[gimp/soc-2011-warp] gimpoperationwarp: implement erase and smooth behavior

[Michael Murà <mmure src gnome org>]

commit ae702511f2803f1300997a8ccdb48cfd2d722cfe
Author: Michael Murà <batolettre gmail com>
Date:   Sat Jul 2 14:00:51 2011 +0200

    gimpoperationwarp: implement erase and smooth behavior

 app/gegl/gimp-gegl-enums.c   |    4 ++++
 app/gegl/gimp-gegl-enums.h   |    4 +++-
 app/gegl/gimpoperationwarp.c |   35 +++++++++++++++++++++++++++++++++++
 3 files changed, 42 insertions(+), 1 deletions(-)
---
diff --git a/app/gegl/gimp-gegl-enums.c b/app/gegl/gimp-gegl-enums.c
index 944c030..2cbbefe 100644
--- a/app/gegl/gimp-gegl-enums.c
+++ b/app/gegl/gimp-gegl-enums.c
@@ -48,6 +48,8 @@ gimp_warp_behavior_get_type (void)
     { GIMP_WARP_BEHAVIOR_SHRINK, "GIMP_WARP_BEHAVIOR_SHRINK", "shrink" },
     { GIMP_WARP_BEHAVIOR_SWIRL_CW, "GIMP_WARP_BEHAVIOR_SWIRL_CW", "swirl-cw" },
     { GIMP_WARP_BEHAVIOR_SWIRL_CCW, "GIMP_WARP_BEHAVIOR_SWIRL_CCW", "swirl-ccw" },
+    { GIMP_WARP_BEHAVIOR_ERASE, "GIMP_WARP_BEHAVIOR_ERASE", "erase" },
+    { GIMP_WARP_BEHAVIOR_SMOOTH, "GIMP_WARP_BEHAVIOR_SMOOTH", "smooth" },
     { 0, NULL, NULL }
   };
 
@@ -58,6 +60,8 @@ gimp_warp_behavior_get_type (void)
     { GIMP_WARP_BEHAVIOR_SHRINK, NC_("warp-behavior", "Shrink area"), NULL },
     { GIMP_WARP_BEHAVIOR_SWIRL_CW, NC_("warp-behavior", "Swirl clockwise"), NULL },
     { GIMP_WARP_BEHAVIOR_SWIRL_CCW, NC_("warp-behavior", "Swirl counter-clockwise"), NULL },
+    { GIMP_WARP_BEHAVIOR_ERASE, NC_("warp-behavior", "Erase warping"), NULL },
+    { GIMP_WARP_BEHAVIOR_SMOOTH, NC_("warp-behavior", "Smooth warping"), NULL },
     { 0, NULL, NULL }
   };
 
diff --git a/app/gegl/gimp-gegl-enums.h b/app/gegl/gimp-gegl-enums.h
index cd53d5e..9f455ef 100644
--- a/app/gegl/gimp-gegl-enums.h
+++ b/app/gegl/gimp-gegl-enums.h
@@ -41,7 +41,9 @@ typedef enum
   GIMP_WARP_BEHAVIOR_GROW,        /*< desc="Grow area"                           >*/
   GIMP_WARP_BEHAVIOR_SHRINK,      /*< desc="Shrink area"                         >*/
   GIMP_WARP_BEHAVIOR_SWIRL_CW,    /*< desc="Swirl clockwise"                     >*/
-  GIMP_WARP_BEHAVIOR_SWIRL_CCW    /*< desc="Swirl counter-clockwise"             >*/
+  GIMP_WARP_BEHAVIOR_SWIRL_CCW,   /*< desc="Swirl counter-clockwise"             >*/
+  GIMP_WARP_BEHAVIOR_ERASE,       /*< desc="Erase warping"                       >*/
+  GIMP_WARP_BEHAVIOR_SMOOTH       /*< desc="Smooth warping"                      >*/
 } GimpWarpBehavior;
 
 #endif /* __GIMP_GEGL_ENUMS_H__ */
diff --git a/app/gegl/gimpoperationwarp.c b/app/gegl/gimpoperationwarp.c
index 7f8d5c1..e19c2da 100644
--- a/app/gegl/gimpoperationwarp.c
+++ b/app/gegl/gimpoperationwarp.c
@@ -252,6 +252,7 @@ gimp_operation_warp_stamp (GimpOperationWarp *ow,
   GeglBufferIterator  *it;
   Babl                *format;
   gdouble              influence;
+  gdouble              x_mean, y_mean;
   gint                 x_iter, y_iter;
   GeglRectangle        area = {x - ow->size / 2.0,
                                y - ow->size / 2.0,
@@ -267,6 +268,32 @@ gimp_operation_warp_stamp (GimpOperationWarp *ow,
       return;
     }
 
+  /* If needed, compute the mean deformation */
+  if (ow->behavior == GIMP_WARP_BEHAVIOR_SMOOTH)
+    {
+      gint pixel_count = 0;
+      x_mean = y_mean = 0.0;
+
+      it = gegl_buffer_iterator_new (ow->buffer, &area, format, GEGL_BUFFER_READ);
+
+      while (gegl_buffer_iterator_next (it))
+        {
+          gint    n_pixels    = it->length;
+          gfloat *coords      = it->data[0];
+
+          while (n_pixels--)
+            {
+              x_mean += coords[0];
+              y_mean += coords[1];
+              coords += 2;
+            }
+          pixel_count += it->roi->width * it->roi->height;
+        }
+      x_mean /= pixel_count;
+      y_mean /= pixel_count;
+    }
+
+
   format = babl_format_n (babl_type ("float"), 2);
 
   it = gegl_buffer_iterator_new (ow->buffer, &area, format, GEGL_BUFFER_READWRITE);
@@ -308,6 +335,14 @@ gimp_operation_warp_stamp (GimpOperationWarp *ow,
                 coords[0] -= influence * (y_iter - y) / ow->size;
                 coords[1] += influence * (x_iter - x) / ow->size;
                 break;
+              case GIMP_WARP_BEHAVIOR_ERASE:
+                coords[0] *= 1.0 - MIN (influence, 1.0);
+                coords[1] *= 1.0 - MIN (influence, 1.0);
+                break;
+              case GIMP_WARP_BEHAVIOR_SMOOTH:
+                coords[0] -= influence * (coords[0] - x_mean);
+                coords[1] -= influence * (coords[1] - y_mean);
+                break;
             }
 
           coords += 2;