[gegl] alpha-inpaint: also examine warmest ray in other direction

[Øyvind "pippin" Kolås <ok src gnome org>]

commit 11b607625e1a348a834c99cad3daf329cf83612c
Author: Øyvind Kolås <pippin gimp org>
Date:   Mon Jul 8 20:13:40 2019 +0200

    alpha-inpaint: also examine warmest ray in other direction
    
    For the scale invariance, get closer to computing the dominant gradient of the
    involved patch, by subtracting the energy of the opposite ray when looking for
    the direction of most energy.

 operations/workshop/alpha-inpaint.c | 33 +++++++++++++++++++++++++--------
 1 file changed, 25 insertions(+), 8 deletions(-)
---
diff --git a/operations/workshop/alpha-inpaint.c b/operations/workshop/alpha-inpaint.c
index b8106799a..d68a8f907 100644
--- a/operations/workshop/alpha-inpaint.c
+++ b/operations/workshop/alpha-inpaint.c
@@ -25,11 +25,11 @@
 
 #ifdef GEGL_PROPERTIES
 
-property_int (seek_distance, "seek radius", 9)
+property_int (seek_distance, "seek radius", 16)
   description ("Maximum distance in neighborhood we look for better candidates per improvement.")
   value_range (1, 512)
 
-property_double (seek_reduction, "seek reduction", 0.9)
+property_double (seek_reduction, "seek reduction", 0.8)
   description ("factor seek distance is shortened, until we're about 2px short per iteration, 1.0 means no 
reduction")
   value_range (0.0, 1.0)
 
@@ -45,11 +45,11 @@ property_int (max_iter, "max runs", 200)
   description ("Mostly a saftey valve, so that we terminate")
   value_range (1, 40000)
 
-property_int (iterations, "iterations per round per probe", 10)
+property_int (iterations, "iterations per round per probe", 8)
   description ("number of improvement iterations, after initial search - that each probe gets.")
   value_range (1, 1000)
 
-property_int (rounds, "rounds", 32)
+property_int (rounds, "rounds", 64)
   description ("number of improvement iterations, after initial search - that each probe gets.")
   value_range (1, 1000)
 
@@ -87,22 +87,22 @@ property_double (ring_twist, "ring twist", 0.0)
   value_range (0.0, 1.0)
   ui_steps    (0.01, 0.2)
 
-property_double (ring_gap1,    "ring gap1", 1.3)
+property_double (ring_gap1,    "ring gap1", 1.0)
   description ("radius, in pixels of nearest to pixel circle of neighborhood metric")
   value_range (0.0, 16.0)
   ui_steps    (0.25, 0.25)
 
-property_double (ring_gap2,    "ring gap2", 2.5)
+property_double (ring_gap2,    "ring gap2", 2.0)
   description ("radius, in pixels of second nearest to pixel circle")
   value_range (0.0, 16.0)
   ui_steps    (0.25, 0.25)
 
-property_double (ring_gap3,    "ring gap3", 3.7)
+property_double (ring_gap3,    "ring gap3", 3.0)
   description ("radius, in pixels of third pixel circle")
   value_range (0.0, 16.0)
   ui_steps    (0.25, 0.25)
 
-property_double (ring_gap4, "ring gap4", 5.5)
+property_double (ring_gap4, "ring gap4", 4.5)
   description ("radius, in pixels of fourth pixel circle (not always in use)")
   value_range (0.0, 16.0)
   ui_steps    (0.25, 0.25)
@@ -433,13 +433,30 @@ static void extract_site (PixelDuster *duster, GeglBuffer *buffer, double x, dou
     {
       float energy = 0.0;
       int count = 0;
+      int anti_ray = ray + RAYS/2;
+      if (anti_ray >= RAYS)
+        anti_ray -= RAYS;
+
       for (int circle = 0; circle < RINGS; circle++)
+      {
         if (dst[ ( circle * RAYS  + ray )*4 + 3] > 0.01)
         {
           for (int c = 0; c < 3; c++)
             energy += dst[ ( circle * RAYS  + ray )*4 + c];
           count ++;
         }
+      }
+
+      for (int circle = 0; circle < RINGS; circle++)
+      {
+        if (dst[ ( circle * RAYS  + anti_ray )*4 + 3] > 0.01)
+        {
+          for (int c = 0; c < 3; c++)
+            energy -= dst[ ( circle * RAYS  + anti_ray )*4 + c];
+          count ++;
+        }
+      }
+
       if (count)
         energy/=count;
       if (energy > warmest_ray_energy)