fix: handle color value 256 (#104)

When an entity has "ByLayer 62" we want to use the color defined in the entity instead of the layer, unless the color is 256. 256 is a special value to say that the entity has to use the color defined in the layer. 

Co-authored-by: Rafa <rafa@debian-BULLSEYE-live-builder-AMD64>

src/getRGBForEntity.js

@@ -4,7 +4,8 @@ import logger from './util/logger'
 export default (layers, entity) => {
   const layerTable = layers[entity.layer]
   if (layerTable) {
-    const colorNumber = ('colorNumber' in entity) ? entity.colorNumber : layerTable.colorNumber
+    const colorDefinedInEntity = ('colorNumber' in entity && entity.colorNumber !== 256)
+    const colorNumber = colorDefinedInEntity ? entity.colorNumber : layerTable.colorNumber
     const rgb = colors[colorNumber]
     if (rgb) {
       return rgb

test/unit/colorbylayer.test.js

@@ -0,0 +1,18 @@
+import expect from 'expect'
+
+import getRGBForEntity from '../../src/getRGBForEntity'
+
+describe('colors', () => {
+  it('Color defined in the entity but with value 256 means that we have to use the color defined in the layer.', () => {
+    const fakeEntity = {
+      layer: "0",
+      colorNumber: 256
+    };
+    const fakeLayers = {
+      "0": {
+        colorNumber: 1
+      }
+    }
+    expect(getRGBForEntity(fakeLayers, fakeEntity)).toEqual([255, 0, 0])
+  })
+})