[gegl] polar-coordinates: Add the polar-coordinates op from soc-2011-ops branch

[Mukund Sivaraman <muks src gnome org>]

commit aa03e587bdd3519d6570b7c33c46179068441573
Author: Robert Sasu <sasu robert gmail com>
Date:   Tue Aug 30 20:27:59 2011 +0530

    polar-coordinates: Add the polar-coordinates op from soc-2011-ops branch

 operations/workshop/polar-coordinates.c |  404 +++++++++++++++++++++++++++++++
 1 files changed, 404 insertions(+), 0 deletions(-)
---
diff --git a/operations/workshop/polar-coordinates.c b/operations/workshop/polar-coordinates.c
new file mode 100644
index 0000000..14dde0a
--- /dev/null
+++ b/operations/workshop/polar-coordinates.c
@@ -0,0 +1,404 @@
+/* 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/>.
+ *
+ * Polarize plug-in --- maps a rectangle to a circle or vice-versa
+ * Copyright (C) 1997 Daniel Dunbar
+ * Email: ddunbar diads com
+ * WWW:   http://millennium.diads.com/gimp/
+ * Copyright (C) 1997 Federico Mena Quintero
+ * federico nuclecu unam mx
+ * Copyright (C) 1996 Marc Bless
+ * E-mail: bless ai-lab fh-furtwangen de
+ * WWW:    www.ai-lab.fh-furtwangen.de/~bless
+ *
+ * Copyright (C) 2011 Robert Sasu <sasu robert gmail com>
+ */
+
+#include "config.h"
+#include <glib/gi18n-lib.h>
+
+#ifdef GEGL_CHANT_PROPERTIES
+
+gegl_chant_double (depth, _("Circle depth in percent"), 0.0, 100.0, 100.0,
+                   _("Circle depth in percent."))
+gegl_chant_double (angle, _("Offset angle"), 0.0, 359.9, 0.0,
+                   _("Offset angle."))
+gegl_chant_boolean (bw, _("Map backwards"), FALSE, _("Map backwards."))
+gegl_chant_boolean (top, _("Map from top"), TRUE, _("Map from top"))
+gegl_chant_boolean (polar, _("To polar"), TRUE, _("To polar."))
+gegl_chant_int (pole_x, _("X:"), 0, G_MAXINT, 0, 
+                _("Origin point for the polar coordinates"))
+gegl_chant_int (pole_y, _("Y:"), 0, G_MAXINT, 0,
+                _("Origin point for the polar coordinates"))
+gegl_chant_boolean (middle, _("Choose middle"), TRUE,
+                    _("Let origin point to be the middle one"))
+
+
+#else
+
+#define GEGL_CHANT_TYPE_FILTER
+#define GEGL_CHANT_C_FILE       "polar-coordinates.c"
+
+#include "gegl-chant.h"
+#include <stdio.h>
+#include <math.h>
+
+#define WITHIN(a, b, c) ((((a) <= (b)) && ((b) <= (c))) ? 1 : 0)
+#define SQR(x) (x)*(x)
+
+#define SCALE_WIDTH     200
+#define ENTRY_WIDTH      60
+
+static void prepare (GeglOperation *operation)
+{
+  gegl_operation_set_format (operation, "input", 
+                             babl_format ("RGBA float"));
+  gegl_operation_set_format (operation, "output",
+                             babl_format ("RGBA float"));
+}
+
+static gboolean
+calc_undistorted_coords (gdouble        wx,
+                         gdouble        wy,
+                         gdouble       *x,
+                         gdouble       *y,
+                         GeglChantO    *o,
+                         GeglRectangle  boundary)
+{
+  gboolean inside;
+  gdouble  phi, phi2;
+  gdouble  xx, xm, ym, yy;
+  gint     xdiff, ydiff;
+  gdouble  r;
+  gdouble  m;
+  gdouble  xmax, ymax, rmax;
+  gdouble  x_calc, y_calc;
+  gdouble  xi, yi, cen_x, cen_y;
+  gdouble  circle, angl, t, angle;
+  gint     x1, x2, y1, y2;
+
+  /* initialize */
+
+  phi = 0.0;
+  r   = 0.0;
+
+  x1     = 0;
+  y1     = 0;
+  x2     = boundary.width;
+  y2     = boundary.height;
+  xdiff  = x2 - x1;
+  ydiff  = y2 - y1;
+  xm     = xdiff / 2.0;
+  ym     = ydiff / 2.0;
+  circle = o->depth;
+  angle  = o->angle;
+  angl   = (gdouble) angle / 180.0 * G_PI;
+  cen_x  = o->pole_x;
+  cen_y  = o->pole_y;
+  
+
+  if (o->polar)
+    {
+      if (wx >= cen_x)
+        {
+          if (wy > cen_y)
+            {
+              phi = G_PI - atan (((double)(wx - cen_x))/
+                                 ((double)(wy - cen_y)));
+            }
+          else if (wy < cen_y)
+            {
+              phi = atan (((double)(wx - cen_x))/((double)(cen_y - wy)));
+            }
+          else
+            {
+              phi = G_PI / 2;
+            }
+        }
+      else if (wx < cen_x)
+        {
+          if (wy < cen_y)
+            {
+              phi = 2 * G_PI - atan (((double)(cen_x -wx)) /
+                                     ((double)(cen_y - wy)));
+            }
+          else if (wy > cen_y)
+            {
+              phi = G_PI + atan (((double)(cen_x - wx))/
+                                 ((double)(wy - cen_y)));
+            }
+          else
+            {
+              phi = 1.5 * G_PI;
+            }
+        }
+
+      r   = sqrt (SQR (wx - cen_x) + SQR (wy - cen_y));
+
+      if (wx != cen_x)
+        {
+          m = fabs (((double)(wy - cen_y)) / ((double)(wx - cen_x)));
+        }
+      else
+        {
+          m = 0;
+        }
+
+      if (m <= ((double)(y2 - y1) / (double)(x2 - x1)))
+        {
+          if (wx == cen_x)
+            {
+              xmax = 0;
+              ymax = cen_y - y1;
+            }
+          else
+            {
+              xmax = cen_x - x1;
+              ymax = m * xmax;
+            }
+        }
+      else
+        {
+          ymax = cen_y - y1;
+          xmax = ymax / m;
+        }
+
+      rmax = sqrt ( (double)(SQR (xmax) + SQR (ymax)) );
+
+      t = ((cen_y - y1) < (cen_x - x1)) ? (cen_y - y1) : (cen_x - x1);
+      rmax = (rmax - t) / 100 * (100 - circle) + t;
+
+      phi = fmod (phi + angl, 2*G_PI);
+
+      if (o->bw)
+        x_calc = x2 - 1 - (x2 - x1 - 1)/(2*G_PI) * phi;
+      else
+        x_calc = (x2 - x1 - 1)/(2*G_PI) * phi + x1;
+
+      if (o->top)
+        y_calc = (y2 - y1)/rmax   * r   + y1;
+      else
+        y_calc = y2 - (y2 - y1)/rmax * r;
+    }
+  else
+    {
+      if (o->bw)
+        phi = (2 * G_PI) * (x2 - wx) / xdiff;
+      else
+        phi = (2 * G_PI) * (wx - x1) / xdiff;
+
+      phi = fmod (phi + angl, 2 * G_PI);
+
+      if (phi >= 1.5 * G_PI)
+        phi2 = 2 * G_PI - phi;
+      else if (phi >= G_PI)
+        phi2 = phi - G_PI;
+      else if (phi >= 0.5 * G_PI)
+        phi2 = G_PI - phi;
+      else
+        phi2 = phi;
+
+      xx = tan (phi2);
+      if (xx != 0)
+        m = (double) 1.0 / xx;
+      else
+        m = 0;
+
+      if (m <= ((double)(ydiff) / (double)(xdiff)))
+        {
+          if (phi2 == 0)
+            {
+              xmax = 0;
+              ymax = ym - y1;
+            }
+          else
+            {
+              xmax = xm - x1;
+              ymax = m * xmax;
+            }
+        }
+      else
+        {
+          ymax = ym - y1;
+          xmax = ymax / m;
+        }
+
+      rmax = sqrt ((double)(SQR (xmax) + SQR (ymax)));
+
+      t = ((ym - y1) < (xm - x1)) ? (ym - y1) : (xm - x1);
+
+      rmax = (rmax - t) / 100.0 * (100 - circle) + t;
+
+      if (o->top)
+        r = rmax * (double)((wy - y1) / (double)(ydiff));
+      else
+        r = rmax * (double)((y2 - wy) / (double)(ydiff));
+
+      xx = r * sin (phi2);
+      yy = r * cos (phi2);
+
+      if (phi >= 1.5 * G_PI)
+        {
+          x_calc = (double)xm - xx;
+          y_calc = (double)ym - yy;
+        }
+      else if (phi >= G_PI)
+        {
+          x_calc = (double)xm - xx;
+          y_calc = (double)ym + yy;
+        }
+      else if (phi >= 0.5 * G_PI)
+        {
+          x_calc = (double)xm + xx;
+          y_calc = (double)ym + yy;
+        }
+      else
+        {
+          x_calc = (double)xm + xx;
+          y_calc = (double)ym - yy;
+        }
+    }
+
+  xi = (int) (x_calc + 0.5);
+  yi = (int) (y_calc + 0.5);
+
+  inside = (WITHIN (0, xi, boundary.width - 1) && WITHIN (0, yi, boundary.height - 1));
+  if (inside)
+    {
+      *x = x_calc;
+      *y = y_calc;
+    }
+  return inside;
+}
+
+
+static GeglRectangle
+get_effective_area (GeglOperation *operation)
+{
+  GeglRectangle  result = {0,0,0,0};
+  GeglRectangle *in_rect = gegl_operation_source_get_bounding_box (operation, "input");
+
+  gegl_rectangle_copy(&result, in_rect);
+
+  return result;
+}
+
+static gboolean
+process (GeglOperation       *operation,
+         GeglBuffer          *input,
+         GeglBuffer          *output,
+         const GeglRectangle *result)
+{
+  GeglChantO              *o            = GEGL_CHANT_PROPERTIES (operation);
+  GeglRectangle            boundary     = get_effective_area (operation);
+  Babl                    *format       = babl_format ("RGBA float");
+
+  gint      x,y;
+  gfloat   *src_buf, *dst_buf;
+  gfloat    dest[4];
+  gint      i, offset = 0;
+  gboolean  inside;
+  gdouble   px, py;
+
+  GeglMatrix2  scale;        /* a matrix indicating scaling factors around the
+                                current center pixel.
+                              */
+
+  src_buf = g_new0 (gfloat, result->width * result->height * 4);
+  dst_buf = g_new0 (gfloat, result->width * result->height * 4);
+
+  gegl_buffer_get (input, 1.0, result, format, src_buf, GEGL_AUTO_ROWSTRIDE);
+
+  if (o->middle)
+     {
+        o->pole_x = boundary.width / 2;
+        o->pole_y = boundary.height / 2;
+     }
+
+  for (y = result->y; y < result->y + result->height; y++)
+      for (x = result->x; x < result->x + result->width; x++)
+           {
+#define gegl_unmap(u,v,ud,vd) {\
+              gdouble rx, ry;\
+              inside = calc_undistorted_coords ((gdouble)x, (gdouble)y, \
+                                                 &rx, &ry, o, boundary);\
+              ud = rx;\
+              vd = ry;\
+             }
+              gegl_sampler_compute_scale (scale, x, y);
+              gegl_unmap(x,y,px,py);
+#undef gegl_unmap
+
+           if (inside)
+              gegl_buffer_sample (input, px, py, &scale, dest, format,
+                                  GEGL_INTERPOLATION_LOHALO);
+           else
+              for (i=0; i<4; i++)
+                 dest[i] = 0.0;
+
+           for (i=0; i<4; i++)
+              dst_buf[offset++] = dest[i];
+           }
+
+  gegl_buffer_set (output, result, format, dst_buf, GEGL_AUTO_ROWSTRIDE);
+
+  g_free (src_buf);
+  g_free (dst_buf);
+
+  return  TRUE;
+}
+
+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)
+    return result;
+
+  return *in_rect;
+}
+
+static GeglRectangle
+get_required_for_output (GeglOperation       *operation,
+                         const gchar         *input_pad,
+                         const GeglRectangle *roi)
+{
+  return get_bounding_box (operation);
+}
+
+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->get_bounding_box        = get_bounding_box;
+  operation_class->get_required_for_output = get_required_for_output;
+
+
+  operation_class->categories  = "enhance";
+  operation_class->name        = "gegl:polar-coordinates";
+  operation_class->description = _("Performs polar-coordinates on the image.");
+}
+
+#endif