feat(stdlib): make possible to fill a specified amount of LEDs from the tail

workspace/__ardulib__/WS2812_NoBufffer/WS2812.h

@@ -33,7 +33,7 @@ public:
     WS2812(uint8_t pin, uint32_t length);
     void fill(uint8_t r, uint8_t g, uint8_t b);
     void fill(XColor color);
-    void fill(XColor color, uint32_t pixelsCount);
+    void fill(XColor color, uint32_t pixelCount, bool fromTail = false);
     void fillPattern(Pattern* pat, uint32_t shift = 0);
     void sendPixel(uint8_t r, uint8_t g, uint8_t b);
     void show();

workspace/__ardulib__/WS2812_NoBufffer/WS2812.inl

@@ -162,9 +162,16 @@ void WS2812::fill(XColor color) {
   show();
 }
 
-void WS2812::fill(XColor color, uint32_t pixelsCount) {
+void WS2812::fill(XColor color, uint32_t pixelCount, bool fromTail = false) {
   cli();
-  for (uint32_t i = 0; i < pixelsCount && i < _length; i++) {
+  // If fromTail is true
+  // Skip pixels by filling them with black color
+  uint32_t pixelsToSkip = fromTail ? _length - pixelCount : 0;
+  for (uint32_t i = 0; i < pixelsToSkip && i < _length; i++) {
+      sendPixel(0, 0, 0);
+  }
+  // Fill pixels
+  for (uint32_t i = pixelsToSkip; i < (pixelsToSkip + pixelCount); i++) {
       sendPixel(color.r, color.g, color.b);
   }
   sei();

workspace/__lib__/xod-dev/ws2812/example-fill-part/patch.xodp

@@ -1,61 +1,133 @@
 {
+  "comments": [
+    {
+      "content": "This example shows how to clear the whole LED strip and then fill with the red color only last four LEDs.",
+      "id": "SJe1xTTeI",
+      "position": {
+        "units": "slots",
+        "x": 0,
+        "y": -1
+      },
+      "size": {
+        "height": 1,
+        "units": "slots",
+        "width": 10
+      }
+    },
+    {
+      "content": "<- Clear all LEDs.",
+      "id": "SJeBeTpl8",
+      "position": {
+        "units": "slots",
+        "x": 5,
+        "y": 1
+      },
+      "size": {
+        "height": 1,
+        "units": "slots",
+        "width": 5
+      }
+    },
+    {
+      "content": "<- Fill only last 4 LEDs.",
+      "id": "SkUHe66gL",
+      "position": {
+        "units": "slots",
+        "x": 5,
+        "y": 2
+      },
+      "size": {
+        "height": 1,
+        "units": "slots",
+        "width": 5
+      }
+    },
+    {
+      "content": "<- Setup the device.",
+      "id": "rkXNe66l8",
+      "position": {
+        "units": "slots",
+        "x": 5,
+        "y": 0
+      },
+      "size": {
+        "height": 1,
+        "units": "slots",
+        "width": 5
+      }
+    }
+  ],
   "links": [
     {
-      "id": "ByXhflqlU",
+      "id": "Hy7HJmgceI",
       "input": {
-        "nodeId": "BJznMxqlU",
+        "nodeId": "rJ-Hymxqx8",
+        "pinKey": "B1387L5RS"
+      },
+      "output": {
+        "nodeId": "ByxryXe9e8",
+        "pinKey": "Symaj-NYCB"
+      }
+    },
+    {
+      "id": "SyGrJQgqgL",
+      "input": {
+        "nodeId": "ByxryXe9e8",
         "pinKey": "By6jbVYCB"
       },
       "output": {
-        "nodeId": "BJhjMxcx8",
+        "nodeId": "S1BkQl5e8",
         "pinKey": "SJxz8XtRS"
       }
     },
     {
-      "id": "SJunfe5e8",
+      "id": "r1spDhTeU",
       "input": {
-        "nodeId": "ryD3fl5xL",
-        "pinKey": "B1387L5RS"
+        "nodeId": "rJ-Hymxqx8",
+        "pinKey": "rJWh8XIqAB"
       },
       "output": {
-        "nodeId": "BJznMxqlU",
-        "pinKey": "Symaj-NYCB"
+        "nodeId": "ByxryXe9e8",
+        "pinKey": "Hk46jWVFAS"
       }
     }
   ],
   "nodes": [
     {
       "boundLiterals": {
-        "HyI-5XSAr": "A4",
-        "S1C-cQBRB": "16"
+        "SyzTjbEKCH": "On Boot"
       },
-      "id": "BJhjMxcx8",
+      "id": "ByxryXe9e8",
       "position": {
         "units": "slots",
-        "x": 2,
-        "y": 1
-      },
-      "type": "@/ws2812-device"
-    },
-    {
-      "id": "BJznMxqlU",
-      "position": {
-        "units": "slots",
-        "x": 4,
+        "x": 0,
         "y": 1
       },
       "type": "@/clear"
     },
     {
       "boundLiterals": {
-        "SJxhUmIcCr": "#100000",
-        "SkcHZece8": "4"
+        "HyI-5XSAr": "A4",
+        "S1C-cQBRB": "16"
       },
-      "id": "ryD3fl5xL",
+      "id": "S1BkQl5e8",
       "position": {
         "units": "slots",
-        "x": 6,
-        "y": 1
+        "x": 0,
+        "y": 0
+      },
+      "type": "@/ws2812-device"
+    },
+    {
+      "boundLiterals": {
+        "SJxhUmIcCr": "#FF0000",
+        "SkcHZece8": "-4"
+      },
+      "id": "rJ-Hymxqx8",
+      "position": {
+        "units": "slots",
+        "x": 0,
+        "y": 2
       },
       "type": "@/fill-solid"
     }

workspace/__lib__/xod-dev/ws2812/fill-solid/patch.cpp

@@ -9,12 +9,14 @@ void evaluate(Context ctx) {
     if (isInputDirty<input_DO>(ctx)) {
         auto color = getValue<input_C>(ctx);
         auto num = getValue<input_NUM>(ctx);
-        if (num == -1) {
+        if (isinf(num)) {
             // Fill all the LEDs
             dev->fill(color);
         } else {
             // Fill only specified number of LEDs
-            dev->fill(color, (uint32_t)num);
+            bool fromTail = num < 0;
+            uint32_t pixelsCount = (uint32_t) abs(num);
+            dev->fill(color, pixelsCount, fromTail);
         }
 
         emitValue<output_DONE>(ctx, 1);

workspace/__lib__/xod-dev/ws2812/fill-solid/patch.xodp

@@ -24,7 +24,7 @@
       "type": "xod/patch-nodes/output-pulse"
     },
     {
-      "description": "Color value",
+      "description": "The color",
       "id": "SJxhUmIcCr",
       "label": "C",
       "position": {
@@ -36,9 +36,9 @@
     },
     {
       "boundLiterals": {
-        "__out__": "-1"
+        "__out__": "Inf"
       },
-      "description": "Number of LEDs to fill up with the solid color. Set `-1` to fill all LEDs.",
+      "description": "Number of LEDs to fill up with the solid color. Set `Inf` to fill all LEDs. Set to a negative value to fill from the tail.",
       "id": "SkcHZece8",
       "label": "NUM",
       "position": {