[gegl] operations: add gegl:engrave

[Thomas Manni <tmanni src gnome org>]

commit afc4707c2f5c7ec741980c50b7d085822e12eb1c
Author: Thomas Manni <thomas manni free fr>
Date:   Mon Dec 15 19:00:07 2014 +0100

    operations: add gegl:engrave

 operations/common/Makefile.am            |    1 +
 operations/common/engrave.c              |  206 ++++++++++++++++++++++++++++++
 po/POTFILES.in                           |    1 +
 tests/compositions/Makefile.am           |    1 +
 tests/compositions/engrave.xml           |   14 ++
 tests/compositions/reference/engrave.png |  Bin 0 -> 14082 bytes
 6 files changed, 223 insertions(+), 0 deletions(-)
---
diff --git a/operations/common/Makefile.am b/operations/common/Makefile.am
index a6ad566..0ed85b3 100644
--- a/operations/common/Makefile.am
+++ b/operations/common/Makefile.am
@@ -42,6 +42,7 @@ op_LTLIBRARIES = \
        edge-laplace.la \
        edge-sobel.la \
        emboss.la \
+       engrave.la \
        exp-combine.la \
        exposure.la \
        fattal02.la \
diff --git a/operations/common/engrave.c b/operations/common/engrave.c
new file mode 100644
index 0000000..af7608e
--- /dev/null
+++ b/operations/common/engrave.c
@@ -0,0 +1,206 @@
+/* This file is an image processing operation for GEGL
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * This operation is a port of the GIMP Engrave plug-in
+ *
+ * Copyright (C) 1995 Spencer Kimball and Peter Mattis
+ * Copyright (C) 1997 Eiichi Takamori
+ * Copyright (C) 1996, 1997 Torsten Martinsen
+ * 
+ * GEGL Port: Thomas Manni <thomas manni free fr>
+ *
+ */
+
+#include "config.h"
+#include <glib/gi18n-lib.h>
+
+#ifdef GEGL_PROPERTIES
+
+property_int (row_height, _("Height"), 10)
+    description (_("Resolution in pixels"))
+    value_range (2, 16)
+    ui_range    (2, 16)
+
+property_boolean (limit, _("Limit line width"), FALSE)
+    description (_("Limit line width"))
+
+#else
+
+#define GEGL_OP_AREA_FILTER
+#define GEGL_OP_C_FILE "engrave.c"
+
+#include "gegl-op.h"
+
+static void
+engrave_row (gfloat        *in_row,
+             GeglRectangle *in_rect,
+             gfloat        *out_row,
+             GeglRectangle *out_rect,
+             gboolean      limit)
+{
+  gfloat average, v;
+  gint   x, y, y_offset, real_y, inten;
+
+  y_offset = in_rect->height - out_rect->height;
+
+  for (x = 0; x < in_rect->width; x++)
+    {
+      average = 0.0f;
+
+      for (y = 0; y < in_rect->height; y++)
+        {
+          average += in_row[(x + y * in_rect->width) * 2];
+        }
+      
+      inten = average; 
+
+      for (y = 0; y < out_rect->height; y++)
+        {
+          real_y = y;
+
+          if (in_rect->y != out_rect->y)
+            real_y += y_offset;
+
+          v = inten > real_y ? 1.0f : 0.0f;
+
+          if (limit)
+            {
+              if (real_y == 0)
+                v = 1.0f;
+              else if (real_y == in_rect->height - 1)
+                v = 0.0f;
+            }
+
+          out_row[(x + y * out_rect->width) * 2] = v;
+
+          /* restore alpha */
+          out_row[(x + y * out_rect->width) * 2 + 1] = in_row[(x + real_y * in_rect->width) * 2 + 1];
+        }
+    }
+}
+
+static void
+prepare (GeglOperation *operation)
+{
+  GeglOperationAreaFilter *area = GEGL_OPERATION_AREA_FILTER (operation);
+  GeglProperties          *o = GEGL_PROPERTIES (operation);
+  const Babl              *format = babl_format ("Y'A float");
+
+  area->left = area->right  = 0;
+  area->top  = area->bottom = o->row_height;
+
+  gegl_operation_set_format (operation, "input", format);
+  gegl_operation_set_format (operation, "output", format);
+}
+
+static GeglRectangle
+get_bounding_box (GeglOperation *operation)
+{
+  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;
+}
+
+static gboolean
+process (GeglOperation       *operation,
+         GeglBuffer          *input,
+         GeglBuffer          *output,
+         const GeglRectangle *roi,
+         gint                 level)
+{
+  GeglProperties *o      = GEGL_PROPERTIES (operation);
+  const Babl     *format = babl_format ("Y'A float");
+
+  GeglRectangle *whole_region;
+  GeglRectangle in_rect;
+  GeglRectangle out_rect;
+
+  gint row_count;
+  gint top_offset, bottom_offset;
+  gint extended_roi_y, extended_roi_height;
+  gint i;
+
+  whole_region = gegl_operation_source_get_bounding_box (operation, "input");
+
+  top_offset = roi->y % o->row_height;
+  bottom_offset = (roi->y + roi->height) % o->row_height;
+
+  extended_roi_y = roi->y - top_offset;
+  extended_roi_height = roi->height + top_offset + (o->row_height - bottom_offset);
+
+  row_count = extended_roi_height / o->row_height;
+
+  for (i = 0; i < row_count; i++)
+    {
+      gfloat *in_buf;
+      gfloat *out_buf;
+      gint   in_y;
+
+      in_y = extended_roi_y + i * o->row_height;
+
+      gegl_rectangle_set (&in_rect, roi->x, in_y, roi->width, o->row_height);
+      gegl_rectangle_intersect (&in_rect, &in_rect, whole_region);
+
+      gegl_rectangle_set (&out_rect, roi->x, in_y, roi->width, o->row_height);
+      gegl_rectangle_intersect (&out_rect, &out_rect, roi);
+
+      in_buf = g_new (gfloat, in_rect.width * in_rect.height * 2);
+      out_buf = g_new (gfloat, out_rect.width * out_rect.height * 2);
+
+      gegl_buffer_get (input, &in_rect, 1.0, format, in_buf,
+                       GEGL_AUTO_ROWSTRIDE, GEGL_ABYSS_NONE);
+
+      engrave_row (in_buf, &in_rect, out_buf, &out_rect, o->limit);
+
+      gegl_buffer_set (output, &out_rect, 0, format, out_buf,
+                       GEGL_AUTO_ROWSTRIDE);
+
+      g_free (in_buf);
+      g_free (out_buf);
+    }
+
+  return TRUE;
+}
+
+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->process             = process;
+  operation_class->prepare          = prepare;
+  operation_class->get_bounding_box = get_bounding_box;
+
+  gegl_operation_class_set_keys (operation_class,
+    "name",        "gegl:engrave",
+    "title",       _("Engrave"),
+    "categories",  "distort",
+    "license",     "GPL3+",
+    "description", _("Simulate an antique engraving"),
+    NULL);
+}
+
+#endif
diff --git a/po/POTFILES.in b/po/POTFILES.in
index cf74f9d..7e6fa1e 100644
--- a/po/POTFILES.in
+++ b/po/POTFILES.in
@@ -36,6 +36,7 @@ operations/common/dropshadow.c
 operations/common/edge-laplace.c
 operations/common/edge-sobel.c
 operations/common/emboss.c
+operations/common/engrave.c
 operations/common/exp-combine.c
 operations/common/exposure.c
 operations/common/fattal02.c
diff --git a/tests/compositions/Makefile.am b/tests/compositions/Makefile.am
index b85e81d..131c00d 100644
--- a/tests/compositions/Makefile.am
+++ b/tests/compositions/Makefile.am
@@ -27,6 +27,7 @@ TESTS = \
   contrast-curve.xml              \
   edge-laplace.xml                \
   edge-sobel.xml                  \
+  engrave.xml                     \
   fattal02.xml                    \
        gegl.xml                        \
   gamma.xml                       \
diff --git a/tests/compositions/engrave.xml b/tests/compositions/engrave.xml
new file mode 100644
index 0000000..ffa5427
--- /dev/null
+++ b/tests/compositions/engrave.xml
@@ -0,0 +1,14 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<gegl>
+  <node operation='gegl:engrave'>
+    <params>
+      <param name='row_height'>4</param>
+      <param name='limit'>false</param>
+    </params>
+  </node>
+  <node operation='gegl:load'>
+    <params>
+      <param name='path'>data/duck.png</param>
+    </params>
+  </node>
+</gegl>
diff --git a/tests/compositions/reference/engrave.png b/tests/compositions/reference/engrave.png
new file mode 100644
index 0000000..3f2e2a4
Binary files /dev/null and b/tests/compositions/reference/engrave.png differ