1141 | Validate canvas width, height (#1183)

* 1141 | Validate canvas width, height

* Add tests for canvas extend

* Rename to validate size and fix spacing

* Apply suggestions from code review

---------

Co-authored-by: Jonatan Aponte <jonatan-armando.aponte-duenas@xarvio.com>
Co-authored-by: Jonatan Aponte <jonatanaponte@Jonatans-MBP.fritz.box>
Co-authored-by: Ian Thomas <ianthomas23@gmail.com>

datashader/core.py

@@ -1227,9 +1227,14 @@ def validate_ranges(self, x_range, y_range):
  self.x_axis.validate(x_range)
  self.y_axis.validate(y_range)
 
+ def validate_size(self, width, height):
+ if width <= 0 or height <= 0:
+ raise ValueError("Invalid size: plot_width and plot_height must be bigger than 0")
+
  def validate(self):
  """Check that parameter settings are valid for this object"""
  self.validate_ranges(self.x_range, self.y_range)
+ self.validate_size(self.plot_width, self.plot_height)
 
 
 def bypixel(source, canvas, glyph, agg, *, antialias=False):

datashader/tests/test_dask.py

@@ -1564,3 +1564,21 @@ def test_line_antialias_where(npartitions):
  sol_where_min[j, i] = agg_where_min[j, i] = nan
 
  assert_eq_ndarray(agg_where_min.data, sol_where_min)
+
+
+def test_canvas_size():
+ cvs_list = [
+ ds.Canvas(plot_width=0, plot_height=6),
+ ds.Canvas(plot_width=5, plot_height=0),
+ ds.Canvas(plot_width=0, plot_height=0),
+ ds.Canvas(plot_width=-1, plot_height=1),
+ ds.Canvas(plot_width=10, plot_height=-1)
+ ]
+ msg = r'Invalid size: plot_width and plot_height must be bigger than 0'
+ df = pd.DataFrame(dict(x=[0, 0.2, 1], y=[0, 0.4, 1], z=[10, 20, 30]))
+ ddf = dd.from_pandas(df, 1)
+
+ for cvs in cvs_list:
+ with pytest.raises(ValueError, match=msg): 
+ cvs.points(ddf, "x", "y", ds.mean("z"))
+

datashader/tests/test_pandas.py

@@ -2393,3 +2393,20 @@ def test_line_coordinate_lengths():
  for ny in (1, 3):
  with pytest.raises(ValueError, match=msg):
  cvs.line(source=df, x=["x0", "x1"], y=np.arange(ny), axis=1)
+
+
+def test_canvas_size():
+ cvs_list = [
+ ds.Canvas(plot_width=0, plot_height=6),
+ ds.Canvas(plot_width=5, plot_height=0),
+ ds.Canvas(plot_width=0, plot_height=0),
+ ds.Canvas(plot_width=-1, plot_height=1),
+ ds.Canvas(plot_width=10, plot_height=-1)
+ ]
+ msg = r'Invalid size: plot_width and plot_height must be bigger than 0'
+ df = pd.DataFrame(dict(x=[0, 0.2, 1], y=[0, 0.4, 1], z=[10, 20, 30]))
+
+ for cvs in cvs_list:
+ with pytest.raises(ValueError, match=msg): 
+ cvs.points(df, "x", "y", ds.mean("z"))
+