native-libs: patches to adjust Pango font-face matching

racket/src/native-libs/build.rkt

@@ -141,6 +141,12 @@
 ;; Merge a Pango patch that fixes a decoding problem
 (define-runtime-path pango-emojiiter-patch "patches/pango-emojiiter.patch")
 
+;; Allow more flexible font matching
+(define-runtime-path pango-match-patch "patches/pango-match.patch")
+
+;; Detect oblique before italic on Mac OS
+(define-runtime-path pango-preferoblique-patch "patches/pango-preferoblique.patch")
+
 ;; Needed when building with old GCC, such as 4.0:
 (define-runtime-path gmp-weak-patch "patches/gmp-weak.patch")
 
@@ -533,7 +539,11 @@
                                         coretext-fontreg-patch
                                         coretext-nullarray
                                         win32text-patch
-                                        pango-emojiiter-patch)
+                                        pango-emojiiter-patch
+                                        pango-match-patch)
+                                  (if mac?
+                                      (list pango-preferoblique-patch)
+                                      null)
                                   (if (and mac? m32?)
                                       (list pango-surrogate-patch)
                                       null)

racket/src/native-libs/patches/pango-match.patch

@@ -0,0 +1,57 @@
+diff -u -r old/pango-1.42.0/pango/fonts.c new/pango-1.42.0/pango/fonts.c
+--- old/pango-1.42.0/pango/fonts.c	2018-01-03 10:48:10.000000000 -0700
++++ new/pango-1.42.0/pango/fonts.c	2019-02-14 06:44:15.000000000 -0700
+@@ -718,19 +718,30 @@
+ compute_distance (const PangoFontDescription *a,
+ 		  const PangoFontDescription *b)
+ {
+-  if (a->style == b->style)
+-    {
+-      return abs((int)(a->weight) - (int)(b->weight));
+-    }
+-  else if (a->style != PANGO_STYLE_NORMAL &&
+-	   b->style != PANGO_STYLE_NORMAL)
+-    {
+-      /* Equate oblique and italic, but with a big penalty
+-       */
+-      return 1000000 + abs ((int)(a->weight) - (int)(b->weight));
+-    }
+-  else
+-    return G_MAXINT;
++  gint dist;
++
++  dist = abs((int)(a->weight) - (int)(b->weight));
++    
++  if (a->variant != b->variant)
++    dist += 10000;
++
++  if (a->stretch != b->stretch)
++    dist += 1000 * abs((int)a->stretch - (int)b->stretch);
++  
++  if (a->style != b->style) {
++    if (a->style != PANGO_STYLE_NORMAL &&
++        b->style != PANGO_STYLE_NORMAL)
++      /* Equate oblique and italic, but with a modest penalty */
++      dist += 10000;
++    else
++      /* Normal and oblique/italic has a larger penalty */
++      dist += 20000;
++  }
++
++  if (a->gravity != b->gravity)
++    dist += 100000;
++
++  return dist;
+ }
+ 
+ /**
+@@ -761,9 +772,6 @@
+   g_return_val_if_fail (desc != NULL, G_MAXINT);
+   g_return_val_if_fail (new_match != NULL, G_MAXINT);
+ 
+-  if (new_match->variant == desc->variant &&
+-      new_match->stretch == desc->stretch &&
+-      new_match->gravity == desc->gravity)
+     {
+       int old_distance = old_match ? compute_distance (desc, old_match) : G_MAXINT;
+       int new_distance = compute_distance (desc, new_match);

racket/src/native-libs/patches/pango-preferoblique.patch

@@ -0,0 +1,18 @@
+diff -r -u old/pango-1.42.0/pango/pangocoretext-fontmap.c new/pango-1.42.0/pango/pangocoretext-fontmap.c
+--- old/pango-1.42.0/pango/pangocoretext-fontmap.c	2017-08-15 15:53:10.000000000 -0600
++++ new/pango-1.42.0/pango/pangocoretext-fontmap.c	2019-02-14 08:33:52.000000000 -0700
+@@ -415,10 +415,10 @@
+   font_traits = ct_font_descriptor_get_traits (desc);
+   style_name = ct_font_descriptor_get_style_name (desc);
+ 
+-  if ((font_traits & kCTFontItalicTrait) == kCTFontItalicTrait)
+-    pango_font_description_set_style (font_desc, PANGO_STYLE_ITALIC);
+-  else if (pango_core_text_style_name_is_oblique (style_name))
++  if (pango_core_text_style_name_is_oblique (style_name))
+     pango_font_description_set_style (font_desc, PANGO_STYLE_OBLIQUE);
++  else if ((font_traits & kCTFontItalicTrait) == kCTFontItalicTrait)
++    pango_font_description_set_style (font_desc, PANGO_STYLE_ITALIC);
+   else
+     pango_font_description_set_style (font_desc, PANGO_STYLE_NORMAL);
+ 
+Only in new/pango-1.42.0/pango: pangocoretext-fontmap.c~