ENH: Add sample_distance trait

Author: thewtex

itkwidgets/widget_viewer.py

@@ -238,6 +238,8 @@ class Viewer(ViewerParent):
                             help="Size limit for 2D image visualization.").tag(sync=False)
     size_limit_3d = NDArray(dtype=np.int64, default_value=np.array([192, 192, 192], dtype=np.int64),
                             help="Size limit for 3D image visualization.").tag(sync=False)
+    sample_distance = CFloat(default_value=0.25,
+                            help="Normalized volume rendering sample distance.").tag(sync=True)
     _scale_factors = NDArray(dtype=np.uint8, default_value=np.array([1, 1, 1], dtype=np.uint8),
                              help="Image downscaling factors.").tag(sync=True, **array_serialization)
     _downsampling = CBool(default_value=False,
@@ -906,6 +908,11 @@ def view(image=None,  # noqa: C901
         Size limit for 3D image visualization. If the roi is larger than this
         size, it will be downsampled for visualization.
 
+    sample_distance: float, default: 0.25
+        Sampling distance for volume rendering, normalized from 0.0 to 1.0.
+        Lower values result in a higher quality rendering. High values improve
+        the framerate.
+
     Returns
     -------
     viewer : ipywidget

js/lib/viewer.js

@@ -132,6 +132,7 @@ const ViewerModel = widgets.DOMWidgetModel.extend(
         z_slice: null,
         clicked_slice_point: null,
         gradient_opacity: 0.2,
+        sample_distance: 0.25,
         opacity_gaussians: null,
         channels: null,
         blend_mode: 'composite',
@@ -733,6 +734,7 @@ const ViewerView = widgets.DOMWidgetView.extend({
     if (rendered_image) {
       this.shadow_changed()
       this.gradient_opacity_changed()
+      this.sample_distance_changed()
       this.channels_changed()
       this.blend_mode_changed()
     }
@@ -1010,6 +1012,16 @@ const ViewerView = widgets.DOMWidgetView.extend({
       this.model.itkVtkViewer.on('gradientOpacityChanged',
         onGradientOpacityChange
       )
+
+      const onVolumeSampleDistanceChange = (distance) => {
+        if (distance !== this.model.get('sample_distance')) {
+          this.model.set('sample_distance', distance)
+          this.model.save_changes()
+        }
+      }
+      this.model.itkVtkViewer.on('volumeSampleDistanceChanged',
+        onVolumeSampleDistanceChange
+      )
     } // end use2D
 
     const onCameraChanged = macro.throttle(() => {
@@ -1080,6 +1092,11 @@ const ViewerView = widgets.DOMWidgetView.extend({
       this.gradient_opacity_changed,
       this
     )
+    this.model.on(
+      'change:sample_distance',
+      this.sample_distance_changed,
+      this
+    )
     this.model.on('change:blend_mode', this.blend_mode_changed, this)
     this.model.on('change:select_roi', this.select_roi_changed, this)
     this.model.on('change:_scale_factors', this.scale_factors_changed, this)
@@ -1583,6 +1600,13 @@ const ViewerView = widgets.DOMWidgetView.extend({
     }
   },
 
+  sample_distance_changed: function () {
+    const sample_distance = this.model.get('sample_distance')
+    if (this.model.hasOwnProperty('itkVtkViewer') && !this.model.use2D) {
+      this.model.itkVtkViewer.setVolumeSampleDistance(sample_distance)
+    }
+  },
+
   opacity_gaussians_changed: function () {
     const opacity_gaussians = this.model.get('opacity_gaussians')
     if (this.model.hasOwnProperty('itkVtkViewer') && !this.model.use2D) {