Initial HyperDRM 0.6.0: webOS ambient light app and native service

native/histogram.h

@@ -0,0 +1,15 @@
+#ifndef LG_HISTOGRAM_H
+#define LG_HISTOGRAM_H
+#include <stdint.h>
+#include <stddef.h>
+/* LG ABI: region ID followed by three planar channels, 256 uint16 bins
+ * per channel. Bin index is the 8-bit intensity (0..255). */
+typedef struct { uint32_t id; uint16_t bins[3][256]; } Histogram;
+_Static_assert(sizeof(Histogram)==0x604,"LG ABI record size");
+_Static_assert(offsetof(Histogram,bins)==4,"LG ABI channel offset");
+static inline unsigned char histogram_mean(const uint16_t bins[256]) {
+ uint64_t count=0,weight=0;
+ for(unsigned b=0;b<256;b++){count+=bins[b];weight+=(uint64_t)bins[b]*b;}
+ return count?(unsigned char)((weight+count/2)/count):0;
+}
+#endif