Initial data commit

Task/Hough-transform/Sidef/hough-transform.sidef

@@ -0,0 +1,36 @@
+require('Imager')
+
+func hough(im, width=460, height=360) {
+
+    height = 2*floor(height / 2)
+
+    var xsize = im.getwidth
+    var ysize = im.getheight
+
+    var ht = %s|Imager|.new(xsize => width, ysize => height)
+    var canvas = height.of { width.of(255) }
+
+    ht.box(filled => true, color => 'white')
+
+    var rmax = hypot(xsize, ysize)
+    var dr = 2*(rmax / height)
+    var dth = (Num.pi / width)
+
+    for y,x in (^ysize ~X ^xsize) {
+        var col = im.getpixel(x => x, y => y)
+        var (r,g,b) = col.rgba
+        (r==255 && g==255 && b==255) && next
+        for k in ^width {
+            var th = dth*k
+            var r = (x*cos(th) + y*sin(th))
+            var iry = (height/2 + int(r/dr + 0.5))
+            ht.setpixel(x => k, y => iry, color => 3.of(--canvas[iry][k]))
+        }
+    }
+
+    return ht
+}
+
+var img = %s|Imager|.new(file => 'Pentagon.png')
+var ht = hough(img)
+ht.write(file => 'Hough transform.png')