Release 0.13.1

native/test_dark_color.c

@@ -0,0 +1,21 @@
+#include <assert.h>
+#include <stdio.h>
+#include "dark_color.h"
+int main(void) {
+    for (unsigned v = 0; v <= 255; v++) {
+        unsigned char gray[3] = {v, v, v};
+        dark_color_filter(gray);
+        unsigned expected = v <= 12 ? 0 : v >= 24 ? v : (v * (v - 12) + 6) / 12;
+        for (unsigned c = 0; c < 3; c++) assert(gray[c] == expected);
+    }
+    unsigned char residual[3] = {4, 8, 2};
+    dark_color_filter(residual);
+    assert(!residual[0] && !residual[1] && !residual[2]);
+    unsigned char transition[3] = {9, 18, 6};
+    dark_color_filter(transition);
+    assert(transition[0] == 5 && transition[1] == 9 && transition[2] == 3);
+    unsigned char saturated[3] = {0, 24, 0};
+    dark_color_filter(saturated);
+    assert(saturated[0] == 0 && saturated[1] == 24 && saturated[2] == 0);
+    puts("PASS: near-black suppression, gradual transition, unchanged brighter colors");
+}