any form of dash seems broken if pen width is 1

[zenspider]

If pen width is 1 and you use 'long-dash or any other variant, dashes are only drawn on the horizontal lines. If width is set to 2, they appear fine.

Repro is here, runs in drracket or racket-mode:

#lang racket/base

(require racket/draw
         racket/class)

(define (draw-box broken)
  (define canvas (make-bitmap 51 28))
  (define dc (send canvas make-dc))

  (send dc set-brush "WhiteSmoke" 'solid)

  (send dc set-pen "black"
        (if broken 1 2)                 ; BUG
        'long-dash)

  (send dc draw-rectangle 1 1 50 25)

  canvas)

(printf "BUG: only dashed on the sides:~n")
(draw-box 'broken)

(printf "correctly dashed, but needs to be 2x wide:~n")
(draw-box #f)

I can't track this down. The cairo binding code is really dense for me.

[zenspider]

ping