Release 0.13.1

native/capture_loop.h

@@ -153,11 +153,14 @@ static int tick(void *unused) {
     }
     for (int c = 0; c < 3; c++)
         capture_ctx.sent_rgb[c] = (unsigned char)(aggregate[c] / 16);
+    dark_color_filter(capture_ctx.sent_rgb);
     unsigned char boosted_mean[3];
     boost_color(capture_ctx.sent_rgb, boosted_mean);
     memcpy(capture_ctx.sent_rgb, boosted_mean, 3);
     unsigned char mapped_rgb[16][3], stable_rgb[16][3];
     calibration_colors(capture_ctx.rgb, mapped_rgb);
+    for (unsigned i = 0; i < 16; i++)
+        dark_color_filter(mapped_rgb[i]);
     continuity_frame(&capture_ctx.continuity, true, mapped_rgb, now, stable_rgb);
     receiver_layout.interpolation = receiver_layout.count && calibration_effective() != CAL_AVERAGE;
     char *line = region_command(stable_rgb, receiver_layout.blends, receiver_layout.count, 1500);

native/dark_color.h

@@ -0,0 +1,16 @@
+#ifndef HYPERDRM_DARK_COLOR_H
+#define HYPERDRM_DARK_COLOR_H
+/* Suppress near-black histogram residuals without changing channel ratios.
+ * Apply only to fresh histogram colors, before continuity and interpolation. */
+static inline void dark_color_filter(unsigned char color[3]) {
+    unsigned peak = color[0];
+    for (unsigned c = 1; c < 3; c++)
+        if (color[c] > peak)
+            peak = color[c];
+    if (peak >= 24)
+        return;
+    unsigned gain = peak > 12 ? peak - 12 : 0;
+    for (unsigned c = 0; c < 3; c++)
+        color[c] = (unsigned char)((color[c] * gain + 6) / 12);
+}
+#endif

native/service.c

@@ -199,6 +199,7 @@ static bool respond(void *h, void *m, const char *s) {
 #include "receiver_stream.h"
 #include "source_bridge.h"
 #include "service_api.h"
+#include "dark_color.h"
 #include "capture_loop.h"
 static void *symbol(void *lib, const char *name) {
     void *s = dlsym(lib, name);

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");
+}

native/version.h

@@ -1,4 +1,4 @@
 #ifndef HYPERDRM_VERSION_H
 #define HYPERDRM_VERSION_H
-#define HYPERDRM_VERSION "0.13.0"
+#define HYPERDRM_VERSION "0.13.1"
 #endif