From e1b4c6ddc6e2a980a7ffbf7c3f81ffc929c234d0 Mon Sep 17 00:00:00 2001
From: nyamatongwe <devnull@localhost>
Date: Sun, 10 Jul 2011 11:24:11 +1000
Subject: Display and measure text in different encodings.

---
 cocoa/PlatCocoa.mm       | 82 ++++++++++++++++++++++++++++++++++--------------
 cocoa/QuartzTextLayout.h | 12 +++++--
 2 files changed, 69 insertions(+), 25 deletions(-)

diff --git a/cocoa/PlatCocoa.mm b/cocoa/PlatCocoa.mm
index dba386750..4465e36ae 100644
--- a/cocoa/PlatCocoa.mm
+++ b/cocoa/PlatCocoa.mm
@@ -149,6 +149,10 @@ Font::~Font()
 
 //--------------------------------------------------------------------------------------------------
 
+static int FontCharacterSet(Font &f) {
+	return reinterpret_cast<QuartzTextStyle *>(f.GetID())->getCharacterSet();
+}
+
 /**
  * Creates a Quartz 2D font with the given properties.
  * TODO: rewrite to use NSFont.
@@ -905,55 +909,86 @@ CFStringEncoding EncodingFromCharacterSet(bool unicode, int characterSet)
 void SurfaceImpl::DrawTextTransparent(PRectangle rc, Font &font_, int ybase, const char *s, int len, 
                                       ColourAllocated fore)
 {
+	CFStringEncoding encoding = EncodingFromCharacterSet(unicodeMode, FontCharacterSet(font_));
 	ColourDesired colour(fore.AsLong());
 	CGColorRef color = CGColorCreateGenericRGB(colour.GetRed()/255.0,colour.GetGreen()/255.0,colour.GetBlue()/255.0,1.0);
 
 	QuartzTextStyle* style = reinterpret_cast<QuartzTextStyle*>(font_.GetID());
 	style->setCTStyleColor(color);
 
-	textLayout->setText (reinterpret_cast<const UInt8*>(s), len, *reinterpret_cast<QuartzTextStyle*>(font_.GetID()));
+	textLayout->setText (reinterpret_cast<const UInt8*>(s), len, encoding, *reinterpret_cast<QuartzTextStyle*>(font_.GetID()));
 	textLayout->draw(rc.left, ybase);
 }
 
+static size_t utf8LengthFromLead(unsigned char uch) {
+	if (uch >= (0x80 + 0x40 + 0x20 + 0x10)) {
+		return 4;
+	} else if (uch >= (0x80 + 0x40 + 0x20)) {
+		return 3;
+	} else if (uch >= (0x80)) {
+		return 2;
+	} else {
+		return 1;
+	}
+}
+
 //--------------------------------------------------------------------------------------------------
 
 void SurfaceImpl::MeasureWidths(Font &font_, const char *s, int len, int *positions)
 {
+	CFStringEncoding encoding = EncodingFromCharacterSet(unicodeMode, FontCharacterSet(font_));
 	for (int i = 0; i < len; i++)
 		positions [i] = 0;
-	textLayout->setText (reinterpret_cast<const UInt8*>(s), len, *reinterpret_cast<QuartzTextStyle*>(font_.GetID()));
+	textLayout->setText (reinterpret_cast<const UInt8*>(s), len, encoding, *reinterpret_cast<QuartzTextStyle*>(font_.GetID()));
 	
 	CTLineRef mLine = textLayout->getCTLine();
 	assert(mLine != NULL);
 	
-	CGFloat* secondaryOffset= 0;
-	int unicodeCharStart = 0;
-	for ( int  i = 0; i < len+1; i ++ ){
-		unsigned char uch = s[i];
-		CFIndex charIndex = unicodeCharStart+1;
-		CGFloat advance = CTLineGetOffsetForStringIndex(mLine, charIndex, secondaryOffset);
-		
-		if ( unicodeMode ) 
-		{
-			unsigned char mask = 0xc0;
-			int lcount = 1;
-			// Add one additonal byte for each extra high order one in the byte
-			while ( uch >= mask && lcount < 8 ) 
-			{
-				positions[i++] = (int)(advance+0.5);
-				lcount ++;
-				mask = mask >> 1 | 0x80; // add an additional one in the highest order position
+	if (unicodeMode) {
+		// Map the widths given for UTF-16 characters back onto the UTF-8 input string
+		int fit = textLayout->getStringLength();
+		int ui=0;
+		const unsigned char *us = reinterpret_cast<const unsigned char *>(s);
+		int i=0;
+		while (ui<fit) {
+			size_t lenChar = utf8LengthFromLead(us[i]);
+			size_t codeUnits = (lenChar < 4) ? 1 : 2;
+			CGFloat xPosition = CTLineGetOffsetForStringIndex(mLine, ui+1, NULL);
+			for (unsigned int bytePos=0; (bytePos<lenChar) && (i<len); bytePos++) {
+				positions[i++] = lround(xPosition);
 			}
+			ui += codeUnits;
+		}
+		int lastPos = 0;
+		if (i > 0)
+			lastPos = positions[i-1];
+		while (i<len) {
+			positions[i++] = lastPos;
+		}
+	} else if (codePage) {
+		int ui = 0;
+		for (int i=0;i<len;) {
+			size_t lenChar = Platform::IsDBCSLeadByte(codePage, s[i]) ? 2 : 1;
+			CGFloat xPosition = CTLineGetOffsetForStringIndex(mLine, ui+1, NULL);
+			for (unsigned int bytePos=0; (bytePos<lenChar) && (i<len); bytePos++) {
+				positions[i++] = lround(xPosition);
+			}
+			ui++;
+		}
+	} else {	// Single byte encoding
+		for (int i=0;i<len;i++) {
+			CGFloat xPosition = CTLineGetOffsetForStringIndex(mLine, i+1, NULL);
+			positions[i] = lround(xPosition);
 		}
-		positions[i] = (int)(advance+0.5);
-		unicodeCharStart++;
 	}
+
 }
 
 int SurfaceImpl::WidthText(Font &font_, const char *s, int len) {
   if (font_.GetID())
   {
-    textLayout->setText (reinterpret_cast<const UInt8*>(s), len, *reinterpret_cast<QuartzTextStyle*>(font_.GetID()));
+    CFStringEncoding encoding = EncodingFromCharacterSet(unicodeMode, FontCharacterSet(font_));
+    textLayout->setText (reinterpret_cast<const UInt8*>(s), len, encoding, *reinterpret_cast<QuartzTextStyle*>(font_.GetID()));
     
 	return textLayout->MeasureStringWidth();
   }
@@ -964,7 +999,8 @@ int SurfaceImpl::WidthChar(Font &font_, char ch) {
   char str[2] = { ch, '\0' };
   if (font_.GetID())
   {
-    textLayout->setText (reinterpret_cast<const UInt8*>(str), 1, *reinterpret_cast<QuartzTextStyle*>(font_.GetID()));
+    CFStringEncoding encoding = EncodingFromCharacterSet(unicodeMode, FontCharacterSet(font_));
+    textLayout->setText (reinterpret_cast<const UInt8*>(str), 1, encoding, *reinterpret_cast<QuartzTextStyle*>(font_.GetID()));
     
     return textLayout->MeasureStringWidth();
   }
diff --git a/cocoa/QuartzTextLayout.h b/cocoa/QuartzTextLayout.h
index 033ac98fb..c789ed10f 100644
--- a/cocoa/QuartzTextLayout.h
+++ b/cocoa/QuartzTextLayout.h
@@ -24,6 +24,7 @@ public:
     {
 		mString = NULL;
 		mLine = NULL;
+		stringLength = 0;
         setContext(context);
     }
 
@@ -41,12 +42,14 @@ public:
 		}	
     }
 
-    inline void setText( const UInt8* buffer, size_t byteLength, const QuartzTextStyle& r )
+    inline void setText( const UInt8* buffer, size_t byteLength, CFStringEncoding encoding, const QuartzTextStyle& r )
     {
-		CFStringRef str = CFStringCreateWithBytes( NULL, buffer, byteLength, kCFStringEncodingUTF8, false );
+		CFStringRef str = CFStringCreateWithBytes( NULL, buffer, byteLength, encoding, false );
         if (!str)
             return;
 		
+	        stringLength = CFStringGetLength(str);
+
 		CFMutableDictionaryRef stringAttribs = r.getCTStyle();
 		
 		if (mString != NULL)
@@ -89,6 +92,10 @@ public:
         return mLine;
     }
 	
+    CFIndex getStringLength() {
+	    return stringLength;
+    }
+
     inline void setContext (CGContextRef context)
     {
         gc = context;
@@ -98,6 +105,7 @@ private:
     CGContextRef gc;
 	CFAttributedStringRef mString;
 	CTLineRef mLine;
+	CFIndex stringLength;
 };
 
 #endif
-- 
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