From 8f9606007fee4caece23214b0b20dc36a3a7c010 Mon Sep 17 00:00:00 2001
From: Matthew Flatt <mflatt@racket-lang.org>
Date: Tue, 19 Feb 2013 08:08:30 -0700
Subject: [PATCH] racket/draw win32: work around a Pango bug

Pango crashes (with an assertion failure) on characters U+1D173
through U+1D17A. Trying to fix (or even just compile) Pango for
Windows is hard, so skip the characters at the `draw-text' and
`text-extent' level.

The bug is unlikely to be specific to just those characters in the
long run, but only those characters appear to be problematic on my
Windows 7 installation. So, the workaround may be enough for many
installations, and hopefully the Pango bug wil be fixed one day.

Relevant to PR 13513
---
 collects/racket/draw/private/dc.rkt | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/collects/racket/draw/private/dc.rkt b/collects/racket/draw/private/dc.rkt
index 0be6628e6a..3d26a54d48 100644
--- a/collects/racket/draw/private/dc.rkt
+++ b/collects/racket/draw/private/dc.rkt
@@ -44,6 +44,11 @@
           black)
       (color->immutable-color c)))
 
+;; The Windows version of Pango crashes on characters
+;; #\U1D173 through #\U1D17A (which are unusual characters
+;; replated to music notation), so work around it:
+(define broken-music-pango? (eq? (system-type) 'windows))
+
 ;; dc-backend : interface
 ;;
 ;; This is the interface that the backend specific code must implement
@@ -1279,11 +1284,19 @@
              [blank? (string=? s "")]
              [s (if (and (not draw-mode) blank?) " " s)]
              [s (if (for/or ([c (in-string s)])
-                      (or (eqv? c #\uFFFE) (eqv? c #\uFFFF)))
+                      (or (eqv? c #\uFFFE)
+			  (eqv? c #\uFFFF)
+			  (and broken-music-pango?
+			       (let ([n (char->integer c)])
+				 (<= #x1D173 n #x1D17A)))))
                     ;; Since \uFFFE and \uFFFF are not supposed to be in any
                     ;; interchange, we must replace them away before passing a
                     ;; string to Pango:
-                    (regexp-replace* #rx"[\uFFFE\uFFFF]" s "\uFFFD")
+                    (regexp-replace* (if broken-music-pango?
+					 #rx"[\uFFFE\uFFFF\U1D173-\U1D17A]"
+					 #rx"[\uFFFE\uFFFF]")
+				     s
+				     "\uFFFD")
                     s)]
              [rotate? (and draw-mode (not (zero? angle)))]
              [smoothing-index (get-smoothing-index font)]