[gegl] map-{absolute,relative}: minor performance improvements

[N/A <ell src gnome org>]

commit 38f5e31d2800c47c72b6ffff9d6ddeed76916c82
Author: Ell <ell_se yahoo com>
Date:   Sun May 21 17:15:50 2017 -0400

    map-{absolute,relative}: minor performance improvements
    
    Pedantic, really, but marginally faster :)
    
    Also, fix map-absolute sampling shortcut to test for center-of-
    pixels, instead of corner-of-pixels.

 operations/common/map-absolute.c |   56 +++++++++++++++++----------------
 operations/common/map-relative.c |   64 ++++++++++++++++++-------------------
 2 files changed, 60 insertions(+), 60 deletions(-)
---
diff --git a/operations/common/map-absolute.c b/operations/common/map-absolute.c
index d1d1721..e25c04c 100644
--- a/operations/common/map-absolute.c
+++ b/operations/common/map-absolute.c
@@ -92,41 +92,43 @@ process (GeglOperation       *operation,
 
       while (gegl_buffer_iterator_next (it))
         {
-          gint        i;
-          gint        n_pixels = it->length;
-          gint        x = it->roi->x; /* initial x                   */
-          gint        y = it->roi->y; /*           and y coordinates */
+          gint        w;
+          gint        h;
+          gfloat      x;
+          gfloat      y;
           gfloat     *in = it->data[index_in];
           gfloat     *out = it->data[index_out];
           gfloat     *coords = it->data[index_coords];
 
-          for (i=0; i<n_pixels; i++)
-            {
-              /* if the coordinate asked is an exact pixel, we fetch it directly, to avoid the blur of 
sampling */
-              if (coords[0] == x && coords[1] == y)
-                {
-                  out[0] = in[0];
-                  out[1] = in[1];
-                  out[2] = in[2];
-                  out[3] = in[3];
-                }
-              else
-                {
-                  gegl_sampler_get (sampler, coords[0], coords[1], NULL, out, o->abyss_policy);
-                }
+          y = it->roi->y + 0.5; /* initial y coordinate */
 
-              coords += 2;
-              in += 4;
-              out += 4;
+          for (h = it->roi->height; h; h--, y++)
+            {
+              x = it->roi->x + 0.5; /* initial x coordinate */
 
-              /* update x and y coordinates */
-              x++;
-              if (x >= (it->roi->x + it->roi->width))
+              for (w = it->roi->width; w; w--, x++)
                 {
-                  x = it->roi->x;
-                  y++;
+                  /* if the coordinate asked is an exact pixel, we fetch it
+                   * directly, to avoid the blur of sampling */
+                  if (coords[0] == x && coords[1] == y)
+                    {
+                      out[0] = in[0];
+                      out[1] = in[1];
+                      out[2] = in[2];
+                      out[3] = in[3];
+                    }
+                  else
+                    {
+                      gegl_sampler_get (sampler, coords[0],
+                                                 coords[1],
+                                                 NULL, out,
+                                                 o->abyss_policy);
+                    }
+
+                  coords += 2;
+                  in += 4;
+                  out += 4;
                 }
-
             }
         }
     }
diff --git a/operations/common/map-relative.c b/operations/common/map-relative.c
index a32a55e..7fa4dbb 100644
--- a/operations/common/map-relative.c
+++ b/operations/common/map-relative.c
@@ -83,7 +83,7 @@ process (GeglOperation       *operation,
 
   sampler = gegl_buffer_sampler_new_at_level (input, format_io, o->sampler_type, level);
 
-  if (aux != NULL)
+  if (aux != NULL && o->scaling != 0.0)
     {
       it = gegl_buffer_iterator_new (output, result, level, format_io,
                                      GEGL_ACCESS_WRITE, GEGL_ABYSS_NONE);
@@ -96,46 +96,44 @@ process (GeglOperation       *operation,
 
       while (gegl_buffer_iterator_next (it))
         {
-          gint        i;
-          gint        n_pixels = it->length;
-          gint        x = it->roi->x; /* initial x                   */
-          gint        y = it->roi->y; /*           and y coordinates */
-          gdouble     scaling = GEGL_PROPERTIES (operation)->scaling;
+          gint        w;
+          gint        h;
+          gfloat      x;
+          gfloat      y;
+          gfloat      scaling = GEGL_PROPERTIES (operation)->scaling;
           gfloat     *in = it->data[index_in];
           gfloat     *out = it->data[index_out];
           gfloat     *coords = it->data[index_coords];
 
-          for (i=0; i<n_pixels; i++)
-            {
-              /* if the coordinate asked is an exact pixel, we fetch it
-               * directly, to avoid the blur of sampling */
-              if (coords[0] == 0 && coords[1] == 0)
-                {
-                  out[0] = in[0];
-                  out[1] = in[1];
-                  out[2] = in[2];
-                  out[3] = in[3];
-                }
-              else
-                {
-                  gegl_sampler_get (sampler, x + coords[0] * scaling + 0.5,
-                                             y + coords[1] * scaling + 0.5,
-                                             NULL, out,
-                                             o->abyss_policy);
-                }
+          y = it->roi->y + 0.5; /* initial y coordinate */
 
-              coords += 2;
-              in += 4;
-              out += 4;
+          for (h = it->roi->height; h; h--, y++)
+            {
+              x = it->roi->x + 0.5; /* initial x coordinate */
 
-              /* update x and y coordinates */
-              x++;
-              if (x >= (it->roi->x + it->roi->width))
+              for (w = it->roi->width; w; w--, x++)
                 {
-                  x = it->roi->x;
-                  y++;
+                  /* if the coordinate asked is an exact pixel, we fetch it
+                   * directly, to avoid the blur of sampling */
+                  if (coords[0] == 0.0f && coords[1] == 0.0f)
+                    {
+                      out[0] = in[0];
+                      out[1] = in[1];
+                      out[2] = in[2];
+                      out[3] = in[3];
+                    }
+                  else
+                    {
+                      gegl_sampler_get (sampler, x + coords[0] * scaling,
+                                                 y + coords[1] * scaling,
+                                                 NULL, out,
+                                                 o->abyss_policy);
+                    }
+
+                  coords += 2;
+                  in += 4;
+                  out += 4;
                 }
-
             }
         }
     }