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 GlivImage *current_image;
  37
  38 /* Horizontal Scrollbar. */
  39 static GtkHScrollbar *hscroll;
  40
  41 /* Vertical Scrollbar. */
  42 static GtkVScrollbar *vscroll;
  43
  44 gboolean toggle_scrollbars(void)
  45 {
  46     GtkWidget *widgets[2];
  47
  48     widgets[0] = GTK_WIDGET(hscroll);
  49     widgets[1] = GTK_WIDGET(vscroll);
  50
  51     if (toggle_widgets(widgets, 2, &options->scrollbars) && options->scrollbars)
  52         update_scrollbars();
  53
  54     return FALSE;
  55 }
  56
  57 /* Update a given scrollbar. */
  58 static void update_scroll(GtkScrollbar * scroll, gfloat min, gfloat max,
  59                           gfloat dim)
  60 {
  61     GtkAdjustment *adj;
  62     gboolean update_needed = FALSE;
  63     gfloat previous;
  64
  65     adj = gtk_range_get_adjustment(GTK_RANGE(scroll));
  66
  67     /* Smallest length containing the image and the window = window U image. */
  68     previous = adj->lower;
  69     adj->lower = MIN(min, 0.0);
  70     update_needed = update_needed || !float_equal(previous, adj->lower);
  71
  72     previous = adj->upper;
  73     adj->upper = MAX(max, dim);
  74     update_needed = update_needed || !float_equal(previous, adj->upper);
  75
  76     /* Window size. */
  77     adj->page_size = dim;
  78
  79     adj->step_increment = MOVE_OFFSET;
  80     adj->page_increment = dim;
  81
  82     /* The offset is actually computed with adj->lower and adj->upper. */
  83     adj->value = 0.0;
  84
  85     if (update_needed) {
  86         gtk_adjustment_changed(adj);
  87         gdk_window_process_updates(GTK_WIDGET(scroll)->window, FALSE);
  88     }
  89 }
  90
  91 /* Update both scrollbars. */
  92 void update_scrollbars(void)
  93 {
  94     gfloat min_x, max_x, min_y, max_y;
  95
  96     if (current_image == NULL || options->scrollbars == FALSE)
  97         return;
  98
  99     get_matrix_bounding_box(&min_x, &max_x, &min_y, &max_y);
 100
 101     update_scroll(GTK_SCROLLBAR(hscroll), min_x, max_x,
 102                   (gfloat) rt->wid_size->width);
 103
 104     update_scroll(GTK_SCROLLBAR(vscroll), min_y, max_y,
 105                   (gfloat) rt->wid_size->height);
 106 }
 107
 108 static gboolean scroll_val(GtkRange * range)
 109 {
 110     gfloat offset;
 111
 112     offset = -1.0 * gtk_range_get_value(range);
 113
 114     if (range == GTK_RANGE(hscroll))
 115         matrix_move(offset, 0.0);
 116     else
 117         /* range == GTK_RANGE(vscroll) */
 118         matrix_move(0.0, offset);
 119
 120     refresh(REFRESH_BURST | APPEND_HISTORY);
 121     update_scrollbars();
 122     return FALSE;
 123 }
 124
 125 /* Called during the initialization to build the two scrollbars. */
 126 GtkWidget *get_new_scrollbar(gboolean horizontal)
 127 {
 128     GtkRange *range;
 129
 130     if (horizontal) {
 131         range = GTK_RANGE(gtk_hscrollbar_new(NULL));
 132         hscroll = GTK_HSCROLLBAR(range);
 133     } else {
 134         range = GTK_RANGE(gtk_vscrollbar_new(NULL));
 135         vscroll = GTK_VSCROLLBAR(range);
 136     }
 137
 138     gtk_range_set_update_policy(range, GTK_UPDATE_CONTINUOUS);
 139
 140     g_signal_connect(range, "value-changed", G_CALLBACK(scroll_val), NULL);
 141
 142     return GTK_WIDGET(range);
 143 }
 144
 145 void hide_scrollbars(void)
 146 {
 147     gtk_widget_hide(GTK_WIDGET(hscroll));
 148     gtk_widget_hide(GTK_WIDGET(vscroll));
 149 }