feat(TranferFunctionEditor): upgrade for axis labels

package.json

@@ -44,7 +44,7 @@
     "itk-image-io": "^1.0.0-b.84",
     "itk-mesh-io": "^1.0.0-b.84",
     "itk-viewer-color-maps": "^1.2.0",
-    "itk-viewer-transfer-function-editor": "^1.5.0",
+    "itk-viewer-transfer-function-editor": "^1.6.0",
     "itk-wasm": "^1.0.0-b.83",
     "mobx": "^5.15.7",
     "mousetrap": "^1.6.5",

src/Rendering/VTKJS/Images/mapToPiecewiseFunctionNodes.js

@@ -1,15 +1,4 @@
-import { windowPointsForSort } from 'itk-viewer-transfer-function-editor'
-
-const getNodes = (range, points) => {
-  const delta = range[1] - range[0]
-  const windowedPoints = windowPointsForSort(points)
-  return windowedPoints.map(([x, y]) => ({
-    x: range[0] + delta * x,
-    y,
-    midpoint: 0.5,
-    sharpness: 0,
-  }))
-}
+import { getNodes } from 'itk-viewer-transfer-function-editor'
 
 // grab head and tail or fallback to data range if 1 or less points
 const getRange = nodes =>

src/UI/Layers/createLayersUIMachine.js

@@ -205,14 +205,17 @@ const assignImageContext = assign({
       if (!actorContext.piecewiseFunctionPoints.has(component)) {
         // Assign default piecewiseFunction
         const points = context.use2D
-          ? [
-              [0, 1],
-              [1, 1],
-            ]
+          ? [[0.5, 1]]
           : [
               [0, 0],
               [0.9, 0.9],
             ]
+        if (context.use2D && components === 1) {
+          // For 2D ImageMapper, if multiple components,
+          // opacity function sets component contribution factor.
+          // If just 1 component, opacity function is irrelevant.
+          points.length = 0
+        }
         actorContext.piecewiseFunctionPoints.set(component, points)
       }
       actorContext.colorRanges.set(component, [0.2, 0.8])