[gegl] ripple: add sawtooth wave type using an enum property

[Michael Murà <mmure src gnome org>]

commit 4447d8deadb553057571116651f9f00f5959dc92
Author: Michael Murà <batolettre gmail com>
Date:   Sun Sep 4 19:11:30 2011 +0200

    ripple: add sawtooth wave type using an enum property

 gegl/gegl-enums.c            |   15 +++++++++++++++
 gegl/gegl-enums.h            |   12 ++++++++++++
 operations/workshop/ripple.c |   30 +++++++++++++++++++++++++-----
 3 files changed, 52 insertions(+), 5 deletions(-)
---
diff --git a/gegl/gegl-enums.c b/gegl/gegl-enums.c
index acfd319..57cefdc 100644
--- a/gegl/gegl-enums.c
+++ b/gegl/gegl-enums.c
@@ -26,6 +26,21 @@ gegl_sampler_type_get_type (void)
   return etype;
 }
 
+GType
+gegl_ripple_wave_type_get_type (void)
+{
+  static GType etype = 0;
+  if (etype == 0) {
+    static const GEnumValue values[] = {
+      { GEGl_RIPPLE_WAVE_TYPE_SINE, "sine", "sine" },
+      { GEGl_RIPPLE_WAVE_TYPE_SAWTOOTH, "sawtooth", "sawtooth" },
+      { 0, NULL, NULL }
+    };
+    etype = g_enum_register_static ("GeglRippleWaveType", values);
+  }
+  return etype;
+}
+
 
 /* Generated data ends here */
 
diff --git a/gegl/gegl-enums.h b/gegl/gegl-enums.h
index 9bc8242..a20bfef 100644
--- a/gegl/gegl-enums.h
+++ b/gegl/gegl-enums.h
@@ -41,6 +41,18 @@ typedef enum {
 GType gegl_sampler_type_get_type   (void) G_GNUC_CONST;
 #define GEGL_TYPE_SAMPLER_TYPE (gegl_sampler_type_get_type())
 
+/*
+ * Operation specific enum
+ */
+
+typedef enum {
+  GEGl_RIPPLE_WAVE_TYPE_SINE,
+  GEGl_RIPPLE_WAVE_TYPE_SAWTOOTH
+} GeglRippleWaveType;
+GType gegl_ripple_wave_type_get_type   (void) G_GNUC_CONST;
+#define GEGL_RIPPLE_WAVE_TYPE (gegl_ripple_wave_type_get_type())
+
+
 G_END_DECLS
 
 #endif /* __GEGL_ENUMS_H__ */
\ No newline at end of file
diff --git a/operations/workshop/ripple.c b/operations/workshop/ripple.c
index d40d296..8e45be2 100644
--- a/operations/workshop/ripple.c
+++ b/operations/workshop/ripple.c
@@ -39,6 +39,9 @@ gegl_chant_double (angle, _("Angle"), -180.0, 180.0, 0.0,
 gegl_chant_enum (sampler_type, _("Sampler"), GeglSamplerType, GEGL_TYPE_SAMPLER_TYPE,
                  GEGL_SAMPLER_CUBIC, _("Sampler used internaly"))
 
+gegl_chant_enum (wave_type, _("Wave type"), GeglRippleWaveType, GEGL_RIPPLE_WAVE_TYPE,
+                 GEGl_RIPPLE_WAVE_TYPE_SINE, _("Type of wave"))
+
 #else
 
 #define GEGL_CHANT_TYPE_AREA_FILTER
@@ -47,6 +50,7 @@ gegl_chant_enum (sampler_type, _("Sampler"), GeglSamplerType, GEGL_TYPE_SAMPLER_
 #include "gegl-chant.h"
 #include <stdio.h>
 #include <math.h>
+#include <stdlib.h>
 
 static void prepare (GeglOperation *operation)
 {
@@ -90,14 +94,30 @@ process (GeglOperation       *operation,
 
   while (n_pixels--)
     {
-      gdouble angle_rad = o->angle / 180.0 * G_PI;
+      gdouble shift;
+      gdouble coordsx;
+      gdouble coordsy;
+      gdouble lambda;
 
+      gdouble angle_rad = o->angle / 180.0 * G_PI;
       gdouble nx = x * cos (angle_rad) + y * sin (angle_rad);
 
-      gdouble shift = o->amplitude * sin (2.0 * G_PI * nx / o->period + 2.0 * G_PI * o->phi);
+      switch (o->wave_type)
+        {
+          case GEGl_RIPPLE_WAVE_TYPE_SINE:
+            shift = o->amplitude * sin (2.0 * G_PI * nx / o->period + 2.0 * G_PI * o->phi);
+            break;
+
+          case GEGl_RIPPLE_WAVE_TYPE_SAWTOOTH:
+            lambda = div (nx,o->period).rem - o->phi * o->period;
+            if (lambda < 0)
+              lambda += o->period;
+            shift = o->amplitude * (fabs (((lambda / o->period) * 4) - 2) - 1);
+            break;
+        }
 
-      gdouble coordsx = x + shift * sin (angle_rad);
-      gdouble coordsy = y + shift * cos (angle_rad);
+      coordsx = x + shift * sin (angle_rad);
+      coordsy = y + shift * cos (angle_rad);
 
       gegl_sampler_get (sampler,
                         coordsx,