ref: 4e545a974d714250dd3d693bccabf612a7c18029
parent: d260eef4796b2bbbd41676c2bd25b4aa4e5efd7b
author: phil9 <telephil9@gmail.com>
date: Sun Nov 28 12:05:35 EST 2021
more accurate color averages
--- a/blur.c
+++ b/blur.c
@@ -16,9 +16,8 @@
box(uchar *data, int w, int h, int depth)
{uchar *out;
- int x, y, r, c, s;
+ int x, y, c, s;
- r = w * depth;
out = malloc(depth*w*h*sizeof(uchar));
if(out == nil)
return nil;
@@ -26,16 +25,18 @@
for(y = 1; y < h - 1; y++){ for(x = 1; x < w - 1; x++){ for(c = 0; c < 3; c++){ /* R G B */- s = data[(x - 1)*depth + r * (y + 1) + c] +
- data[(x + 0)*depth + r * (y + 1) + c] +
- data[(x + 1)*depth + r * (y + 1) + c] +
- data[(x - 1)*depth + r * (y + 0) + c] +
- data[(x + 0)*depth + r * (y + 0) + c] +
- data[(x + 1)*depth + r * (y + 0) + c] +
- data[(x - 1)*depth + r * (y - 1) + c] +
- data[(x + 0)*depth + r * (y - 1) + c] +
- data[(x + 1)*depth + r * (y - 1) + c];
- out[x * depth + r * y + c] = s / 9;
+#define P²(X,Y,C) (data[((X) + w*(Y))*depth + C] * data[((X) + w*(Y))*depth + C])
+ s = P²(x - 1, y + 1, c) +
+ P²(x + 0, y + 1, c) +
+ P²(x + 1, y + 1, c) +
+ P²(x - 1, y + 0, c) +
+ P²(x + 0, y + 0, c) +
+ P²(x + 1, y + 0, c) +
+ P²(x - 1, y - 1, c) +
+ P²(x + 0, y - 1, c) +
+ P²(x + 1, y - 1, c);
+ out[(x + w * y) * depth + c] = sqrt(s / 9);
+#undef P²
}
}
}
@@ -59,14 +60,14 @@
for(oy = y; oy < y+size; oy++){ for(ox = x; ox < x+size; ox++){oi = (ox + w * oy) * depth;
- sr += data[oi + 0];
- sg += data[oi + 1];
- sb += data[oi + 2];
+ sr += data[oi + 0]*data[oi + 0];
+ sg += data[oi + 1]*data[oi + 0];
+ sb += data[oi + 2]*data[oi + 0];
}
}
- sr /= (size*size);
- sg /= (size*size);
- sb /= (size*size);
+ sr = sqrt(sr/(size*size));
+ sg = sqrt(sg/(size*size));
+ sb = sqrt(sb/(size*size));
for(oy = y; oy < y+size; oy++){ for(ox = x; ox < x+size; ox++){oi = (ox + w * oy) * depth;