Initial data commit

Task/Bitmap-Midpoint-circle-algorithm/UNIX-Shell/bitmap-midpoint-circle-algorithm.sh

@@ -0,0 +1,56 @@
+#! /bin/bash
+# Based on https://en.wikipedia.org/wiki/Midpoint_circle_algorithm
+
+function putpixel {
+    echo -en "\e[$2;$1H#"
+}
+
+function drawcircle {
+    x0=$1
+    y0=$2
+    radius=$3
+
+    for y in $( seq $((y0-radius)) $((y0+radius)) )
+    do
+        echo -en "\e[${y}H"
+    	for x in $( seq $((x0+radius)) )
+	do
+		echo -n "-"
+	done
+    done
+
+    x=$((radius-1))
+    y=0
+    dx=1
+    dy=1
+    err=$((dx-(radius<<1)))
+
+    while [ $x -ge $y ]
+    do
+        putpixel $(( x0 + x )) $(( y0 + y ))
+        putpixel $(( x0 + y )) $(( y0 + x ))
+        putpixel $(( x0 - y )) $(( y0 + x ))
+        putpixel $(( x0 - x )) $(( y0 + y ))
+        putpixel $(( x0 - x )) $(( y0 - y ))
+        putpixel $(( x0 - y )) $(( y0 - x ))
+        putpixel $(( x0 + y )) $(( y0 - x ))
+        putpixel $(( x0 + x )) $(( y0 - y ))
+
+        if [ $err -le 0 ]
+        then
+	    ((++y))
+            ((err+=dy))
+            ((dy+=2))
+        fi
+        if [ $err -gt 0 ]
+	then
+            ((--x))
+            ((dx+=2))
+            ((err+=dx-(radius<<1)))
+        fi
+    done
+}
+
+clear
+drawcircle 13 13 11
+echo -en "\e[H"