add circleview

frontend/views/__init__.py

@@ -1 +1,2 @@
-from .number import NumberView
+from .number import NumberView
+from .circle import CircleView

frontend/views/base.py

@@ -15,6 +15,8 @@ class View(Frame):
         self.canvas = Canvas(self, width=144, height=168, background='white')
         self.canvas.pack()
 
+        self.center = (144 // 2, 168 // 2)
+
         self._init_canvas()
 
     def _init_canvas(self):

frontend/views/circle.py

@@ -0,0 +1,45 @@
+import tkinter as tk
+from tkinter import ttk
+
+from .base import View
+
+class CircleView(View):
+
+    def _init_canvas(self):
+        self.target_r = self.center[0] - 10
+        self.draw_circle(self.center[0], self.center[1],
+                         self.target_r,
+                         outline="#000000")
+        
+        self.target_frame = tk.Frame(self.actions)
+        self.target_frame.pack()
+        self.target_label = ttk.Label(self.target_frame, text="Target (g)")
+        self.target_label.pack(side=tk.LEFT)
+        self.target = ttk.Entry(self.target_frame)
+        self.target.insert(0, 100.0)
+        self.target.pack(side=tk.LEFT)
+
+    def draw_circle(self, x, y, r, **kwargs):
+        self.canvas.create_oval(x-r, y-r, x+r, y+r, **kwargs)
+    
+    def update_weight(self, weight):
+        self.canvas.delete("all")
+
+        weight_r = 0.0
+        try:
+            target = float(self.target.get())
+            weight_r = weight / target * self.target_r
+
+            self.draw_circle(self.center[0], self.center[1],
+                            weight_r,
+                            fill="#000000")
+        except:
+            pass
+        finally:
+            target_outline = "#000000"
+            if weight_r > self.target_r:
+                target_outline = "#FFFFFF"
+            self.draw_circle(self.center[0], self.center[1],
+                            self.target_r,
+                            outline=target_outline)
+