Merge pull request #212 from Professr/issue#197

Add cpp clamp function to utils.h, converted signal strength to %

src/esp32/main-esp32.cpp

@@ -5,6 +5,7 @@
 #include "main.h"
 #include "power.h"
 #include "sleep.h"
+#include "utils.h"
 #include "target_specific.h"
 
 bool bluetoothOn;
@@ -81,8 +82,7 @@ void readPowerStatus()
         } else {
             // If the AXP192 returns a percentage less than 0, the feature is either not supported or there is an error
             // In that case, we compute an estimate of the charge percent based on maximum and minimum voltages defined in power.h
-            int calculatedPercentage = ((powerStatus.batteryVoltageMv - BAT_MILLIVOLTS_EMPTY) * 1e2) / (BAT_MILLIVOLTS_FULL - BAT_MILLIVOLTS_EMPTY);
+            powerStatus.batteryChargePercent = clamp((int)(((powerStatus.batteryVoltageMv - BAT_MILLIVOLTS_EMPTY) * 1e2) / (BAT_MILLIVOLTS_FULL - BAT_MILLIVOLTS_EMPTY)), 0, 100);
-            powerStatus.batteryChargePercent = (calculatedPercentage < 0) ? 0 : (calculatedPercentage > 100) ? 100 : calculatedPercentage;
         }
         DEBUG_MSG("Battery %dmV %d%%\n", powerStatus.batteryVoltageMv, powerStatus.batteryChargePercent);
     }

src/screen.cpp

@@ -31,6 +31,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include "main.h"
 #include "mesh-pb-constants.h"
 #include "screen.h"
+#include "utils.h"
 
 #define FONT_HEIGHT 14 // actually 13 for "ariel 10" but want a little extra space
 #define FONT_HEIGHT_16 (ArialMT_Plain_16[1] + 1)
@@ -379,7 +380,7 @@ static void drawNodeInfo(OLEDDisplay *display, OLEDDisplayUiState *state, int16_
     const char *username = node->has_user ? node->user.long_name : "Unknown Name";
 
     static char signalStr[20];
-    snprintf(signalStr, sizeof(signalStr), "Signal: %.0f", node->snr);
+    snprintf(signalStr, sizeof(signalStr), "Signal: %d%%", clamp((int)((node->snr + 10) * 5), 0, 100));
 
     uint32_t agoSecs = sinceLastSeen(node);
     static char lastStr[20];

src/utils.h

@@ -0,0 +1,7 @@
+#pragma once
+
+/// C++ v17+ clamp function, limits a given value to a range defined by lo and hi
+template<class T>
+constexpr const T& clamp( const T& v, const T& lo, const T& hi ) {
+    return (v < lo) ? lo : (hi < v) ? hi : v;
+}