[Feature] Increase the color width value

[lsw123lwq-cell]

Hi! 👋

Firstly, thanks for your work on this project! 🙂

Today I used patch-package to patch @kitware/vtk.js@34.15.1 for the project I'm working on.

Currently, the color width is set using model.renderable.getColorTextureWidth(), but if the image’s scalar range exceeds that value, I want the color width to automatically expand to the maximum size.

Here is the diff that solved my problem:

diff --git a/node_modules/@kitware/vtk.js/Rendering/OpenGL/ImageMapper.js b/node_modules/@kitware/vtk.js/Rendering/OpenGL/ImageMapper.js
index bb676c7..cee022a 100644
--- a/node_modules/@kitware/vtk.js/Rendering/OpenGL/ImageMapper.js
+++ b/node_modules/@kitware/vtk.js/Rendering/OpenGL/ImageMapper.js
@@ -581,6 +581,7 @@ function vtkOpenGLImageMapper(publicAPI, model) {
     if (!imgScalars) {
       return;
     }
+    const maxScalarRange = image.getPointData().getScalars().getRange()[1];
     const dataType = imgScalars.getDataType();
     const numComp = imgScalars.getNumberOfComponents();
     const actorProperty = actor.getProperty();
@@ -602,7 +603,7 @@ function vtkOpenGLImageMapper(publicAPI, model) {
       });
       model.colorTexture.setOpenGLRenderWindow(model._openGLRenderWindow);
       let cWidth = model.renderable.getColorTextureWidth();
-      if (cWidth <= 0) {
+      if (cWidth <= 0 || maxScalarRange > cWidth) {
         cWidth = model.context.getParameter(model.context.MAX_TEXTURE_SIZE);
       }
       const cSize = cWidth * textureHeight * 3;
@@ -680,7 +681,7 @@ function vtkOpenGLImageMapper(publicAPI, model) {
     const reBuildPwf = !pwfTex?.oglObject?.getHandle() || pwfTex?.hash !== pwfunToString;
     if (reBuildPwf) {
       let pwfWidth = model.renderable.getOpacityTextureWidth();
-      if (pwfWidth <= 0) {
+      if (pwfWidth <= 0 || maxScalarRange > pwfWidth) {
         pwfWidth = model.context.getParameter(model.context.MAX_TEXTURE_SIZE);
       }
       const pwfSize = pwfWidth * textureHeight;

This issue body was partially generated by patch-package.

[finetjul]

I'm confused, the color "texture size" is not really related to the "scalar values".
What if you have a scalars rangeing as such: [100000.0, 100001.0]