def ClassBackwards():
""" Move backwards through the classes. """
global img_d, mask
if ClassState.get() == 1:
ClassDrawButton.config(state=NORMAL)
if CurrentClass.get() > 1:
# Set the class number to be equal to the first class
CurrentClass.set(CurrentClass.get() - 1);
elif CurrentClass.get() == 1 or CurrentClass.get() == 0:
# Set the class number to be back to the top
CurrentClass.set(int(ClassNumber.get()));
ttk.Label(Class, text="Class: {} / {}".format(CurrentClass.get(),ClassNumber.get())).grid(column=1, row=1, sticky=W)
# Create the mask
mask = Masking(img,img_d);
f = plt.figure(figsize=(6,6), dpi=175, tight_layout=True)
f.subplots_adjust(wspace=0, hspace=0)
a = f.add_subplot(111)
a.imshow(img*mask);
a.axis('off');
# Matplotlib plot embedded in the canvas
canvas = FigureCanvasTkAgg(f,ImageViewer);
canvas.show();
canvas.get_tk_widget().grid(column=1,row=1,sticky=(N,S,E,W));
canvas.update()
# Toolbar for plot
toolbar = NavigationToolbar2TkAgg(canvas,ImageViewer);
toolbar.grid(column=1,row=2,sticky=(N,S,E,W));
## Upate Cover Metric ##
CoverageVar.set( format((img_d==CurrentClass.get()).sum()/np.float((img_d!=0).sum()),'.4f') );
ttk.Label(Class, text="{}".format(CoverageVar.get())).grid(column=1, row=12, sticky=W)
elif ClassState.get() == 0:
print 'You have to turn on the Class first to access a pickle file of classes.'
