wcap: Compute per-component deltas
diff --git a/src/screenshooter.c b/src/screenshooter.c
index da06ae3..246796e 100644
--- a/src/screenshooter.c
+++ b/src/screenshooter.c
@@ -240,6 +240,18 @@
return p;
}
+static uint32_t
+component_delta(uint32_t next, uint32_t prev)
+{
+ unsigned char dr, dg, db;
+
+ dr = (next >> 16) - (prev >> 16);
+ dg = (next >> 8) - (prev >> 8);
+ db = (next >> 0) - (prev >> 0);
+
+ return (dr << 16) | (dg << 8) | (db << 0);
+}
+
static void
weston_recorder_frame_notify(struct wl_listener *listener, void *data)
{
@@ -295,7 +307,7 @@
stride * (r[i].y2 - j - 1) + r[i].x1;
for (k = 0; k < width; k++) {
next = *s++;
- delta = (next - *d) & 0x00ffffff;
+ delta = component_delta(next, *d);
*d++ = next;
if (run == 0 || delta == prev) {
run++;