spec for display conversion

diff --git a/layout/subseg2display.c b/layout/subseg2display.c
new file mode 100644 (file)
index 0000000..ebd9e7e
--- /dev/null
+++ b/layout/subseg2display.c
@@ -0,0 +1,26 @@
+/*
+ * usage:
+ *   subseg2display encoding.ppm [status-info ...]
+ *
+ * status-info args are:
+ *   <subseg> <alpha> <red> <green> <blue>
+ *
+ * <subseg> is
+ *   <segnum>               for fixed track
+ *   <segnum>.<movfeatpos>  for part of a moveable feature
+ * where numbers are in strtoul format, movfeatpos is the
+ * moveable feature and position as in segcmapassign and
+ * if <subseg> is `.', spec is for unspecified segments.
+ *
+ * Resulting pixel is
+ *                                               [ red   ]
+ *    (alpha * DIRECTION_COLOUR) + ((1-alpha) *  [ green ] )
+ *                                               [ blue  ]
+ *
+ * status.bin has the following format:
+ *   16 bits number of segments
+ *   2 
+ */
+
+int main(int argc, const char *const *argv) {
+}