/** @brief State for multidrag_begin() and its callbacks */
struct multidrag_begin_state {
GtkTreeView *view;
+ multidrag_row_predicate *predicate;
int rows;
int index;
GdkPixmap **pixmaps;
/** @brief Callback to construct a row pixmap */
static void multidrag_make_row_pixmaps(GtkTreeModel attribute((unused)) *model,
GtkTreePath *path,
- GtkTreeIter attribute((unused)) *iter,
+ GtkTreeIter *iter,
gpointer data) {
struct multidrag_begin_state *qdbs = data;
- qdbs->pixmaps[qdbs->index++]
- = gtk_tree_view_create_row_drag_icon(qdbs->view, path);
+ if(qdbs->predicate(path, iter)) {
+ qdbs->pixmaps[qdbs->index++]
+ = gtk_tree_view_create_row_drag_icon(qdbs->view, path);
+ }
}
/** @brief Called when a drag operation starts
* @param w Source widget (the tree view)
* @param dc Drag context
- * @param user_data Not used
+ * @param user_data Row predicate
*/
static void multidrag_drag_begin(GtkWidget *w,
GdkDragContext attribute((unused)) *dc,
- gpointer attribute((unused)) user_data) {
+ gpointer user_data) {
struct multidrag_begin_state qdbs[1];
GdkPixmap *icon;
GtkTreeSelection *sel;
//fprintf(stderr, "drag-begin\n");
memset(qdbs, 0, sizeof *qdbs);
qdbs->view = GTK_TREE_VIEW(w);
+ qdbs->predicate = (multidrag_row_predicate *)user_data;
sel = gtk_tree_view_get_selection(qdbs->view);
/* Find out how many rows there are */
if(!(qdbs->rows = gtk_tree_selection_count_selected_rows(sel)))
gtk_tree_selection_selected_foreach(sel,
multidrag_make_row_pixmaps,
qdbs);
+ /* Might not have used all rows */
+ qdbs->rows = qdbs->index;
/* Determine the size of the final icon */
int height = 0, width = 0;
for(int n = 0; n < qdbs->rows; ++n) {
NULL);
}
+static gboolean multidrag_default_predicate(GtkTreePath attribute((unused)) *path,
+ GtkTreeIter attribute((unused)) *iter) {
+ return TRUE;
+}
+
/** @brief Allow multi-row drag for @p w
* @param w A GtkTreeView widget
+ * @param predicate Function called to test rows for draggability, or NULL
+ *
+ * Suppresses the restriction of selections when a drag is started, and
+ * intercepts drag-begin to construct an icon.
*
- * Suppresses the restriction of selections when a drag is started.
+ * @p predicate should return TRUE for draggable rows and FALSE otherwise, to
+ * control what goes in the icon. If NULL, equivalent to a function that
+ * always returns TRUE.
*/
-void make_treeview_multidrag(GtkWidget *w) {
+void make_treeview_multidrag(GtkWidget *w,
+ multidrag_row_predicate *predicate) {
+ if(!predicate)
+ predicate = multidrag_default_predicate;
g_signal_connect(w, "button-press-event",
G_CALLBACK(multidrag_button_press_event), NULL);
g_signal_connect(w, "button-release-event",
G_CALLBACK(multidrag_button_release_event), NULL);
g_signal_connect(w, "drag-begin",
- G_CALLBACK(multidrag_drag_begin), NULL);
+ G_CALLBACK(multidrag_drag_begin), predicate);
}
/*