From 70297713f2fb1b6518b34230195109ade067d7fe Mon Sep 17 00:00:00 2001
From: Manolo Gouy <Manolo>
Date: Thu, 16 Jul 2015 15:16:24 +0000
Subject: [PATCH] Correctly handle Unicode's 'Variation selectors' where a
 Unicode codepoint modifies the glyph used to draw the previous Unicode
 codepoint.

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@10792 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
---
 src/fl_font_mac.cxx | 25 +++++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/src/fl_font_mac.cxx b/src/fl_font_mac.cxx
index 597b16087..0d25f3649 100644
--- a/src/fl_font_mac.cxx
+++ b/src/fl_font_mac.cxx
@@ -304,6 +304,18 @@ static CGFloat surrogate_width(const UniChar *txt, Fl_Font_Descriptor *fl_fontsi
   if(must_release) CFRelease(font2);
   return a.width;
 }
+
+static CGFloat variation_selector_width(CFStringRef str16, Fl_Font_Descriptor *fl_fontsize)
+{
+  CGFloat retval;
+  CFDictionarySetValue(attributes, kCTFontAttributeName, fl_fontsize->fontref);
+  CFAttributedStringRef mastr = CFAttributedStringCreate(kCFAllocatorDefault, str16, attributes);
+  CTLineRef ctline = CTLineCreateWithAttributedString(mastr);
+  CFRelease(mastr);
+  retval = CTLineGetOffsetForStringIndex(ctline, 2, NULL);
+  CFRelease(ctline);
+  return retval;
+}
 #endif
 
 static double fl_mac_width(const UniChar* txt, int n, Fl_Font_Descriptor *fl_fontsize) {
@@ -319,6 +331,13 @@ if (fl_mac_os_version >= Fl_X::CoreText_threshold) {
       i++; // because a pair of UniChar's represent a single character
       continue;
     }
+    if (i+1 < n && txt[i+1] >= 0xFE00 && txt[i+1] <= 0xFE0F) { // handles variation selectors
+      CFStringRef substr = CFStringCreateWithCharacters(NULL, txt + i, 2);
+      retval += variation_selector_width(substr, fl_fontsize);
+      CFRelease(substr);
+      i++;
+      continue;
+    }
     const int block = 0x10000 / (sizeof(fl_fontsize->width)/sizeof(float*)); // block size
     // r: index of the character block containing uni
     unsigned int r = uni >> 7; // change 7 if sizeof(width) is changed
@@ -492,18 +511,12 @@ static CGColorRef flcolortocgcolor(Fl_Color i)
 #endif
 
 static void fl_mac_draw(const char *str, int n, float x, float y, Fl_Graphics_Driver *driver) {
-  // the range [0xFE00-0xFE0F] corresponds to Unicode's 'variation selectors'
-  static CFCharacterSetRef set = CFCharacterSetCreateWithCharactersInRange(NULL, CFRangeMake(0xFE00, 16));
-  CFRange res;
   // convert to UTF-16 first
   UniChar *uniStr = mac_Utf8_to_Utf16(str, n, &n);
 #if MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_5
   if (fl_mac_os_version >= Fl_X::CoreText_threshold) {
     CFMutableStringRef str16 = CFStringCreateMutableWithExternalCharactersNoCopy(NULL, uniStr, n,  n, kCFAllocatorNull);
     if (str16 == NULL) return; // shd not happen
-    while (CFStringFindCharacterFromSet(str16, set, CFRangeMake(0, CFStringGetLength(str16)), 0, &res)) {
-      CFStringReplace(str16, res, CFSTR("")); // remove all variation selectors from the input string
-    }
     CGColorRef color = flcolortocgcolor(driver->color());
     CFDictionarySetValue (attributes, kCTFontAttributeName, driver->font_descriptor()->fontref);
     CFDictionarySetValue (attributes, kCTForegroundColorAttributeName, color);