From b9f207ce4cb0a0470e73edbd2807b043b8611627 Mon Sep 17 00:00:00 2001
From: "R. Aidan Campbell" <raidancampbell@users.noreply.github.com>
Date: Wed, 27 Dec 2017 12:35:26 -0500
Subject: [PATCH] Implement `line`

arguments and order matches the C implementation here:
https://github.com/micropython/micropython/blob/master/extmod/modframebuf.c#L408
---
 framebuf.py | 30 +++++++++++++++++++++++++++---
 1 file changed, 27 insertions(+), 3 deletions(-)

diff --git a/framebuf.py b/framebuf.py
index fc8fd61..b07097d 100755
--- a/framebuf.py
+++ b/framebuf.py
@@ -107,9 +107,33 @@ def rect(self, x, y, width, height, color):
         self.fill_rect(self, x, y, 1, height, color)
         self.fill_rect(self, x+width, y, 1, height, color)
 
-    def line(self):
-        raise NotImplementedError()
-
+    def line(self, x0, y0, x1, y1, color):
+        """Bresenham's line algorithm"""
+        dx = abs(x1 - x0)
+        dy = abs(y1 - y0)
+        x, y = x0, y0
+        sx = -1 if x0 > x1 else 1
+        sy = -1 if y0 > y1 else 1
+        if dx > dy:
+            err = dx / 2.0
+            while x != x1:
+                self.pixel(x,y,color)
+                err -= dy
+                if err < 0:
+                    y += sy
+                    err += dx
+                x += sx
+        else:
+            err = dy / 2.0
+            while y != y1:
+                self.pixel(x,y,1)
+                err -= dx
+                if err < 0:
+                    x += sx
+                    err += dy
+                y += sy
+        self.pixel(x,y,1)
+    
     def blit(self):
         raise NotImplementedError()