path: root/widgets/misc/e-canvas-utils.c

/*
 *
 * This program 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 of the License, or (at your option) version 3.
 *
 * This program 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 the program; if not, see <http://www.gnu.org/licenses/>
 *
 *
 * Authors:
 *      Chris Lahey <clahey@ximian.com>
 *
 * Copyright (C) 1999-2008 Novell, Inc. (www.novell.com)
 *
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "e-canvas-utils.h"

void
e_canvas_item_move_absolute (GnomeCanvasItem *item,
                             gdouble dx,
                             gdouble dy)
{
    cairo_matrix_t translate;

    g_return_if_fail (GNOME_IS_CANVAS_ITEM (item));

    cairo_matrix_init_translate (&translate, dx, dy);

    gnome_canvas_item_set_matrix (item, &translate);
}

static double
compute_offset (gint top,
                gint bottom,
                gint page_top,
                gint page_bottom)
{
    gint size = bottom - top;
    gint offset = 0;

    if (top <= page_top && bottom >= page_bottom)
        return 0;

    if (bottom > page_bottom)
        offset = (bottom - page_bottom);
    if (top < page_top + offset)
        offset = (top - page_top);

    if (top <= page_top + offset && bottom >= page_bottom + offset)
        return offset;

    if (top < page_top + size * 3 / 2 + offset)
        offset = top - (page_top + size * 3 / 2);
    if (bottom > page_bottom - size * 3 / 2 + offset)
        offset = bottom - (page_bottom - size * 3 / 2);
    if (top < page_top + size * 3 / 2 + offset)
        offset = top - ((page_top + page_bottom - (bottom - top)) / 2);

    return offset;
}

static void
e_canvas_show_area (GnomeCanvas *canvas,
                    gdouble x1,
                    gdouble y1,
                    gdouble x2,
                    gdouble y2)
{
    GtkAdjustment *h, *v;
    gint dx = 0, dy = 0;
    gdouble page_size;
    gdouble lower;
    gdouble upper;
    gdouble value;

    g_return_if_fail (canvas != NULL);
    g_return_if_fail (GNOME_IS_CANVAS (canvas));

    h = gtk_scrollable_get_hadjustment (GTK_SCROLLABLE (canvas));
    page_size = gtk_adjustment_get_page_size (h);
    lower = gtk_adjustment_get_lower (h);
    upper = gtk_adjustment_get_upper (h);
    value = gtk_adjustment_get_value (h);
    dx = compute_offset (x1, x2, value, value + page_size);
    if (dx)
        gtk_adjustment_set_value (h, CLAMP (value + dx, lower, upper - page_size));

    v = gtk_scrollable_get_vadjustment (GTK_SCROLLABLE (canvas));
    page_size = gtk_adjustment_get_page_size (v);
    lower = gtk_adjustment_get_lower (v);
    upper = gtk_adjustment_get_upper (v);
    value = gtk_adjustment_get_value (v);
    dy = compute_offset (y1, y2, value, value + page_size);
    if (dy)
        gtk_adjustment_set_value (v, CLAMP (value + dy, lower, upper - page_size));
}

void
e_canvas_item_show_area (GnomeCanvasItem *item,
                         gdouble x1,
                         gdouble y1,
                         gdouble x2,
                         gdouble y2)
{
    g_return_if_fail (item != NULL);
    g_return_if_fail (GNOME_IS_CANVAS_ITEM (item));

    gnome_canvas_item_i2w (item, &x1, &y1);
    gnome_canvas_item_i2w (item, &x2, &y2);

    e_canvas_show_area (item->canvas, x1, y1, x2, y2);
}

static gboolean
e_canvas_area_shown (GnomeCanvas *canvas,
                     gdouble x1,
                     gdouble y1,
                     gdouble x2,
                     gdouble y2)
{
    GtkAdjustment *h, *v;
    gint dx = 0, dy = 0;
    gdouble page_size;
    gdouble lower;
    gdouble upper;
    gdouble value;

    g_return_val_if_fail (canvas != NULL, FALSE);
    g_return_val_if_fail (GNOME_IS_CANVAS (canvas), FALSE);

    h = gtk_scrollable_get_hadjustment (GTK_SCROLLABLE (canvas));
    page_size = gtk_adjustment_get_page_size (h);
    lower = gtk_adjustment_get_lower (h);
    upper = gtk_adjustment_get_upper (h);
    value = gtk_adjustment_get_value (h);
    dx = compute_offset (x1, x2, value, value + page_size);
    if (CLAMP (value + dx, lower, upper - page_size) - value != 0)
        return FALSE;

    v = gtk_scrollable_get_vadjustment (GTK_SCROLLABLE (canvas));
    page_size = gtk_adjustment_get_page_size (v);
    lower = gtk_adjustment_get_lower (v);
    upper = gtk_adjustment_get_upper (v);
    value = gtk_adjustment_get_value (v);
    dy = compute_offset (y1, y2, value, value + page_size);
    if (CLAMP (value + dy, lower, upper - page_size) - value != 0)
        return FALSE;
    return TRUE;
}

gboolean
e_canvas_item_area_shown (GnomeCanvasItem *item,
                          gdouble x1,
                          gdouble y1,
                          gdouble x2,
                          gdouble y2)
{
    g_return_val_if_fail (item != NULL, FALSE);
    g_return_val_if_fail (GNOME_IS_CANVAS_ITEM (item), FALSE);

    gnome_canvas_item_i2w (item, &x1, &y1);
    gnome_canvas_item_i2w (item, &x2, &y2);

    return e_canvas_area_shown (item->canvas, x1, y1, x2, y2);
}

typedef struct {
    gdouble x1;
    gdouble y1;
    gdouble x2;
    gdouble y2;
    GnomeCanvas *canvas;
} DoubsAndCanvas;

static gboolean
show_area_timeout (gpointer data)
{
    DoubsAndCanvas *dac = data;

    e_canvas_show_area (dac->canvas, dac->x1, dac->y1, dac->x2, dac->y2);
    g_object_unref (dac->canvas);
    g_free (dac);
    return FALSE;
}

void
e_canvas_item_show_area_delayed (GnomeCanvasItem *item,
                                 gdouble x1,
                                 gdouble y1,
                                 gdouble x2,
                                 gdouble y2,
                                 gint delay)
{
    DoubsAndCanvas *dac;

    g_return_if_fail (item != NULL);
    g_return_if_fail (GNOME_IS_CANVAS_ITEM (item));

    gnome_canvas_item_i2w (item, &x1, &y1);
    gnome_canvas_item_i2w (item, &x2, &y2);

    dac = g_new (DoubsAndCanvas, 1);
    dac->x1 = x1;
    dac->y1 = y1;
    dac->x2 = x2;
    dac->y2 = y2;
    dac->canvas = item->canvas;
    g_object_ref (item->canvas);
    g_timeout_add (delay, show_area_timeout, dac);
}