; Examples for the GIF decode/encode extension v2
; see http://www.ulisp.com/show?3IUQ

; Display an image from an SD Card

(with-sd-card (str "JapanCat.gif") (decode-gif str))

; Control how an image is displayed

(with-sd-card (str "JapanCat.gif")
  (display-gif
   str
   #'(lambda (x y c) (draw-pixel (- 319 x) y c))))

; Save a screendump to an SD card

(defun screendump (filename &optional (colours 256))
  (bind (width height) (display-size)
    (with-sd-card (str filename 2)
       (encode-gif str width height colours))))

; Encode an image defined by a function and save it to SD card

(defun ellipses (xx yy colours)
  (bind (width height) (display-size)
    (let* ((x (- xx (truncate width 2)))
           (y (- yy (truncate height 2)))
           (f (truncate (+ (* x (+ x y)) (* y y)) 17)))
      (mod f colours))))

(defun test2 ()
  (bind (width height) (display-size)
    (let ((colours 64))
      (with-sd-card (str "ellipses.gif" 2) 
        (encode-gif str width height colours ellipses)))))

(with-sd-card (str "ellipses.gif") (decode-gif str))

; Encode with an alternative encoding

(defun test2 ()
  (bind (width height) (display-size)
    (let ((colours 64))
      (with-sd-card (str "ellipse2.gif" 2) 
        (encode-gif str width height colours ellipses t)))))

; Display the palette for a given number of colours

(defun palette (colours)
  (bind (xsize ysize) (display-size)
    (let* ((p (- (integer-length colours) 2))
           (xn (ash 1 (truncate (+ p 2) 2)))
           (yn (ash 1 (truncate (+ p 1) 2)))
           (h (truncate xsize xn))
           (v (truncate ysize yn))
           (filename (format nil "P~a.gif" colours)))
      (with-sd-card (str filename 2)
        (encode-gif str xsize ysize colours
                    #'(lambda (x y colours)
                        (+ (* (truncate y v) xn) (truncate x h))))))))

(with-sd-card (str "P256.GIF") (decode-gif str))

; Encode an image with fewer colours

(defun test3 ()
  (bind (width height) (display-size)
    (with-sd-card (str "JapanCat.gif") (decode-gif str))
    (with-sd-card (str "Cat2.gif" 2) (encode-gif str width height 64))
    (with-sd-card (str "Cat2.gif") (decode-gif str))))

; Load an image from the web

(wifi-connect "Geronimo" "secret99")

(defun display-pic ()
  (with-client (s "www.ulisp.com" 80)
    (format s "GET /pictures/3j/japancat240x135.gif HTTP/1.0~a~%" #\return)
    (format s "Host: www.ulisp.com~a~%" #\return)
    (format s "Connection: close~a~%" #\return)
    (format s "~a~%" #\return)
    (loop (when (= (length (read-line s)) 1) (return))) ; Skip headers
    (decode-gif s)))

; Capture a screen display over the web

(defun clock ()
  (wifi-server)
  (format t "Connect your web browser to ~a~%" (wifi-localip))
  (bind (xs ys) (display-size)
   (let ((lastminute -1))
   ; Wait for time
      (loop (when (get-time) (return)))
      ; Update time
      (loop
       (bind (year month day hour minute &rest others) (get-time)
         (unless (= minute lastminute)
           (fill-screen)
           (with-gfx (str)
             (set-text-size 8) (set-cursor 0 40) (set-text-color #xf81f)
             (format str "~a:~2,'0d" hour minute))
           (setq lastminute minute)))
       ; Check for web client
       (serve-gif)
       (delay 10000)))))

(defun serve-gif ()
  (bind (xs ys) (display-size)
    (with-client (s)
      (loop (when (= (length (read-line s)) 1) (return)))
      (format s "HTTP/1.1 200 OK~a~%" #\return)
      (format s "Content-Type: image/gif~a~%" #\return)
      (format s "Connection: close~a~%" #\return)
      (format s "~a~%" #\return)
      (encode-gif s xs ys 8))))

; Return a GIF generated from a function over the web

(defun plot (x y colours)
  (truncate 
   (* (1- colours)
      (/ (+ 2 
            (cos (/ (- x (/ 320 2)) 20)) 
            (cos (/ (- y (/ 240 2)) 20))) 4))))

(defun 3dplot ()
  (wifi-server)
  (format t "Connect your web browser to ~a~%" (wifi-localip))
  (loop
   (with-client (s)
     (loop (when (= (length (read-line s)) 1) (return)))
     (format s "HTTP/1.1 200 OK~a~%" #\return)
     (format s "Content-Type: image/gif~a~%" #\return)
     (format s "Connection: close~a~%" #\return)
     (format s "~a~%" #\return)
     (encode-gif s 320 240 64 plot))
   (delay 10000)))