[gegl] added simple grid render operation

[Øyvind Kolås <ok src gnome org>]

commit 8575cc6a251453c757a05c0299aad82273d5f0f1
Author: Andy Gill <andyggill gmail com>
Date:   Thu Jan 13 21:40:23 2011 +0000

    added simple grid render operation

 operations/common/grid.c |  130 ++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 130 insertions(+), 0 deletions(-)
---
diff --git a/operations/common/grid.c b/operations/common/grid.c
new file mode 100644
index 0000000..8fe89c2
--- /dev/null
+++ b/operations/common/grid.c
@@ -0,0 +1,130 @@
+/* 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 <http://www.gnu.org/licenses/>.
+ *
+ * Copyright 2006 �yvind Kolås <pippin gimp org>
+ */
+
+#include "config.h"
+#include <glib/gi18n-lib.h>
+
+#ifdef GEGL_CHANT_PROPERTIES
+
+gegl_chant_int   (x,        _("Width"),  1, G_MAXINT, 32,
+                  _("Horizontal width of cells pixels."))
+gegl_chant_int   (y,        _("Height"), 1, G_MAXINT, 32,
+                  _("Vertical width of cells in pixels."))
+gegl_chant_int   (x_offset, _("X offset"), -G_MAXINT, G_MAXINT, 0,
+                  _("Horizontal offset (from origin) for start of grid."))
+gegl_chant_int   (y_offset, _("Y offset"), -G_MAXINT, G_MAXINT,  0,
+                  _("Vertical offset (from origin) for start of grid."))
+gegl_chant_int   (line_width, _("Line Width"),  0, G_MAXINT, 4,
+                  _("Width of grid lines in pixels."))
+gegl_chant_int   (line_height, _("Line Height"), 0, G_MAXINT, 4,
+                  _("Height of grid lines in pixels."))
+gegl_chant_color (line_color,   _("Color"), "black",
+                  _("Color of the grid lines"))
+
+#else
+
+#define GEGL_CHANT_TYPE_POINT_RENDER
+#define GEGL_CHANT_C_FILE       "grid.c"
+
+#include "gegl-chant.h"
+
+static void
+prepare (GeglOperation *operation)
+{
+  gegl_operation_set_format (operation, "output", babl_format ("RGBA float"));
+}
+
+static GeglRectangle
+get_bounding_box (GeglOperation *operation)
+{
+  return gegl_rectangle_infinite_plane ();
+}
+
+static gboolean
+process (GeglOperation       *operation,
+         void                *out_buf,
+         glong                n_pixels,
+         const GeglRectangle *roi)
+{
+  GeglChantO *o = GEGL_CHANT_PROPERTIES (operation);
+  gfloat     *out_pixel = out_buf;
+  gfloat      line_color[4];
+  gint        x = roi->x; /* initial x         */
+  gint        y = roi->y; /* and y coordinates */
+
+  gegl_color_get_rgba4f (o->line_color, line_color);
+
+  while (n_pixels--)
+    {
+      gint nx,ny;
+
+      nx = (x - o->x_offset) % o->x;
+      ny = (y - o->y_offset) % o->y;
+      /* handle case where % returns a negative number */
+      nx += nx < 0 ? o->x : 0;
+      ny += ny < 0 ? o->y : 0;
+
+      if (nx < o->line_width || ny < o->line_height)
+        {
+          out_pixel[0]=line_color[0];
+          out_pixel[1]=line_color[1];
+          out_pixel[2]=line_color[2];
+          out_pixel[3]=line_color[3];
+        }
+      else
+        {
+          out_pixel[0]=0.0f;
+          out_pixel[1]=0.0f;
+          out_pixel[2]=0.0f;
+          out_pixel[3]=0.0f;
+        }
+
+      out_pixel += 4;
+
+      /* update x and y coordinates */
+      x++;
+      if (x>=roi->x + roi->width)
+        {
+          x=roi->x;
+          y++;
+        }
+    }
+
+  return  TRUE;
+}
+
+
+static void
+gegl_chant_class_init (GeglChantClass *klass)
+{
+  GeglOperationClass            *operation_class;
+  GeglOperationPointRenderClass *point_render_class;
+
+  operation_class = GEGL_OPERATION_CLASS (klass);
+  point_render_class = GEGL_OPERATION_POINT_RENDER_CLASS (klass);
+
+  point_render_class->process = process;
+  operation_class->get_bounding_box = get_bounding_box;
+  operation_class->prepare = prepare;
+
+  operation_class->name        = "gegl:grid";
+  operation_class->categories  = "render";
+  operation_class->description = _("Grid renderer");
+}
+
+#endif