refactor(compose-functions): drop unused dataRange param from compose()

compose() no longer needs an explicit dataRange since outputFn's
mapping range is already derived from its node positions via
addRGBPoint's sortAndUpdateRange. Update the example and tests to
match the new compose(fnList, colorFn, outputFn) signature.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: jadh4v

Examples/Rendering/ComposePiecewiseFunctions/index.js

@@ -121,9 +121,9 @@ function buildColorFunction(presetName) {
   colorFn.applyColorMap(vtkColorMaps.getPresetByName(presetName));
 }
 
-function example_recompose(dataRange) {
+function example_recompose() {
   const fnList = [modalityFn, voiFn, userFn];
-  compose(dataRange, fnList, colorFn, resultFn);
+  compose(fnList, colorFn, resultFn);
   actor.getProperty().setUseLookupTableScalarRange(true);
   actor.getProperty().setRGBTransferFunction(0, resultFn);
 }
@@ -303,7 +303,7 @@ function renderDicom(file) {
     // User interactive adjustment (window/level)
     buildUserFn(getOutputRange(voiFn), colorWindow, colorLevel);
     // Compose into a single transferfunction to feed into the mapper.
-    example_recompose(dataRange);
+    example_recompose();
 
     if (!renderer.getActors().length) {
       renderer.addActor(actor);
@@ -354,7 +354,7 @@ function renderDicom(file) {
       (val) => {
         modalityShift = val;
         buildModalityFunction(dataRange, modalityShift, modalityScale);
-        example_recompose(dataRange);
+        example_recompose();
         renderWindow.render();
       }
     );
@@ -369,7 +369,7 @@ function renderDicom(file) {
       (val) => {
         modalityScale = val;
         buildModalityFunction(dataRange, modalityShift, modalityScale);
-        example_recompose(dataRange);
+        example_recompose();
         renderWindow.render();
       },
       scaleFormat
@@ -422,7 +422,7 @@ function renderDicom(file) {
           Number(windowInput.value),
           Number(levelInput.value)
         );
-        example_recompose(dataRange);
+        example_recompose();
         renderWindow.render();
       }
     );
@@ -443,7 +443,7 @@ function renderDicom(file) {
           Number(windowInput.value),
           Number(levelInput.value)
         );
-        example_recompose(dataRange);
+        example_recompose();
         renderWindow.render();
       },
       scaleFormat
@@ -468,7 +468,7 @@ function renderDicom(file) {
       1,
       (val) => {
         buildUserFn(getOutputRange(voiFn), val, Number(levelInput.value));
-        example_recompose(dataRange);
+        example_recompose();
         renderWindow.render();
       }
     ));
@@ -482,7 +482,7 @@ function renderDicom(file) {
       1,
       (val) => {
         buildUserFn(getOutputRange(voiFn), Number(windowInput.value), val);
-        example_recompose(dataRange);
+        example_recompose();
         renderWindow.render();
       }
     ));
@@ -519,7 +519,7 @@ function renderDicom(file) {
     presetSelector.addEventListener('change', () => {
       currentPreset = presetSelector.value;
       buildColorFunction(currentPreset);
-      example_recompose(dataRange);
+      example_recompose();
       renderWindow.render();
     });
     controlPanel.appendChild(presetSelector);

Sources/Common/DataModel/PiecewiseFunction/helpers.js

@@ -19,12 +19,11 @@ function getColorFunctionXValues(cfun) {
  * and must be pulled back through f-inverse; h's x-values need g-inverse then
  * f-inverse, and so on.
  *
- * @param {Range} dataRange input data range to apply to the output function
  * @param {vtkPiecewiseFunction[]} fnList ordered list of value transform functions, e.g. [modalityFn, voiFn, userFn]
  * @param {vtkColorTransferFunction} colorFn final-stage color transfer function
  * @param {vtkColorTransferFunction} outputFn function to populate with the composed result
  */
-export function compose(dataRange, fnList, colorFn, outputFn) {
+export function compose(fnList, colorFn, outputFn) {
   const xSet = new Set();
 
   // Each function's breakpoint x-values live in that function's input domain.
@@ -54,6 +53,9 @@ export function compose(dataRange, fnList, colorFn, outputFn) {
     if (t != null) xSet.add(t);
   });
 
+  // Now use the gathered x values to propogate through the entire set of
+  // functions to determine the final color values for each, and add them
+  // as nodes to our new color transfer function.
   const xs = Array.from(xSet).sort((a, b) => a - b);
   outputFn.removeAllPoints();
   xs.forEach((x) => {
@@ -62,9 +64,4 @@ export function compose(dataRange, fnList, colorFn, outputFn) {
     colorFn.getColor(finalScalar, rgb);
     outputFn.addRGBPoint(x, rgb[0], rgb[1], rgb[2]);
   });
-
-  outputFn.setRange(...dataRange);
-  outputFn.setMappingRange(...dataRange);
-  outputFn.updateRange();
-  outputFn.modified();
 }

Sources/Common/DataModel/PiecewiseFunction/test/testHelpers.js

@@ -23,7 +23,7 @@ it('Test compose with an identity transform passes colorFn through unchanged', (
   colorFn.addRGBPoint(100, 0, 0, 1);
 
   const outputFn = vtkColorTransferFunction.newInstance();
-  compose([0, 100], [identityFn], colorFn, outputFn);
+  compose([identityFn], colorFn, outputFn);
 
   expect(getNodeXs(outputFn)).toEqual([0, 100]);
   expect(outputFn.getRange()).toEqual([0, 100]);
@@ -49,7 +49,7 @@ it('Test compose maps a color function breakpoint back to its source domain', ()
   colorFn.addRGBPoint(110, 0, 0, 1);
 
   const outputFn = vtkColorTransferFunction.newInstance();
-  compose([0, 100], [fn], colorFn, outputFn);
+  compose([fn], colorFn, outputFn);
 
   const xs = getNodeXs(outputFn);
   expect(xs.length).toBe(3);
@@ -84,7 +84,7 @@ it('Test compose chains multiple transform functions and propagates breakpoints
   colorFn.addRGBPoint(100, 0, 0, 1);
 
   const outputFn = vtkColorTransferFunction.newInstance();
-  compose([0, 100], [fn1, fn2], colorFn, outputFn);
+  compose([fn1, fn2], colorFn, outputFn);
 
   const xs = getNodeXs(outputFn);
   expect(xs.length).toBe(3);
@@ -115,12 +115,12 @@ it('Test compose clears previously composed points on subsequent calls', () => {
   colorFn.addRGBPoint(100, 0, 0, 1);
 
   const outputFn = vtkColorTransferFunction.newInstance();
-  compose([0, 100], [fn], colorFn, outputFn);
+  compose([fn], colorFn, outputFn);
   expect(outputFn.getSize()).toBe(3);
 
   colorFn.removeAllPoints();
   colorFn.addRGBPoint(0, 1, 1, 1);
   colorFn.addRGBPoint(100, 0, 0, 0);
-  compose([0, 100], [fn], colorFn, outputFn);
+  compose([fn], colorFn, outputFn);
   expect(outputFn.getSize()).toBe(2);
 });