[gimp] app: improve warp-tool invalidated-area calculation

[Ell <ell src gnome org>]

commit aa915280841f7e660d08696fe6a4f56d909ff120
Author: Ell <ell_se yahoo com>
Date:   Sun Mar 3 14:10:40 2019 -0500

    app: improve warp-tool invalidated-area calculation
    
    In the warp tool, use the gegl:map-relative node to calculate the
    invalidated drawable area when the displacement field changes, to
    account for box filtering.

 app/tools/gimpwarptool.c | 27 ++++++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)
---
diff --git a/app/tools/gimpwarptool.c b/app/tools/gimpwarptool.c
index f281235c8b..7ae3766e9e 100644
--- a/app/tools/gimpwarptool.c
+++ b/app/tools/gimpwarptool.c
@@ -20,7 +20,7 @@
 #include "config.h"
 
 #include <gegl.h>
-#include "gegl-utils.h"
+#include <gegl-plugin.h>
 #include <gtk/gtk.h>
 #include <gdk/gdkkeysyms.h>
 
@@ -127,6 +127,8 @@ static GeglRectangle
                   gimp_warp_tool_get_node_bounds    (GeglNode              *node);
 static void       gimp_warp_tool_clear_node_bounds  (GeglNode              *node);
 static void       gimp_warp_tool_update_bounds      (GimpWarpTool          *wt);
+static void       gimp_warp_tool_update_area        (GimpWarpTool          *wt,
+                                                     const GeglRectangle   *area);
 static void       gimp_warp_tool_update_stroke      (GimpWarpTool          *wt,
                                                      GeglNode              *node);
 static void       gimp_warp_tool_stroke_changed     (GeglPath              *stroke,
@@ -1044,6 +1046,25 @@ gimp_warp_tool_update_bounds (GimpWarpTool *wt)
   gimp_drawable_filter_set_crop (wt->filter, &bounds, FALSE);
 }
 
+static void
+gimp_warp_tool_update_area (GimpWarpTool        *wt,
+                            const GeglRectangle *area)
+{
+  GeglRectangle rect = *area;
+
+  if (! wt->filter)
+    return;
+
+  if (wt->render_node)
+    {
+      GeglOperation *operation = gegl_node_get_gegl_operation (wt->render_node);
+
+      rect = gegl_operation_get_invalidated_by_change (operation, "aux", &rect);
+    }
+
+  gimp_drawable_filter_apply (wt->filter, &rect);
+}
+
 static void
 gimp_warp_tool_update_stroke (GimpWarpTool *wt,
                               GeglNode     *node)
@@ -1073,7 +1094,7 @@ gimp_warp_tool_update_stroke (GimpWarpTool *wt,
               bounds.width, bounds.height);
 #endif
 
-      gimp_drawable_filter_apply (wt->filter, &bounds);
+      gimp_warp_tool_update_area (wt, &bounds);
     }
 }
 
@@ -1107,7 +1128,7 @@ gimp_warp_tool_stroke_changed (GeglPath            *path,
       gimp_warp_tool_update_bounds (wt);
     }
 
-  gimp_drawable_filter_apply (wt->filter, &update_region);
+  gimp_warp_tool_update_area (wt, &update_region);
 }
 
 static void