draw565: Add width to the line drawing function

Currently all lines are a single pixel wide. To draw wider lines we
must draw two parallel lines with a single pixel offset and this is
a *very* inefficient approach, espeically on ST7789 where we spend
longer setting the clipping window than we do drawing each pixel.

Fix this by constructing a line using a variable sized square rather than
a single pixel. This will "overdraw" (some pixels will be drawn more than
once) but since square blocks can be efficiently transferred to the
display the overdraw is acceptable.

Note: It is a difficult decision whether to maintain the convention that
      color is the last argument or to keep compatibility with existing
      line drawing tests. This patch opts for the former and fixes up
      all uses within the existing codebase.

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

2 files changed, 16 insertions, 9 deletions

diff --git a/wasp/apps/testapp.py b/wasp/apps/testapp.py
index 2b2e05b..6b813e4 100644
--- a/wasp/apps/testapp.py
+++ b/wasp/apps/testapp.py
@@ -183,10 +183,10 @@ class TestApp():
         t = machine.Timer(id=1, period=8000000)
         t.start()
         for x, y in points:
-            draw.line(120, 120, 120+x, 120+y, 0xfbc0)
-            draw.line(120, 120, 120+y, 120-x, 0x07c0)
-            draw.line(120, 120, 120-x, 120-y, 0x6b3f)
-            draw.line(120, 120, 120-y, 120+x, 0xffe0)
+            draw.line(120, 120, 120+x, 120+y, 4, 0xfb00)  # red
+            draw.line(120, 120, 120+y, 120-x, 3, 0x07c0)  # green
+            draw.line(120, 120, 120-x, 120-y, 5, 0x6b3f)  # blue
+            draw.line(120, 120, 120-y, 120+x, 2, 0xffe0)  # yellow
         elapsed = t.time()
         t.stop()
         del t
diff --git a/wasp/draw565.py b/wasp/draw565.py
index 869a6d6..26e7aef 100644
--- a/wasp/draw565.py
+++ b/wasp/draw565.py
@@ -356,7 +356,7 @@ class Draw565(object):
 
         return chunks
 
-    def line(self, x0, y0, x1, y1, color=None):
+    def line(self, x0, y0, x1, y1, width=1, color=None):
         """Draw a line between points (x0, y0) and (x1, y1).
 
         Example:
@@ -370,14 +370,21 @@ class Draw565(object):
         :param y0: Y coordinate of the start of the line
         :param x1: X coordinate of the end of the line
         :param y1: Y coordinate of the end of the line
+        :param width: Width of the line in pixels
         :param color: Colour to draw line, defaults to the foreground colour
         """
         if color is None:
             color = self._bgfg & 0xffff
-        px = bytes(((color >> 8) & 0xFF, color & 0xFF))
+        px = bytes(((color >> 8) & 0xFF, color & 0xFF)) * (width * width)
         write_data = self._display.write_data
         set_window = self._display.set_window
 
+        dw = (width - 1) // 2
+        x0 -= dw
+        y0 -= dw
+        x1 -= dw
+        y1 -= dw
+
         dx =  abs(x1 - x0)
         sx = 1 if x0 < x1 else -1
         dy = -abs(y1 - y0)
@@ -387,12 +394,12 @@ class Draw565(object):
             if x1 < x0 or y1 < y0:
                 x0, x1 = x1, x0
                 y0, y1 = y1, y0
-            w = 1 if dx == 0 else dx
-            h = 1 if dy == 0 else -dy
+            w = width if dx == 0 else dx
+            h = width if dy == 0 else -dy
             self.fill(color, x0, y0, w, h)
             return
         while True:
-            set_window(x0, y0, 1, 1)
+            set_window(x0, y0, width, width)
             write_data(px)
             if x0 == x1 and y0 == y1:
                 break