Add graph and control panel

tutorials/device-dashboard/full-dashboard/server.c

@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: GPL-2.0-only or commercial
 
 #include "mongoose.h"
+#include "math.h"
 
 #if MG_ARCH == MG_ARCH_UNIX || MG_ARCH == MG_ARCH_WIN32
 #define HTTP_ADDR "http://0.0.0.0:8000"
@@ -9,6 +10,40 @@
 #define HTTP_ADDR "http://0.0.0.0:80"
 #endif
 
+#define NUM_POINTS 256   // How many data points to send
+// #define INTERVAL_MS 200  // How often, in milliseconds
+
+struct point {
+  uint16_t x;   // X coordinate of the data point, usually this is time
+  uint16_t y1;  // We can plot multiple values per graph,
+  uint16_t y2;  // let's plot 2 values: y1 and y2.
+};
+
+// This function prints a JSON array of plot points
+size_t print_points(void (*fn)(char, void *), void *arg, va_list *ap) {
+  size_t i, n = 0;
+  const char *comma = "";
+  (void) ap;
+  n += mg_xprintf(fn, arg, "[");
+  for (i = 0; i < NUM_POINTS; i++) {
+    struct point p;
+    p.x = (uint16_t) i;
+    // rand() - 0.5 + sin(x * 0.00002) * 40 + sin(x * 0.001) * 5 + sin(x * 0.1)
+    // * 2;
+    p.y1 = 100 + 50 * sin(i * 0.1) + rand() % 21;
+    p.y2 = 70 + 30 * sin(i * 0.03) + rand() % 17;
+    n += mg_xprintf(fn, arg, "%s[%hu,%hu,%hu]", comma, p.x, p.y1, p.y2);
+    comma = ",";
+  }
+  n += mg_xprintf(fn, arg, "]");
+  return n;
+}
+
+static void get_points(union mg_val *val) {
+  val->fn = (void (*)(void)) print_points;
+}
+
+
 static bool s_led;
 
 static void get_led(union mg_val *val) {
@@ -22,6 +57,7 @@ static void set_led(const union mg_val *val) {
 // Modify this. This represents device's state to the dashboard
 static struct mg_field fields[] = {
     {"led", MG_VAL_BOOL, get_led, set_led},
+    {"points", MG_VAL_FN, get_points, NULL},
     {NULL, 0, 0, 0},
 };