correct calculation text extents (#89)

correct calculation text extents for (member anchor '(left center right)), to avoid allocating too much vertical space for very wide labels

Author: bdeket

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

@@ -31,7 +31,7 @@
     (: dys (Listof Real))
     (define dys (case anchor
                   [(top-left top top-right)  (list (- dist) (- height dist))]
-                  [(left center right)       (list (* -1/2 height) (* 1/2 width))]
+                  [(left center right)       (list (* -1/2 height) (* 1/2 height))]
                   [else                      (list (- dist height) dist)]))
 
     (for*/list : (Listof (Vector Real Real)) ([dx  (in-list dxs)] [dy  (in-list dys)])

plot-test/plot/tests/PRs/89.rkt

@@ -0,0 +1,29 @@
+#lang racket
+(require rackunit
+         plot pict racket/runtime-path
+         "../helpers.rkt")
+
+; tests for PR#89, https://github.com/racket/plot/pull/89
+; "fix calculation of text-extends for anchor 'right center left"
+
+(define (do-plot output-fn)
+  (parameterize ([plot-x-label #f]
+                 [plot-y-label #f])
+    (output-fn
+     (polar (lambda (t) 1))
+      #:x-min 4025584149602844706/10000000000000000000
+      #:x-max 4025584149602844712/10000000000000000000
+      #:y-min 6805367900508167/10000000000000000
+      #:y-max 6805367900508171/10000000000000000)))
+
+(define-runtime-path pr89 "./test-data/pr89.dat")
+
+(define pr86-test-suite
+  (test-suite
+   "PR#89: text-extents"
+   (test-case "PR89: text-extents"
+     (check-draw-steps do-plot pr89))))
+
+(module+ test
+  (require rackunit/text-ui)
+  (run-tests pr86-test-suite))