print min max error per channel

BUG=324
TESTED=TestFullYUV
R=harryjin@google.com

Review URL: https://webrtc-codereview.appspot.com/40499004

git-svn-id: http://libyuv.googlecode.com/svn/trunk@1244 16f28f9a-4ce2-e073-06de-1de4eb20be90

unit_test/color_test.cc

@@ -270,11 +270,15 @@ TEST_F(libyuvTest, TestGreyYUV) {
 }
 
 // This full test should be run occassionally to test all values are accurate.
-// TODO(fbarchard): Determine error distribution.
 TEST_F(libyuvTest, TestFullYUV) {
+  int i;
   // If using small image, step faster.
   int step = benchmark_width_ <= 128 ? 3 : 1;
   int r0, g0, b0, r1, g1, b1;
+  int rn[256] = { 0, }, gn[256] = { 0, },
+      bn[256] = { 0, }, rx[256] = { 0, },
+      gx[256] = { 0, }, bx[256] = { 0, };
+  int rh[256] = { 0, }, gh[256] = { 0, }, bh[256] = { 0, };
   for (int y = 0; y < 256; y += step) {
     for (int u = 0; u < 256; u += step) {
       for (int v = 0; v < 256; v += step) {
@@ -283,9 +287,52 @@ TEST_F(libyuvTest, TestFullYUV) {
         EXPECT_NEAR(r0, r1, ERROR_R);
         EXPECT_NEAR(g0, g1, ERROR_G);
         EXPECT_NEAR(b0, b1, ERROR_B);
+        int rd = r1 - r0;
+        int gd = g1 - g0;
+        int bd = b1 - b0;
+        ++rh[rd + 128];
+        ++gh[gd + 128];
+        ++bh[bd + 128];
+        if (rd < rn[r0]) { rn[r0] = rd; }
+        if (gd < gn[g0]) { gn[g0] = gd; }
+        if (bd < bn[b0]) { bn[b0] = bd; }
+        if (rd > rx[r0]) { rx[r0] = rd; }
+        if (gd > gx[g0]) { gx[g0] = gd; }
+        if (bd > bx[b0]) { bx[b0] = bd; }
       }
     }
   }
+  if (step == 1) {
+    for (i = 0; i < 256; ++i) {
+      printf("red %d %d, green %d %d, blue %d %d\n",
+             rn[i], rx[i], gn[i], gx[i], bn[i], bx[i]);
+    }
+  }
+  printf("hist\t");
+  for (i = 0; i < 256; ++i) {
+    if (rh[i] || gh[i] || bh[i]) {
+      printf("\t%d", i - 128);
+    }
+  }
+  printf("\nred\t");
+  for (i = 0; i < 256; ++i) {
+    if (rh[i] || gh[i] || bh[i]) {
+      printf("\t%d", rh[i]);
+    }
+  }
+  printf("\ngreen\t");
+  for (i = 0; i < 256; ++i) {
+    if (rh[i] || gh[i] || bh[i]) {
+      printf("\t%d", gh[i]);
+    }
+  }
+  printf("\nblue\t");
+  for (i = 0; i < 256; ++i) {
+    if (rh[i] || gh[i] || bh[i]) {
+      printf("\t%d", bh[i]);
+    }
+  }
+  printf("\n");
 }
 
 }  // namespace libyuv