Add drag and drop support for symbols.

liblogdiag/ld-category-symbol-view.c

@@ -30,21 +30,6 @@
 #define SYMBOL_HEIGHT   40   /* Height of a symbol. */
 #define SYMBOL_SPACING  10   /* Spacing between symbols, and also borders. */
 
-/*
- * LdCategorySymbolViewPrivate:
- * @category: a category object assigned as a model.
- * @path: path to the category within the library.
- * @layout: (element-type SymbolData *): current layout of symbols.
- * @height_negotiation: whether we are negotiating height right now.
- */
-struct _LdCategorySymbolViewPrivate
-{
-	LdCategory *category;
-	gchar *path;
-	GSList *layout;
-	guint height_negotiation : 1;
-};
-
 typedef struct
 {
 	LdSymbol *symbol;        /* The associated symbol, ref'ed. */
@@ -56,6 +41,23 @@ typedef struct
 }
 SymbolData;
 
+/*
+ * LdCategorySymbolViewPrivate:
+ * @category: a category object assigned as a model.
+ * @path: path to the category within the library.
+ * @layout: (element-type SymbolData *): current layout of symbols.
+ * @preselected: currently preselected symbol.
+ * @height_negotiation: whether we are negotiating height right now.
+ */
+struct _LdCategorySymbolViewPrivate
+{
+	LdCategory *category;
+	gchar *path;
+	GSList *layout;
+	SymbolData *preselected;
+	guint height_negotiation : 1;
+};
+
 enum
 {
 	PROP_0,
@@ -103,6 +105,112 @@ ld_category_symbol_view_class_init (LdCategorySymbolViewClass *klass)
 	g_type_class_add_private (klass, sizeof (LdCategorySymbolViewPrivate));
 }
 
+static void
+symbol_redraw (LdCategorySymbolView *self, SymbolData *symbol)
+{
+	gtk_widget_queue_draw_area (GTK_WIDGET (self),
+		symbol->rect.x,
+		symbol->rect.y,
+		symbol->rect.width,
+		symbol->rect.height);
+}
+
+static void
+symbol_deselect (LdCategorySymbolView *self)
+{
+	if (!self->priv->preselected)
+		return;
+
+	symbol_redraw (self, self->priv->preselected);
+	self->priv->preselected = NULL;
+	gtk_drag_source_unset (GTK_WIDGET (self));
+}
+
+static gboolean
+on_leave_notify (GtkWidget *widget, GdkEventCrossing *event, gpointer user_data)
+{
+	symbol_deselect (LD_CATEGORY_SYMBOL_VIEW (widget));
+	return FALSE;
+}
+
+static gboolean
+on_motion_notify (GtkWidget *widget, GdkEventMotion *event, gpointer user_data)
+{
+	LdCategorySymbolView *self;
+	GSList *iter;
+
+	if (event->state & GDK_BUTTON1_MASK)
+		return FALSE;
+
+	self = LD_CATEGORY_SYMBOL_VIEW (widget);
+	for (iter = self->priv->layout; iter; iter = iter->next)
+	{
+		SymbolData *data;
+
+		data = iter->data;
+		if (event->x <  data->rect.x
+		 || event->y <  data->rect.y
+		 || event->x >= data->rect.x + data->rect.width
+		 || event->y >= data->rect.y + data->rect.height)
+			continue;
+
+		if (data != self->priv->preselected)
+		{
+			GtkTargetEntry target = {"ld-symbol", GTK_TARGET_SAME_APP, 0};
+
+			symbol_deselect (self);
+			self->priv->preselected = data;
+			symbol_redraw (self, data);
+
+			gtk_drag_source_set (widget,
+				GDK_BUTTON1_MASK, &target, 1, GDK_ACTION_COPY);
+		}
+		return FALSE;
+	}
+
+	symbol_deselect (self);
+	return FALSE;
+}
+
+static void
+on_drag_data_get
+(GtkWidget *widget, GdkDragContext *ctx, GtkSelectionData *selection_data,
+	guint target_type, guint time, gpointer user_data)
+{
+	LdCategorySymbolView *self;
+
+	self = LD_CATEGORY_SYMBOL_VIEW (widget);
+	g_return_if_fail (self->priv->preselected != NULL);
+
+	gtk_selection_data_set (selection_data,
+		gtk_selection_data_get_target (selection_data),
+		8, (guchar *) self->priv->preselected->path,
+		strlen (self->priv->preselected->path));
+}
+
+static void
+on_drag_begin (GtkWidget *widget, GdkDragContext *ctx, gpointer user_data)
+{
+	LdCategorySymbolView *self;
+	GdkPixbuf *pbuf;
+
+	self = LD_CATEGORY_SYMBOL_VIEW (widget);
+	g_return_if_fail (self->priv->preselected != NULL);
+
+	/* Some of the larger previews didn't work, and we have to get rid of
+	 * the icon later when we're hovering above LdDiagramView anyway. */
+	pbuf = gdk_pixbuf_new (GDK_COLORSPACE_RGB, TRUE, 8, 1, 1);
+	gdk_pixbuf_fill (pbuf, 0x00000000);
+	gtk_drag_set_icon_pixbuf (ctx, pbuf, 0, 0);
+	g_object_unref (pbuf);
+}
+
+static void
+on_drag_end (GtkWidget *widget, GdkDragContext *ctx, gpointer user_data)
+{
+	symbol_deselect (LD_CATEGORY_SYMBOL_VIEW (widget));
+}
+
 static void
 ld_category_symbol_view_init (LdCategorySymbolView *self)
 {
@@ -116,6 +224,18 @@ ld_category_symbol_view_init (LdCategorySymbolView *self)
 	g_signal_connect (self, "expose-event",
 		G_CALLBACK (on_expose_event), NULL);
 
+	g_signal_connect (self, "motion-notify-event",
+		G_CALLBACK (on_motion_notify), NULL);
+	g_signal_connect (self, "leave-notify-event",
+		G_CALLBACK (on_leave_notify), NULL);
+
+	g_signal_connect (self, "drag-begin",
+		G_CALLBACK (on_drag_begin), NULL);
+	g_signal_connect (self, "drag-data-get",
+		G_CALLBACK (on_drag_data_get), NULL);
+	g_signal_connect (self, "drag-end",
+		G_CALLBACK (on_drag_end), NULL);
+
 	gtk_widget_add_events (GTK_WIDGET (self),
 		GDK_POINTER_MOTION_MASK | GDK_POINTER_MOTION_HINT_MASK
 		| GDK_BUTTON_PRESS_MASK | GDK_BUTTON_RELEASE_MASK
@@ -136,6 +256,7 @@ layout_destroy (LdCategorySymbolView *self)
 	g_slist_foreach (self->priv->layout, (GFunc) symbol_data_free, NULL);
 	g_slist_free (self->priv->layout);
 	self->priv->layout = NULL;
+	self->priv->preselected = NULL;
 }
 
 static void
@@ -331,11 +452,15 @@ on_expose_event (GtkWidget *widget, GdkEventExpose *event, gpointer user_data)
 		gdk_cairo_rectangle (cr, &data->rect);
 		cairo_clip (cr);
 
+		gdk_cairo_set_source_color (cr,
+			&gtk_widget_get_style (widget)->text[GTK_STATE_NORMAL]);
+
+		if (data == self->priv->preselected)
+			cairo_paint_with_alpha (cr, 0.1);
+
 		cairo_translate (cr, data->rect.x + data->dx, data->rect.y + data->dy);
 		cairo_scale (cr, data->scale, data->scale);
 
-		gdk_cairo_set_source_color (cr,
-			&gtk_widget_get_style (widget)->text[GTK_STATE_NORMAL]);
 		cairo_set_line_width (cr, 1 / data->scale);
 		ld_symbol_draw (data->symbol, cr);
 

liblogdiag/ld-diagram-view.c

@@ -129,6 +129,9 @@ Color;
  * @y: the Y coordinate of the center of view.
  * @zoom: the current zoom.
  * @show_grid: whether to show the grid.
+ * @dnd_symbol: currently dragged symbol.
+ * @dnd_last_position: last cursor movement position.
+ * @dnd_left: whether the user has stopped dragging.
  * @terminal: position of the highlighted terminal.
  * @terminal_hovered: whether a terminal is hovered.
  * @drag_start_pos: position of the mouse pointer when dragging started.
@@ -152,6 +155,10 @@ struct _LdDiagramViewPrivate
 
 	gboolean show_grid;
 
+	LdDiagramObject *dnd_symbol;
+	LdPoint dnd_last_position;
+	guint dnd_left : 1;
+
 	LdPoint terminal;
 	gboolean terminal_hovered;
 
@@ -343,6 +350,16 @@ static gboolean on_button_release (GtkWidget *widget, GdkEventButton *event,
 static gboolean on_scroll (GtkWidget *widget, GdkEventScroll *event,
 	gpointer user_data);
 
+static gboolean on_drag_motion (GtkWidget *widget, GdkDragContext *drag_ctx,
+	gint x, gint y, guint time, gpointer user_data);
+static gboolean on_drag_drop (GtkWidget *widget, GdkDragContext *drag_ctx,
+	gint x, gint y, guint time, gpointer user_data);
+static void on_drag_data_received (GtkWidget *widget, GdkDragContext *drag_ctx,
+	gint x, gint y, GtkSelectionData *data, guint info,
+	guint time, gpointer user_data);
+static void on_drag_leave (GtkWidget *widget, GdkDragContext *drag_ctx,
+	guint time, gpointer user_data);
+
 static gboolean on_expose_event (GtkWidget *widget, GdkEventExpose *event,
 	gpointer user_data);
 static void draw_grid (GtkWidget *widget, DrawData *data);
@@ -486,6 +503,8 @@ ld_diagram_view_class_init (LdDiagramViewClass *klass)
 static void
 ld_diagram_view_init (LdDiagramView *self)
 {
+	GtkTargetEntry target = {"ld-symbol", GTK_TARGET_SAME_APP, 0};
+
 	self->priv = G_TYPE_INSTANCE_GET_PRIVATE
 		(self, LD_TYPE_DIAGRAM_VIEW, LdDiagramViewPrivate);
 
@@ -517,12 +536,23 @@ ld_diagram_view_init (LdDiagramView *self)
 	g_signal_connect (self, "scroll-event",
 		G_CALLBACK (on_scroll), NULL);
 
+	g_signal_connect (self, "drag-motion",
+		G_CALLBACK (on_drag_motion), NULL);
+	g_signal_connect (self, "drag-leave",
+		G_CALLBACK (on_drag_leave), NULL);
+	g_signal_connect (self, "drag-drop",
+		G_CALLBACK (on_drag_drop), NULL);
+	g_signal_connect (self, "drag-data-received",
+		G_CALLBACK (on_drag_data_received), NULL);
+
 	g_object_set (self, "can-focus", TRUE, NULL);
 
 	gtk_widget_add_events (GTK_WIDGET (self),
 		GDK_POINTER_MOTION_MASK | GDK_POINTER_MOTION_HINT_MASK
 		| GDK_BUTTON_PRESS_MASK | GDK_BUTTON_RELEASE_MASK
 		| GDK_LEAVE_NOTIFY_MASK);
+
+	gtk_drag_dest_set (GTK_WIDGET (self), 0, &target, 1, GDK_ACTION_COPY);
 }
 
 static void
@@ -541,6 +571,8 @@ ld_diagram_view_finalize (GObject *gobject)
 	}
 	if (self->priv->library)
 		g_object_unref (self->priv->library);
+	if (self->priv->dnd_symbol)
+		g_object_unref (self->priv->dnd_symbol);
 
 	/* Chain up to the parent class. */
 	G_OBJECT_CLASS (ld_diagram_view_parent_class)->finalize (gobject);
@@ -2424,6 +2456,109 @@ on_scroll (GtkWidget *widget, GdkEventScroll *event, gpointer user_data)
 	return TRUE;
 }
 
+static gboolean
+on_drag_motion (GtkWidget *widget, GdkDragContext *drag_ctx,
+	gint x, gint y, guint time, gpointer user_data)
+{
+	LdDiagramView *self;
+	GdkAtom target;
+
+	self = LD_DIAGRAM_VIEW (widget);
+	target = gtk_drag_dest_find_target (widget, drag_ctx, NULL);
+	if (target == GDK_NONE)
+	{
+		gdk_drag_status (drag_ctx, 0, time);
+		return TRUE;
+	}
+
+	gdk_drag_status (drag_ctx,
+		gdk_drag_context_get_suggested_action (drag_ctx), time);
+
+	/* Discard leftovers from any previous unsuccessful drag. */
+	if (self->priv->dnd_left)
+	{
+		g_object_unref (self->priv->dnd_symbol);
+		self->priv->dnd_symbol = NULL;
+		self->priv->dnd_left = FALSE;
+	}
+
+	self->priv->dnd_last_position.x = x;
+	self->priv->dnd_last_position.y = y;
+
+	if (!self->priv->dnd_symbol)
+		gtk_drag_get_data (widget, drag_ctx, target, time);
+	else
+	{
+		queue_object_draw (self, self->priv->dnd_symbol);
+		move_object_to_point (self, self->priv->dnd_symbol,
+			&self->priv->dnd_last_position);
+		queue_object_draw (self, self->priv->dnd_symbol);
+	}
+
+	return TRUE;
+}
+
+static void
+on_drag_data_received (GtkWidget *widget, GdkDragContext *drag_ctx,
+	gint x, gint y, GtkSelectionData *data, guint info, guint time,
+	gpointer user_data)
+{
+	LdDiagramView *self;
+	LdDiagramSymbol *symbol;
+	const gchar *klass;
+
+	self = LD_DIAGRAM_VIEW (widget);
+
+	g_return_if_fail (gtk_selection_data_get_length (data) >= 0);
+	g_return_if_fail (self->priv->dnd_symbol == NULL);
+
+	klass = (const gchar *) gtk_selection_data_get_data (data);
+	symbol = ld_diagram_symbol_new (NULL);
+	ld_diagram_symbol_set_class (symbol, klass);
+	self->priv->dnd_symbol = LD_DIAGRAM_OBJECT (symbol);
+
+	move_object_to_point (self, self->priv->dnd_symbol,
+		&self->priv->dnd_last_position);
+	queue_object_draw (self, self->priv->dnd_symbol);
+}
+
+static void
+on_drag_leave (GtkWidget *widget, GdkDragContext *drag_ctx,
+	guint time, gpointer user_data)
+{
+	LdDiagramView *self;
+
+	self = LD_DIAGRAM_VIEW (widget);
+	self->priv->dnd_left = TRUE;
+	queue_object_draw (self, self->priv->dnd_symbol);
+}
+
+static gboolean
+on_drag_drop (GtkWidget *widget, GdkDragContext *drag_ctx,
+	gint x, gint y, guint time, gpointer user_data)
+{
+	LdDiagramView *self;
+	gboolean del;
+
+	del = gdk_drag_context_get_suggested_action (drag_ctx)
+		== GDK_ACTION_MOVE;
+
+	self = LD_DIAGRAM_VIEW (widget);
+	if (!self->priv->dnd_symbol)
+		gtk_drag_finish (drag_ctx, FALSE, del, time);
+	else
+	{
+		gtk_drag_finish (drag_ctx, TRUE,  del, time);
+
+		ld_diagram_insert_object (self->priv->diagram,
+			self->priv->dnd_symbol, -1);
+		g_object_unref (self->priv->dnd_symbol);
+		self->priv->dnd_symbol = NULL;
+		self->priv->dnd_left = FALSE;
+	}
+	return TRUE;
+}
+
 static gboolean
 on_expose_event (GtkWidget *widget, GdkEventExpose *event, gpointer user_data)
 {
@@ -2572,6 +2707,9 @@ draw_diagram (GtkWidget *widget, DrawData *data)
 		break;
 	}
 
+	if (data->self->priv->dnd_symbol && !data->self->priv->dnd_left)
+		draw_object (data->self->priv->dnd_symbol, data);
+
 	cairo_restore (data->cr);
 }