wasp: widgets: Add a scrolling indicator

As we enrich the navigation options we will increasinly need to visualize
between apps where up/down will switch us between rings and there
up/down is needed to scroll through content.

wasp/apps/testapp.py

@@ -11,6 +11,7 @@ class TestApp():
     def __init__(self):
         self.tests = ('Touch', 'String', 'Button', 'Crash')
         self.test = self.tests[0]
+        self.scroll = wasp.widgets.ScrollIndicator()
 
     def foreground(self):
         """Activate the application."""
@@ -75,6 +76,7 @@ class TestApp():
         draw.fill()
         draw.string('{} test'.format(self.test),
                 0, 6, width=240)
+        self.scroll.draw()
 
         if self.test == 'Crash':
             draw.string("Press button to", 12, 24+24)

wasp/icons.py

@@ -4,3 +4,8 @@
 # 1-bit RLE, generated from res/battery.png, 189 bytes
 battery = (36, 48, b'\x97\x0e\x14\x12\x11\x14\x10\x14\x0c\x08\x0c\x08\x08\x08\x0c\x08\x08\x08\x0c\x08\x08\x08\x0c\x08\x08\x04\x14\x04\x08\x04\x14\x04\x08\x04\x0c\x04\x04\x04\x08\x04\x0b\x05\x04\x04\x08\x04\n\x06\x04\x04\x08\x04\t\x07\x04\x04\x08\x04\x08\x07\x05\x04\x08\x04\x07\x07\x06\x04\x08\x04\x06\x07\x07\x04\x08\x04\x05\x07\x08\x04\x08\x04\x04\x0e\x02\x04\x08\x04\x03\x0f\x02\x04\x08\x04\x02\x10\x02\x04\x08\x04\x02\x10\x02\x04\x08\x04\x02\x0f\x03\x04\x08\x04\x02\x0e\x04\x04\x08\x04\x08\x07\x05\x04\x08\x04\x07\x07\x06\x04\x08\x04\x06\x07\x07\x04\x08\x04\x05\x07\x08\x04\x08\x04\x04\x07\t\x04\x08\x04\x04\x06\n\x04\x08\x04\x04\x05\x0b\x04\x08\x04\x04\x04\x0c\x04\x08\x04\x14\x04\x08\x04\x14\x04\x08\x04\x14\x04\x08\x04\x14\x04\x08\x1c\x08\x1c\x08\x1c\x08\x1c\x98')
 
+# 1-bit RLE, generated from res/up_arrow.png, 16 bytes
+up_arrow = (16, 9, b'\x07\x02\r\x04\x0b\x06\t\x08\x07\n\x05\x0c\x03\x0e\x01 ')
+
+# 1-bit RLE, generated from res/down_arrow.png, 17 bytes
+down_arrow = (16, 9, b'\x00 \x01\x0e\x03\x0c\x05\n\x07\x08\t\x06\x0b\x04\r\x02\x07')

wasp/widgets.py

@@ -11,7 +11,7 @@ class BatteryMeter(object):
     def draw(self):
         self.level = -2
         self.update()
-        
+
     def update(self):
         icon = icons.battery
         draw = watch.drawable
@@ -50,3 +50,19 @@ class BatteryMeter(object):
                 draw.fill(rgb, x, 38 - h, w, h)
 
             self.level = level
+
+class ScrollIndicator():
+    def __init__(self, x=240-18, y=240-24):
+        self._pos = (x, y)
+        self.up = True
+        self.down = True
+
+    def draw(self):
+        self.update()
+
+    def update(self):
+        draw = watch.drawable
+        if self.up:
+            draw.rleblit(icons.up_arrow, pos=self._pos, fg=0x7bef)
+        if self.down:
+            draw.rleblit(icons.down_arrow, pos=(self._pos[0], self._pos[1] + 13), fg=0x7bef)