gnome-canvas: Change GnomeCanvasItem->point vfunc

Previously the function returned the distance to the nearest item. Now
it only returns an item that is hit. This slightly changes semantics
(button events are no longer dispatched to the nearest item, but only to
the item actually clicked on), but makes the code way simpler and
actually does what one would expect.

1 files changed, 17 insertions, 47 deletions

diff --git a/libgnomecanvas/gnome-canvas.c b/libgnomecanvas/gnome-canvas.c
index f79b37e75e..958fc45e1c 100644
--- a/libgnomecanvas/gnome-canvas.c
+++ b/libgnomecanvas/gnome-canvas.c
@@ -512,13 +512,12 @@ gnome_canvas_item_invoke_update (GnomeCanvasItem *item,
  * This is potentially evil, as we are relying on matrix inversion (Lauris)
  */
 
-static double
+static GnomeCanvasItem *
 gnome_canvas_item_invoke_point (GnomeCanvasItem *item,
                                 gdouble x,
                                 gdouble y,
                                 gint cx,
-                                gint cy,
-                                GnomeCanvasItem **actual_item)
+                                gint cy)
 {
 	/* Calculate x & y in item local coordinates */
 
@@ -555,9 +554,9 @@ gnome_canvas_item_invoke_point (GnomeCanvasItem *item,
 #endif
 
 	if (GNOME_CANVAS_ITEM_GET_CLASS (item)->point)
-		return GNOME_CANVAS_ITEM_GET_CLASS (item)->point (item, x, y, cx, cy, actual_item);
+		return GNOME_CANVAS_ITEM_GET_CLASS (item)->point (item, x, y, cx, cy);
 
-	return 1e18;
+	return NULL;
 }
 
 /**
@@ -1400,10 +1399,9 @@ static void   gnome_canvas_group_draw        (GnomeCanvasItem *item,
 					      GdkDrawable *drawable,
 					      gint x, gint y,
 					      gint width, gint height);
-static gdouble gnome_canvas_group_point       (GnomeCanvasItem *item,
+static GnomeCanvasItem *gnome_canvas_group_point (GnomeCanvasItem *item,
 					      gdouble x, gdouble y,
-					      gint cx, gint cy,
-					      GnomeCanvasItem **actual_item);
+					      gint cx, gint cy);
 static void   gnome_canvas_group_bounds      (GnomeCanvasItem *item,
 					      gdouble *x1, gdouble *y1,
 					      gdouble *x2, gdouble *y2);
@@ -1746,55 +1744,34 @@ gnome_canvas_group_draw (GnomeCanvasItem *item, GdkDrawable *drawable,
 }
 
 /* Point handler for canvas groups */
-static double
+static GnomeCanvasItem *
 gnome_canvas_group_point (GnomeCanvasItem *item,
                           gdouble x,
                           gdouble y,
                           gint cx,
-                          gint cy,
-                          GnomeCanvasItem **actual_item)
+                          gint cy)
 {
 	GnomeCanvasGroup *group;
 	GList *list;
 	GnomeCanvasItem *child, *point_item;
-	gdouble gx, gy;
-	gdouble dist, best;
-	gint has_point;
 
 	group = GNOME_CANVAS_GROUP (item);
 
-	best = 0.0;
-	*actual_item = NULL;
-
-	gx = x;
-	gy = y;
-
-	dist = 0.0; /* keep gcc happy */
-
-	for (list = group->item_list; list; list = list->next) {
+	for (list = g_list_last (group->item_list); list; list = list->prev) {
 		child = list->data;
 
 		if ((child->x1 > cx) || (child->y1 > cy) || (child->x2 < cx) || (child->y2 < cy))
 			continue;
 
-		point_item = NULL; /* cater for incomplete item implementations */
-
-		if ((child->flags & GNOME_CANVAS_ITEM_VISIBLE)
-		    && GNOME_CANVAS_ITEM_GET_CLASS (child)->point) {
-			dist = gnome_canvas_item_invoke_point (child, gx, gy, cx, cy, &point_item);
-			has_point = TRUE;
-		} else
-			has_point = FALSE;
+		if (!(child->flags & GNOME_CANVAS_ITEM_VISIBLE))
+                        continue;
 
-		if (has_point
-		    && point_item
-		    && ((gint) (dist * item->canvas->pixels_per_unit + 0.5) <= 0)) {
-			best = dist;
-			*actual_item = point_item;
-		}
+		point_item = gnome_canvas_item_invoke_point (child, x, y, cx, cy);
+		if (point_item)
+                        return point_item;
 	}
 
-	return best;
+	return NULL;
 }
 
 /* Bounds handler for canvas groups */
@@ -2690,8 +2667,7 @@ pick_current_item (GnomeCanvas *canvas, GdkEvent *event)
 		/* find the closest item */
 
 		if (canvas->root->flags & GNOME_CANVAS_ITEM_VISIBLE)
-			gnome_canvas_item_invoke_point (canvas->root, x, y, cx, cy,
-							&canvas->new_current_item);
+			canvas->new_current_item = gnome_canvas_item_invoke_point (canvas->root, x, y, cx, cy);
 		else
 			canvas->new_current_item = NULL;
 	} else
@@ -3570,19 +3546,13 @@ gnome_canvas_update_now (GnomeCanvas *canvas)
 GnomeCanvasItem *
 gnome_canvas_get_item_at (GnomeCanvas *canvas, gdouble x, gdouble y)
 {
-	GnomeCanvasItem *item;
-	gdouble dist;
 	gint cx, cy;
 
 	g_return_val_if_fail (GNOME_IS_CANVAS (canvas), NULL);
 
 	gnome_canvas_w2c (canvas, x, y, &cx, &cy);
 
-	dist = gnome_canvas_item_invoke_point (canvas->root, x, y, cx, cy, &item);
-	if ((gint) (dist * canvas->pixels_per_unit + 0.5) <= 0)
-		return item;
-	else
-		return NULL;
+	return gnome_canvas_item_invoke_point (canvas->root, x, y, cx, cy);
 }
 
 /* Queues an update of the canvas */