Initial data commit

Task/Bitmap-Bresenhams-line-algorithm/Ruby/bitmap-bresenhams-line-algorithm.rb

@@ -0,0 +1,48 @@
+Pixel = Struct.new(:x, :y)
+
+class Pixmap
+
+  def draw_line(p1, p2, colour)
+    validate_pixel(p1.x, p2.y)
+    validate_pixel(p2.x, p2.y)
+
+    x1, y1 = p1.x, p1.y
+    x2, y2 = p2.x, p2.y
+
+    steep = (y2 - y1).abs > (x2 - x1).abs
+
+    if steep
+      x1, y1 = y1, x1
+      x2, y2 = y2, x2
+    end
+
+    if x1 > x2
+      x1, x2 = x2, x1
+      y1, y2 = y2, y1
+    end
+
+    deltax = x2 - x1
+    deltay = (y2 - y1).abs
+    error = deltax / 2
+    ystep = y1 < y2 ? 1 : -1
+
+    y = y1
+    x1.upto(x2) do |x|
+      pixel = steep ? [y,x] : [x,y]
+      self[*pixel] = colour
+      error -= deltay
+      if error < 0
+        y += ystep
+        error += deltax
+      end
+    end
+  end
+end
+
+bitmap = Pixmap.new(500, 500)
+bitmap.fill(RGBColour::BLUE)
+10.step(430, 60) do |a|
+  bitmap.draw_line(Pixel[10, 10], Pixel[490,a], RGBColour::YELLOW)
+  bitmap.draw_line(Pixel[10, 10], Pixel[a,490], RGBColour::YELLOW)
+end
+bitmap.draw_line(Pixel[10, 10], Pixel[490,490], RGBColour::YELLOW)