[gegl] ripple experimentation with gegl

[Michael Murà <mmure src gnome org>]

commit 41970fff1eb3c566fe28fa675196eefdd2c32da0
Author: Hans Lo <hansshulo gmail com>
Date:   Fri Apr 8 03:56:26 2011 -0400

    ripple experimentation with gegl

 operations/common/ripple-test.c |  149 +++++++++++++++++++++++++++++++++++++++
 1 files changed, 149 insertions(+), 0 deletions(-)
---
diff --git a/operations/common/ripple-test.c b/operations/common/ripple-test.c
new file mode 100644
index 0000000..dc62973
--- /dev/null
+++ b/operations/common/ripple-test.c
@@ -0,0 +1,149 @@
+#include "config.h"
+#include <glib/gi18n-lib.h>
+
+#ifdef GEGL_CHANT_PROPERTIES
+
+gegl_chant_int (amplitude, _("Amplitude"), 0, 200, 50,
+   _("Amplitude of ripple."))
+
+gegl_chant_int (period, _("Period"), 0, 200, 50,
+   _("Period of ripple."))
+
+gegl_chant_double (phi, _("Phase Shift"), -1.0, 1.0, 0.0,
+   _("As proportion of pi."))
+
+gegl_chant_boolean (antialias,   _("Antialiasing"),   FALSE,
+                    _("Antialiasing"))
+
+#else
+
+#define GEGL_CHANT_TYPE_AREA_FILTER
+#define GEGL_CHANT_C_FILE       "ripple-test.c"
+
+#include "gegl-chant.h"
+#include <stdio.h>
+#include <math.h>
+
+
+static gdouble
+displace_amount (gint location, gint amplitude, gint period, gdouble phi)
+{
+  return ((gdouble)amplitude *
+	  sin (2 * G_PI * (((gdouble)location / (gdouble)period) + G_PI*phi)));
+}
+
+static void
+horizontal_shift (GeglBuffer          *src,
+      const GeglRectangle *src_rect,
+      GeglBuffer          *dst,
+      const GeglRectangle *dst_rect,
+      gint amplitude,
+      gint period,
+      gdouble phi,
+      gboolean antialias)
+{
+  gint u,v;
+  gint src_offset, dst_offset;
+  gfloat *src_buf;
+  gfloat *dst_buf;
+  src_buf = g_new0 (gfloat, src_rect->width * src_rect->height * 4);
+  dst_buf = g_new0 (gfloat, dst_rect->width * dst_rect->height * 4);
+  gegl_buffer_get (src, 1.0, src_rect, babl_format ("RaGaBaA float"), src_buf, GEGL_AUTO_ROWSTRIDE);
+  src_offset = 0;
+  dst_offset = 0;
+  for (v=0; v<dst_rect->height; v++)
+    {
+      gdouble shift = displace_amount(v+dst_rect->y, amplitude, period, phi);
+      gdouble floor_shift = floor(shift);
+      gdouble remainder = shift-floor_shift;
+      gdouble temp_value;
+      
+      for (u=0; u<(dst_rect->width); u++)
+        {
+          gint i;
+      
+          for (i=0; i<4; i++)
+            {
+              gint new_pixel = src_offset + (4*amplitude + 4*amplitude*2*v + 4*(gint)floor_shift);
+              //antialias
+
+      
+              temp_value = src_buf[new_pixel];
+
+              if(antialias && u>3 && i < 3)
+                {
+                  gint upper_pixel = new_pixel - 4;
+                  temp_value = (remainder)*src_buf[new_pixel] + (1.0-remainder)*src_buf[upper_pixel];
+      
+                }
+      
+              dst_buf[dst_offset] = temp_value;
+              src_offset++;
+              dst_offset++;
+            }
+        }
+    }
+
+  gegl_buffer_set (dst, dst_rect, babl_format ("RaGaBaA float"), dst_buf, GEGL_AUTO_ROWSTRIDE);
+  g_free (src_buf);
+  g_free (dst_buf);
+}
+
+static void prepare (GeglOperation *operation)
+{
+  GeglChantO              *o;
+  GeglOperationAreaFilter *op_area;
+
+  op_area = GEGL_OPERATION_AREA_FILTER (operation);
+  o       = GEGL_CHANT_PROPERTIES (operation);
+
+    op_area->left   =
+    op_area->right  = o->amplitude;
+    //op_area->top    =
+    //op_area->bottom = 
+
+  gegl_operation_set_format (operation, "output",
+                             babl_format ("RaGaBaA float"));
+
+}
+
+static gboolean
+process (GeglOperation       *operation,
+         GeglBuffer          *input,
+         GeglBuffer          *output,
+         const GeglRectangle *result)
+{
+
+  GeglRectangle rect;
+  GeglChantO *o = GEGL_CHANT_PROPERTIES (operation);
+  GeglOperationAreaFilter *op_area;
+  op_area = GEGL_OPERATION_AREA_FILTER (operation);
+
+  rect = *result;
+
+  rect.x-=op_area->left;
+  rect.width+=op_area->left + op_area->right;
+  horizontal_shift(input, &rect, output, result, o->amplitude, o->period, o->phi, o->antialias);
+  return  TRUE;
+}
+
+
+static void
+gegl_chant_class_init (GeglChantClass *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->categories  = "blur";
+  operation_class->name        = "gegl:ripple-test";
+  operation_class->description =
+       _("Trying out GEGL.");
+}
+
+#endif