Merge pull request #518 from plotly/2d-density

Added _make_colorscale method and 2D Density Plot

Author: Kully

plotly/graph_reference/default-schema.json

@@ -5977,6 +5977,7 @@
                         "width": {
                             "arrayOk": true,
                             "description": "Sets the width (in px) of the lines bounding the marker points.",
+                            "dflt": 0,
                             "min": 0,
                             "role": "style",
                             "valType": "number"

plotly/tests/test_core/test_tools/test_figure_factory.py

@@ -1365,6 +1365,111 @@ def test_gantt_all_args(self):
         self.assertEqual(test_gantt_chart['layout'],
                          exp_gantt_chart['layout'])
 
+
+class Test2D_Density(TestCase):
+
+    def test_validate_2D_density(self):
+
+        # validate that x and y contain only numbers
+        x = [1, 2]
+        y = ['a', 2]
+
+        pattern = ("All elements of your 'x' and 'y' lists must be numbers.")
+
+        self.assertRaisesRegexp(PlotlyError, pattern,
+                                tls.FigureFactory.create_2D_density, x, y)
+
+        # validate that x and y are the same length
+        x2 = [1]
+        y2 = [1, 2]
+
+        pattern2 = ("Both lists 'x' and 'y' must be the same length.")
+
+        self.assertRaisesRegexp(PlotlyError, pattern2,
+                                tls.FigureFactory.create_2D_density, x2, y2)
+
+    def test_2D_density_all_args(self):
+
+        # check if 2D_density data matches with expected output
+        x = [1, 2]
+        y = [2, 4]
+
+        colorscale = ['#7A4579', '#D56073', 'rgb(236,158,105)',
+                      (1, 1, 0.2), (0.98, 0.98, 0.98)]
+
+        test_2D_density_chart = tls.FigureFactory.create_2D_density(
+            x, y, colorscale=colorscale, hist_color='rgb(255, 237, 222)',
+            point_size=3, height=800, width=800)
+
+        exp_2D_density_chart = {
+            'data': [{'marker': {'color': 'rgb(0.0, 0.0, 127.5)',
+                      'opacity': 0.4,
+                      'size': 3},
+                      'mode': 'markers',
+                      'name': 'points',
+                      'type': 'scatter',
+                      'x': [1, 2],
+                      'y': [2, 4]},
+                     {'colorscale': [[0.0, 'rgb(122.0, 69.0, 121.0)'],
+                                     [0.25, 'rgb(213.0, 96.0, 115.0)'],
+                                     [0.5, 'rgb(236.0, 158.0, 105.0)'],
+                                     [0.75, 'rgb(255.0, 255.0, 51.0)'],
+                                     [1.0, 'rgb(249.9, 249.9, 249.9)']],
+                      'name': 'density',
+                      'ncontours': 20,
+                      'reversescale': True,
+                      'showscale': False,
+                      'type': 'histogram2dcontour',
+                      'x': [1, 2],
+                      'y': [2, 4]},
+                     {'marker': {'color': 'rgb(255.0, 237.0, 222.0)'},
+                      'name': 'x density',
+                      'type': 'histogram',
+                      'x': [1, 2],
+                      'yaxis': 'y2'},
+                     {'marker': {'color': 'rgb(255.0, 237.0, 222.0)'},
+                      'name': 'y density',
+                      'type': 'histogram',
+                      'xaxis': 'x2',
+                      'y': [2, 4]}],
+            'layout': {'autosize': False,
+                       'bargap': 0,
+                       'height': 800,
+                       'hovermode': 'closest',
+                       'margin': {'t': 50},
+                       'showlegend': False,
+                       'title': 'Love',
+                       'width': 800,
+                       'xaxis': {'domain': [0, 0.85],
+                                 'showgrid': False,
+                                 'zeroline': False},
+                       'xaxis2': {'domain': [0.85, 1],
+                                  'showgrid': False,
+                                  'zeroline': False},
+                       'yaxis': {'domain': [0, 0.85],
+                                 'showgrid': False,
+                                 'zeroline': False},
+                       'yaxis2': {'domain': [0.85, 1],
+                                  'showgrid': False,
+                                  'zeroline': False}}
+        }
+
+        self.assertEqual(test_2D_density_chart['data'][0],
+                         exp_2D_density_chart['data'][0])
+
+        self.assertEqual(test_2D_density_chart['data'][1],
+                         exp_2D_density_chart['data'][1])
+
+        self.assertEqual(test_2D_density_chart['data'][2],
+                         exp_2D_density_chart['data'][2])
+
+        self.assertEqual(test_2D_density_chart['data'][3],
+                         exp_2D_density_chart['data'][3])
+
+        self.assertEqual(test_2D_density_chart['layout'],
+                         exp_2D_density_chart['layout'])
+
+
 # class TestDistplot(TestCase):
 
 #     def test_scipy_import_error(self):

plotly/tools.py

@@ -1476,6 +1476,161 @@ class FigureFactory(object):
     more information and examples of a specific chart type.
     """
 
+    @staticmethod
+    def _make_linear_colorscale(colors):
+        """
+        Makes a list of colors into a colorscale-acceptable form
+
+        For documentation regarding to the form of the output, see
+        https://plot.ly/python/reference/#mesh3d-colorscale
+        """
+        scale = 1./(len(colors) - 1)
+        return[[i * scale, color] for i, color in enumerate(colors)]
+
+    @staticmethod
+    def create_2D_density(x, y, colorscale='Earth', ncontours=20,
+                          hist_color=(0, 0, 0.5), point_color=(0, 0, 0.5),
+                          point_size=2, height=600, width=600):
+        """
+        Returns figure for a 2D density plot
+
+        :param (list|array) x: x-axis data for plot generation
+        :param (list|array) y: y-axis data for plot generation
+        :param (str|tuple|list) colorscale: either a plotly scale name, an rgb
+            or hex color, a color tuple or a list or tuple of colors. An rgb
+            color is of the form 'rgb(x, y, z)' where x, y, z belong to the
+            interval [0, 255] and a color tuple is a tuple of the form
+            (a, b, c) where a, b and c belong to [0, 1]. If colormap is a
+            list, it must contain the valid color types aforementioned as its
+            members.
+        :param (int) ncontours: the number of 2D contours to draw on the plot
+        :param (str) hist_color: the color of the plotted histograms
+        :param (str) point_color: the color of the scatter points
+        :param (str) point_size: the color of the scatter points
+        :param (float) height: the height of the chart
+        :param (float) width: the width of the chart
+
+        Example 1: Simple 2D Density Plot
+        ```
+        import plotly.plotly as py
+        from plotly.tools import FigureFactory as FF
+
+        # Make data points
+        t = np.linspace(-1,1.2,2000)
+        x = (t**3)+(0.3*np.random.randn(2000))
+        y = (t**6)+(0.3*np.random.randn(2000))
+
+        # Create a figure
+        fig = FF.create_2D_density(x, y)
+
+        # Plot the data
+        py.iplot(fig, filename='simple-2d-density')
+        ```
+
+        Example 2: Using Parameters
+        ```
+        import plotly.plotly as py
+        from plotly.tools import FigureFactory as FF
+
+        # Make data points
+        t = np.linspace(-1,1.2,2000)
+        x = (t**3)+(0.3*np.random.randn(2000))
+        y = (t**6)+(0.3*np.random.randn(2000))
+
+        # Create custom colorscale
+        colorscale = ['#7A4579', '#D56073', 'rgb(236,158,105)',
+                      (1, 1, 0.2), (0.98,0.98,0.98)]
+
+        # Create a figure
+        fig = FF.create_2D_density(
+            x, y, colorscale=colorscale,
+            hist_color='rgb(255, 237, 222)', point_size=3)
+
+        # Plot the data
+        py.iplot(fig, filename='use-parameters')
+        ```
+        """
+        from plotly.graph_objs import graph_objs
+        from numbers import Number
+
+        # validate x and y are filled with numbers only
+        for array in [x, y]:
+            if not all(isinstance(element, Number) for element in array):
+                raise exceptions.PlotlyError(
+                    "All elements of your 'x' and 'y' lists must be numbers."
+                )
+
+        # validate x and y are the same length
+        if len(x) != len(y):
+            raise exceptions.PlotlyError(
+                "Both lists 'x' and 'y' must be the same length."
+            )
+
+        colorscale = FigureFactory._validate_colors(colorscale, 'rgb')
+        colorscale = FigureFactory._make_linear_colorscale(colorscale)
+
+        # validate hist_color and point_color
+        hist_color = FigureFactory._validate_colors(hist_color, 'rgb')
+        point_color = FigureFactory._validate_colors(point_color, 'rgb')
+
+        trace1 = graph_objs.Scatter(
+            x=x, y=y, mode='markers', name='points',
+            marker=dict(
+                color=point_color[0],
+                size=point_size,
+                opacity=0.4
+            )
+        )
+        trace2 = graph_objs.Histogram2dcontour(
+            x=x, y=y, name='density', ncontours=ncontours,
+            colorscale=colorscale, reversescale=True, showscale=False
+        )
+        trace3 = graph_objs.Histogram(
+            x=x, name='x density',
+            marker=dict(color=hist_color[0]), yaxis='y2'
+        )
+        trace4 = graph_objs.Histogram(
+            y=y, name='y density',
+            marker=dict(color=hist_color[0]), xaxis='x2'
+        )
+        data = [trace1, trace2, trace3, trace4]
+
+        layout = graph_objs.Layout(
+            showlegend=False,
+            autosize=False,
+            title='Love',
+            height=height,
+            width=width,
+            xaxis=dict(
+                domain=[0, 0.85],
+                showgrid=False,
+                zeroline=False
+            ),
+            yaxis=dict(
+                domain=[0, 0.85],
+                showgrid=False,
+                zeroline=False
+            ),
+            margin=dict(
+                t=50
+            ),
+            hovermode='closest',
+            bargap=0,
+            xaxis2=dict(
+                domain=[0.85, 1],
+                showgrid=False,
+                zeroline=False
+            ),
+            yaxis2=dict(
+                domain=[0.85, 1],
+                showgrid=False,
+                zeroline=False
+            )
+        )
+
+        fig = graph_objs.Figure(data=data, layout=layout)
+        return fig
+
     @staticmethod
     def _validate_gantt(df):
         """