bitwidgets: Add a "Dialog" box to the toolkit

This allows for simple messages to be displayed on top of the screen.

g13gui/bitwidgets/dialog.py

@@ -0,0 +1,36 @@
+from g13gui.bitwidgets.widget import Widget
+from g13gui.bitwidgets.rectangle import Rectangle
+from g13gui.bitwidgets.label import Label
+from g13gui.bitwidgets.fonts import Fonts
+from g13gui.bitwidgets import DISPLAY_WIDTH
+from g13gui.bitwidgets import DISPLAY_HEIGHT
+
+
+class Dialog(Widget):
+    def __init__(self, text):
+        Widget.__init__(self)
+
+        self._text = text
+        self._rect = Rectangle(0, 0, DISPLAY_WIDTH - 1, DISPLAY_HEIGHT - 1,
+                               fill=False, outline=True, width=3)
+        self._label = Label(0, 0, text, font=Fonts.LARGE)
+        self.addChild(self._rect)
+        self.addChild(self._label)
+
+        self._updateLayout()
+
+    @property
+    def text(self):
+        return self._text
+
+    @text.setter
+    def text(self, value):
+        self.setProperty('text', value)
+        self._label.text = value
+        self._updateLayout()
+
+    def _updateLayout(self):
+        (w, h) = self._label.bounds
+        x = ((DISPLAY_WIDTH - 1) // 2) - (w // 2)
+        y = ((DISPLAY_HEIGHT - 1) // 2) - (h // 2)
+        self._label.position = (x, y)