;; Neon Glow effect - glowing edge effect
;; @param edge_low int [10, 200] default 50
;; @param edge_high int [50, 300] default 150
;; @param glow_radius int [1, 50] default 15
;; @param glow_intensity float [0.5, 5] default 2
;; @param background float [0, 1] default 0.3

(define-effect neon_glow
  ((edge_low 50) (edge_high 150) (glow_radius 15)
   (glow_intensity 2) (background 0.3))
  (let* ((edge-img (edges frame edge_low edge_high))
         (glow (blur edge-img glow_radius))
         ;; Intensify the glow
         (bright-glow (map-pixels glow
                        (lambda (x y c)
                          (rgb (clamp (* (red c) glow_intensity) 0 255)
                               (clamp (* (green c) glow_intensity) 0 255)
                               (clamp (* (blue c) glow_intensity) 0 255))))))
    (blend-mode (blend-images frame (make-image (width frame) (height frame) (list 0 0 0))
                              (- 1 background))
                bright-glow
                "screen")))