Simplify ImageSimilarityData comparison

* Run alternate_image_sim_compare_fast() once
* Deduplicate ImageSimilarityData comparison

diff --git a/src/similar.cc b/src/similar.cc
index a2ae52c..bcd4366 100644 (file)
--- a/src/similar.cc
+++ b/src/similar.cc
@@ -21,7 +21,9 @@
 
 #include "similar.h"
 
+#include <algorithm>
 #include <cstdlib>
+#include <functional>
 
 #include "options.h"
 
@@ -51,6 +53,60 @@
  * find images that have been re-saved to other formats, dimensions, or compression.
  */
 
+namespace
+{
+
+using ImageSimilarityCheckAbort = std::function<bool(gdouble)>;
+
+/*
+ * 4 rotations (0, 90, 180, 270) combined with two mirrors (0, H)
+ * generate all possible isometric transformations
+ * = 8 tests
+ * = change dir of x, change dir of y, exchange x and y = 2^3 = 8
+ */
+gdouble image_sim_data_compare_transfo(const ImageSimilarityData *a, const ImageSimilarityData *b, gchar transfo, const ImageSimilarityCheckAbort &check_abort)
+{
+       if (!a || !b || !a->filled || !b->filled) return 0.0;
+
+       gint sim = 0.0;
+       gint i2;
+       gint *i;
+       gint j2;
+       gint *j;
+
+       if (transfo & 1) { i = &j2; j = &i2; } else { i = &i2; j = &j2; }
+       for (gint j1 = 0; j1 < 32; j1++)
+               {
+               if (transfo & 2) *j = 31-j1; else *j = j1;
+               for (gint i1 = 0; i1 < 32; i1++)
+                       {
+                       if (transfo & 4) *i = 31-i1; else *i = i1;
+                       sim += abs(a->avg_r[i1*32+j1] - b->avg_r[i2*32+j2]);
+                       sim += abs(a->avg_g[i1*32+j1] - b->avg_g[i2*32+j2]);
+                       sim += abs(a->avg_b[i1*32+j1] - b->avg_b[i2*32+j2]);
+                       /* check for abort, if so return 0.0 */
+                       if (check_abort(sim)) return 0.0;
+                       }
+               }
+
+       return 1.0 - (static_cast<gdouble>(sim) / (255.0 * 1024.0 * 3.0));
+}
+
+gdouble image_sim_data_compare(const ImageSimilarityData *a, const ImageSimilarityData *b, const ImageSimilarityCheckAbort &check_abort)
+{
+       gchar max_t = (options->rot_invariant_sim ? 8 : 1);
+       gdouble max_score = 0;
+
+       for (gchar t = 0; t < max_t; t++)
+       {
+               max_score = std::max(image_sim_data_compare_transfo(a, b, t, check_abort), max_score);
+       }
+
+       return max_score;
+}
+
+} // namespace
+
 ImageSimilarityData *image_sim_new()
 {
        auto sd = g_new0(ImageSimilarityData, 1);
@@ -284,7 +340,7 @@ ImageSimilarityData *image_sim_new_from_pixbuf(GdkPixbuf *pixbuf)
        return sd;
 }
 
-static gdouble alternate_image_sim_compare_fast(ImageSimilarityData *a, ImageSimilarityData *b, gdouble min)
+static gdouble alternate_image_sim_compare_fast(const ImageSimilarityData *a, const ImageSimilarityData *b, gdouble min)
 {
        gint sim;
        gint i;
@@ -293,7 +349,6 @@ static gdouble alternate_image_sim_compare_fast(ImageSimilarityData *a, ImageSim
 
        if (!a || !b || !a->filled || !b->filled) return 0.0;
 
-       min = 1.0 - min;
        sim = 0.0;
        ld = 0;
 
@@ -321,95 +376,9 @@ static gdouble alternate_image_sim_compare_fast(ImageSimilarityData *a, ImageSim
        return (1.0 - ((gdouble)sim / (255.0 * 1024.0 * 4.0)) );
 }
 
-gdouble image_sim_compare_transfo(ImageSimilarityData *a, ImageSimilarityData *b, gchar transfo)
-{
-       gint sim;
-       gint i1;
-       gint i2;
-       gint *i;
-       gint j1;
-       gint j2;
-       gint *j;
-
-       if (!a || !b || !a->filled || !b->filled) return 0.0;
-
-       sim = 0.0;
-
-       if (transfo & 1) { i = &j2; j = &i2; } else { i = &i2; j = &j2; }
-       for (j1 = 0; j1 < 32; j1++)
-               {
-               if (transfo & 2) *j = 31-j1; else *j = j1;
-               for (i1 = 0; i1 < 32; i1++)
-                       {
-                       if (transfo & 4) *i = 31-i1; else *i = i1;
-                       sim += abs(a->avg_r[i1*32+j1] - b->avg_r[i2*32+j2]);
-                       sim += abs(a->avg_g[i1*32+j1] - b->avg_g[i2*32+j2]);
-                       sim += abs(a->avg_b[i1*32+j1] - b->avg_b[i2*32+j2]);
-                       }
-               }
-
-       return 1.0 - (static_cast<gdouble>(sim) / (255.0 * 1024.0 * 3.0));
-}
-
 gdouble image_sim_compare(ImageSimilarityData *a, ImageSimilarityData *b)
 {
-       gint max_t = (options->rot_invariant_sim ? 8 : 1);
-
-       gint t;
-       gdouble score;
-       gdouble max_score = 0;
-
-       for(t = 0; t < max_t; t++)
-       {
-               score = image_sim_compare_transfo(a, b, t);
-               if (score > max_score) max_score = score;
-       }
-       return max_score;
-}
-
-
-/*
-4 rotations (0, 90, 180, 270) combined with two mirrors (0, H)
-generate all possible isometric transformations
-= 8 tests
-= change dir of x, change dir of y, exchange x and y = 2^3 = 8
-*/
-gdouble image_sim_compare_fast_transfo(ImageSimilarityData *a, ImageSimilarityData *b, gdouble min, gchar transfo)
-{
-       gint sim;
-       gint i1;
-       gint i2;
-       gint *i;
-       gint j1;
-       gint j2;
-       gint *j;
-
-       if (options->alternate_similarity_algorithm.enabled)
-               {
-               return alternate_image_sim_compare_fast(a, b, min);
-               }
-
-       if (!a || !b || !a->filled || !b->filled) return 0.0;
-
-       min = 1.0 - min;
-       sim = 0.0;
-
-       if (transfo & 1) { i = &j2; j = &i2; } else { i = &i2; j = &j2; }
-       for (j1 = 0; j1 < 32; j1++)
-               {
-               if (transfo & 2) *j = 31-j1; else *j = j1;
-               for (i1 = 0; i1 < 32; i1++)
-                       {
-                       if (transfo & 4) *i = 31-i1; else *i = i1;
-                       sim += abs(a->avg_r[i1*32+j1] - b->avg_r[i2*32+j2]);
-                       sim += abs(a->avg_g[i1*32+j1] - b->avg_g[i2*32+j2]);
-                       sim += abs(a->avg_b[i1*32+j1] - b->avg_b[i2*32+j2]);
-                       }
-               /* check for abort, if so return 0.0 */
-               if (static_cast<gdouble>(sim) / (255.0 * 1024.0 * 3.0) > min) return 0.0;
-               }
-
-       return (1.0 - (static_cast<gdouble>(sim) / (255.0 * 1024.0 * 3.0)) );
+       return image_sim_data_compare(a, b, [](gdouble){ return false; });
 }
 
 /* this uses a cutoff point so that it can abort early when it gets to
@@ -417,17 +386,13 @@ gdouble image_sim_compare_fast_transfo(ImageSimilarityData *a, ImageSimilarityDa
  */
 gdouble image_sim_compare_fast(ImageSimilarityData *a, ImageSimilarityData *b, gdouble min)
 {
-       gint max_t = (options->rot_invariant_sim ? 8 : 1);
+       min = 1.0 - min;
 
-       gint t;
-       gdouble score;
-       gdouble max_score = 0;
+       if (options->alternate_similarity_algorithm.enabled)
+               {
+               return alternate_image_sim_compare_fast(a, b, min);
+               }
 
-       for(t = 0; t < max_t; t++)
-       {
-               score = image_sim_compare_fast_transfo(a, b, min, t);
-               if (score > max_score) max_score = score;
-       }
-       return max_score;
+       return image_sim_data_compare(a, b, [min](gdouble sim){ return (sim / (255.0 * 1024.0 * 3.0)) > min; });
 }
 /* vim: set shiftwidth=8 softtabstop=0 cindent cinoptions={1s: */