[gegl] workshop: new op boxblur-1d

[Thomas Manni <tmanni src gnome org>]

commit 70d0729a209d8ca6b8d759c4cd6be3376c64c554
Author: Thomas Manni <thomas manni free fr>
Date:   Tue Jun 25 12:38:52 2019 +0200

    workshop: new op boxblur-1d
    
    A one dimensional box blur filter which handles RGB, Y and CMYK color models
    with appropriate multithreads splitting strategy.

 operations/workshop/Makefile.am  |   1 +
 operations/workshop/boxblur-1d.c | 325 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 326 insertions(+)
---
diff --git a/operations/workshop/Makefile.am b/operations/workshop/Makefile.am
index faacec525..b805083ef 100644
--- a/operations/workshop/Makefile.am
+++ b/operations/workshop/Makefile.am
@@ -11,6 +11,7 @@ LIBS = $(op_libs)
 ops = \
        bayer-matrix.la \
        bilateral-filter-fast.la \
+       boxblur-1d.la \
        connected-components.la \
        demosaic-bimedian.la \
        demosaic-simple.la \
diff --git a/operations/workshop/boxblur-1d.c b/operations/workshop/boxblur-1d.c
new file mode 100644
index 000000000..b5e3cfde3
--- /dev/null
+++ b/operations/workshop/boxblur-1d.c
@@ -0,0 +1,325 @@
+/* This file is an image processing operation for GEGL
+ * GEGL is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * GEGL is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with GEGL; if not, see <https://www.gnu.org/licenses/>.
+ *
+ * Copyright 2019 Thomas Manni <thomas manni free fr>
+ *
+ * TODO:
+ * - manage mipmap level
+ * - add opencl support
+ */
+
+ #include "config.h"
+#include <glib/gi18n-lib.h>
+
+#ifdef GEGL_PROPERTIES
+
+property_int (radius, _("Radius"), 4)
+   description(_("Radius of row pixel region, (size will be radius*2+1)"))
+   value_range (0, 1000)
+   ui_range    (0, 100)
+   ui_gamma   (1.5)
+
+property_enum (orientation, _("Orientation"),
+               GeglOrientation, gegl_orientation,
+               GEGL_ORIENTATION_HORIZONTAL)
+  description (_("The orientation of the blur - hor/ver"))
+
+#else
+
+#define GEGL_OP_AREA_FILTER
+#define GEGL_OP_NAME     boxblur_1d
+#define GEGL_OP_C_SOURCE boxblur-1d.c
+
+#include "gegl-op.h"
+
+static void
+prepare (GeglOperation *operation)
+{
+  GeglProperties          *o = GEGL_PROPERTIES (operation);
+  GeglOperationAreaFilter *op_area = GEGL_OPERATION_AREA_FILTER (operation);
+  const Babl *space      = gegl_operation_get_source_space (operation, "input");
+  const Babl *src_format = gegl_operation_get_source_format (operation, "input"); 
+  const char *format     = "RaGaBaA float";
+
+  if (o->orientation == GEGL_ORIENTATION_HORIZONTAL)
+    {
+      op_area->left = op_area->right = o->radius;
+    }
+  else
+    {
+      op_area->top = op_area->bottom = o->radius;    
+    }
+
+  if (src_format)
+    {
+      const Babl *model = babl_format_get_model (src_format);
+
+      if (babl_model_is (model, "RGB") || babl_model_is (model, "R'G'B'"))
+        {
+          format = "RGB float";
+        }
+      else if (babl_model_is (model, "Y") || babl_model_is (model, "Y'"))
+        {
+          format = "Y float";
+        }
+      else if (babl_model_is (model, "YA") || babl_model_is (model, "Y'A") ||
+               babl_model_is (model, "YaA") || babl_model_is (model, "Y'aA"))
+        {
+          format = "YaA float";
+        }
+      else if (babl_model_is (model, "cmyk"))
+        {
+          format = "cmyk float";
+        }
+      else if (babl_model_is (model, "CMYK"))
+        {
+          format = "CMYK float";
+        }
+      else if (babl_model_is (model, "cmykA") || 
+               babl_model_is (model, "camayakaA") ||
+               babl_model_is (model, "CMYKA") ||
+               babl_model_is (model, "CaMaYaKaA"))
+        {
+          format = "camayakaA float";
+        }
+    }
+
+  gegl_operation_set_format (operation, "input",
+                             babl_format_with_space (format, space));
+  gegl_operation_set_format (operation, "output",
+                             babl_format_with_space (format, space));
+}
+
+static GeglSplitStrategy
+get_split_strategy (GeglOperation        *operation,
+                    GeglOperationContext *context,
+                    const gchar          *output_prop,
+                    const GeglRectangle  *result,
+                    gint                  level)
+{
+  GeglProperties *o = GEGL_PROPERTIES (operation);
+
+  if (o->orientation == GEGL_ORIENTATION_HORIZONTAL)
+    return GEGL_SPLIT_STRATEGY_HORIZONTAL;
+  else
+    return GEGL_SPLIT_STRATEGY_VERTICAL;
+}
+
+static GeglRectangle
+get_bounding_box (GeglOperation *operation)
+{
+  GeglRectangle *in_rect;
+
+  in_rect = gegl_operation_source_get_bounding_box (operation,"input");
+
+  if (! in_rect)
+    return *GEGL_RECTANGLE (0, 0, 0, 0);
+  
+  return *in_rect;
+}
+
+static GeglRectangle
+get_cached_region (GeglOperation       *operation,
+                   const GeglRectangle *output_roi)
+{
+  GeglProperties    *o        = GEGL_PROPERTIES (operation);
+  const GeglRectangle in_rect = get_bounding_box (operation);
+  GeglRectangle      cached_region = *output_roi;
+
+  if (! gegl_rectangle_is_empty (&in_rect) &&
+      ! gegl_rectangle_is_infinite_plane (&in_rect))
+    {
+      if (o->orientation == GEGL_ORIENTATION_HORIZONTAL)
+        {
+          cached_region.x     = in_rect.x;
+          cached_region.width = in_rect.width;
+        }
+      else
+        {
+          cached_region.y      = in_rect.y;
+          cached_region.height = in_rect.height;
+        }
+    }
+
+  return cached_region;
+}
+
+static inline void
+box_blur_1d (gfloat  *src_buf,
+             gfloat  *dst_buf,
+             gint     dst_size,
+             gint     radius,
+             gint     n_components)
+{
+  gint   n, i;
+  gint   src_offset;
+  gint   dst_offset = 0;
+  gint   prev_rad = radius * n_components + n_components;
+  gint   next_rad = radius * n_components;
+  gfloat rad1 = 1.f / (gfloat)(radius * 2 + 1);
+
+  for (i = 0; i < (2 * radius + 1); i++)
+    {
+      src_offset = i * n_components;
+      for (n = 0; n < n_components; n++)
+        {
+          dst_buf[dst_offset + n] += src_buf[src_offset + n] * rad1;
+        }    
+    }
+  
+  dst_offset += n_components;
+  
+  for (i = 1; i < dst_size; i++)
+    {
+      src_offset = (i + radius) * n_components;
+      for (n = 0; n < n_components; n++)
+        {
+          dst_buf[dst_offset] = dst_buf[dst_offset - n_components]
+                              - src_buf[src_offset - prev_rad] * rad1
+                              + src_buf[src_offset + next_rad] * rad1;
+          src_offset++;
+          dst_offset++;
+        }
+    }
+}
+
+static gboolean
+process (GeglOperation       *operation,
+         GeglBuffer          *input,
+         GeglBuffer          *output,
+         const GeglRectangle *roi,
+         gint                 level)
+{
+  GeglProperties  *o = GEGL_PROPERTIES (operation);
+  const Babl *format = gegl_operation_get_format (operation, "input");
+  gint n_components  = babl_format_get_n_components (format);
+  GeglRectangle src_rect;
+  GeglRectangle dst_rect;
+  gfloat       *src_buf;
+  gfloat       *dst_buf;
+
+  if (o->orientation == GEGL_ORIENTATION_HORIZONTAL)
+    {
+      src_rect.x      = roi->x - o->radius;
+      src_rect.width  = roi->width + 2 * o->radius;
+      src_rect.height = 1;
+      
+      dst_rect.x      = roi->x;
+      dst_rect.width  = roi->width;
+      dst_rect.height = 1; 
+      
+      src_buf = g_new (gfloat, src_rect.width * n_components);
+
+      for (src_rect.y = roi->y; src_rect.y < roi->y + roi->height; src_rect.y++)
+        {
+          dst_rect.y = src_rect.y;
+          dst_buf = g_new0 (gfloat, dst_rect.width * n_components);
+
+          gegl_buffer_get (input, &src_rect, 1.0, format, src_buf,
+                           GEGL_AUTO_ROWSTRIDE, GEGL_ABYSS_CLAMP);
+
+          box_blur_1d (src_buf, dst_buf, dst_rect.width, o->radius, n_components);
+
+          gegl_buffer_set (output, &dst_rect, 0, format, dst_buf,
+                           GEGL_AUTO_ROWSTRIDE);
+          g_free (dst_buf);
+        }
+    }
+  else
+    {
+      src_rect.y      = roi->y - o->radius;
+      src_rect.width  = 1;
+      src_rect.height = roi->height + 2 * o->radius;
+      
+      dst_rect.y      = roi->y;
+      dst_rect.width  = 1;
+      dst_rect.height = roi->height;
+      
+      src_buf = g_new  (gfloat, src_rect.height * n_components);
+
+      for (src_rect.x = roi->x; src_rect.x < roi->x + roi->width; src_rect.x++)
+        {
+          dst_rect.x = src_rect.x;
+          dst_buf = g_new0 (gfloat, dst_rect.height * n_components);
+
+          gegl_buffer_get (input, &src_rect, 1.0, format, src_buf,
+                           GEGL_AUTO_ROWSTRIDE, GEGL_ABYSS_CLAMP);
+
+          box_blur_1d (src_buf, dst_buf, dst_rect.height, o->radius, n_components);
+
+          gegl_buffer_set (output, &dst_rect, 0, format, dst_buf,
+                           GEGL_AUTO_ROWSTRIDE);
+          g_free (dst_buf);
+        }
+    }  
+
+  g_free (src_buf);
+
+  return TRUE;
+}
+
+/* Pass-through if radius is zero
+ */
+static gboolean
+operation_process (GeglOperation        *operation,
+                   GeglOperationContext *context,
+                   const gchar          *output_prop,
+                   const GeglRectangle  *result,
+                   gint                  level)
+{
+  GeglOperationClass  *operation_class;
+  GeglProperties      *o = GEGL_PROPERTIES (operation);
+
+  operation_class = GEGL_OPERATION_CLASS (gegl_op_parent_class);
+      
+  if (! o->radius)
+    {
+      gpointer in = gegl_operation_context_get_object (context, "input");
+      gegl_operation_context_take_object (context, "output",
+                                          g_object_ref (G_OBJECT (in)));
+      return TRUE;
+    }
+  
+  return operation_class->process (operation, context, output_prop, result,
+                                   gegl_operation_context_get_level (context));
+}
+
+static void
+gegl_op_class_init (GeglOpClass *klass)
+{
+  GeglOperationClass       *operation_class;
+  GeglOperationFilterClass *filter_class;
+
+  operation_class = GEGL_OPERATION_CLASS (klass);
+  filter_class    = GEGL_OPERATION_FILTER_CLASS (klass);
+
+  filter_class->get_split_strategy   = get_split_strategy;
+  filter_class->process              = process;
+
+  operation_class->get_bounding_box  = get_bounding_box;
+  operation_class->get_cached_region = get_cached_region;
+  operation_class->opencl_support    = FALSE;
+  operation_class->prepare           = prepare;
+  operation_class->process           = operation_process;
+
+  gegl_operation_class_set_keys (operation_class,
+      "name",        "gegl:boxblur-1d",
+      "categories",  "hidden:blur",
+      "title",       _("1D Box Blur"),
+      "description", _("Blur resulting from averaging the colors of a row "
+                       "neighbourhood."),
+      NULL);
+}
+
+#endif
\ No newline at end of file