| 1 | /* Derived from gtktreeview.c |
| 2 | * Copyright (C) 2000 Red Hat, Inc., Jonathan Blandford <jrb@redhat.com> |
| 3 | * Portions copyright (C) 2009 Richard Kettlewell |
| 4 | * |
| 5 | * This library is free software; you can redistribute it and/or |
| 6 | * modify it under the terms of the GNU Library General Public |
| 7 | * License as published by the Free Software Foundation; either |
| 8 | * version 2 of the License, or (at your option) any later version. |
| 9 | * |
| 10 | * This library is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 | * Library General Public License for more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU Library General Public |
| 16 | * License along with this library; if not, write to the |
| 17 | * Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
| 18 | * Boston, MA 02111-1307, USA. |
| 19 | */ |
| 20 | /** @file disobedience/autoscroll.c |
| 21 | * @brief Automatic scrolling of a GtkTreeView |
| 22 | * |
| 23 | * GTK+ doesn't expose the automatic scrolling support if you don't use its |
| 24 | * high-level treeview drag+drop features. |
| 25 | * |
| 26 | * Adapted from GTK+ upstream as of commit |
| 27 | * 7fda8e6378d90bc8cf670ffe9dea682911e5e241. |
| 28 | */ |
| 29 | |
| 30 | #include <config.h> |
| 31 | |
| 32 | #include <glib.h> |
| 33 | #include <gtk/gtk.h> |
| 34 | |
| 35 | #include "autoscroll.h" |
| 36 | |
| 37 | /** @brief Object data key used to track the autoscroll timeout */ |
| 38 | #define AUTOSCROLL_KEY "autoscroll.greenend.org.uk" |
| 39 | |
| 40 | /** @brief Controls size of edge region that provokes scrolling |
| 41 | * |
| 42 | * Actually this is half the size of the scroll region. In isolation this may |
| 43 | * seem bizarre, but GTK+ uses the value internally for other purposes. |
| 44 | */ |
| 45 | #define SCROLL_EDGE_SIZE 15 |
| 46 | |
| 47 | /** @brief Called from time to time to check whether auto-scrolling is needed |
| 48 | * @param data The GtkTreeView |
| 49 | * @return TRUE, to keep on truckin' |
| 50 | */ |
| 51 | static gboolean autoscroll_timeout(gpointer data) { |
| 52 | GtkTreeView *tree_view = data; |
| 53 | GdkRectangle visible_rect; |
| 54 | gint wx, wy, tx, ty; |
| 55 | gint offset; |
| 56 | gfloat value; |
| 57 | |
| 58 | /* First we must find the pointer Y position in tree coordinates. GTK+ |
| 59 | * natively knows what the bin window is and can get the pointer in bin |
| 60 | * coords and convert to tree coords. But there is no published way for us |
| 61 | * to find the bin window, so we must start in widget coords. */ |
| 62 | gtk_widget_get_pointer(GTK_WIDGET(tree_view), &wx, &wy); |
| 63 | //fprintf(stderr, "widget coords: %d, %d\n", wx, wy); |
| 64 | gtk_tree_view_convert_widget_to_tree_coords(tree_view, wx, wy, &tx, &ty); |
| 65 | //fprintf(stderr, "tree coords: %d, %d\n", tx, ty); |
| 66 | |
| 67 | gtk_tree_view_get_visible_rect (tree_view, &visible_rect); |
| 68 | |
| 69 | /* see if we are near the edge. */ |
| 70 | offset = ty - (visible_rect.y + 2 * SCROLL_EDGE_SIZE); |
| 71 | if (offset > 0) { |
| 72 | offset = ty - (visible_rect.y + visible_rect.height - 2 * SCROLL_EDGE_SIZE); |
| 73 | if (offset < 0) |
| 74 | return TRUE; |
| 75 | } |
| 76 | |
| 77 | GtkAdjustment *vadjustment = gtk_tree_view_get_vadjustment(tree_view); |
| 78 | |
| 79 | value = CLAMP (vadjustment->value + offset, 0.0, |
| 80 | vadjustment->upper - vadjustment->page_size); |
| 81 | gtk_adjustment_set_value (vadjustment, value); |
| 82 | |
| 83 | return TRUE; |
| 84 | } |
| 85 | |
| 86 | /** @brief Enable autoscrolling |
| 87 | * @param tree_view Tree view to enable autoscrolling |
| 88 | * |
| 89 | * It's harmless to call this if autoscrolling is already enabled. |
| 90 | * |
| 91 | * It's up to you to cancel the callback when no longer required (including |
| 92 | * object destruction). |
| 93 | */ |
| 94 | void autoscroll_add(GtkTreeView *tree_view) { |
| 95 | guint *scrolldata = g_object_get_data(G_OBJECT(tree_view), AUTOSCROLL_KEY); |
| 96 | if(!scrolldata) { |
| 97 | /* Set up the callback */ |
| 98 | scrolldata = g_new(guint, 1); |
| 99 | *scrolldata = gdk_threads_add_timeout(150, autoscroll_timeout, tree_view); |
| 100 | g_object_set_data(G_OBJECT(tree_view), AUTOSCROLL_KEY, scrolldata); |
| 101 | //fprintf(stderr, "autoscroll enabled\n"); |
| 102 | } |
| 103 | } |
| 104 | |
| 105 | /** @brief Disable autoscrolling |
| 106 | * @param tree_view Tree view to enable autoscrolling |
| 107 | * |
| 108 | * It's harmless to call this if autoscrolling is not enabled. |
| 109 | */ |
| 110 | void autoscroll_remove(GtkTreeView *tree_view) { |
| 111 | guint *scrolldata = g_object_get_data(G_OBJECT(tree_view), AUTOSCROLL_KEY); |
| 112 | if(scrolldata) { |
| 113 | g_object_set_data(G_OBJECT(tree_view), AUTOSCROLL_KEY, NULL); |
| 114 | g_source_remove(*scrolldata); |
| 115 | g_free(scrolldata); |
| 116 | //fprintf(stderr, "autoscroll disabled\n"); |
| 117 | } |
| 118 | } |
| 119 | |
| 120 | /* |
| 121 | Local Variables: |
| 122 | c-basic-offset:2 |
| 123 | comment-column:40 |
| 124 | fill-column:79 |
| 125 | indent-tabs-mode:nil |
| 126 | End: |
| 127 | */ |