June 2018 Update

Task/Bitmap-Midpoint-circle-algorithm/Julia/bitmap-midpoint-circle-algorithm.julia

@@ -0,0 +1,31 @@
+function drawcircle!(img::Matrix{T}, col::T, x0::Int, y0::Int, radius::Int) where T
+    x = radius - 1
+    y = 0
+    δx = δy = 1
+    er = δx - (radius << 1)
+
+    s = x + y
+    while x ≥ y
+        for opx in (+, -), opy in (+, -), el in (x, y)
+            @inbounds img[opx(x0, el) + 1, opy(y0, s - el) + 1] = col
+        end
+        if er ≤ 0
+            y  += 1
+            er += δy
+            δy += 2
+        end
+        if er > 0
+            x  -= 1
+            δx += 2
+            er += (-radius << 1) + δx
+        end
+        s = x + y
+    end
+    return img
+end
+
+# Test
+using Images
+
+img = fill(Gray(255.0), 25, 25);
+drawcircle!(img, Gray(0.0), 12, 12, 12)