feat(delayspectrum): give user control over datashade function

Allow user to select datashade or renderize. datashade automatically sets the colormap for each zoom level and it does not support displaying the colormap. Default: renderize.
chime-experiment · Jun 25, 2020 · f4e2233 · f4e2233
1 parent ece43c0
commit f4e2233
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Showing 2 changed files with 16 additions and 9 deletions.
diff --git a/bondia/plot/delayspectrum.py b/bondia/plot/delayspectrum.py
@@ -3,7 +3,7 @@
 import panel
 import param
 import holoviews as hv
-from holoviews.operation.datashader import datashade
+from holoviews.operation.datashader import datashade, rasterize
 from holoviews.plotting.util import process_cmap
 import numpy as np
 
@@ -38,8 +38,10 @@ class DelaySpectrumPlot(param.Parameterized, BondiaPlot):
     helper_lines = param.Boolean(default=True)
 
     # Default: turn on datashader and disable colormap range
-    serverside_rendering = param.Boolean(default=True)
-    colormap_range = param.Range(default=(0.1, 10000), constant=True)
+    serverside_rendering = param.Selector(
+        objects=[None, rasterize, datashade], default=rasterize
+    )
+    colormap_range = param.Range(default=(0.1, 10000), constant=False)
 
     # Hide lsd selector by setting precedence < 0
     lsd = param.Selector(precedence=-1)
@@ -53,7 +55,7 @@ def __init__(self, data, **params):
     @param.depends("serverside_rendering", watch=True)
     def update_serverside_rendering(self):
         # Disable colormap range selection if using datashader (because it uses auto values)
-        self.param["colormap_range"].constant = self.serverside_rendering
+        self.param["colormap_range"].constant = self.serverside_rendering == datashade
 
     @param.depends(
         "lsd",
@@ -131,7 +133,7 @@ def view(self):
                 ylim=ylim,
             )
 
-            if not self.serverside_rendering:
+            if self.serverside_rendering is None:
                 if self.helper_lines:
                     img = (img * hv.VLine(0) * hv.HLine(0)).opts(
                         hv.opts.VLine(color="white", line_width=3, line_dash="dotted"),
@@ -149,8 +151,8 @@ def view(self):
                 else:
                     normalization = "linear"
 
-                # datashade
-                img = datashade(
+                # datashade/rasterize the image
+                img = self.serverside_rendering(
                     img,
                     cmap=cmap_inferno,
                     precompute=True,

diff --git a/bondia/plot/plot.py b/bondia/plot/plot.py
@@ -1,4 +1,4 @@
-from panel import Column, Row
+from panel import Column, Row, Param
 
 
 class BondiaPlot:
@@ -26,7 +26,12 @@ def panel_row(self):
             if self._panel_col_active:
 
                 self._panel_col = Column(
-                    self.title, Row(self.view, self.param), width_policy="max"
+                    self.title,
+                    # Stop param from showing the expand button of the datashading function
+                    # selector. It would be nice to show it, but there are options that can make
+                    # the whole server crash.
+                    Row(self.view, Param(self, expand_button=False)),
+                    width_policy="max",
                 )
             else:
                 self._panel_col = Column(None, Row())