widgets: button: Add a simple Button widget

Signed-off-by: Daniel Thompson <daniel@redfelineninja.org.uk>

TODO.rst

@@ -44,7 +44,7 @@ Wasp-os
 
 * [ ] Widgets
 
-  * [ ] Add a button widget
+  * [X] Add a button widget
   * [X] Add a checkbox widget
   * [X] Add a spinner widget
 

wasp/widgets.py

@@ -215,6 +215,46 @@ class ScrollIndicator:
         if self.down:
             draw.blit(icons.down_arrow, self._pos[0], self._pos[1]+13, fg=color)
 
+class Button():
+    """A button with a text label."""
+    def __init__(self, x, y, w, h, label):
+        self._im = (x, y, w, h, label)
+
+    def draw(self):
+        """Draw the button."""
+        draw = wasp.watch.drawable
+        im = self._im
+        bg = draw.darken(wasp.system.theme('ui'))
+        frame = wasp.system.theme('mid')
+        txt = wasp.system.theme('bright')
+
+        draw.fill(bg, im[0], im[1], im[2], im[3])
+        draw.set_color(txt, bg)
+        draw.set_font(fonts.sans24)
+        draw.string(im[4], im[0], im[1]+(im[3]//2)-12, width=im[2])
+
+        draw.fill(frame, im[0],im[1],          im[2], 2)
+        draw.fill(frame, im[0], im[1]+im[3]-2, im[2], 2)
+        draw.fill(frame, im[0],         im[1], 2, im[3])
+        draw.fill(frame, im[0]+im[2]-2, im[1], 2, im[3])
+
+    def touch(self, event):
+        """Handle touch events."""
+        x = event[1]
+        y = event[2]
+
+        # Adopt a slightly oversized hit box
+        im = self._im
+        x1 = im[0] - 10
+        x2 = x1 + im[2] + 20
+        y1 = im[1] - 10
+        y2 = y1 + im[3] + 20
+
+        if x >= x1 and x < x2 and y >= y1 and y < y2:
+            return True
+
+        return False
+
 class Checkbox():
     """A simple (labelled) checkbox."""
     def __init__(self, x, y, label=None):