Added examples of custom axis scaling and ticks

Added examples/custom_axis_scaling.py which shows three examples: 1)
simple example of custom axis scaling, 2) similar to 1 but showing
custom axis ticks, 3) more detailed example plotting the full range of
data on the left and a zoomed region on the right.

Author: tgwoodcock

examples/custom_axis_scaling.py

@@ -0,0 +1,147 @@
+import ternary
+
+## Simple example:
+## Boundary and Gridlines
+scale = 9
+figure, tax = ternary.figure(scale=scale)
+
+tax.ax.axis("off")
+figure.set_facecolor('w')
+
+# Draw Boundary and Gridlines
+tax.boundary(linewidth=1.0)
+tax.gridlines(color="black", multiple=1, linewidth=0.5,ls='-')
+
+# Set Axis labels and Title
+fontsize = 16
+tax.left_axis_label("Logs", fontsize=fontsize, offset=0.13)
+tax.right_axis_label("Dogs", fontsize=fontsize, offset=0.12)
+tax.bottom_axis_label("Hogs", fontsize=fontsize, offset=0.06)
+
+
+# Set custom axis limits by passing a dict into set_limits.
+# The keys are b, l and r for the three axes and the vals are a list
+# of the min and max in data coords for that axis. max-min for each
+# axis must be the same as the scale i.e. 9 in this case.
+tax.set_axis_limits({'b':[67,76],'l':[24,33],'r':[0,9]})
+# get and set the custom ticks:
+tax.get_ticks_from_axis_limits()
+tax.set_custom_ticks(fsize=10,offset=0.02)
+
+# data can be plotted by entering data coords (rather than simplex coords):
+points = [(70,3,27),(73,2,25),(68,6,26)]
+points_c = tax.convert_coordinates(points,axisorder='brl')
+tax.scatter(points_c,marker='o',s=25,c='r')
+
+tax.ax.set_aspect('equal', adjustable='box')
+tax._redraw_labels()
+
+
+## Simple example with axis tick formatting:
+## Boundary and Gridlines
+scale = 9
+figure, tax = ternary.figure(scale=scale)
+
+tax.ax.axis("off")
+figure.set_facecolor('w')
+
+# Draw Boundary and Gridlines
+tax.boundary(linewidth=1.0)
+tax.gridlines(color="black", multiple=1, linewidth=0.5,ls='-')
+
+# Set Axis labels and Title
+fontsize = 16
+tax.left_axis_label("Logs", fontsize=fontsize, offset=0.13)
+tax.right_axis_label("Dogs", fontsize=fontsize, offset=0.12)
+tax.bottom_axis_label("Hogs", fontsize=fontsize, offset=0.06)
+
+
+# Set custom axis limits by passing a dict into set_limits.
+# The keys are b, l and r for the three axes and the vals are a list
+# of the min and max in data coords for that axis. max-min for each
+# axis must be the same as the scale i.e. 9 in this case.
+tax.set_axis_limits({'b':[67,76],'l':[24,33],'r':[0,9]})
+# get and set the custom ticks:
+# custom tick formats:
+# tick_formats can either be a dict, like below or a single format string
+# e.g. "%.3e" (valid for all 3 axes) or None, in which case, ints are
+# plotted for all 3 axes.
+tick_formats = {'b' : "%.2f",'r' : "%d",'l' : "%.1f"}
+
+tax.get_ticks_from_axis_limits()
+tax.set_custom_ticks(fsize=10,offset=0.02,tick_formats=tick_formats)
+
+# data can be plotted by entering data coords (rather than simplex coords):
+points = [(70,3,27),(73,2,25),(68,6,26)]
+points_c = tax.convert_coordinates(points,axisorder='brl')
+tax.scatter(points_c,marker='o',s=25,c='r')
+
+tax.ax.set_aspect('equal', adjustable='box')
+tax._redraw_labels()
+
+
+
+## Zoom example:
+## Draw a plot with the full range on the left and a second plot which
+## shows a zoomed region of the left plot.
+fig = ternary.plt.figure(figsize=(11,6))
+ax1 = fig.add_subplot(2,1,1)
+ax2 = fig.add_subplot(2,1,2)
+
+tax1 = ternary.TernaryAxesSubplot(ax=ax1,scale=100)
+tax1.boundary(linewidth=1.0)
+tax1.gridlines(color="black", multiple=10, linewidth=0.5,ls='-')
+tax1.ax.axis("equal")
+tax1.ax.axis("off")
+
+tax2 = ternary.TernaryAxesSubplot(ax=ax2,scale=30)
+axes_colors = {'b' : 'r',
+               'r' : 'r',
+               'l' : 'r'
+               }
+tax2.boundary(linewidth=1.0,axes_colors=axes_colors)
+tax2.gridlines(color="r", multiple=5, linewidth=0.5,ls='-')
+tax2.ax.axis("equal")
+tax2.ax.axis("off")
+
+fontsize = 16
+tax1.set_title("Entire range")
+tax1.left_axis_label("Logs", fontsize=fontsize, offset=0.12)
+tax1.right_axis_label("Dogs", fontsize=fontsize, offset=0.12)
+tax1.bottom_axis_label("Hogs", fontsize=fontsize, offset=0.)
+tax2.set_title("Zoomed region",color='r')
+tax2.left_axis_label("Logs", fontsize=fontsize, offset=0.17,color='r')
+tax2.right_axis_label("Dogs", fontsize=fontsize, offset=0.17,color='r')
+tax2.bottom_axis_label("Hogs", fontsize=fontsize, offset=0.03,color='r')
+
+tax1.ticks(multiple=10,offset=0.02)
+
+tax2.set_axis_limits({'b':[60,75],'l':[15,30],'r':[10,25]})
+tax2.get_ticks_from_axis_limits(multiple=5)
+tick_formats = "%.1f"
+tax2.set_custom_ticks(fsize=10,offset=0.025,multiple=5,axes_colors=axes_colors,
+                      tick_formats=tick_formats)
+
+# plot some data
+points = [(62,12,26),(63.5,13.5,23),(65,14,21),(61,15,24),(62,16,22),
+          (67.5,14.5,18),(68.2,16.5,15.3),(62,22.5,15.5)]
+
+# data coords == simplex coords:
+tax1.scatter(points,marker='^',s=25,c='b')
+# data coords != simplex coords:
+points_c = tax2.convert_coordinates(points,axisorder='brl')
+tax2.scatter(points_c,marker='^',s=25,c='b')
+
+# draw the zoom region on the first plot
+tax1.line((60,10,30),(75,10,15),color='r',lw=2.0)
+tax1.line((60,10,30),(60,25,15),color='r',lw=2.0)
+tax1.line((75,10,15),(60,25,15),color='r',lw=2.0)
+
+fig.set_facecolor("w")
+
+tax1.ax.set_position([0.01,0.05,0.46,0.8])
+tax2.ax.set_position([0.50,0.05,0.46,0.8])
+
+tax1.resize_drawing_canvas()
+tax2.resize_drawing_canvas()
+ternary.plt.show()