New Visual: Bar

examples/scene/bar_plot.py

@@ -0,0 +1,45 @@
+# -*- coding: utf-8 -*-
+# vispy: gallery 2
+# -----------------------------------------------------------------------------
+# Copyright (c) Vispy Development Team. All Rights Reserved.
+# Distributed under the (new) BSD License. See LICENSE.txt for more info.
+# -----------------------------------------------------------------------------
+"""
+Vertical bar plot with Axis 
+===========================
+"""
+
+import numpy as np
+from vispy import scene, app
+
+if __name__ == "__main__":
+
+    canvas = scene.SceneCanvas(keys='interactive', vsync=False)
+    canvas.size = 800, 600
+    canvas.show()
+
+    grid = canvas.central_widget.add_grid()
+    grid.padding = 10
+
+    vb1 = grid.add_view(row=0, col=1, camera='panzoom')
+
+    x_axis1 = scene.AxisWidget(orientation='bottom')
+    x_axis1.stretch = (1, 0.1)
+    grid.add_widget(x_axis1, row=1, col=1)
+    x_axis1.link_view(vb1)
+    y_axis1 = scene.AxisWidget(orientation='left')
+    y_axis1.stretch = (0.1, 1)
+    grid.add_widget(y_axis1, row=0, col=0)
+    y_axis1.link_view(vb1)
+
+    grid_lines1 = scene.visuals.GridLines(parent=vb1.scene)
+
+    color_array = np.array([[1,0,0], [0,1,0], [0, 0, 1], [0.5, 1, 0.25], [1, 0.5, 0.25], [0.25, 0.5, 1], [1,0,0], [0,1,0], [0, 0, 1], [0.5, 1, 0.25], [1, 0.5, 0.25], [0.25, 0.5, 1]])
+
+    bar1 = scene.Bar(height=np.arange(0, 6, 0.5),  # for a more traditional horizontal plot, either remove the 
+                     bottom=np.arange(0, 3, 0.25), width=0.8, shift=0.5,  # orientation paramenter outright
+                     orientation='v', color_array=color_array, parent=vb1.scene)  # or set it to 'h'
+
+    vb1.camera.set_range()
+
+    app.run()

vispy/scene/visuals.py

@@ -232,6 +232,7 @@ def generate_docstring(subclass, clsname):
 
 Arrow = create_visual_node(visuals.ArrowVisual)
 Axis = create_visual_node(visuals.AxisVisual)
+Bar = create_visual_node(visuals.BarVisual)
 Box = create_visual_node(visuals.BoxVisual)
 ColorBar = create_visual_node(visuals.ColorBarVisual)
 Compound = create_visual_node(visuals.CompoundVisual)

vispy/visuals/__init__.py

@@ -12,6 +12,7 @@
 """
 
 from .axis import AxisVisual  # noqa
+from .bar import BarVisual  # noqa
 from .box import BoxVisual  # noqa
 from .cube import CubeVisual  # noqa
 from .ellipse import EllipseVisual  # noqa

vispy/visuals/bar.py

@@ -0,0 +1,99 @@
+# -*- coding: utf-8 -*-
+# -----------------------------------------------------------------------------
+# Copyright (c) Vispy Development Team. All Rights Reserved.
+# Distributed under the (new) BSD License. See LICENSE.txt for more info.
+# -----------------------------------------------------------------------------
+
+import numpy as np
+from .mesh import MeshVisual
+
+
+class BarVisual(MeshVisual):
+    """Visual that calculates and displays a bar graph
+
+    Parameters
+    ----------
+    data : array-like
+        1st column is the height, optional 2nd column is bottom
+    height : array-like
+        Height of the bars
+    bottom : array-like
+        Bottom of the bars
+    width : int | float
+        Width of all bars
+    shift : int | float
+        Shift of all bars along the x-axis
+    color : instance of Color
+        Color of the bar.
+    orientation : {'h', 'v'}
+        Orientation of the bars - 'h' is default
+    color_array : array-like
+        [[1, 0, 0], [0, 1, 0], [0, 0, 1]] exactly one rgb array for each bar. This would be for 3 Bars 
+    """
+
+    def __init__(self, height, bottom=None, width=0.8, shift=0.0, color='w', orientation='h', color_array=None):
+        if bottom is None:
+            bottom = np.zeros(height.shape[0])
+
+        if height.shape != bottom.shape:
+            raise ValueError("Height and Bottom must be same shape: Height: " + height.shape + " Bottom: " + bottom.shape)
+
+        rr, tris = calc_vertices(height, bottom, width, shift, orientation)
+
+        if color_array is not None and color_array.shape[0] == height.shape[0] and color_array.shape[1] == 3:
+            MeshVisual.__init__(self, rr, tris, face_colors=np.repeat(color_array, 2, axis=0))
+        else:
+            MeshVisual.__init__(self, rr, tris, color=color)
+
+    def update_data(self, height, bottom=None, width=0.8, shift=0.0, color='w', orientation='h', color_array=None):
+        if bottom is None:
+            bottom = np.zeros(height.shape[0])
+
+        if height.shape != bottom.shape:
+            raise ValueError("Height and Bottom must be same shape: Height: " + height.shape + " Bottom: " + bottom.shape)
+
+        rr, tris = calc_vertices(height, bottom, width, shift, orientation)
+
+        if color_array is not None and color_array.shape[0] == height.shape[0] and color_array.shape[1] == 3:
+            MeshVisual.set_data(self, rr, tris, face_colors=np.repeat(color_array, 2, axis=0))
+        else:
+            MeshVisual.set_data(self, rr, tris, color=color)
+
+
+
+def calc_vertices(height, bottom, width, shift, orientation):
+
+    y_position = np.zeros((height.shape[0], 2))
+
+    y_position[:, 0] = height
+    y_position[:, 1] = bottom
+
+    y_position = y_position.flatten().repeat(2)
+
+    stack_n_x2 = np.arange(height.shape[0]).repeat(2).reshape(-1, 1)
+
+    vertices = np.array([
+        [-width/2 + shift, 1],
+        [width/2 + shift, 1],
+        [width/2 + shift, 0],
+        [-width/2 + shift, 0]])
+
+    vertices = np.tile(vertices, (height.shape[0], 1))
+
+    if orientation == 'h':
+        vertices[:, 0] = vertices[:, 0] + stack_n_x2[:, 0].repeat(2)
+        vertices[:, 1] = y_position
+
+    elif orientation == 'v':
+        vertices[:, 1] = vertices[:, 0] + stack_n_x2[:, 0].repeat(2)
+        vertices[:, 0] = y_position
+    else:
+        raise ValueError('orientation can only be v (vertical) or h (horizontal). You specified: ' + str(orientation))
+
+    base_faces = np.array([[0, 1, 2], [0, 2, 3]])
+
+    base_faces = np.tile(base_faces, (height.shape[0], 1))
+
+    faces = stack_n_x2 * 4 + base_faces
+
+    return vertices, faces