fixed confusion of byteCount and charCount in ServerFont::StringWidth(), just in case anyone really uses it later. Added UTF8CountChars() to moreUTF8.h, but then I didn't need it...

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@12750 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/interface/moreUTF8.h

@@ -24,20 +24,6 @@ UTF8NextCharLen(const char *text)
 	return ptr - text;
 }
 
-static inline uint32
-UTF8CountBytes(const char *text, uint32 numChars)
-{
-	const char *ptr = text;
-
-	while (numChars) {
-		ptr += UTF8NextCharLen(ptr);
-		numChars--;
-	}
-
-	return ptr - text;
-}
-
-
 static inline uint32
 UTF8PreviousCharLen(const char *text, const char *limit)
 {
@@ -55,4 +41,33 @@ UTF8PreviousCharLen(const char *text, const char *limit)
 	return text - ptr;
 }
 
+static inline uint32
+UTF8CountBytes(const char *text, uint32 numChars)
+{
+	const char *ptr = text;
+
+	while (numChars) {
+		ptr += UTF8NextCharLen(ptr);
+		numChars--;
+	}
+
+	return ptr - text;
+}
+
+static inline uint32
+UTF8CountChars(const char *text, int32 numBytes)
+{
+	const char* ptr = text;
+	const char* last = ptr + numBytes - 1;
+
+	uint32 count = 0;
+	while (ptr <= last) {
+		ptr += UTF8NextCharLen(ptr);
+		count++;
+	}
+
+	return count;
+}
+
+
 #endif

headers/private/servers/app/ServerFont.h

@@ -120,7 +120,7 @@ class ServerFont {
 											   float widthArray[],
 											   escapement_delta delta) const;
 
-			float				StringWidth(const char* string, int32 numChars) const;
+			float				StringWidth(const char* string, int32 numBytes) const;
 
 			FT_Face				GetFTFace() const
 									{ return fStyle->GetFTFace(); };

src/servers/app/ServerFont.cpp

@@ -402,22 +402,39 @@ ServerFont::GetEscapements(const char charArray[], int32 numChars,
 
 // StringWidth
 float
-ServerFont::StringWidth(const char* string, int32 numChars) const
+ServerFont::StringWidth(const char* string, int32 numBytes) const
 {
-	// TODO: we're lazy for now and reuse the existing
+	if (!string || numBytes <= 0)
-	// functionality in GetEscapements
+		return 0.0;
-	escapement_delta delta;
-	delta.space = 0.0;
-	delta.nonspace = 0.0;
 
-	float* widthArray = new float[numChars];
+	FT_Face face = fStyle->GetFTFace();
+	if (!face)
+		return 0.0;
 
-	GetEscapements(string, numChars, widthArray, delta);
 	float width = 0.0;
-	for (int32 i = 0; i < numChars; i++)
-		width += widthArray[i] * fSize;
 
-	delete[] widthArray;
+	int32 convertedLength = numBytes * 2;
+	char* convertedBuffer = new char[convertedLength];
+
+	int32 state = 0;
+	status_t ret;
+	if ((ret = convert_from_utf8(B_UNICODE_CONVERSION, 
+								 string, &numBytes,
+								 convertedBuffer, &convertedLength,
+								 &state, B_SUBSTITUTE)) >= B_OK
+		&& (ret = swap_data(B_INT16_TYPE, convertedBuffer, convertedLength,
+							B_SWAP_BENDIAN_TO_HOST)) >= B_OK) {
+
+		uint16* glyphIndex = (uint16*)convertedBuffer;
+		// just to be sure
+		int numChars = convertedLength / sizeof(uint16);
+
+		for (int i = 0; i < numChars; i++) {
+			FT_Load_Char(face, glyphIndex[i], FT_LOAD_NO_BITMAP);
+			width += ((float)face->glyph->metrics.horiAdvance / 64.0) / fSize;
+		}
+	}
+	delete[] convertedBuffer;
 
 	return width;
 }