Handle nodata option for rasterized RGB image (#5774)

holoviz · Jul 20, 2023 · ef1dd3b · ef1dd3b
1 parent b2accaf
commit ef1dd3b
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Showing 3 changed files with 33 additions and 2 deletions.
diff --git a/holoviews/plotting/bokeh/raster.py b/holoviews/plotting/bokeh/raster.py
@@ -177,10 +177,17 @@ def get_data(self, element, ranges, style):
 
         img = np.dstack([element.dimension_values(d, flat=False)
                          for d in element.vdims])
+
+        nan_mask = np.isnan(img)
+        img[nan_mask] = 0
+
         if img.ndim == 3:
-            if img.dtype.kind == 'f':
+            img_max = img.max() if img.size else np.nan
+            # Can be 0 to 255 if nodata has been used
+            if img.dtype.kind == 'f' and img_max <= 1:
                 img = img*255
-            if img.size and (img.min() < 0 or img.max() > 255):
+                # img_max * 255 <- have no effect
+            if img.size and (img.min() < 0 or img_max > 255):
                 self.param.warning('Clipping input data to the valid '
                                    'range for RGB data ([0..1] for '
                                    'floats or [0..255] for integers).')
@@ -197,6 +204,8 @@ def get_data(self, element, ranges, style):
                 img = img.copy()
             img = img.view(dtype=np.uint32).reshape((N, M))
 
+        img[nan_mask.any(-1)] = 0
+
         # Ensure axis inversions are handled correctly
         l, b, r, t = element.bounds.lbrt()
         if self.invert_axes:

diff --git a/holoviews/tests/element/test_raster.py b/holoviews/tests/element/test_raster.py
@@ -55,6 +55,19 @@ def test_not_using_class_variables_vdims(self):
             assert i is not c
             assert i == c
 
+    def test_nodata(self):
+        N = 2
+        rgb_d = np.linspace(0, 1, N * N * 3).reshape(N, N, 3)
+        rgb = RGB(rgb_d)
+        assert sum(np.isnan(rgb["R"])) == 0
+        assert sum(np.isnan(rgb["G"])) == 0
+        assert sum(np.isnan(rgb["B"])) == 0
+
+        rgb_n = rgb.redim.nodata(R=0)
+        assert sum(np.isnan(rgb_n["R"])) == 1
+        assert sum(np.isnan(rgb_n["G"])) == 0
+        assert sum(np.isnan(rgb_n["B"])) == 0
+
 class TestHSV(ComparisonTestCase):
 
     def setUp(self):

diff --git a/holoviews/tests/plotting/bokeh/test_rasterplot.py b/holoviews/tests/plotting/bokeh/test_rasterplot.py
@@ -42,6 +42,15 @@ def test_nodata_array_uint(self):
         self.assertEqual(source.data['image'][0],
                          np.array([[2, np.NaN], [np.NaN, 1]]))
 
+    def test_nodata_rgb(self):
+        N = 2
+        rgb_d = np.linspace(0, 1, N * N * 3).reshape(N, N, 3)
+        rgb = RGB(rgb_d).redim.nodata(R=0)
+        plot = bokeh_renderer.get_plot(rgb)
+        image_data = plot.handles["source"].data["image"][0]
+        # Image sets nan-values to 0
+        assert (image_data == 0).sum() == 1
+
     def test_raster_invert_axes(self):
         arr = np.array([[0, 1, 2], [3, 4,  5]])
         raster = Raster(arr).opts(invert_axes=True)