source: trunk/third/gtkhtml3/src/htmlobject.c @ 21460

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/*  This file is part of the GtkHTML library.

    Copyright (C) 1997 Martin Jones (mjones@kde.org)
    Copyright (C) 1997 Torben Weis (weis@kde.org)
    Copyright (C) 1999, 2000 Helix Code, Inc.

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public License
    along with this library; see the file COPYING.LIB.  If not, write to
    the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
    Boston, MA 02111-1307, USA.
*/

#include <config.h>
#include <string.h>
#include <glib/gdataset.h>
#include <glib/gquark.h>

#include "htmlclue.h"
#include "htmlclueflow.h"
#include "htmlcluealigned.h"
#include "htmlcluev.h"
#include "htmlcolor.h"
#include "htmlcolorset.h"
#include "htmlcursor.h"
#include "htmlengine.h"
#include "htmlengine-edit.h"
#include "htmlengine-save.h"
#include "htmlframe.h"
#include "htmlinterval.h"
#include "htmlobject.h"
#include "htmlpainter.h"
#include "htmltable.h"
#include "htmltext.h"
#include "htmlrule.h"
#include "htmltype.h"
#include "htmlsettings.h"

#include "gtkhtmldebug.h"


HTMLObjectClass html_object_class;

#define HO_CLASS(x) HTML_OBJECT_CLASS (HTML_OBJECT (x)->klass)

static void
destroy (HTMLObject *self)
{
#define GTKHTML_MEM_DEBUG 1
#if GTKHTML_MEM_DEBUG
        self->parent = HTML_OBJECT (0xdeadbeef);
        self->next = HTML_OBJECT (0xdeadbeef);
        self->prev = HTML_OBJECT (0xdeadbeef);
#else
        self->next = NULL;
        self->prev = NULL;
#endif

        g_datalist_clear (&self->object_data);
        g_datalist_clear (&self->object_data_nocp);
        
        if (self->redraw_pending) {
                self->free_pending = TRUE;
        } else {
                g_free (self);
        }
}

static void
copy (HTMLObject *self,
      HTMLObject *dest)
{
        dest->klass = self->klass;
        dest->parent = NULL;
        dest->prev = NULL;
        dest->next = NULL;
        dest->x = 0;
        dest->y = 0;
        dest->ascent = self->ascent;
        dest->descent = self->descent;
        dest->width = self->width;
        dest->min_width = self->min_width;
        dest->max_width = self->max_width;
        dest->pref_width = self->pref_width;
        dest->percent = self->percent;
        dest->flags = self->flags;
        dest->redraw_pending = FALSE;
        dest->selected = FALSE;
        dest->free_pending = FALSE;
        dest->change = self->change;
        dest->draw_focused = FALSE;

        g_datalist_init (&dest->object_data);
        html_object_copy_data_from_object (dest, self);

        g_datalist_init (&dest->object_data_nocp);
}

static HTMLObject *
op_copy (HTMLObject *self, HTMLObject *parent, HTMLEngine *e, GList *from, GList *to, guint *len)
{
        if ((!from || GPOINTER_TO_INT (from->data) == 0)
            && (!to || GPOINTER_TO_INT (to->data) == html_object_get_length (self))) {
                *len += html_object_get_recursive_length (self);

                return html_object_dup (self);
        } else
                return html_engine_new_text_empty (e);
}

static HTMLObject *
op_cut (HTMLObject *self, HTMLEngine *e, GList *from, GList *to, GList *left, GList *right, guint *len)
{
        if ((!from || GPOINTER_TO_INT (from->data) == 0)
            && (!to || GPOINTER_TO_INT (to->data) == html_object_get_length (self))) {
                if (!html_object_could_remove_whole (self, from, to, left, right)) {
                        HTMLObject *empty = html_engine_new_text_empty (e);

                        if (e->cursor->object == self)
                                e->cursor->object = empty;
                        html_clue_append_after (HTML_CLUE (self->parent), empty, self);
                        html_object_change_set (empty, HTML_CHANGE_ALL_CALC);
                        html_object_check_cut_lists (self, empty, left, right);
                } else
                        html_object_move_cursor_before_remove (self, e);

                html_object_change_set (self, HTML_CHANGE_ALL_CALC);
                html_object_change_set (self->parent, HTML_CHANGE_ALL_CALC);
                /* force parent redraw */
                self->parent->width = 0;
                html_object_remove_child (self->parent, self);
                *len += html_object_get_recursive_length (self);

                return self;
        } else
                return html_engine_new_text_empty (e);
}

static gboolean
merge (HTMLObject *self, HTMLObject *with, HTMLEngine *e, GList **left, GList **right, HTMLCursor *cursor)
{
        if (self->parent) {
                html_object_change_set (self->parent, HTML_CHANGE_ALL_CALC);
                self->parent->width = 0;
        }

        return FALSE;
}

static void
remove_child (HTMLObject *self, HTMLObject *child)
{
        g_warning ("REMOVE CHILD unimplemented for ");
        gtk_html_debug_dump_object_type (self);
        g_assert_not_reached ();
}

static void
split (HTMLObject *self, HTMLEngine *e, HTMLObject *child, gint offset, gint level, GList **left, GList **right)
{
        if (child || (offset && html_object_get_length (self) != offset)) {
                g_warning ("don't know how to SPLIT ");
                gtk_html_debug_dump_object_type (self);
                return;
        }

        if (offset) {
                if (!self->next) {
                        html_clue_append (HTML_CLUE (self->parent), html_engine_new_text_empty (e));
                }
                *left  = g_list_prepend (*left,  self);
                *right = g_list_prepend (*right, self->next);
        } else {
                if (!self->prev) {
                        e->cursor->object = html_engine_new_text_empty (e);
                        e->cursor->offset = 0;
                        html_clue_prepend (HTML_CLUE (self->parent), e->cursor->object);
                }
                *left  = g_list_prepend (*left,  self->prev);
                *right = g_list_prepend (*right, self);
        }
        level--;

        if (level && self->parent)
                html_object_split (self->parent, e, offset ? self->next : self, 0, level, left, right);
}

static void
draw (HTMLObject *o,
      HTMLPainter *p,
      gint x, gint y,
      gint width, gint height,
      gint tx, gint ty)
{
        /* Do nothing by default.  We don't know how to paint ourselves.  */
}

static gboolean
is_transparent (HTMLObject *self)
{
        return TRUE;
}

static HTMLFitType
fit_line (HTMLObject *o,
          HTMLPainter *painter,
          gboolean start_of_line,
          gboolean first_run,
          gboolean next_to_floating,
          gint width_left)
{
        return (o->width <= width_left || (first_run && !next_to_floating)) ? HTML_FIT_COMPLETE : HTML_FIT_NONE;
}

static gboolean
html_object_real_calc_size (HTMLObject *o, HTMLPainter *painter, GList **changed_objs)
{
        return FALSE;
}

static gint
calc_min_width (HTMLObject *o, HTMLPainter *painter)
{
        html_object_calc_size (o, painter, FALSE);
        return o->width;
}

static gint
calc_preferred_width (HTMLObject *o, HTMLPainter *painter)
{
        html_object_calc_size (o, painter, FALSE);
        return o->width;
}
        
static void
set_max_width (HTMLObject *o, HTMLPainter *painter, gint max_width)
{
        o->max_width = max_width;
}

static void
set_max_height (HTMLObject *o, HTMLPainter *painter, gint max_height)
{
}

static gint
get_left_margin (HTMLObject *self, HTMLPainter *painter, gint y, gboolean with_aligned)
{
        return 0;
}

static gint
get_right_margin (HTMLObject *self, HTMLPainter *painter, gint y, gboolean with_aligned)
{
        return MAX (self->max_width, self->width);
}

static void
set_painter (HTMLObject *o, HTMLPainter *painter)
{
}

static void
reset (HTMLObject *o)
{
        /* o->width = 0;
           o->ascent = 0;
           o->descent = 0; */
}

static const gchar *
get_url (HTMLObject *o, gint offset)
{
        return NULL;
}

static const gchar *
get_target (HTMLObject *o, gint offset)
{
        return NULL;
}

static const gchar *
get_src (HTMLObject *o)
{
        return NULL;
}

static HTMLAnchor *
find_anchor (HTMLObject *o,
             const gchar *name,
             gint *x, gint *y)
{
        return NULL;
}

static void
set_bg_color (HTMLObject *o,
              GdkColor *color)
{
}

static GdkColor *
get_bg_color (HTMLObject *o,
              HTMLPainter *p)
{
        if (o->parent)
                return html_object_get_bg_color (o->parent, p); 

        if (p->widget && GTK_IS_HTML (p->widget))
                return &((html_colorset_get_color (GTK_HTML (p->widget)->engine->settings->color_set,
                                                   HTMLBgColor))->color);
        return NULL;
}

static HTMLObject*
check_point (HTMLObject *self,
             HTMLPainter *painter,
             gint x, gint y,
             guint *offset_return,
             gboolean for_cursor)
{
        if (x >= self->x
            && x < self->x + self->width
            && y >= self->y - self->ascent
            && y < self->y + self->descent) {
                if (offset_return != NULL)
                        *offset_return = 0;
                return self;
        }
    
        return NULL;
}

static gboolean
relayout (HTMLObject *self,
          HTMLEngine *engine,
          HTMLObject *child)
{
        /* FIXME int types of this stuff might change in `htmlobject.h',
           remember to sync.  */
        guint prev_width;
        guint prev_ascent, prev_descent;
        gboolean changed;

        if (html_engine_frozen (engine))
                return FALSE;

        prev_width = self->width;
        prev_ascent = self->ascent;
        prev_descent = self->descent;

        /* Notice that this will reset ascent and descent which we
           need afterwards.  Yeah, yuck, bleargh.  */
        html_object_reset (self);

        /* Crappy hack to make crappy htmlclueflow.c happy.  */
        if (self->y < self->ascent + self->descent) {
                g_warning ("htmlobject.c:relayout -- Eeek! This should not happen!  "
                           "Y value < height of object!\n");
                self->y = 0;
        } else {
                self->y -= prev_ascent + prev_descent;
        }

        changed = html_object_calc_size (self, engine->painter, FALSE);

        if (prev_width == self->width
            && prev_ascent == self->ascent
            && prev_descent == self->descent) {
                gtk_html_debug_log (engine->widget,
                                    "relayout: %s %p did not change.\n",
                                    html_type_name (HTML_OBJECT_TYPE (self)),
                                    self);
                if (changed)
                        html_engine_queue_draw (engine, self);

                return FALSE;
        }
        
        gtk_html_debug_log (engine->widget, "relayout: %s %p changed.\n",
                            html_type_name (HTML_OBJECT_TYPE (self)), self);

        if (self->parent == NULL) {
                /* FIXME resize the widget, e.g. scrollbars and such.  */
                html_engine_queue_draw (engine, self);

                /* FIXME extreme ugliness.  */
                self->x = 0;
                self->y = self->ascent;
        } else {
                /* Relayout our parent starting from us.  */
                if (! html_object_relayout (self->parent, engine, self))
                        html_engine_queue_draw (engine, self);
        }

        /* If the object has shrunk, we have to clean the areas around
           it so that we don't leave garbage on the screen.  FIXME:
           this wastes some time if there is an object on the right of
           or under this one.  */

        if (prev_ascent + prev_descent > self->ascent + self->descent)
                html_engine_queue_clear (engine,
                                         self->x,
                                         self->y + self->descent,
                                         self->width,
                                         (prev_ascent + prev_descent
                                          - (self->ascent + self->descent)));

        if (prev_width > self->width)
                html_engine_queue_clear (engine,
                                         self->x + self->width,
                                         self->y - self->ascent,
                                         prev_width - self->width,
                                         self->ascent + self->descent);

        return TRUE;
}

static HTMLVAlignType
get_valign (HTMLObject *self)
{
        return HTML_VALIGN_BOTTOM;
}

static gboolean
accepts_cursor (HTMLObject *self)
{
        return FALSE;
}

static void
get_cursor (HTMLObject *self,
            HTMLPainter *painter,
            guint offset,
            gint *x1, gint *y1,
            gint *x2, gint *y2)
{
        html_object_get_cursor_base (self, painter, offset, x2, y2);

        *x1 = *x2;
        *y1 = *y2 - self->ascent;
        *y2 += self->descent - 1;
}

static void
get_cursor_base (HTMLObject *self,
                 HTMLPainter *painter,
                 guint offset,
                 gint *x, gint *y)
{
        html_object_calc_abs_position (self, x, y);

        if (offset > 0)
                *x += self->width;
}

static guint
get_length (HTMLObject *self)
{
        return html_object_accepts_cursor (self) ? 1 : 0;
}

static guint
get_line_length (HTMLObject *self, HTMLPainter *p, gint line_offset)
{
        return html_object_get_length (self);
}

static guint
get_recursive_length (HTMLObject *self)
{
        return html_object_get_length (self);
}

static gboolean
select_range (HTMLObject *self,
              HTMLEngine *engine,
              guint start,
              gint length,
              gboolean queue_draw)
{
        gboolean selected;
        gboolean changed;

        selected = length > 0 || (length == -1 && start < html_object_get_length (self)) || html_object_is_container (self) ? TRUE : FALSE;
        changed  = (! selected && self->selected) || (selected && ! self->selected) ? TRUE : FALSE;

        self->selected = selected;

        return changed;
}

static void
append_selection_string (HTMLObject *self,
                         GString *buffer)
{
}

static void
forall (HTMLObject *self,
        HTMLEngine *e,
        HTMLObjectForallFunc func,
        gpointer data)
{
        (* func) (self, e, data);
}

static HTMLEngine *
get_engine (HTMLObject *self,
            HTMLEngine *e)
{
        return e;
}

static gboolean
is_container (HTMLObject *self)
{
        return FALSE;
}

static gboolean
save (HTMLObject *self,
      HTMLEngineSaveState *state)
{
        return TRUE;
}

static gboolean
save_plain (HTMLObject *self,
            HTMLEngineSaveState *state,
            gint requested_width)
{
        return TRUE;
}

static gint
check_page_split (HTMLObject *self, HTMLPainter *p, gint y)
{
        return 0;
}

static gboolean
search (HTMLObject *self, HTMLSearch *info)
{
        /* not found by default */
        return FALSE;
}

static HTMLObject *
next (HTMLObject *self, HTMLObject *child)
{
        return child->next;
}

static HTMLObject *
prev (HTMLObject *self, HTMLObject *child)
{
        return child->prev;
}

static HTMLObject *
head (HTMLObject *self)
{
        return NULL;
}

static HTMLObject *
tail (HTMLObject *self)
{
        return NULL;
}

static HTMLClearType
get_clear (HTMLObject *self)
{
        return HTML_CLEAR_NONE;
}

/* Class initialization.  */

void
html_object_type_init (void)
{
        html_object_class_init (&html_object_class, HTML_TYPE_OBJECT, sizeof (HTMLObject));
}

void
html_object_class_init (HTMLObjectClass *klass,
                        HTMLType type,
                        guint object_size)
{
        g_return_if_fail (klass != NULL);

        /* Set type.  */
        klass->type = type;
        klass->object_size = object_size;

        /* Install virtual methods.  */
        klass->destroy = destroy;
        klass->copy = copy;
        klass->op_copy = op_copy;
        klass->op_cut = op_cut;
        klass->merge = merge;
        klass->remove_child = remove_child;
        klass->split = split;
        klass->draw = draw;
        klass->is_transparent = is_transparent;
        klass->fit_line = fit_line;
        klass->calc_size = html_object_real_calc_size;
        klass->set_max_width = set_max_width;
        klass->set_max_height = set_max_height;
        klass->get_left_margin = get_left_margin;
        klass->get_right_margin = get_right_margin;
        klass->set_painter = set_painter;
        klass->reset = reset;
        klass->calc_min_width = calc_min_width;
        klass->calc_preferred_width = calc_preferred_width;
        klass->get_url = get_url;
        klass->get_target = get_target;
        klass->get_src = get_src;
        klass->find_anchor = find_anchor;
        klass->set_link = NULL;
        klass->set_bg_color = set_bg_color;
        klass->get_bg_color = get_bg_color;
        klass->check_point = check_point;
        klass->relayout = relayout;
        klass->get_valign = get_valign;
        klass->accepts_cursor = accepts_cursor;
        klass->get_cursor = get_cursor;
        klass->get_cursor_base = get_cursor_base;
        klass->select_range = select_range;
        klass->append_selection_string = append_selection_string;
        klass->forall = forall;
        klass->is_container = is_container;
        klass->save = save;
        klass->save_plain = save_plain;
        klass->check_page_split = check_page_split;
        klass->search = search;
        klass->search_next = search;
        klass->get_length = get_length;
        klass->get_line_length = get_line_length;
        klass->get_recursive_length = get_recursive_length;
        klass->next = next;
        klass->prev = prev;
        klass->head = head;
        klass->tail = tail;
        klass->get_engine = get_engine;
        klass->get_clear = get_clear;
}

void
html_object_init (HTMLObject *o,
                  HTMLObjectClass *klass)
{
        o->klass = klass;

        o->parent = NULL;
        o->prev = NULL;
        o->next = NULL;

        /* we don't have any info cached in the beginning */
        o->change = HTML_CHANGE_ALL;

        o->x = 0;
        o->y = 0;

        o->ascent = 0;
        o->descent = 0;

        o->width = 0;
        o->max_width = 0;
        o->min_width = 0;
        o->pref_width = 0;
        o->percent = 0;

        o->flags = HTML_OBJECT_FLAG_FIXEDWIDTH; /* FIXME Why? */

        o->redraw_pending = FALSE;
        o->free_pending = FALSE;
        o->selected = FALSE;
        o->draw_focused = FALSE;

        g_datalist_init (&o->object_data);
        g_datalist_init (&o->object_data_nocp);
}

HTMLObject *
html_object_new (HTMLObject *parent)
{
        HTMLObject *o;
        
        o = g_new0 (HTMLObject, 1);
        html_object_init (o, &html_object_class);

        return o;
}


/* Object duplication.  */

HTMLObject *
html_object_dup (HTMLObject *object)
{
        HTMLObject *new;

        g_return_val_if_fail (object != NULL, NULL);

        new = g_malloc (object->klass->object_size);
        html_object_copy (object, new);

        return new;
}

HTMLObject *
html_object_op_copy (HTMLObject *self, HTMLObject *parent, HTMLEngine *e, GList *from, GList *to, guint *len)
{
        return (* HO_CLASS (self)->op_copy) (self, parent, e, from, to, len);
}

HTMLObject *
html_object_op_cut (HTMLObject *self, HTMLEngine *e, GList *from, GList *to, GList *left, GList *right, guint *len)
{
        return (* HO_CLASS (self)->op_cut) (self, e, from, to, left, right, len);
}

gboolean
html_object_merge (HTMLObject *self, HTMLObject *with, HTMLEngine *e, GList **left, GList **right, HTMLCursor *cursor)
{
        if ((HTML_OBJECT_TYPE (self) == HTML_OBJECT_TYPE (with)
             /* FIXME */
             || (HTML_OBJECT_TYPE (self) == HTML_TYPE_TABLECELL && HTML_OBJECT_TYPE (with) == HTML_TYPE_CLUEV)
             || (HTML_OBJECT_TYPE (with) == HTML_TYPE_TABLECELL && HTML_OBJECT_TYPE (self) == HTML_TYPE_CLUEV))
            && (* HO_CLASS (self)->merge) (self, with, e, left, right, cursor)) {
                if (with->parent)
                        html_object_remove_child (with->parent, with);
                html_object_destroy (with);
                return TRUE;
        }
        return FALSE;
}

void
html_object_remove_child (HTMLObject *self, HTMLObject *child)
{
        g_assert (self);
        g_assert (child);

        (* HO_CLASS (self)->remove_child) (self, child);
}

void
html_object_split (HTMLObject *self, HTMLEngine *e, HTMLObject *child, gint offset, gint level,
                   GList **left, GList **right)
{
        g_assert (self);

        (* HO_CLASS (self)->split) (self, e, child, offset, level, left, right);
}


void
html_object_set_parent (HTMLObject *o, HTMLObject *parent)
{
        o->parent = parent;
}


static void
frame_offset (HTMLObject *o, 
              gint *x_return, gint *y_return)
{
        if (html_object_is_frame (o)) {
                HTMLEngine *e = html_object_get_engine (o, NULL);
                *x_return -= e->x_offset;
                *y_return -= e->y_offset;
        } 
}

void
html_object_calc_abs_position (HTMLObject *o,
                               gint *x_return, gint *y_return)
{
        HTMLObject *p;

        g_return_if_fail (o != NULL);

        *x_return = o->x;
        *y_return = o->y;
        
        frame_offset (o, x_return, y_return);

        for (p = o->parent; p != NULL; p = p->parent) {
                *x_return += p->x;
                *y_return += p->y - p->ascent;
                
                frame_offset (p, x_return, y_return);
        }
}

GdkRectangle *
html_object_get_bounds (HTMLObject *o, GdkRectangle *bounds)
{
        if (!bounds)
                bounds = g_new (GdkRectangle, 1);

        bounds->x = o->x;
        bounds->y = o->y - o->ascent;
        bounds->width = o->width;
        bounds->height = o->ascent + o->descent;

        return bounds;
}

gboolean
html_object_intersect (HTMLObject *o, GdkRectangle *result, gint x, gint y, gint width, gint height)
{
        GdkRectangle b;
        GdkRectangle a;

        a.x = x;
        a.y = y;
        a.width = width;
        a.height = height;

        return gdk_rectangle_intersect (html_object_get_bounds (o, &b), &a, result);
}


/* Virtual methods.  */

void
html_object_destroy (HTMLObject *self)
{
        (* HO_CLASS (self)->destroy) (self);
}

void
html_object_copy (HTMLObject *self,
                  HTMLObject *dest)
{
        (* HO_CLASS (self)->copy) (self, dest);
}

void
html_object_draw (HTMLObject *o,
                  HTMLPainter *p,
                  gint x, gint y,
                  gint width, gint height,
                  gint tx, gint ty)
{
        (* HO_CLASS (o)->draw) (o, p, x, y, width, height, tx, ty);
}

gboolean
html_object_is_transparent (HTMLObject *self)
{
        g_return_val_if_fail (self != NULL, TRUE);

        return (* HO_CLASS (self)->is_transparent) (self);
}

HTMLFitType
html_object_fit_line (HTMLObject *o,
                      HTMLPainter *painter,
                      gboolean start_of_line, 
                      gboolean first_run,
                      gboolean next_to_floating,
                      gint width_left)
{
        return (* HO_CLASS (o)->fit_line) (o, painter, start_of_line, first_run, next_to_floating, width_left);
}

gboolean
html_object_calc_size (HTMLObject *o, HTMLPainter *painter, GList **changed_objs)
{
        gboolean rv;

        rv = (* HO_CLASS (o)->calc_size) (o, painter, changed_objs);
        o->change &= ~HTML_CHANGE_SIZE;

        return rv;
}

void
html_object_set_max_width (HTMLObject *o, HTMLPainter *painter, gint max_width)
{
        (* HO_CLASS (o)->set_max_width) (o, painter, max_width);
}

void
html_object_set_max_height (HTMLObject *o, HTMLPainter *painter, gint max_height)
{
        (* HO_CLASS (o)->set_max_height) (o, painter, max_height);
}

gint
html_object_get_left_margin (HTMLObject *self, HTMLPainter *painter, gint y, gboolean with_aligned)
{
        return (* HO_CLASS (self)->get_left_margin) (self, painter, y, with_aligned);
}

gint
html_object_get_right_margin (HTMLObject *self, HTMLPainter *painter, gint y, gboolean with_aligned)
{
        return (* HO_CLASS (self)->get_right_margin) (self, painter, y, with_aligned);
}

static void
set_painter_forall (HTMLObject *o, HTMLEngine *e, gpointer data)
{
        (* HO_CLASS (o)->set_painter) (o, HTML_PAINTER (data));
}

void
html_object_set_painter (HTMLObject *o, HTMLPainter *painter)
{
        html_object_forall (o, NULL, set_painter_forall, painter);
}

void
html_object_reset (HTMLObject *o)
{
        (* HO_CLASS (o)->reset) (o);
}

gint
html_object_calc_min_width (HTMLObject *o,
                            HTMLPainter *painter)
{
        if (o->change & HTML_CHANGE_MIN_WIDTH) {
                o->min_width = (* HO_CLASS (o)->calc_min_width) (o, painter);
                o->change &= ~HTML_CHANGE_MIN_WIDTH;
        }
        return o->min_width;
}

gint
html_object_calc_preferred_width (HTMLObject *o,
                                  HTMLPainter *painter)
{
        if (o->change & HTML_CHANGE_PREF_WIDTH) {
                o->pref_width = (* HO_CLASS (o)->calc_preferred_width) (o, painter);
                o->change &= ~HTML_CHANGE_PREF_WIDTH;
        }
        return o->pref_width;
}

#if 0
gint
html_object_get_uris (HTMLObject *o, char **link, char **target, char **src) 
{
        return TRUE;
}
#endif 

const gchar *
html_object_get_url (HTMLObject *o, gint offset)
{
        return (* HO_CLASS (o)->get_url) (o, offset);
}

const gchar *
html_object_get_target (HTMLObject *o, gint offset)
{
        return (* HO_CLASS (o)->get_target) (o, offset);
}

gchar *
html_object_get_complete_url (HTMLObject *o, gint offset)
{
        const gchar *url, *target;

        url = html_object_get_url (o, offset);
        target = html_object_get_target (o, offset);
        return url || target ? g_strconcat (url ? url : "#", url ? (target && *target ? "#" : NULL) : target,
                                              url ? target : NULL, NULL) : NULL;
}

const gchar *
html_object_get_src (HTMLObject *o)
{
        return (* HO_CLASS (o)->get_src) (o);
}

HTMLAnchor *
html_object_find_anchor (HTMLObject *o,
                         const gchar *name,
                         gint *x, gint *y)
{
        return (* HO_CLASS (o)->find_anchor) (o, name, x, y);
}

void
html_object_set_bg_color (HTMLObject *o, GdkColor *color)
{
        (* HO_CLASS (o)->set_bg_color) (o, color);
}

GdkColor *
html_object_get_bg_color (HTMLObject *o, HTMLPainter *p)
{
        return (* HO_CLASS (o)->get_bg_color) (o, p);
}

HTMLObject *
html_object_check_point (HTMLObject *self,
                         HTMLPainter *painter,
                         gint x, gint y,
                         guint *offset_return,
                         gboolean for_cursor)
{
        if (self->width == 0 || self->ascent + self->descent == 0)
                return NULL;

        return (* HO_CLASS (self)->check_point) (self, painter, x, y, offset_return, for_cursor);
}

gboolean
html_object_relayout (HTMLObject *self,
                      HTMLEngine *engine,
                      HTMLObject *child)
{
        g_return_val_if_fail (self != NULL, TRUE);
        return (* HO_CLASS (self)->relayout) (self, engine, child);
}

HTMLVAlignType
html_object_get_valign (HTMLObject *self)
{
        g_return_val_if_fail (self != NULL, HTML_VALIGN_BOTTOM);

        return (* HO_CLASS (self)->get_valign) (self);
}

gboolean
html_object_accepts_cursor (HTMLObject *self)
{
        return (* HO_CLASS (self)->accepts_cursor) (self);
}

/* Warning: `calc_size()' must have been called on `self' before this so that
   this works correctly.  */
void
html_object_get_cursor (HTMLObject *self,
                        HTMLPainter *painter,
                        guint offset,
                        gint *x1, gint *y1,
                        gint *x2, gint *y2)
{
        (* HO_CLASS (self)->get_cursor) (self, painter, offset, x1, y1, x2, y2);
        if (!html_object_is_text (self) && *y2 - *y1 < 10) {
                gint missing = 10 - (*y2 - *y1);

                *y1 -= (missing >> 1) + ((missing >> 1) & 1);
                *y2 += missing >> 1;
        }
}

/* Warning: `calc_size()' must have been called on `self' before this so that
   this works correctly.  */
void
html_object_get_cursor_base (HTMLObject *self,
                             HTMLPainter *painter,
                             guint offset,
                             gint *x, gint *y)
{
        (* HO_CLASS (self)->get_cursor_base) (self, painter, offset, x, y);
}


gboolean
html_object_select_range (HTMLObject *self,
                          HTMLEngine *engine,
                          guint start,
                          gint length,
                          gboolean queue_draw)
{
        return (* HO_CLASS (self)->select_range) (self, engine, start, length, queue_draw);
}

void
html_object_append_selection_string (HTMLObject *self,
                                     GString *buffer)
{
        g_return_if_fail (self != NULL);
        g_return_if_fail (buffer != NULL);

        (* HO_CLASS (self)->append_selection_string) (self, buffer);
}

HTMLEngine *
html_object_get_engine (HTMLObject *self, HTMLEngine *e)
{
        return (* HO_CLASS (self)->get_engine) (self, e);
}

HTMLEngine *
html_object_engine (HTMLObject *o, HTMLEngine *e)
{
        while (o) {
                e = html_object_get_engine (o, e);
                if (html_object_is_frame (o))
                        break;
                o = o->parent;
        }

        return e;
}

void
html_object_forall (HTMLObject *self,
                    HTMLEngine *e,
                    HTMLObjectForallFunc func,
                    gpointer data)
{
        (* HO_CLASS (self)->forall) (self, e, func, data);
}

/* Ugly.  We should have an `is_a' implementation.  */
gboolean
html_object_is_container (HTMLObject *self)
{
        return (* HO_CLASS (self)->is_container) (self);
}


/* Ugly.  We should have an `is_a' implementation.  */

gboolean
html_object_is_text (HTMLObject *object)
{
        HTMLType type;

        g_return_val_if_fail (object != NULL, FALSE);

        type = HTML_OBJECT_TYPE (object);

        return (type == HTML_TYPE_TEXT || type == HTML_TYPE_LINKTEXT);
}

gboolean
html_object_is_clue (HTMLObject *object)
{
        HTMLType type;

        g_return_val_if_fail (object != NULL, FALSE);

        type = HTML_OBJECT_TYPE (object);

        return (type == HTML_TYPE_CLUE || type == HTML_TYPE_CLUEV || type == HTML_TYPE_TABLECELL
                || type == HTML_TYPE_CLUEFLOW || type == HTML_TYPE_CLUEALIGNED);
}

HTMLObject *
html_object_next_not_type (HTMLObject *object, HTMLType t)
{
        HTMLObject *p;

        g_return_val_if_fail (object != NULL, NULL);
        g_return_val_if_fail (object->parent, NULL);

        p = html_object_next (object->parent, object);
        while (p && HTML_OBJECT_TYPE (p) == t)
                p = html_object_next (p->parent, p);

        return p;
}

HTMLObject *
html_object_prev_not_type (HTMLObject *object, HTMLType t)
{
        HTMLObject *p;

        g_return_val_if_fail (object != NULL, NULL);
        g_return_val_if_fail (object->parent, NULL);

        p = html_object_prev (object->parent, object);
        while (p && HTML_OBJECT_TYPE (p) == t)
                p = html_object_prev (p->parent, p);

        return p;
}

HTMLObject *
html_object_next_not_slave (HTMLObject *object)
{
        return html_object_next_not_type (object, HTML_TYPE_TEXTSLAVE);
}

HTMLObject *
html_object_prev_not_slave (HTMLObject *object)
{
        return html_object_prev_not_type (object, HTML_TYPE_TEXTSLAVE);
}


gboolean
html_object_save (HTMLObject *self,
                  HTMLEngineSaveState *state)
{
        return (* HO_CLASS (self)->save) (self, state);
}

gboolean
html_object_save_plain (HTMLObject *self,
                        HTMLEngineSaveState *state,
                        gint requested_width)
{
        return (* HO_CLASS (self)->save_plain) (self, state, requested_width);
}

gint
html_object_check_page_split  (HTMLObject *self, HTMLPainter *p, gint y)
{
        g_return_val_if_fail (self != NULL, 0);

        return (* HO_CLASS (self)->check_page_split) (self, p, y);
}

void
html_object_change_set (HTMLObject *self, HTMLChangeFlags f)
{
        HTMLObject *obj = self;

        g_assert (self != NULL);

        if (f != HTML_CHANGE_NONE) {
                while (obj) {
                        obj->change |= f;
                        obj = obj->parent;
                }
        }
}

static void
change (HTMLObject *o, HTMLEngine *e, gpointer data)
{
        o->change |= GPOINTER_TO_INT (data);
}

void
html_object_change_set_down (HTMLObject *self, HTMLChangeFlags f)
{
        html_object_forall (self, NULL, (HTMLObjectForallFunc) change, GINT_TO_POINTER (f));
}

gboolean
html_object_search (HTMLObject *self, HTMLSearch *info)
{
        return (* HO_CLASS (self)->search) (self, info);
}

gboolean
html_object_search_next (HTMLObject *self, HTMLSearch *info)
{
        return (* HO_CLASS (self)->search_next) (self, info);
}

HTMLObject *
html_object_set_link (HTMLObject *self,
                      HTMLColor *color,
                      const gchar *url,
                      const gchar *target)
{
        return (HO_CLASS (self)->set_link) ? (* HO_CLASS (self)->set_link) (self, color, url, target) : NULL;
}

HTMLObject *
html_object_remove_link (HTMLObject *self,
                         HTMLColor *color)
{
        return (HO_CLASS (self)->set_link) ? (* HO_CLASS (self)->set_link) (self, color, NULL, NULL) : NULL;
}

guint
html_object_get_length (HTMLObject *self)
{
        return (* HO_CLASS (self)->get_length) (self);
}

guint
html_object_get_line_length (HTMLObject *self, HTMLPainter *p, gint line_offset)
{
        return (* HO_CLASS (self)->get_line_length) (self, p, line_offset);
}

guint
html_object_get_recursive_length (HTMLObject *self)
{
        return (* HO_CLASS (self)->get_recursive_length) (self);
}

HTMLObject *
html_object_next_by_type (HTMLObject *self, HTMLType t)
{
        HTMLObject *next;

        g_assert (self);

        next = self->next;
        while (next && HTML_OBJECT_TYPE (next) != t)
                next = next->next;

        return next;
}

HTMLObject *
html_object_prev_by_type (HTMLObject *self, HTMLType t)
{
        HTMLObject *prev;

        g_assert (self);

        prev = self->prev;
        while (prev && HTML_OBJECT_TYPE (prev) != t)
                prev = prev->prev;

        return prev;
}

/* Movement functions */

HTMLObject *
html_object_next (HTMLObject *self, HTMLObject *child)
{
        return (* HO_CLASS (self)->next) (self, child);
}

HTMLObject *
html_object_prev (HTMLObject *self, HTMLObject *child)
{
        return (* HO_CLASS (self)->prev) (self, child);
}

HTMLObject *
html_object_head (HTMLObject *self)
{
        return (* HO_CLASS (self)->head) (self);
}

HTMLObject *
html_object_tail (HTMLObject *self)
{
        return (* HO_CLASS (self)->tail) (self);
}

HTMLObject *
html_object_tail_not_slave (HTMLObject *self)
{
        HTMLObject *o = html_object_tail (self);

        if (o && HTML_OBJECT_TYPE (o) == HTML_TYPE_TEXTSLAVE)
                o = html_object_prev_not_slave (o);
        return o;
}

gboolean
html_object_cursor_forward (HTMLObject *self, HTMLCursor *cursor)
{
        gint len;

        g_assert (self);
        g_assert (cursor->object == self);

        if (html_object_is_container (self))
                return FALSE;

        len = html_object_get_length (self);
        if (cursor->offset < len) {
                cursor->offset ++;
                cursor->position ++;
                return TRUE;
        } else
                return FALSE;
}

gboolean
html_object_cursor_backward (HTMLObject *self, HTMLCursor *cursor)
{
        HTMLObject *prev;

        g_assert (self);
        g_assert (cursor->object == self);

        if (html_object_is_container (self))
                return FALSE;

        if (cursor->offset > 1 || (cursor->offset > 0 && (! (prev = html_object_prev_not_slave (self))
                                                          || HTML_IS_CLUEALIGNED (prev) || !html_object_accepts_cursor (prev)))) {
                cursor->offset --;
                cursor->position --;
                return TRUE;
        }

        return FALSE;
}

/*********************
 * movement on leafs
 */

/* go up in tree so long as we can get object in neighborhood given by function next_fn */

static HTMLObject *
next_object_uptree (HTMLObject *obj, HTMLObject * (*next_fn ) (HTMLObject *, HTMLObject *))
{
        HTMLObject *next = NULL;

        while (obj->parent && !(next = (*next_fn) (obj->parent, obj)))
                obj = obj->parent;

        return next;
}

/* go down in tree to leaf in way given by down_fn children */

static HTMLObject *
move_object_downtree (HTMLObject *obj, HTMLObject * (*down_fn ) (HTMLObject *))
{
        HTMLObject *down;

        while ((down = (*down_fn) (obj)))
                obj = down;

        return obj;
}

static HTMLObject *
move_object (HTMLObject *obj, HTMLObject * (*next_fn ) (HTMLObject *, HTMLObject *), HTMLObject * (*down_fn ) (HTMLObject *))
{
        obj = next_object_uptree (obj, next_fn);
        if (obj)
                obj = move_object_downtree (obj, down_fn);
        return obj;
}

HTMLObject *
html_object_next_leaf (HTMLObject *self)
{
        return move_object (self, html_object_next, html_object_head);
}

HTMLObject *
html_object_next_leaf_not_type (HTMLObject *self, HTMLType t)
{
        HTMLObject *rv = self;
        while ((rv = html_object_next_leaf (rv)) && HTML_OBJECT_TYPE (rv) == t);

        return rv;
}

HTMLObject *
html_object_prev_leaf (HTMLObject *self)
{
        return move_object (self, html_object_prev, html_object_tail);
}

HTMLObject *
html_object_prev_leaf_not_type (HTMLObject *self, HTMLType t)
{
        HTMLObject *rv = self;
        while ((rv = html_object_prev_leaf (rv)) && HTML_OBJECT_TYPE (rv) == t);

        return rv;
}

/* movement on cursor accepting objects */

/* go up in tree so long as we can get object in neighborhood given by function next_fn */

static HTMLObject *
next_object_uptree_cursor (HTMLObject *obj, HTMLObject * (*next_fn ) (HTMLObject *))
{
        HTMLObject *next = NULL;

        while (obj->parent && !(next = (*next_fn) (obj))) {
                obj = obj->parent;
                if (html_object_accepts_cursor (obj))
                        return obj;
        }

        return next;
}

/* go down in tree to leaf in way given by down_fn children */

static HTMLObject *
move_object_downtree_cursor (HTMLObject *obj, HTMLObject * (*down_fn ) (HTMLObject *), HTMLObject * (*next_fn ) (HTMLObject *))
{
        HTMLObject *last_obj = obj;

        while ((obj = (*down_fn) (obj))) {
                if (html_object_accepts_cursor (obj))
                        break;
                last_obj = obj;
        }

        if (!obj && last_obj) {
                obj = last_obj;

                while ((obj = (*next_fn) (obj)))
                        if (html_object_accepts_cursor (obj))
                                break;
        }

        return obj;
}

static HTMLObject *
move_object_cursor (HTMLObject *obj, gint *offset, gboolean forward,
                    HTMLObject * (*next_fn ) (HTMLObject *), HTMLObject * (*down_fn ) (HTMLObject *))
{
        HTMLObject *down, *before;

        do {
                gboolean found = FALSE;
                if (((*offset == 0 && forward) || (*offset && !forward)) && html_object_is_container (obj))
                        if ((down = (*down_fn) (obj))) {
                                down = move_object_downtree_cursor (down, down_fn, next_fn);
                                if (down) {
                                        if (html_object_is_container (down))
                                                *offset = forward ? 0 : 1;
                                        return down;
                                }
                        }

                before = obj;
                do {
                        obj = next_object_uptree_cursor (obj, next_fn);
                        if (obj) {
                                if (html_object_accepts_cursor (obj)) {
                                        if (html_object_is_container (obj))
                                                *offset = before->parent == obj->parent
                                                        ? forward ? 0 : 1
                                                        : forward ? 1 : 0;
                                        found = TRUE;
                                } else {
                                        HTMLObject *down;
                                        down = move_object_downtree_cursor (obj, down_fn, next_fn);
                                        if (down) {
                                                if (html_object_is_container (down))
                                                        *offset = forward ? 0 : 1;
                                                obj = down;
                                                found = TRUE;
                                        }
                                }
                        }
                } while (obj && !found);
        } while (obj && !html_object_accepts_cursor (obj));

        return obj;
}

HTMLObject *
html_object_next_cursor (HTMLObject *self, gint *offset)
{
        return move_object_cursor (self, offset, TRUE, html_object_next_not_slave, html_object_head);
}

HTMLObject *
html_object_prev_cursor (HTMLObject *self, gint *offset)
{
        return move_object_cursor (self, offset, FALSE, html_object_prev_not_slave, html_object_tail_not_slave);
}

/***/

guint
html_object_get_bytes (HTMLObject *self)
{
        return html_object_is_text (self) ? html_text_get_bytes (HTML_TEXT (self)) : html_object_get_length (self);
}

guint
html_object_get_index (HTMLObject *self, guint offset)
{
        return html_object_is_text (self) ? html_text_get_index (HTML_TEXT (self), offset) : offset;
}

void
html_object_set_data_nocp (HTMLObject *object, const gchar *key, const gchar *value)
{
        g_datalist_set_data_full (&object->object_data_nocp, key, g_strdup (value), g_free);
}

void
html_object_set_data_full_nocp (HTMLObject *object, const gchar *key, const gpointer value, GDestroyNotify func)
{
        g_datalist_set_data_full (&object->object_data_nocp, key, value, func);
}

gpointer
html_object_get_data_nocp (HTMLObject *object, const gchar *key)
{
        return g_datalist_get_data (&object->object_data_nocp, key);
}

void
html_object_set_data (HTMLObject *object, const gchar *key, const gchar *value)
{
        g_datalist_set_data_full (&object->object_data, key, g_strdup (value), g_free);
}

void
html_object_set_data_full (HTMLObject *object, const gchar *key, const gpointer value, GDestroyNotify func)
{
        g_datalist_set_data_full (&object->object_data, key, value, func);
}

gpointer
html_object_get_data (HTMLObject *object, const gchar *key)
{
        return g_datalist_get_data (&object->object_data, key);
}

static void
copy_data (GQuark key_id, gpointer data, gpointer user_data)
{
        HTMLObject *o = HTML_OBJECT (user_data);

        g_datalist_id_set_data_full (&o->object_data,
                                     key_id,
                                     g_strdup ((gchar *) data), g_free);
}

void
html_object_copy_data_from_object (HTMLObject *dst, HTMLObject *src)
{
        g_datalist_foreach (&src->object_data, copy_data, dst);
}

static void
object_save_data (GQuark key_id, gpointer data, gpointer user_data)
{
        HTMLEngineSaveState *state = (HTMLEngineSaveState *) user_data;
        const gchar *str;

        str = html_engine_get_class_data (state->engine, state->save_data_class_name, g_quark_to_string (key_id));
        /* printf ("object %s %s\n", g_quark_to_string (key_id), str); */
        if (!str) {
                /* printf ("save %s %s -> %s\n", state->save_data_class_name, g_quark_to_string (key_id), (gchar *) data); */
                html_engine_save_output_string (state, "<!--+GtkHTML:<DATA class=\"%s\" key=\"%s\" value=\"%s\">-->",
                                                state->save_data_class_name, g_quark_to_string (key_id), (char *) data);
                html_engine_set_class_data (state->engine, state->save_data_class_name, g_quark_to_string (key_id), data);
        }
}

static void
handle_object_data (gpointer key, gpointer value, gpointer data)
{
        HTMLEngineSaveState *state = (HTMLEngineSaveState *) data;
        gchar *str;

        str = html_object_get_data (HTML_OBJECT (state->save_data_object), key);
        /* printf ("handle: %s %s %s %s\n", state->save_data_class_name, key, value, str); */
        if (!str) {
                /* printf ("clear\n"); */
                html_engine_save_output_string (state, "<!--+GtkHTML:<DATA class=\"%s\" clear=\"%s\">-->",
                                                state->save_data_class_name, (char *) key);
                state->data_to_remove = g_slist_prepend (state->data_to_remove, key);
        } else if (strcmp (value, str)) {
                /* printf ("change\n"); */
                html_engine_save_output_string (state, "<!--+GtkHTML:<DATA class=\"%s\" key=\"%s\" value=\"%s\">-->",
                                                state->save_data_class_name, (char *) key, str);
                html_engine_set_class_data (state->engine, state->save_data_class_name, key, value);
        }
}

static void
clear_data (gchar *key, HTMLEngineSaveState *state)
{
        html_engine_clear_class_data (state->engine, state->save_data_class_name, key);
}

gboolean
html_object_save_data (HTMLObject *self, HTMLEngineSaveState *state)
{
        if (state->engine->save_data) {
                GHashTable *t;
                state->save_data_class_name = html_type_name (self->klass->type);
                state->save_data_object = self;
                t = html_engine_get_class_table (state->engine, state->save_data_class_name);
                if (t) {
                        state->data_to_remove = NULL;
                        g_hash_table_foreach (t, handle_object_data, state);
                        g_slist_foreach (state->data_to_remove, (GFunc) clear_data, state);
                        g_slist_free (state->data_to_remove);
                        state->data_to_remove = NULL;
                }
                g_datalist_foreach (&self->object_data, object_save_data, state);
        }

        return TRUE;
}

GList *
html_object_get_bound_list (HTMLObject *self, GList *list)
{
        return list && list->next
                ? (HTML_OBJECT (list->data) == self ? list->next : NULL)
                : NULL;
}

void
html_object_move_cursor_before_remove (HTMLObject *o, HTMLEngine *e)
{
        if (e->cursor->object == o) {
                if (html_object_next_not_slave (o))
                        e->cursor->object = html_object_next_not_slave (o);
                else
                        e->cursor->object = html_object_prev_not_slave (o);
        }
}

gboolean
html_object_could_remove_whole (HTMLObject *o, GList *from, GList *to, GList *left, GList *right)
{
        return ((!from && !to)
                || html_object_next_not_slave (HTML_OBJECT (o))
                || html_object_prev_not_slave (HTML_OBJECT (o)))
                && ((!left  || o != left->data) && (!right || o != right->data));

}

void
html_object_check_cut_lists (HTMLObject *self, HTMLObject *replacement, GList *left, GList *right)
{
        if (left && left->data == self)
                left->data = replacement;
        if (right && right->data == self)
                right->data = replacement;
}


typedef struct {
        HTMLInterval *i;
        GString *buffer;
        gboolean in;
} tmpSelData;

static void
select_object (HTMLObject *o, HTMLEngine *e, gpointer data)
{
        tmpSelData *d = (tmpSelData *) data;

        if (o == d->i->from.object)
                d->in = TRUE;
        if (d->in)
                html_object_select_range (o, NULL,
                                          html_interval_get_start (d->i, o),
                                          html_interval_get_length (d->i, o), FALSE);

        if (o == d->i->to.object)
                d->in = FALSE;
}

static void
unselect_object (HTMLObject *o, HTMLEngine *e, gpointer data)
{
        o->selected = FALSE;
}

gchar *
html_object_get_selection_string (HTMLObject *o, HTMLEngine *e)
{
        HTMLObject *tail;
        tmpSelData data;
        gchar *string;

        g_assert (o);

        tail        = html_object_get_tail_leaf (o);
        data.buffer = g_string_new (NULL);
        data.in     = FALSE;
        data.i      = html_interval_new (html_object_get_head_leaf (o), tail, 0, html_object_get_length (tail));

        html_interval_forall (data.i, e, select_object, &data);
        html_object_append_selection_string (o, data.buffer);
        html_interval_forall (data.i, e, unselect_object, NULL);

        html_interval_destroy (data.i);
        string = data.buffer->str;
        g_string_free (data.buffer, FALSE);

        return string;
}

HTMLObject *
html_object_get_tail_leaf (HTMLObject *o)
{
        HTMLObject *tail, *rv = o;

        do {
                tail = html_object_tail_not_slave (rv);
                if (tail)
                        rv = tail;
        } while (tail);

        return rv;
}

HTMLObject *
html_object_get_head_leaf (HTMLObject *o)
{
        HTMLObject *head, *rv = o;

        do {
                head = html_object_head (rv);
                if (head)
                        rv = head;
        } while (head);

        return rv;
}

HTMLObject *
html_object_nth_parent (HTMLObject *self, gint n)
{
        while (self && n > 0) {
                self = self->parent;
                n --;
        }

        return self;
}

gint
html_object_get_parent_level (HTMLObject *self)
{
        gint level = 0;

        while (self) {
                level ++;
                self = self->parent;
        }

        return level;
}

GList *
html_object_heads_list (HTMLObject *o)
{
        GList *list = NULL;

        g_return_val_if_fail (o, NULL);

        while (o) {
                list = g_list_append (list, o);
                o = html_object_head (o);
        }

        return list;
}

GList *
html_object_tails_list (HTMLObject *o)
{
        GList *list = NULL;

        g_return_val_if_fail (o, NULL);

        while (o) {
                list = g_list_append (list, o);
                o = html_object_tail_not_slave (o);
        }

        return list;
}

static void
merge_down (HTMLEngine *e, GList *left, GList *right)
{
        HTMLObject *lo;
        HTMLObject *ro;

        while (left && right) {
                lo    = HTML_OBJECT (left->data);
                ro    = HTML_OBJECT (right->data);
                left  = left->next;
                right = right->next;
                if (!html_object_merge (lo, ro, e, &left, &right, NULL))
                        break;
        }
}

void
html_object_merge_down (HTMLObject *o, HTMLObject *w, HTMLEngine *e)
{
        merge_down (e, html_object_tails_list (o), html_object_heads_list (w));
}

gboolean
html_object_is_parent (HTMLObject *parent, HTMLObject *child)
{
        g_assert (parent && child);

        while (child) {
                if (child->parent == parent)
                        return TRUE;
                child = child->parent;
        }

        return FALSE;
}

gint
html_object_get_insert_level (HTMLObject *o)
{
        switch (HTML_OBJECT_TYPE (o)) {
        case HTML_TYPE_TABLECELL:
        case HTML_TYPE_CLUEV:
                return 3;
        case HTML_TYPE_CLUEFLOW:
                return 2;
        default:
                return 1;
        }
}

void
html_object_engine_translation (HTMLObject *o, HTMLEngine *e, gint *tx, gint *ty)
{
        HTMLObject *p;

        *tx = 0;
        *ty = 0;

        for (p = o->parent; p != NULL && HTML_OBJECT_TYPE (p) != HTML_TYPE_IFRAME; p = p->parent) {
                *tx += p->x;
                *ty += p->y - p->ascent;
        }

        /* *tx += e->leftBorder; */
        /* *ty += e->topBorder; */
}

gboolean
html_object_engine_intersection (HTMLObject *o, HTMLEngine *e, gint tx, gint ty, gint *x1, gint *y1, gint *x2, gint *y2)
{
        *x1 = o->x + tx;
        *y1 = o->y - o->ascent + ty;
        *x2 = o->x + o->width + tx;
        *y2 = o->y + o->descent + ty;

        return html_engine_intersection (e, x1, y1, x2, y2);
}

void
html_object_add_to_changed (GList **changed_objs, HTMLObject *o)
{
        GList *l, *next;

        if (!changed_objs || (*changed_objs && (*changed_objs)->data == o))
                return;

        for (l = *changed_objs; l; l = next) {
                if (l->data == NULL) {
                        l = l->next;
                        next = l->next;
                        continue;
                }
                next = l->next;
                if (html_object_is_parent (o, HTML_OBJECT (l->data))) {
                        *changed_objs = g_list_remove_link (*changed_objs, l);
                        g_list_free (l);
                } else
                        break;
        }

        *changed_objs = g_list_prepend (*changed_objs, o);
}

gint
html_object_get_n_children (HTMLObject *self)
{
        return HO_CLASS (self)->get_n_children ? (* HO_CLASS (self)->get_n_children) (self) : 0;
}

HTMLObject *
html_object_get_child (HTMLObject *self, gint index)
{
        return HO_CLASS (self)->get_child ? (* HO_CLASS (self)->get_child) (self, index) : NULL;
}


gint
html_object_get_child_index (HTMLObject *self, HTMLObject *child)
{
        return HO_CLASS (self)->get_child_index ? (* HO_CLASS (self)->get_child_index) (self, child) : -1;
}

HTMLClearType
html_object_get_clear (HTMLObject *self)
{
        return (* HO_CLASS (self)->get_clear) (self);
}

static HTMLObject *
next_prev_cursor_object (HTMLObject *o, HTMLEngine *e, gint *offset, gboolean forward)
{
        HTMLCursor cursor;
        gboolean result;

        html_cursor_init (&cursor, o, html_object_is_container (o) ? *offset : (forward ? html_object_get_length (o) : 0));

        result = forward ? html_cursor_forward (&cursor, e) : html_cursor_backward (&cursor, e);
        *offset = cursor.offset;

        return result ? cursor.object : NULL;
}

HTMLObject *
html_object_next_cursor_object (HTMLObject *o, HTMLEngine *e, gint *offset)
{
        return next_prev_cursor_object (o, e, offset, TRUE);
}

HTMLObject *
html_object_prev_cursor_object (HTMLObject *o, HTMLEngine *e, gint *offset)
{
        return next_prev_cursor_object (o, e, offset, FALSE);
}

HTMLObject *
html_object_next_cursor_leaf (HTMLObject *o, HTMLEngine *e)
{
        gint offset = html_object_get_length (o);

        o = html_object_next_cursor_object (o, e, &offset);
        while (o && html_object_is_container (o))
                o = html_object_next_cursor_object (o, e, &offset);

        return o;
}

HTMLObject *
html_object_prev_cursor_leaf (HTMLObject *o, HTMLEngine *e)
{
        gint offset = html_object_get_length (o);

        o = html_object_prev_cursor_object (o, e, &offset);
        while (o && html_object_is_container (o))
                o = html_object_prev_cursor_object (o, e, &offset);

        return o;
}

HTMLClueFlow *
html_object_get_flow (HTMLObject *o)
{
        while (o && !HTML_IS_CLUEFLOW (o))
                o = o->parent;

        return HTML_CLUEFLOW (o);
}