[gegl] median-blur: add "abyss-policy" property

[Ell <ell src gnome org>]

commit 31ee079d114547172fbecb8f319cf865e48cf11a
Author: Ell <ell_se yahoo com>
Date:   Mon Jul 30 07:12:29 2018 -0400

    median-blur: add "abyss-policy" property
    
    Add an "abyss-policy" property to gegl:median-blur, which controls
    the input's abyss policy, and can be one of NONE or CLAMP, for now.
    When the abyss policy is NONE, the op's bounding box is expanded
    according to the blur radius, while when the abyss policy is CLAMP,
    the op's bounding box is clamped to the input bounding box.
    
    The default abyss policy is CLAMP, to keep the current behavior.

 operations/common/median-blur.c | 57 ++++++++++++++++++++++++++++++++---------
 1 file changed, 45 insertions(+), 12 deletions(-)
---
diff --git a/operations/common/median-blur.c b/operations/common/median-blur.c
index 323d81615..b82051d19 100644
--- a/operations/common/median-blur.c
+++ b/operations/common/median-blur.c
@@ -30,6 +30,11 @@ enum_start (gegl_median_blur_neighborhood)
   enum_value (GEGL_MEDIAN_BLUR_NEIGHBORHOOD_DIAMOND, "diamond", N_("Diamond"))
 enum_end (GeglMedianBlurNeighborhood)
 
+enum_start (gegl_median_blur_abyss_policy)
+   enum_value (GEGL_MEDIAN_BLUR_ABYSS_NONE,  "none",  N_("None"))
+   enum_value (GEGL_MEDIAN_BLUR_ABYSS_CLAMP, "clamp", N_("Clamp"))
+enum_end (GeglMedianBlurAbyssPolicy)
+
 property_enum (neighborhood, _("Neighborhood"),
                GeglMedianBlurNeighborhood, gegl_median_blur_neighborhood,
                GEGL_MEDIAN_BLUR_NEIGHBORHOOD_CIRCLE)
@@ -48,6 +53,10 @@ property_double  (alpha_percentile, _("Alpha percentile"), 50)
   value_range (0, 100)
   description (_("Neighborhood alpha percentile"))
 
+property_enum (abyss_policy, _("Abyss policy"), GeglMedianBlurAbyssPolicy,
+               gegl_median_blur_abyss_policy, GEGL_MEDIAN_BLUR_ABYSS_CLAMP)
+  description (_("How image edges are handled"))
+
 property_boolean (high_precision, _("High precision"), FALSE)
   description (_("Avoid clipping and quantization (slower)"))
 
@@ -716,16 +725,37 @@ prepare (GeglOperation *operation)
 static GeglRectangle
 get_bounding_box (GeglOperation *operation)
 {
-  GeglRectangle  result = { 0, 0, 0, 0 };
-  GeglRectangle *in_rect;
+  GeglProperties *o = GEGL_PROPERTIES (operation);
+
+  if (o->abyss_policy != GEGL_MEDIAN_BLUR_ABYSS_NONE)
+    {
+      GeglRectangle  result = { 0, 0, 0, 0 };
+      GeglRectangle *in_rect;
+
+      in_rect = gegl_operation_source_get_bounding_box (operation, "input");
+
+      if (in_rect)
+        result = *in_rect;
+
+      return result;
+    }
+
+  return GEGL_OPERATION_CLASS (gegl_op_parent_class)->get_bounding_box (operation);
+}
+
+static GeglAbyssPolicy
+get_abyss_policy (GeglOperation *operation,
+                  const gchar   *input_pad)
+{
+  GeglProperties *o = GEGL_PROPERTIES (operation);
 
-  in_rect = gegl_operation_source_get_bounding_box (operation, "input");
-  if (in_rect)
-  {
-    result = *in_rect;
-  }
+  switch (o->abyss_policy)
+    {
+    case GEGL_MEDIAN_BLUR_ABYSS_NONE:  return GEGL_ABYSS_NONE;
+    case GEGL_MEDIAN_BLUR_ABYSS_CLAMP: return GEGL_ABYSS_CLAMP;
+    }
 
-  return result;
+  g_return_val_if_reached (GEGL_ABYSS_NONE);
 }
 
 static gboolean
@@ -812,7 +842,7 @@ process (GeglOperation       *operation,
   dst_buf = g_new (gfloat, n_dst_pixels * n_components);
 
   gegl_buffer_get (input, &src_rect, 1.0, format, src_buf,
-                   GEGL_AUTO_ROWSTRIDE, GEGL_ABYSS_CLAMP);
+                   GEGL_AUTO_ROWSTRIDE, get_abyss_policy (operation, "input"));
   convert_values_to_bins (hist, src_buf, n_src_pixels, data->quantize);
 
   src = src_buf + o->radius * (src_rect.width + 1) * n_components;
@@ -944,18 +974,21 @@ finalize (GObject *object)
 static void
 gegl_op_class_init (GeglOpClass *klass)
 {
-  GObjectClass             *object_class;
-  GeglOperationClass       *operation_class;
-  GeglOperationFilterClass *filter_class;
+  GObjectClass                 *object_class;
+  GeglOperationClass           *operation_class;
+  GeglOperationFilterClass     *filter_class;
+  GeglOperationAreaFilterClass *area_class;
 
   object_class    = G_OBJECT_CLASS (klass);
   operation_class = GEGL_OPERATION_CLASS (klass);
   filter_class    = GEGL_OPERATION_FILTER_CLASS (klass);
+  area_class      = GEGL_OPERATION_AREA_FILTER_CLASS (klass);
 
   object_class->finalize            = finalize;
   filter_class->process             = process;
   operation_class->prepare          = prepare;
   operation_class->get_bounding_box = get_bounding_box;
+  area_class->get_abyss_policy      = get_abyss_policy;
 
   gegl_operation_class_set_keys (operation_class,
     "name",           "gegl:median-blur",