source: trunk/third/gtkhtml/src/htmlengine-edit-movement.c @ 16767

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/* This file is part of the GtkHTML library.
   
   Copyright (C) 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 <ctype.h>

#include "htmlengine-edit-cursor.h"
#include "htmlengine-edit-selection-updater.h"
#include "htmlengine-edit-movement.h"
#include "htmlobject.h"


void
html_engine_update_selection_if_necessary (HTMLEngine *e)
{
        if (e->mark == NULL)
                return;

        html_engine_edit_selection_updater_schedule (e->selection_updater);
}


guint
html_engine_move_cursor (HTMLEngine *e,
                         HTMLEngineCursorMovement movement,
                         guint count)
{
        gboolean (* movement_func) (HTMLCursor *, HTMLEngine *);
        guint c;

        g_return_val_if_fail (e != NULL, 0);
        g_return_val_if_fail (HTML_IS_ENGINE (e), 0);

        if (count == 0)
                return 0;

        switch (movement) {
        case HTML_ENGINE_CURSOR_RIGHT:
                movement_func = html_cursor_forward;
                break;

        case HTML_ENGINE_CURSOR_LEFT:
                movement_func = html_cursor_backward;
                break;

        case HTML_ENGINE_CURSOR_UP:
                movement_func = html_cursor_up;
                break;

        case HTML_ENGINE_CURSOR_DOWN:
                movement_func = html_cursor_down;
                break;

        default:
                g_warning ("Unsupported movement %d\n", (gint) movement);
                return 0;
        }

        html_engine_hide_cursor (e);

        for (c = 0; c < count; c++) {
                if (! (* movement_func) (e->cursor, e))
                        break;
        }

        html_engine_show_cursor (e);
        html_engine_update_selection_if_necessary (e);

        return c;
}


/**
 * html_engine_jump_to_object:
 * @e: An HTMLEngine object
 * @object: Object to move the cursor to
 * @offset: Cursor offset within @object
 * 
 * Move the cursor to object @object, at the specified @offset.
 * Notice that this does *not* modify the selection.
 * 
 * Return value: 
 **/
void
html_engine_jump_to_object (HTMLEngine *e,
                            HTMLObject *object,
                            guint offset)
{
        g_return_if_fail (e != NULL);
        g_return_if_fail (HTML_IS_ENGINE (e));
        g_return_if_fail (object != NULL);

        /* Delete the cursor in the original position.  */
        html_engine_hide_cursor (e);

        /* Jump to the specified position.  FIXME: Beep if it fails?  */
        html_cursor_jump_to (e->cursor, e, object, offset);
        html_cursor_normalize (e->cursor);

        /* Draw the cursor in the new position.  */
        html_engine_show_cursor (e);
}

/**
 * html_engine_jump_at:
 * @e: An HTMLEngine object
 * @x: X coordinate
 * @y: Y coordinate
 * 
 * Make the cursor jump at the specified @x, @y pointer position.
 **/
void
html_engine_jump_at (HTMLEngine *e,
                     gint x, gint y)
{
        HTMLObject *obj;
        guint offset;

        g_return_if_fail (e != NULL);
        g_return_if_fail (HTML_IS_ENGINE (e));

        obj = html_engine_get_object_at (e, x, y, &offset, TRUE);
        if (obj == NULL)
                return;

        /* printf ("jump to object type %d - %p\n", HTML_OBJECT_TYPE (obj), obj); */
        html_engine_jump_to_object (e, obj, offset);
        /* printf ("jumped to object type %d - %p\n", HTML_OBJECT_TYPE (e->cursor->object), e->cursor->object); */
}


void
html_engine_beginning_of_document (HTMLEngine *engine)
{
        g_return_if_fail (engine != NULL);
        g_return_if_fail (HTML_IS_ENGINE (engine));

        html_engine_hide_cursor (engine);
        html_cursor_beginning_of_document (engine->cursor, engine);
        html_engine_show_cursor (engine);

        html_engine_update_selection_if_necessary (engine);
}

void
html_engine_end_of_document (HTMLEngine *engine)
{
        g_return_if_fail (engine != NULL);
        g_return_if_fail (HTML_IS_ENGINE (engine));

        html_engine_hide_cursor (engine);
        html_cursor_end_of_document (engine->cursor, engine);
        html_engine_show_cursor (engine);

        html_engine_update_selection_if_necessary (engine);
}


gboolean
html_engine_beginning_of_line (HTMLEngine *engine)
{
        gboolean retval;

        g_return_val_if_fail (engine != NULL, FALSE);
        g_return_val_if_fail (HTML_IS_ENGINE (engine), FALSE);

        html_engine_hide_cursor (engine);
        retval = html_cursor_beginning_of_line (engine->cursor, engine);
        html_engine_show_cursor (engine);

        html_engine_update_selection_if_necessary (engine);

        return retval;
}

gboolean
html_engine_end_of_line (HTMLEngine *engine)
{
        gboolean retval;

        g_return_val_if_fail (engine != NULL, FALSE);
        g_return_val_if_fail (HTML_IS_ENGINE (engine), FALSE);

        html_engine_hide_cursor (engine);
        retval = html_cursor_end_of_line (engine->cursor, engine);
        html_engine_show_cursor (engine);

        html_engine_update_selection_if_necessary (engine);

        return retval;
}

gboolean
html_engine_beginning_of_paragraph (HTMLEngine *engine)
{
        gboolean retval;

        g_return_val_if_fail (engine != NULL, FALSE);
        g_return_val_if_fail (HTML_IS_ENGINE (engine), FALSE);

        html_engine_hide_cursor (engine);
        retval = html_cursor_beginning_of_paragraph (engine->cursor, engine);
        html_engine_show_cursor (engine);

        html_engine_update_selection_if_necessary (engine);

        return retval;
}

gboolean
html_engine_end_of_paragraph (HTMLEngine *engine)
{
        gboolean retval;

        g_return_val_if_fail (engine != NULL, FALSE);
        g_return_val_if_fail (HTML_IS_ENGINE (engine), FALSE);

        html_engine_hide_cursor (engine);
        retval = html_cursor_end_of_paragraph (engine->cursor, engine);
        html_engine_show_cursor (engine);

        html_engine_update_selection_if_necessary (engine);

        return retval;
}


gint
html_engine_scroll_down (HTMLEngine *engine,
                         gint amount)
{
        HTMLCursor *cursor;
        HTMLCursor prev_cursor;
        gint start_x, start_y;
        gint x, y, new_y;

        g_return_val_if_fail (engine != NULL, FALSE);
        g_return_val_if_fail (HTML_IS_ENGINE (engine), FALSE);

        cursor = engine->cursor;

        html_object_get_cursor_base (cursor->object, engine->painter, cursor->offset, &start_x, &start_y);

        html_engine_hide_cursor (engine);

        y = new_y = start_y;

        while (1) {
                html_cursor_copy (&prev_cursor, cursor);

                new_y = html_cursor_down (cursor, engine);
                html_object_get_cursor_base (cursor->object, engine->painter, cursor->offset, &x, &new_y);

                /* FIXME html_cursor_down() is broken.  It should
                   return FALSE and TRUE appropriately.  But I am lazy
                   now.  */
                if (new_y == y)
                        break;

                if (new_y < start_y)
                        return 0;

                if (new_y - start_y >= amount) {
                        html_cursor_copy (cursor, &prev_cursor);
                        break;
                }

                y = new_y;
        }

        html_engine_show_cursor (engine);

        html_engine_update_selection_if_necessary (engine);

        return new_y - start_y;
}

gint
html_engine_scroll_up (HTMLEngine *engine,
                       gint amount)
{
        HTMLCursor *cursor;
        HTMLCursor prev_cursor;
        gint start_x, start_y;
        gint x, y, new_y;

        g_return_val_if_fail (engine != NULL, FALSE);
        g_return_val_if_fail (HTML_IS_ENGINE (engine), FALSE);

        cursor = engine->cursor;

        html_object_get_cursor_base (cursor->object, engine->painter, cursor->offset, &start_x, &start_y);

        html_engine_hide_cursor (engine);

        y = start_y;

        while (1) {
                html_cursor_copy (&prev_cursor, cursor);

                html_cursor_up (cursor, engine);
                html_object_get_cursor_base (cursor->object, engine->painter, cursor->offset, &x, &new_y);

                /* FIXME html_cursor_down() is broken.  It should
                   return FALSE and TRUE appropriately.  But I am lazy
                   now.  */
                if (new_y == y)
                        break;

                if (new_y > start_y) {
                        html_engine_show_cursor (engine);
                        return 0;
                }

                if (start_y - new_y >= amount) {
                        html_cursor_copy (cursor, &prev_cursor);
                        break;
                }

                y = new_y;
        }

        html_engine_show_cursor (engine);

        html_engine_update_selection_if_necessary (engine);

        return start_y - new_y;
}


gboolean
html_engine_forward_word (HTMLEngine *e)
{
        gboolean rv = FALSE;

        g_return_val_if_fail (e != NULL, FALSE);
        g_return_val_if_fail (HTML_IS_ENGINE (e), FALSE);

        html_engine_hide_cursor (e);
        while (!g_unichar_isalnum (html_cursor_get_current_char (e->cursor)) && html_cursor_forward (e->cursor, e))
                rv = TRUE;
        while (g_unichar_isalnum (html_cursor_get_current_char (e->cursor)) && html_cursor_forward (e->cursor, e))
                rv = TRUE;
        html_engine_show_cursor (e);
        html_engine_update_selection_if_necessary (e);

        return rv;
}

gboolean
html_engine_backward_word (HTMLEngine *e)
{
        gboolean rv = FALSE;

        g_return_val_if_fail (e != NULL, FALSE);
        g_return_val_if_fail (HTML_IS_ENGINE (e), FALSE);

        html_engine_hide_cursor (e);
        while (!g_unichar_isalnum (html_cursor_get_prev_char (e->cursor)) && html_cursor_backward (e->cursor, e))
                rv = TRUE;
        while (g_unichar_isalnum (html_cursor_get_prev_char (e->cursor)) && html_cursor_backward (e->cursor, e))
                rv = TRUE;
        html_engine_show_cursor (e);
        html_engine_update_selection_if_necessary (e);

        return rv;
}

void
html_engine_edit_cursor_position_save (HTMLEngine *e)
{
        g_return_if_fail (e != NULL);
        g_return_if_fail (HTML_IS_ENGINE (e));

        e->cursor_position_stack = g_slist_prepend (e->cursor_position_stack, GINT_TO_POINTER (e->cursor->position));
}

void
html_engine_edit_cursor_position_restore (HTMLEngine *e)
{
        g_return_if_fail (e != NULL);
        g_return_if_fail (HTML_IS_ENGINE (e));

        if (!e->cursor_position_stack)
                return;

        html_engine_hide_cursor (e);
        html_cursor_jump_to_position (e->cursor, e, GPOINTER_TO_INT (e->cursor_position_stack->data));
        e->cursor_position_stack = g_slist_remove_link (e->cursor_position_stack, e->cursor_position_stack);
        html_engine_show_cursor (e);
}