feat(ShrinkPolyData): add vtkShrinkPolyData

Author: daker

Documentation/content/docs/gallery/ShrinkPolyData.jpg

@@ -108,7 +108,7 @@ This will allow you to see the some live code running in your browser. Just pick
 [![Cutter Example][Cutter]](./Cutter.html "Cutter")
 [![PolyDataNormals Example][PolyDataNormals]](./PolyDataNormals.html "PolyDataNormals")
 [![ThresholdPoints Example][ThresholdPoints]](./ThresholdPoints.html "Cut/Treshold points with point data criteria")
-
+[![ShrinkPolyData Example][ShrinkPolyData]](./ShrinkPolyData.html "ShrinkPolyData")
 
 </div>
 
@@ -128,6 +128,7 @@ This will allow you to see the some live code running in your browser. Just pick
 [Cutter]: ../docs/gallery/Cutter.jpg
 [PolyDataNormals]: ../docs/gallery/PolyDataNormals.jpg
 [ThresholdPoints]: ../docs/gallery/ThresholdPoints.jpg
+[ShrinkPolyData]: ../docs/gallery/ShrinkPolyData.jpg
 
 # Sources
 

Documentation/content/examples/index.md

@@ -60,6 +60,19 @@ export function pointInPolygon(
   normal: Vector3
 ): PolygonIntersectionState;
 
+/**
+ * Compute the centroid of a polygon.
+ * @param {Array<number>} poly - Array of point indices for the polygon
+ * @param {vtkPoints} points - vtkPoints instance
+ * @param {Vector3} [centroid] - Optional output array (length 3)
+ * @returns {Vector3} The centroid as [x, y, z]
+ */
+export function computeCentroid(
+  poly: Array<number>,
+  points: TypedArray,
+  centroid?: Vector3
+): void;
+
 /**
  * Method used to decorate a given object (publicAPI+model) with vtkPolygon characteristics.
  *

Sources/Common/DataModel/Polygon/index.d.ts

@@ -215,6 +215,31 @@ export function getNormal(poly, points, normal) {
   return vtkMath.normalize(normal);
 }
 
+/**
+ * Compute the centroid of a polygon.
+ * @param {Array<number>} poly - Array of point indices for the polygon
+ * @param {vtkPoints} points - vtkPoints instance
+ * @param {Vector3} [centroid] - Optional output array (length 3)
+ * @returns {Vector3} The centroid as [x, y, z]
+ */
+export function computeCentroid(poly, points, centroid = [0, 0, 0]) {
+  centroid[0] = 0;
+  centroid[1] = 0;
+  centroid[2] = 0;
+  const n = poly.length;
+  const p = [];
+  for (let i = 0; i < n; i++) {
+    points.getPoint(poly[i], p);
+    centroid[0] += p[0];
+    centroid[1] += p[1];
+    centroid[2] += p[2];
+  }
+  centroid[0] /= n;
+  centroid[1] /= n;
+  centroid[2] /= n;
+  return centroid;
+}
+
 // ----------------------------------------------------------------------------
 // Static API
 // ----------------------------------------------------------------------------
@@ -224,6 +249,7 @@ const STATIC = {
   pointInPolygon,
   getBounds,
   getNormal,
+  computeCentroid,
 };
 
 // ----------------------------------------------------------------------------

Sources/Common/DataModel/Polygon/index.js

@@ -0,0 +1,8 @@
+<table>
+  <tr>
+    <td>Shrink Factor</td>
+    <td colspan="3">
+      <input class='shrinkFactor' type="range" min="0.1" max="1" step="0.1" value="0.25" />
+    </td>
+  </tr>
+</table>

Sources/Filters/General/ShrinkPolyData/example/controlPanel.html

@@ -0,0 +1,52 @@
+import '@kitware/vtk.js/favicon';
+
+// Load the rendering pieces we want to use (for both WebGL and WebGPU)
+import '@kitware/vtk.js/Rendering/Profiles/Geometry';
+import '@kitware/vtk.js/IO/Core/DataAccessHelper/HttpDataAccessHelper';
+
+import vtkFullScreenRenderWindow from '@kitware/vtk.js/Rendering/Misc/FullScreenRenderWindow';
+import vtkActor from '@kitware/vtk.js/Rendering/Core/Actor';
+import vtkHttpDataSetReader from '@kitware/vtk.js/IO/Core/HttpDataSetReader';
+import vtkShrinkPolyData from '@kitware/vtk.js/Filters/General/ShrinkPolyData';
+import vtkMapper from '@kitware/vtk.js/Rendering/Core/Mapper';
+import controlPanel from './controlPanel.html';
+
+// ----------------------------------------------------------------------------
+// Standard rendering code setup
+// ----------------------------------------------------------------------------
+
+const fullScreenRenderer = vtkFullScreenRenderWindow.newInstance();
+const renderer = fullScreenRenderer.getRenderer();
+const renderWindow = fullScreenRenderer.getRenderWindow();
+
+fullScreenRenderer.addController(controlPanel);
+
+// ----------------------------------------------------------------------------
+// Example code
+// ----------------------------------------------------------------------------
+const shrinkPolyData = vtkShrinkPolyData.newInstance();
+shrinkPolyData.setShrinkFactor(0.25);
+
+const actor = vtkActor.newInstance();
+const mapper = vtkMapper.newInstance();
+mapper.setInputConnection(shrinkPolyData.getOutputPort());
+actor.setMapper(mapper);
+
+const reader = vtkHttpDataSetReader.newInstance({ fetchGzip: true });
+shrinkPolyData.setInputConnection(reader.getOutputPort());
+
+reader.setUrl(`${__BASE_PATH__}/data/cow.vtp`).then(() => {
+  reader.loadData().then(() => {
+    renderer.addActor(actor);
+    renderer.resetCamera();
+    renderWindow.render();
+  });
+});
+
+['shrinkFactor'].forEach((propertyName) => {
+  document.querySelector(`.${propertyName}`).addEventListener('input', (e) => {
+    const value = Number(e.target.value);
+    shrinkPolyData.set({ [propertyName]: value });
+    renderWindow.render();
+  });
+});

Sources/Filters/General/ShrinkPolyData/example/index.js

@@ -0,0 +1,79 @@
+import { DesiredOutputPrecision } from '../../../Common/DataModel/DataSetAttributes';
+import { vtkAlgorithm, vtkObject } from '../../../interfaces';
+import { Vector3 } from '../../../types';
+
+/**
+ *
+ */
+export interface IShrinkPolyDataInitialValues {
+  shrinkFactor?: number;
+}
+
+type vtkShrinkPolyDataBase = vtkObject & vtkAlgorithm;
+
+export interface vtkShrinkPolyData extends vtkShrinkPolyDataBase {
+  /**
+   * Expose methods
+   * @param inData
+   * @param outData
+   */
+  requestData(inData: any, outData: any): void;
+
+  /**
+   * Get the shrink factor.
+   */
+  getShrinkFactor(): number;
+
+  /**
+   * Set the shrink factor.
+   * @param {Number} shrinkFactor
+   */
+  setShrinkFactor(shrinkFactor: number): boolean;
+
+  /**
+   * Shrink two points towards their midpoint by a shrink factor.
+   * @param {Vector3} p1 - The [x, y, z] coordinates of the first point
+   * @param {Vector3} p2 - The [x, y, z] coordinates of the second point
+   * @param {number} shrinkFactor - The shrink factor (0.0 to 1.0)
+   * @returns {Vector3[]} Array containing the two new points
+   */
+  shrinkLine(p1: Vector3, p2: Vector3, shrinkFactor: number): Vector3[];
+}
+
+/**
+ * Method used to decorate a given object (publicAPI+model) with vtkShrinkPolyData characteristics.
+ *
+ * @param publicAPI object on which methods will be bounds (public)
+ * @param model object on which data structure will be bounds (protected)
+ * @param {IShrinkPolyDataInitialValues} [initialValues] (default: {})
+ */
+export function extend(
+  publicAPI: object,
+  model: object,
+  initialValues?: IShrinkPolyDataInitialValues
+): void;
+
+/**
+ * Method used to create a new instance of vtkShrinkPolyData.
+ * @param {IShrinkPolyDataInitialValues} [initialValues] for pre-setting some of its content
+ */
+export function newInstance(
+  initialValues?: IShrinkPolyDataInitialValues
+): vtkShrinkPolyData;
+
+/**
+ * vtkShrinkPolyData shrinks cells composing a polygonal dataset (e.g.,
+ * vertices, lines, polygons, and triangle strips) towards their centroid. The
+ * centroid of a cell is computed as the average position of the cell points.
+ * Shrinking results in disconnecting the cells from one another. The output
+ * dataset type of this filter is polygonal data.
+ *
+ * During execution the filter passes its input cell data to its output. Point
+ * data attributes are copied to the points created during the shrinking
+ * process.
+ */
+export declare const vtkShrinkPolyData: {
+  newInstance: typeof newInstance;
+  extend: typeof extend;
+};
+export default vtkShrinkPolyData;