+/** @brief State for ql_drag_begin() and its callbacks */
+struct ql_drag_begin_state {
+ struct queuelike *ql;
+ int rows;
+ int index;
+ GdkPixmap **pixmaps;
+};
+
+/** @brief Callback to construct a row pixmap */
+static void ql_drag_make_row_pixmaps(GtkTreeModel attribute((unused)) *model,
+ GtkTreePath *path,
+ GtkTreeIter attribute((unused)) *iter,
+ gpointer data) {
+ struct ql_drag_begin_state *qdbs = data;
+
+ qdbs->pixmaps[qdbs->index++]
+ = gtk_tree_view_create_row_drag_icon(GTK_TREE_VIEW(qdbs->ql->view),
+ path);
+}
+
+/** @brief Called when a drag operation from this queuelike begins
+ * @param w Source widget (the tree view)
+ * @param dc Drag context
+ * @param user_data The queuelike
+ */
+static void ql_drag_begin(GtkWidget attribute((unused)) *w,
+ GdkDragContext attribute((unused)) *dc,
+ gpointer user_data) {
+ struct queuelike *const ql = user_data;
+ struct ql_drag_begin_state qdbs[1];
+ GdkPixmap *icon;
+
+ //fprintf(stderr, "drag-begin\n");
+ memset(qdbs, 0, sizeof *qdbs);
+ qdbs->ql = ql;
+ /* Find out how many rows there are */
+ if(!(qdbs->rows = gtk_tree_selection_count_selected_rows(ql->selection)))
+ return; /* doesn't make sense */
+ /* Generate a pixmap for each row */
+ qdbs->pixmaps = xcalloc(qdbs->rows, sizeof *qdbs->pixmaps);
+ gtk_tree_selection_selected_foreach(ql->selection,
+ ql_drag_make_row_pixmaps,
+ qdbs);
+ /* Determine the size of the final icon */
+ int height = 0, width = 0;
+ for(int n = 0; n < qdbs->rows; ++n) {
+ int pxw, pxh;
+ gdk_drawable_get_size(qdbs->pixmaps[n], &pxw, &pxh);
+ if(pxw > width)
+ width = pxw;
+ height += pxh;
+ }
+ if(!width || !height)
+ return; /* doesn't make sense */
+ /* Construct the icon */
+ icon = gdk_pixmap_new(qdbs->pixmaps[0], width, height, -1);
+ GdkGC *gc = gdk_gc_new(icon);
+ gdk_gc_set_colormap(gc, gtk_widget_get_colormap(ql->view));
+ int y = 0;
+ for(int n = 0; n < qdbs->rows; ++n) {
+ int pxw, pxh;
+ gdk_drawable_get_size(qdbs->pixmaps[n], &pxw, &pxh);
+ gdk_draw_drawable(icon,
+ gc,
+ qdbs->pixmaps[n],
+ 0, 0, /* source coords */
+ 0, y, /* dest coords */
+ pxw, pxh); /* size */
+ y += pxh;
+ }
+ // TODO scale down a bit, the resulting icons are currently a bit on the
+ // large side.
+ gtk_drag_source_set_icon(ql->view,
+ gtk_widget_get_colormap(ql->view),
+ icon,
+ NULL);
+}
+
+static gboolean ql_drag_motion(GtkWidget *w,
+ GdkDragContext *dc,
+ gint x,
+ gint y,
+ guint time_,
+ gpointer attribute((unused)) user_data) {
+ //struct queuelike *const ql = user_data;
+ GdkDragAction action = 0;
+
+ // GTK_DEST_DEFAULT_MOTION vets actions as follows:
+ // 1) if dc->suggested_action is in the gtk_drag_dest_set actions
+ // then dc->suggested_action is taken as the action.
+ // 2) otherwise if dc->actions intersects the gtk_drag_dest_set actions
+ // then the lowest-numbered member of the intersection is chosen.
+ // 3) otherwise no member is chosen and gdk_drag_status() is called
+ // with action=0 to refuse the drop.
+ // Currently we can only accept _MOVE. But in the future we will
+ // need to accept _COPY in some cases.
+ if(dc->suggested_action) {
+ if(dc->suggested_action == GDK_ACTION_MOVE)
+ action = dc->suggested_action;
+ } else if(dc->actions & GDK_ACTION_MOVE)
+ action = dc->actions;
+ /*fprintf(stderr, "suggested %#x actions %#x result %#x\n",
+ dc->suggested_action, dc->actions, action);*/
+ if(action) {
+ // If the action is acceptable then we see if this widget is acceptable
+ if(!gtk_drag_dest_find_target(w, dc, NULL))
+ action = 0;
+ }
+ // Report the status
+ gdk_drag_status(dc, action, time_);
+ if(action) {
+ // Highlight the drop area
+ GtkTreePath *path;
+ GtkTreeViewDropPosition pos;
+
+ if(gtk_tree_view_get_dest_row_at_pos(GTK_TREE_VIEW(w),
+ x, y,
+ &path,
+ &pos)) {
+ //fprintf(stderr, "gtk_tree_view_get_dest_row_at_pos() -> TRUE\n");
+ // Normalize drop position
+ switch(pos) {
+ case GTK_TREE_VIEW_DROP_INTO_OR_BEFORE:
+ pos = GTK_TREE_VIEW_DROP_BEFORE;
+ break;
+ case GTK_TREE_VIEW_DROP_INTO_OR_AFTER:
+ pos = GTK_TREE_VIEW_DROP_AFTER;
+ break;
+ default: break;
+ }
+ // Highlight drop target
+ gtk_tree_view_set_drag_dest_row(GTK_TREE_VIEW(w), path, pos);
+ } else {
+ //fprintf(stderr, "gtk_tree_view_get_dest_row_at_pos() -> FALSE\n");
+ gtk_tree_view_set_drag_dest_row(GTK_TREE_VIEW(w), NULL, 0);
+ }
+ }
+ return TRUE;
+}
+
+static void ql_drag_leave(GtkWidget *w,
+ GdkDragContext attribute((unused)) *dc,
+ guint attribute((unused)) time_,
+ gpointer attribute((unused)) user_data) {
+ //struct queuelike *const ql = user_data;
+
+ gtk_tree_view_set_drag_dest_row(GTK_TREE_VIEW(w), NULL, 0);
+}
+
+/** @brief Callback to add selected tracks to the selection data
+ *
+ * Called from ql_drag_data_get().
+ */
+static void ql_drag_data_get_collect(GtkTreeModel *model,
+ GtkTreePath attribute((unused)) *path,
+ GtkTreeIter *iter,
+ gpointer data) {
+ struct dynstr *const result = data;
+ struct queue_entry *const q = ql_iter_to_q(model, iter);
+
+ dynstr_append_string(result, q->id);
+ dynstr_append(result, '\n');
+ dynstr_append_string(result, q->track);
+ dynstr_append(result, '\n');
+}
+
+/** @brief Called to extract the dragged data from the source queuelike
+ * @param w Source widget (the tree view)
+ * @param dc Drag context
+ * @param data Where to put the answer
+ * @param info_ Target @c info parameter
+ * @param time_ Time data requested (for some reason not a @c time_t)
+ * @param user_data The queuelike
+ */
+static void ql_drag_data_get(GtkWidget attribute((unused)) *w,
+ GdkDragContext attribute((unused)) *dc,
+ GtkSelectionData *data,
+ guint attribute((unused)) info_,
+ guint attribute((unused)) time_,
+ gpointer user_data) {
+ struct queuelike *const ql = user_data;
+ struct dynstr result[1];
+
+ /* The list of tracks is converted into a single string, consisting of IDs
+ * and track names. Each is terminated by a newline. Including both ID and
+ * track name means that the receiver can use whichever happens to be more
+ * convenient. */
+ dynstr_init(result);
+ gtk_tree_selection_selected_foreach(ql->selection,
+ ql_drag_data_get_collect,
+ result);
+ //fprintf(stderr, "drag-data-get: %.*s\n",
+ // result->nvec, result->vec);
+ /* gtk_selection_data_set_text() insists that data->target is one of a
+ * variety of stringy atoms. TODO: where does this value actually come
+ * from? */
+ gtk_selection_data_set(data,
+ GDK_TARGET_STRING,
+ 8, (guchar *)result->vec, result->nvec);
+}
+
+/** @brief Called when drag data is received
+ * @param w Target widget (the tree view)
+ * @param dc Drag context
+ * @param x The drop location
+ * @param y The drop location
+ * @param data The selection data
+ * @param info_ The target type that was chosen
+ * @param time_ Time data received (for some reason not a @c time_t)
+ * @param user_data The queuelike
+ */
+static void ql_drag_data_received(GtkWidget attribute((unused)) *w,
+ GdkDragContext attribute((unused)) *dc,
+ gint x,
+ gint y,
+ GtkSelectionData *data,
+ guint attribute((unused)) info_,
+ guint attribute((unused)) time_,
+ gpointer user_data) {
+ struct queuelike *const ql = user_data;
+ char *result, *p;
+ struct vector ids[1], tracks[1];
+ int parity = 0;
+
+ //fprintf(stderr, "drag-data-received: %d,%d\n", x, y);
+ /* Get the selection string */
+ p = result = (char *)gtk_selection_data_get_text(data);
+ if(!result) {
+ //fprintf(stderr, "gtk_selection_data_get_text() returned NULL\n");
+ return;
+ }
+ //fprintf(stderr, "%s--\n", result);
+ /* Parse it back into IDs and track names */
+ vector_init(ids);
+ vector_init(tracks);
+ while(*p) {
+ char *nl = strchr(p, '\n');
+ if(!nl)
+ break;
+ *nl = 0;
+ //fprintf(stderr, " %s\n", p);
+ vector_append(parity++ & 1 ? tracks : ids, xstrdup(p));
+ p = nl + 1;
+ }
+ g_free(result);
+ if(ids->nvec != tracks->nvec) {
+ //fprintf(stderr, " inconsistent drag data!\n");
+ return;
+ }
+ vector_terminate(ids);
+ vector_terminate(tracks);
+ /* Figure out which row the drop precedes (if any) */
+ GtkTreePath *path;
+ GtkTreeViewDropPosition pos;
+ struct queue_entry *q;
+ if(!gtk_tree_view_get_dest_row_at_pos(GTK_TREE_VIEW(ql->view), x, y,
+ &path, &pos)) {
+ //fprintf(stderr, "gtk_tree_view_get_dest_row_at_pos returned FALSE\n");
+ /* This generally means a drop past the end of the queue. We find the last
+ * element in the queue and ask to move after that. */
+ for(q = ql->q; q && q->next; q = q->next)
+ ;
+ } else {
+ /* Convert the path to a queue entry pointer. */
+ q = ql_path_to_q(GTK_TREE_MODEL(ql->store), path);
+ //fprintf(stderr, " tree view likes to drop near %s\n",
+ // q->id ? q->id : "NULL");
+ /* TODO interpretation of q=NULL */
+ /* Q should point to the entry just before the insertion point, so that
+ * moveafter works, or NULL to insert right at the start. We don't support
+ * dropping into a row, since that doesn't make sense for us. */
+ switch(pos) {
+ case GTK_TREE_VIEW_DROP_BEFORE:
+ case GTK_TREE_VIEW_DROP_INTO_OR_BEFORE:
+ if(q) {
+ q = q->prev;
+ //fprintf(stderr, " ...but we like to drop near %s\n",
+ // q ? q->id : "NULL");
+ }
+ break;
+ default:
+ break;
+ }
+ }
+ /* Note that q->id can match one of ids[]. This doesn't matter for
+ * moveafter but TODO may matter for playlist support. */
+ ql->drop(ql, tracks->nvec, tracks->vec, ids->vec, q);
+}
+