src/scrollbars.c

   1 /*
   2  * This program is free software; you can redistribute it and/or
   3  * modify it under the terms of the GNU General Public License
   4  * as published by the Free Software Foundation; either version 2
   5  * of the License, or (at your option) any later version.
   6  *
   7  * This program is distributed in the hope that it will be useful,
   8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10  * GNU General Public License for more details.
  11  *
  12  * You should have received a copy of the GNU General Public License
  13  * along with this program; if not, write to the Free Software
  14  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  15  *
  16  * See the COPYING file for license information.
  17  *
  18  * Guillaume Chazarain <guichaz@yahoo.fr>
  19  */
  20
  21 /******************************************
  22  * The vertical and horizontal scrollbars *
  23  ******************************************/
  24
  25 #include "gliv.h"
  26 #include "scrollbars.h"
  27 #include "options.h"
  28 #include "gliv_image.h"
  29 #include "windows.h"
  30 #include "matrix.h"
  31 #include "params.h"
  32 #include "rendering.h"
  33
  34 extern rt_struct *rt;
  35 extern options_struct *options;
  36 extern gliv_image *current_image;
  37
  38 /* Horizontal Scrollbar. */
  39 static GtkHScrollbar *hscroll;
  40
  41 /* Vertical Scrollbar. */
  42 static GtkVScrollbar *vscroll;
  43
  44 void toggle_scrollbars(void)
  45 {
  46     /* We are not reentrant. */
  47     static gboolean toggling = FALSE;
  48
  49     if (toggling)
  50         return;
  51
  52     toggling = TRUE;
  53
  54     if (!toggle_widget(GTK_WIDGET(hscroll), &options->scrollbars))
  55         return;
  56
  57     /* To undo the toggle_widget() side effect. */
  58     options->scrollbars ^= TRUE;
  59
  60     if (!toggle_widget(GTK_WIDGET(vscroll), &options->scrollbars))
  61         return;
  62
  63     if (options->scrollbars)
  64         update_scrollbars();
  65
  66     toggling = FALSE;
  67 }
  68
  69 /* Update a given scrollbar. */
  70 static void update_scroll(GtkScrollbar * scroll, gfloat min, gfloat max,
  71                           gfloat dim)
  72 {
  73     GtkAdjustment *adj;
  74     gboolean update_needed = FALSE;
  75     gfloat previous;
  76
  77     adj = gtk_range_get_adjustment(GTK_RANGE(scroll));
  78
  79     /* Smallest length containing the image and the window = window U image. */
  80     previous = adj->lower;
  81     adj->lower = MIN(min, 0.0);
  82     update_needed = update_needed || !float_equal(previous, adj->lower);
  83
  84     previous = adj->upper;
  85     adj->upper = MAX(max, dim);
  86     update_needed = update_needed || !float_equal(previous, adj->upper);
  87
  88     /* Window size. */
  89     adj->page_size = dim;
  90
  91     adj->step_increment = MOVE_OFFSET;
  92     adj->page_increment = dim;
  93
  94     /* The offset is actually computed with adj->lower and adj->upper. */
  95     adj->value = 0.0;
  96
  97     if (update_needed) {
  98         gtk_adjustment_changed(adj);
  99         gdk_window_process_updates(GTK_WIDGET(scroll)->window, FALSE);
 100     }
 101 }
 102
 103 /* Update both scrollbars. */
 104 void update_scrollbars(void)
 105 {
 106     gfloat min_x, max_x, min_y, max_y;
 107
 108     if (current_image == NULL || options->scrollbars == FALSE)
 109         return;
 110
 111     get_matrix_bounding_box(&min_x, &max_x, &min_y, &max_y);
 112
 113     update_scroll(GTK_SCROLLBAR(hscroll), min_x, max_x,
 114                   (gfloat) rt->wid_size->width);
 115
 116     update_scroll(GTK_SCROLLBAR(vscroll), min_y, max_y,
 117                   (gfloat) rt->wid_size->height);
 118 }
 119
 120 static void scroll_val(GtkRange * range)
 121 {
 122     gfloat offset;
 123
 124     offset = -1.0 * gtk_range_get_value(range);
 125
 126     if (range == GTK_RANGE(hscroll))
 127         matrix_move(offset, 0.0);
 128     else
 129         /* range == GTK_RANGE(vscroll) */
 130         matrix_move(0.0, offset);
 131
 132     refresh(REFRESH_BURST | APPEND_HISTORY);
 133     update_scrollbars();
 134 }
 135
 136 /* Called during the initialization to build the two scrollbars. */
 137 GtkWidget *get_new_scrollbar(gboolean horizontal)
 138 {
 139     GtkRange *range;
 140
 141     if (horizontal) {
 142         range = GTK_RANGE(gtk_hscrollbar_new(NULL));
 143         hscroll = GTK_HSCROLLBAR(range);
 144     } else {
 145         range = GTK_RANGE(gtk_vscrollbar_new(NULL));
 146         vscroll = GTK_VSCROLLBAR(range);
 147     }
 148
 149     gtk_range_set_update_policy(range, GTK_UPDATE_CONTINUOUS);
 150
 151     g_signal_connect(range, "value-changed", G_CALLBACK(scroll_val), NULL);
 152
 153     return GTK_WIDGET(range);
 154 }
 155
 156 void hide_scrollbars(void)
 157 {
 158     gtk_widget_hide(GTK_WIDGET(hscroll));
 159     gtk_widget_hide(GTK_WIDGET(vscroll));
 160 }