| 1 | /* |
| 2 | * This file is part of DisOrder |
| 3 | * Copyright (C) 2009 Richard Kettlewell |
| 4 | * |
| 5 | * This program is free software: you can redistribute it and/or modify |
| 6 | * it under the terms of the GNU General Public License as published by |
| 7 | * the Free Software Foundation, either version 3 of the License, or |
| 8 | * (at your option) any later version. |
| 9 | * |
| 10 | * This program 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 |
| 13 | * GNU General Public License for more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU General Public License |
| 16 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 17 | */ |
| 18 | /** @file disobedience/multidrag.c |
| 19 | * @brief Drag multiple rows of a GtkTreeView |
| 20 | * |
| 21 | * Normally when you start a drag, GtkTreeView sets the selection to just row |
| 22 | * you dragged from (because it can't cope with dragging more than one row at a |
| 23 | * time). |
| 24 | * |
| 25 | * Disobedience needs more. To implement this it intercepts button-press-event |
| 26 | * and button-release event and for clicks that might be the start of drags, |
| 27 | * suppresses changes to the selection. A consequence of this is that it needs |
| 28 | * to intercept button-release-event too, to restore the effect of the click, |
| 29 | * if it turns out not to be drag after all. |
| 30 | * |
| 31 | * The location of the initial click is stored in object data called @c |
| 32 | * multidrag-where. |
| 33 | * |
| 34 | * Inspired by similar code in <a |
| 35 | * href="http://code.google.com/p/quodlibet/">Quodlibet</a> (another software |
| 36 | * jukebox, albeit as far as I can see a single-user one). |
| 37 | */ |
| 38 | #include <config.h> |
| 39 | #include <glib.h> |
| 40 | #include <gtk/gtk.h> |
| 41 | |
| 42 | #include "multidrag.h" |
| 43 | |
| 44 | static gboolean multidrag_selection_block(GtkTreeSelection attribute((unused)) *selection, |
| 45 | GtkTreeModel attribute((unused)) *model, |
| 46 | GtkTreePath attribute((unused)) *path, |
| 47 | gboolean attribute((unused)) path_currently_selected, |
| 48 | gpointer data) { |
| 49 | return *(const gboolean *)data; |
| 50 | } |
| 51 | |
| 52 | static void block_selection(GtkWidget *w, gboolean block, |
| 53 | int x, int y) { |
| 54 | static const gboolean which[] = { FALSE, TRUE }; |
| 55 | GtkTreeSelection *s = gtk_tree_view_get_selection(GTK_TREE_VIEW(w)); |
| 56 | gtk_tree_selection_set_select_function(s, |
| 57 | multidrag_selection_block, |
| 58 | (gboolean *)&which[!!block], |
| 59 | NULL); |
| 60 | // Remember the pointer location |
| 61 | int *where = g_object_get_data(G_OBJECT(w), "multidrag-where"); |
| 62 | if(!where) { |
| 63 | where = g_malloc(2 * sizeof (int)); |
| 64 | g_object_set_data(G_OBJECT(w), "multidrag-where", where); |
| 65 | } |
| 66 | where[0] = x; |
| 67 | where[1] = y; |
| 68 | // TODO release 'where' when object is destroyed |
| 69 | } |
| 70 | |
| 71 | static gboolean multidrag_button_press_event(GtkWidget *w, |
| 72 | GdkEventButton *event, |
| 73 | gpointer attribute((unused)) user_data) { |
| 74 | /* By default we assume that anything this button press does should |
| 75 | * act as normal */ |
| 76 | block_selection(w, TRUE, -1, -1); |
| 77 | /* We are only interested in left-button behavior */ |
| 78 | if(event->button != 1) |
| 79 | return FALSE; |
| 80 | /* We are only interested in unmodified clicks (not SHIFT etc) */ |
| 81 | if(event->state & GDK_MODIFIER_MASK) |
| 82 | return FALSE; |
| 83 | /* We are only interested if a well-defined path is clicked */ |
| 84 | GtkTreePath *path; |
| 85 | if(!gtk_tree_view_get_path_at_pos(GTK_TREE_VIEW(w), |
| 86 | event->x, event->y, |
| 87 | &path, |
| 88 | NULL, |
| 89 | NULL, NULL)) |
| 90 | return FALSE; |
| 91 | //gtk_widget_grab_focus(w); // TODO why?? |
| 92 | /* We are only interested if a selected row is clicked */ |
| 93 | GtkTreeSelection *s = gtk_tree_view_get_selection(GTK_TREE_VIEW(w)); |
| 94 | if(!gtk_tree_selection_path_is_selected(s, path)) |
| 95 | return FALSE; |
| 96 | /* We block subsequent selection changes and remember where the |
| 97 | * click was */ |
| 98 | block_selection(w, FALSE, event->x, event->y); |
| 99 | return FALSE; /* propagate */ |
| 100 | } |
| 101 | |
| 102 | static gboolean multidrag_button_release_event(GtkWidget *w, |
| 103 | GdkEventButton *event, |
| 104 | gpointer attribute((unused)) user_data) { |
| 105 | int *where = g_object_get_data(G_OBJECT(w), "multidrag-where"); |
| 106 | |
| 107 | /* Did button-press-event do anything? We just check the outcome rather than |
| 108 | * going through all the conditions it tests. */ |
| 109 | if(where && where[0] != -1) { |
| 110 | // Remember where the down-click was |
| 111 | const int x = where[0], y = where[1]; |
| 112 | // Re-allow selections |
| 113 | block_selection(w, TRUE, -1, -1); |
| 114 | if(x == event->x && y == event->y) { |
| 115 | // If the up-click is at the same location as the down-click, |
| 116 | // it's not a drag. |
| 117 | GtkTreePath *path; |
| 118 | GtkTreeViewColumn *col; |
| 119 | if(gtk_tree_view_get_path_at_pos(GTK_TREE_VIEW(w), |
| 120 | event->x, event->y, |
| 121 | &path, |
| 122 | &col, |
| 123 | NULL, NULL)) { |
| 124 | gtk_tree_view_set_cursor(GTK_TREE_VIEW(w), path, col, FALSE); |
| 125 | } |
| 126 | } |
| 127 | } |
| 128 | return FALSE; /* propagate */ |
| 129 | } |
| 130 | |
| 131 | /** @brief Allow multi-row drag for @p w |
| 132 | * @param w A GtkTreeView widget |
| 133 | * |
| 134 | * Suppresses the restriction of selections when a drag is started. |
| 135 | */ |
| 136 | void make_treeview_multidrag(GtkWidget *w) { |
| 137 | g_signal_connect(w, "button-press-event", |
| 138 | G_CALLBACK(multidrag_button_press_event), NULL); |
| 139 | g_signal_connect(w, "button-release-event", |
| 140 | G_CALLBACK(multidrag_button_release_event), NULL); |
| 141 | } |
| 142 | |
| 143 | /* |
| 144 | Local Variables: |
| 145 | c-basic-offset:2 |
| 146 | comment-column:40 |
| 147 | fill-column:79 |
| 148 | indent-tabs-mode:nil |
| 149 | End: |
| 150 | */ |