add #:scientific? argument to log-ticks and log-ticks-format (#86)

Author: ralsei

plot-doc/plot/scribblings/ticks.scrbl

@@ -296,16 +296,19 @@ To format ticks, @racket[linear-ticks-format] uses @racket[real->plot-label] pas
 @deftogether[(@defproc[(log-ticks-layout [#:number number exact-positive-integer? (ticks-default-number)]
                                          [#:base base (and/c exact-integer? (>=/c 2)) 10])
                        ticks-layout/c]
-              @defproc[(log-ticks-format [#:base base (and/c exact-integer? (>=/c 2)) 10])
+              @defproc[(log-ticks-format [#:base base (and/c exact-integer? (>=/c 2)) 10]
+                                         [#:scientific? scientific? #t])
                        ticks-format/c]
               @defproc[(log-ticks [#:number number exact-positive-integer? (ticks-default-number)]
-                                  [#:base base (and/c exact-integer? (>=/c 2)) 10])
+                                  [#:base base (and/c exact-integer? (>=/c 2)) 10]
+                                  [#:scientific? scientific? #t])
                        ticks?])]{
 The layout function, format function, and combined @racket[ticks] for exponentially spaced major ticks.
 (The minor ticks between are uniformly spaced.)
 Use these ticks for @racket[log-transform]ed axes, because when exponentially spaced tick positions are @racket[log-transform]ed, they become uniformly spaced.
 
 The @racket[#:base] keyword argument is the logarithm base.
+The @racket[#:scientific] keyword argument disables scientific formatting, similarly to @racket[linear-ticks].
 See @racket[plot-z-far-ticks] for an example of use.
 }
 

plot-lib/plot/private/common/ticks.rkt

@@ -216,8 +216,8 @@
                                              (and (zero? i) (zero? m))))]
                     [else  (list (pre-tick x (zero? m)))]))))]))]))
 
-(:: log-ticks-format (->* [] [#:base Positive-Integer] Ticks-Format))
-(define (log-ticks-format #:base [base 10])
+(:: log-ticks-format (->* [] [#:base Positive-Integer #:scientific? Boolean] Ticks-Format))
+(define (log-ticks-format #:base [base 10] #:scientific? [scientific? #t])
   (cond
     [(< base 2)  (error 'log-ticks-format "expected base >= 2; given ~e" base)]
     [else
@@ -231,6 +231,8 @@
            (cond [(<= x 0)  (raise-argument-error 'log-ticks-format
                                                   "(Listof pre-tick) with positive positions"
                                                   2 x-min x-max ts)]
+                 [(not scientific?)
+                  (real->plot-label x base-digits scientific?)]
                  [else
                   (define log-x (floor-log/base base x))
                   (define (major-str)
@@ -241,12 +243,12 @@
                                        (real->plot-label (/ x (expt base log-x)) base-digits)
                                        (major-str))])]))))]))
 
-(:: log-ticks (->* [] [#:number Positive-Integer #:base Positive-Integer] ticks))
-(define (log-ticks #:number [number (ticks-default-number)] #:base [base 10])
+(:: log-ticks (->* [] [#:number Positive-Integer #:base Positive-Integer #:scientific? Boolean] ticks))
+(define (log-ticks #:number [number (ticks-default-number)] #:base [base 10] #:scientific? [scientific? #t])
   (cond
     [(< base 2)  (error 'log-ticks "expected base >= 2; given ~e" base)]
     [else  (ticks (log-ticks-layout #:number number #:base base)
-                  (log-ticks-format #:base base))]))
+                  (log-ticks-format #:base base #:scientific? scientific?))]))
 
 ;; ===================================================================================================
 ;; Date/time helpers

plot-test/plot/tests/PRs/86.rkt

@@ -0,0 +1,34 @@
+#lang racket
+(require rackunit
+         plot pict racket/runtime-path
+         "../helpers.rkt")
+
+; tests for PR#86, https://github.com/racket/plot/pull/86
+; "add scientific? argument to log-ticks and log-ticks-format"
+
+(define ((do-plot scientific? [base 10]) output-fn)
+  (parameterize ([plot-x-ticks (log-ticks #:scientific? scientific? #:base base)]
+                 [plot-x-transform log-transform])
+    (output-fn
+     (function (λ (x) (log x base)) 1 1000))))
+
+(define-runtime-path pr86-base10-sci-data "./test-data/pr86-1.dat")
+(define-runtime-path pr86-base10-nosci-data "./test-data/pr86-2.dat")
+(define-runtime-path pr86-base2-sci-data "./test-data/pr86-3.dat")
+(define-runtime-path pr86-base2-nosci-data "./test-data/pr86-4.dat")
+
+(define pr86-test-suite
+  (test-suite
+   "PR#86: add scientific? to log-ticks"
+   (test-case "PR86: base 10, scientific? #t"
+     (check-draw-steps (do-plot #t 10) pr86-base10-sci-data))
+   (test-case "PR86: base 10, scientific? #f"
+     (check-draw-steps (do-plot #f 10) pr86-base10-nosci-data))
+   (test-case "PR86: base 2, scientific? #t"
+     (check-draw-steps (do-plot #t 2) pr86-base2-sci-data))
+   (test-case "PR86: base 2, scientific? #f"
+     (check-draw-steps (do-plot #f 2) pr86-base2-nosci-data))))
+
+(module+ test
+  (require rackunit/text-ui)
+  (run-tests pr86-test-suite))