예제 #1
0
        public static string NormalizeTextDirection(this string data)
        {
            if (data.Length > 0)
            {
                var lastCharacterDirection = NativeUtils.GetDirectionality(data[data.Length - 1]);

                // 1 = LTR
                // 2 = RTL
                // 8 = NEUTRAL

                // If the last character has strong directionality (direction is not null), then the text direction for the string is already consistent.
                if (lastCharacterDirection == 8)
                {
                    // If the last character has no directionality (neutral character, direction is null), then we may need to add a direction marker to
                    // ensure that the last character doesn't inherit directionality from the outside context.
                    var appTextDirection  = 1;                                   // checks the <html> element's "dir" attribute.
                    var dataTextDirection = NativeUtils.GetDirectionality(data); // Run through the string until a non-neutral character is encountered,
                                                                                 // which determines the text direction.

                    if (appTextDirection != dataTextDirection)
                    {
                        // Add a direction marker only if the data text runs opposite to the directionality of the app as a whole,
                        // which would cause the neutral characters at the ends to flip.
                        var directionMarkerCharacter = dataTextDirection == 2 ? "\u200F" : "\u200E";

                        data += directionMarkerCharacter;

                        // Prepend the direction marker if the data text begins with a neutral character.
                        var firstCharacterDirection = NativeUtils.GetDirectionality(data[0]);
                        if (firstCharacterDirection == 8)
                        {
                            data = directionMarkerCharacter + data;
                        }
                    }
                }
            }

            return(data);
        }