draw565: Fix bounding box calculations

wasp-os uses an drawing optimization technique to automatically place
a single pixel line on the right of glyphs when rendering them. This
results in a change to the bounding box for a rendered string (by adding
a single pixel on the right of the final character). Fix the bounding box
calculations accordingly. Among other things this eliminates graphical
artifacts when rendering labels in 2048.

Fixes: #203
Fixes: 58b5c0378e ("draw565: Optimize the string drawing")
Signed-off-by: Daniel Thompson <daniel@redfelineninja.org.uk>

wasp/boards/simulator/test_unit.py

@@ -53,7 +53,7 @@ def test_font_width(draw):
     for f in (fonts.sans24, fonts.sans28, fonts.sans36):
         draw.set_font(f)
 
-        assert 3 == draw.bounding_box('0000')[0] % 4
+        assert 0 == draw.bounding_box('0000')[0] % 4
 
         if f.max_ch() >= 90:
             assert draw.bounding_box('IIII')[0] < draw.bounding_box('WWWW')[0]

wasp/draw565.py

@@ -75,7 +75,7 @@ def _bounding_box(s, font):
         return (0, font.height())
 
     get_ch = font.get_ch
-    w = len(s) - 1
+    w = len(s)
     for ch in s:
         (_, h, wc) = get_ch(ch)
         w += wc