feat(gui, ambient_light): 鼠标滚轮修改 LED 灯条的灯珠数。

src/assets/transparent-grid-background.svg

@@ -0,0 +1,16 @@
+
+<!-- http://mike.eire.ca/2010/02/25/easy-svg-grid/ -->
+<!-- "I needed a grid in the background while I was debugging an SVG image I was creating, something
+like Photoshop’s transparency grid. Here’s what I did." -->
+
+<svg xmlns="http://www.w3.org/2000/svg" version="1.1" width="200" height="400">
+  <defs>
+    <pattern id="grid" width="10" height="10" patternUnits="userSpaceOnUse">
+      <rect fill="black" x="0" y="0" width="5" height="5" opacity="0.3" />
+      <rect fill="white" x="5" y="0" width="5" height="5" />
+      <rect fill="black" x="5" y="5" width="5" height="5" opacity="0.3" />
+      <rect fill="white" x="0" y="5" width="5" height="5" />
+    </pattern>
+  </defs>
+  <rect fill="url(#grid)" x="0" y="0" width="100%" height="100%" />
+</svg>