
        g_assert(draw->cr);

	_vte_debug_print (VTE_DEBUG_DRAW,
			"draw_fill_rectangle (%d, %d, %d, %d, color=(%d,%d,%d,%.3f))\n",
			x,y,width,height,
			color->red, color->green, color->blue,
			alpha);

	cairo_set_operator (draw->cr, CAIRO_OPERATOR_OVER);
	cairo_rectangle (draw->cr, x, y, width, height);
	_vte_draw_set_source_color_alpha (draw, color, alpha);
	cairo_fill (draw->cr);
}


void
_vte_draw_draw_line(struct _vte_draw *draw,
                    gint x, gint y, gint xp, gint yp,
                    int line_width,
                    vte::color::rgb const *color, double alpha)
{
	_vte_draw_fill_rectangle(draw,
                                 x, y,
                                 MAX(line_width, xp - x + 1), MAX(line_width, yp - y + 1),
                                 color, alpha);
}

static inline double
_vte_draw_get_undercurl_rad(gint width)
{
        return width / 2. / sqrt(2);
}

static inline double
_vte_draw_get_undercurl_arc_height(gint width)
{
        return _vte_draw_get_undercurl_rad(width) * (1. - sqrt(2) / 2.);
}

double
_vte_draw_get_undercurl_height(gint width, double line_width)
{
        return 2. * _vte_draw_get_undercurl_arc_height(width) + line_width;
}

void
_vte_draw_draw_undercurl(struct _vte_draw *draw,
                         gint x, double y,
                         double line_width,
                         gint count,
                         vte::color::rgb const *color, double alpha)
{
        /* The end of the curly line slightly overflows to the next cell, so the canvas
         * caching the rendered look has to be wider not to chop this off. */
        gint x_padding = line_width + 1;  /* ceil, kind of */

        gint surface_top = y;  /* floor */

        g_assert(draw->cr);

        _vte_debug_print (VTE_DEBUG_DRAW,
                        "draw_undercurl (x=%d, y=%f, count=%d, color=(%d,%d,%d,%.3f))\n",
                        x, y, count,
                        color->red, color->green, color->blue,
                        alpha);

        if (G_UNLIKELY (draw->undercurl_surface == NULL)) {
                /* Cache the undercurl's look. The design assumes that until the cached look is
                 * invalidated (the font is changed), this method is always called with the "y"
                 * parameter having the same fractional part, and the same "line_width" parameter.
                 * For caching, only the fractional part of "y" is used. */
                cairo_t *undercurl_cr;

                double rad = _vte_draw_get_undercurl_rad(draw->cell_width);
                double y_bottom = y + _vte_draw_get_undercurl_height(draw->cell_width, line_width);
                double y_center = (y + y_bottom) / 2.;
                gint surface_bottom = y_bottom + 1;  /* ceil, kind of */

                _vte_debug_print (VTE_DEBUG_DRAW,
                                  "caching undercurl shape\n");

                /* Add a line_width of margin horizontally on both sides, for nice antialias overflowing. */
                draw->undercurl_surface = cairo_surface_create_similar (cairo_get_target (draw->cr),
                                                                        CAIRO_CONTENT_ALPHA,
                                                                        draw->cell_width + 2 * x_padding,
                                                                        surface_bottom - surface_top);
                undercurl_cr = cairo_create (draw->undercurl_surface);
                cairo_set_operator (undercurl_cr, CAIRO_OPERATOR_OVER);
                /* First quarter circle, similar to the left half of the tilde symbol. */
                cairo_arc (undercurl_cr, x_padding + draw->cell_width / 4., y_center - surface_top + draw->cell_width / 4., rad, M_PI * 5 / 4, M_PI * 7 / 4);
                /* Second quarter circle, similar to the right half of the tilde symbol. */
                cairo_arc_negative (undercurl_cr, x_padding + draw->cell_width * 3 / 4., y_center - surface_top - draw->cell_width / 4., rad, M_PI * 3 / 4, M_PI / 4);
                cairo_set_line_width (undercurl_cr, line_width);
                cairo_stroke (undercurl_cr);
                cairo_destroy (undercurl_cr);
        }

        /* Paint the cached look of the undercurl using the desired look.
         * The cached look takes the fractional part of "y" into account,
         * here we only offset by its integer part. */
        cairo_save (draw->cr);
        cairo_set_operator (draw->cr, CAIRO_OPERATOR_OVER);
        _vte_draw_set_source_color_alpha (draw, color, alpha);
        for (int i = 0; i < count; i++) {
                cairo_mask_surface (draw->cr, draw->undercurl_surface, x - x_padding + i * draw->cell_width, surface_top);
        }
        cairo_restore (draw->cr);
}
