Data update

Task/Bitmap-Bresenhams-line-algorithm/Pluto/bitmap-bresenhams-line-algorithm.pluto

@@ -0,0 +1,27 @@
+local canvas = require "canvas"
+
+local function line(c, x0, y0, x1, y1, col)
+    local dx = math.abs(x1 - x0)
+    local dy = math.abs(y1 - y0)
+    local sx = (x0 < x1) ? 1 : -1
+    local sy = (y0 < y1) ? 1 : -1
+    local err = (dx > dy ? dx : - dy) // 2
+    while true do
+        c:set(x0, y0, col)
+        if x0 == x1 and y0 == y1 then break end
+        local e2 = err
+        if e2 > -dx then
+            err -= dy
+            x0 += sx
+        end
+        if e2 < dy then
+            err += dx
+            y0 += sy
+        end
+    end
+end
+
+local c = canvas.new(400, 400)
+c:fill(0xffffff)                    -- white background
+line(c, 0, 0, 399, 399, 0x0000ff)   -- draw a red diagonal
+io.contents("mybmp.bmp", c:tobmp()) -- save to a bitmap file