CSC151 2009F, Class 19: Pause for Breath

Admin:
* Please keep your partners from yesterday (through this week).
* I will not have office hours on Wednesday.  Sorry.  Send me email.
* It appears that I will not be able to return exams until Friday.  
  I apologize for the delay.
* Are there questions on Assignment 4?
  * I've been told that it was generating a bit of profanity last evening.
* EC for attending some part of the Rosenfield anniversary symposium 
  on Thursday.
* Don't forget about the history of programming languages talk at 
  noon on Friday in 3821.
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Overview:
* Exploring part 4 of assignment 4

Confusion from Assignment 4
* Mostly about the map procedure and how it interacts with other
  things
  * Problem mostly in more complex expressions
    * Possible solution: 
      * Build up the more complex solution bit-by-bit
      * Test parts along the way
      * Test the built-up solution along the way
  * And doing multiple things at once
    * Build it up part by part
* Difference between drawing-group and drawing-compose
  * The first works with drawings, the second with list
* Issues with rendering
  * Agh!  drawing->image and image-show and ...!
  * Solution?  BUild the rendering procedure once and then forget
    about the component parts

tep one: Make an "interesting" list of shapes

(define numpoints1 32)
(define hshifts1 (map (l-s * 10) (iota numpoints1)))
; divide by 10, compute the sine, multiply by 100, add 100
(define vshifts1 (map (o (l-s + 100)
                         (l-s * 100)
                         sin
                         (r-s / 3))
                      (iota numpoints1)))
(define diameters1 (map (o (l-s * 3) increment (r-s mod 5)) 
                        (iota numpoints1)))

(define blendy-list
  (lambda (rgb1 rgb2 steps)
    (map (lambda (i)
           (rgb-new (modulo (* i 30) 256)
                    (modulo (* i 50) 256)
                    (modulo (* i 70) 256)))
         (iota steps))))

(define colors1 (blendy-list RGB-RED RGB-BLUE numpoints1))


(define points1
  (map drawing-shift 
       (map drawing-scale
            (map drawing-recolor
                 (make-list 32 drawing-unit-circle)
                 colors1)
            diameters1)
       hshifts1 
       vshifts1))

(define newpoints1
  (map drawing-shift 
       (map drawing-scale
            (map drawing-recolor
                 (make-list 32 drawing-unit-circle)
                 (blendy-list RGB-RED RGB-BLUE numpoints1))
            (map (o (l-s * 3) increment (r-s mod 5)) 
                 (iota numpoints1)))
       (map (l-s * 10) (iota numpoints1)) 
       (map (o (l-s + 100)
               (l-s * 100)
               sin
               (r-s / 3))
            (iota numpoints1))))


(define newpoints2
  (map drawing-shift 
       (map drawing-scale
            (map drawing-recolor
                 (make-list 32 drawing-unit-circle)
                 (blendy-list RGB-RED RGB-BLUE numpoints1))
            (map (o (l-s * 3) increment (r-s mod 7)) 
                 (iota numpoints1)))
       (map (l-s * 10) (iota numpoints1)) 
       (map (o (l-s + 120)
               (l-s * 80)
               sin
               (r-s / 4))
            (iota numpoints1))))

(define render-list-of-points
  (lambda (points)
    (image-show (drawing->image (drawing-compose points) 500 500))))

(define render-two-list-of-points
  (lambda (foo1 foo2)
    (image-show (drawing->image (drawing-group
                                 (drawing-compose foo1)
                                 (drawing-compose foo2))
                                500 500))))