From ca6276733208d60e6345f0214517fc7fce1dce45 Mon Sep 17 00:00:00 2001
From: Carlo Baldassi <carlobaldassi@gmail.com>
Date: Tue, 28 Apr 2009 01:22:33 +0200
Subject: [PATCH] Avoid computing the energy twice

---
 lqr/lqr_carver.c      | 35 +++++++++++++++++++++++++++++++++++
 lqr/lqr_carver_priv.h |  2 ++
 lqr/lqr_energy.c      | 42 ++++--------------------------------------
 3 files changed, 41 insertions(+), 38 deletions(-)

diff --git a/lqr/lqr_carver.c b/lqr/lqr_carver.c
index 43e1bb8..9b8328c 100644
--- a/lqr/lqr_carver.c
+++ b/lqr/lqr_carver.c
@@ -91,6 +91,7 @@ LqrCarver * lqr_carver_new_common (gint width, gint height, gint channels)
   lqr_carver_set_energy_function_builtin(r, LQR_EF_GRAD_XABS);
   r->nrg_xmin = NULL;
   r->nrg_xmax = NULL;
+  r->nrg_uptodate = FALSE;
 
   r->leftright = 0;
   r->lr_switch_frequency = 0;
@@ -324,6 +325,10 @@ lqr_carver_set_image_type (LqrCarver * r, LqrImageType image_type)
   }
   r->image_type = image_type;
 
+  g_free(r->rcache);
+  r->rcache = NULL;
+  r->nrg_uptodate = FALSE;
+
   return LQR_OK;
 }
 
@@ -341,6 +346,11 @@ lqr_carver_set_alpha_channel (LqrCarver * r, gint channel_index)
     return LQR_ERROR;
   }
   r->image_type = LQR_CUSTOM_IMAGE;
+
+  g_free(r->rcache);
+  r->rcache = NULL;
+  r->nrg_uptodate = FALSE;
+
   return LQR_OK;
 }
 
@@ -358,6 +368,11 @@ lqr_carver_set_black_channel (LqrCarver * r, gint channel_index)
     return LQR_ERROR;
   }
   r->image_type = LQR_CUSTOM_IMAGE;
+
+  g_free(r->rcache);
+  r->rcache = NULL;
+  r->nrg_uptodate = FALSE;
+
   return LQR_OK;
 }
 
@@ -525,6 +540,11 @@ lqr_carver_build_emap (LqrCarver * r)
 
   CATCH_CANC(r);
 
+  if (r->nrg_uptodate)
+    {
+      return LQR_OK;
+    }
+
   if (r->use_rcache && r->rcache == NULL)
     {
       CATCH_MEM (r->rcache = lqr_carver_generate_rcache (r));
@@ -541,6 +561,8 @@ lqr_carver_build_emap (LqrCarver * r)
         }
     }
 
+  r->nrg_uptodate = TRUE;
+
   return LQR_OK;
 }
 
@@ -985,6 +1007,7 @@ lqr_carver_inflate (LqrCarver * r, gint l)
   g_free (r->rigidity_mask);
 
   r->rcache = NULL;
+  r->nrg_uptodate = FALSE;
 
   r->rgb = new_rgb;
   r->preserve_in_buffer = FALSE;
@@ -1073,6 +1096,8 @@ lqr_carver_carve (LqrCarver * r)
 #endif /* __LQR_DEBUG__ */
         }
     }
+
+  r->nrg_uptodate = FALSE;
 }
 
 
@@ -1083,6 +1108,10 @@ lqr_carver_update_emap (LqrCarver * r)
   gint x, y;
   gint y1, y1_min, y1_max;
 
+  if (r->nrg_uptodate)
+    {
+      return LQR_OK;
+    }
   if (r->use_rcache)
     {
       CATCH_F (r->rcache != NULL);
@@ -1123,6 +1152,9 @@ lqr_carver_update_emap (LqrCarver * r)
           CATCH (lqr_carver_compute_e (r, x, y));
         }
     }
+
+  r->nrg_uptodate = TRUE;
+
   return LQR_OK;
 }
 
@@ -1145,6 +1177,7 @@ lqr_carver_update_mmap (LqrCarver * r)
   gint x_stop;
 
   CATCH_CANC(r);
+  CATCH_F (r->nrg_uptodate);
 
   /* span first row */
   /* x_min = MAX (r->vpath_x[0] - r->delta_x, 0); */
@@ -1482,6 +1515,7 @@ lqr_carver_flatten (LqrCarver * r)
   g_free (r->least);
 
   r->rcache = NULL;
+  r->nrg_uptodate = FALSE;
 
   /* allocate room for new map */
   BUF_TRY_NEW0_RET_LQR(new_rgb, r->w * r->h * r->channels, r->col_depth);
@@ -1648,6 +1682,7 @@ lqr_carver_transpose (LqrCarver * r)
   g_free (r->rgb_ro_buffer);
 
   r->rcache = NULL;
+  r->nrg_uptodate = FALSE;
 
   /* allocate room for the new maps */
   BUF_TRY_NEW0_RET_LQR(new_rgb, r->w0 * r->h0 * r->channels, r->col_depth);
diff --git a/lqr/lqr_carver_priv.h b/lqr/lqr_carver_priv.h
index e808969..ad44dcc 100644
--- a/lqr/lqr_carver_priv.h
+++ b/lqr/lqr_carver_priv.h
@@ -249,6 +249,8 @@ struct _LqrCarver
   gint *nrg_xmin;                 /* auxiliary vector for energy update */
   gint *nrg_xmax;                 /* auxiliary vector for energy update */
 
+  gboolean nrg_uptodate;          /* flag set if energy map is up to date */
+
   gdouble * rcache;               /* array of brightness (or luma or else) levels for energy computation */
   gboolean use_rcache;            /* wheter to cache brightness, luma etc. */
 
diff --git a/lqr/lqr_energy.c b/lqr/lqr_energy.c
index a97fc54..fd3729b 100644
--- a/lqr/lqr_energy.c
+++ b/lqr/lqr_energy.c
@@ -376,44 +376,6 @@ lqr_energy_builtin_null (gint x, gint y, gint img_width, gint img_height, LqrRea
   return 0;
 }
 
-
-#if 0
-/* compute energy at x, y */
-gfloat
-lqr_energy_abs (LqrCarver * r, gint x, gint y)
-{
-  gdouble gx, gy;
-
-  if (y == 0)
-    {
-      gy = (*(r->nrg_builtin->rfabs))(r, x, y + 1, x, y);
-    }
-  else if (y < r->h - 1)
-    {
-      gy = 0.5 * (*(r->nrg_builtin->rfabs))(r, x, y + 1, x, y - 1);
-    }
-  else
-    {
-      gy = (*(r->nrg_builtin->rfabs))(r, x, y, x, y - 1);
-    }
-
-  if (x == 0)
-    {
-      gx = (*(r->nrg_builtin->rfabs))(r, x + 1, y, x, y);
-    }
-  else if (x < r->w - 1)
-    {
-      gx = 0.5 * (*(r->nrg_builtin->rfabs))(r, x + 1, y, x - 1, y);
-    }
-  else
-    {
-      gx = (*(r->nrg_builtin->rfabs))(r, x, y, x - 1, y);
-    }
-  return (*(r->nrg_builtin->gf))(gx, gy);
-}
-#endif
-
-/* gradient function for energy computation */
 LQR_PUBLIC
 LqrRetVal
 lqr_carver_set_energy_function_builtin (LqrCarver * r, LqrEnergyFuncBuiltinType ef_ind)
@@ -460,6 +422,10 @@ lqr_carver_set_energy_function (LqrCarver * r, LqrEnergyFunc en_func, gint radiu
   r->nrg_read_t = reader_type;
   r->nrg_extra_data = extra_data;
 
+  g_free(r->rcache);
+  r->rcache = NULL;
+  r->nrg_uptodate = FALSE;
+
   lqr_rwindow_destroy (r->rwindow);
 
   if (reader_type == LQR_ER_CUSTOM)
-- 
2.11.4.GIT