Fix for UITextField attributedPlaceholder

WorkingTextField

// -- .h

extern const NSString *PLACEHOLDER_BASELINE_ATTRIBUTE;
extern const NSString *PLACEHOLDER_LEFT_ATTRIBUTE;

/**
 * In this UITextField subclass, the attributedPlaceholder text actually works.
 *
 * @author Jed Laudenslayer
 */
@interface WorkingTextField : UITextField

//! The color for the attributed text.
@property (nonatomic, strong) UIColor *placeholderTextColor;

@end

// -- .m
#import "WorkingTextField.h"

const NSString *PLACEHOLDER_BASELINE_ATTRIBUTE = @"baseline_attribute";
const NSString *PLACEHOLDER_LEFT_ATTRIBUTE = @"left_attribute";

@implementation WorkingTextField
{
    NSAttributedString *realAttributedPlaceholder_;
}

@synthesize placeholderTextColor = placeholderTextColor_;

- (void)setAttributedPlaceholder:(NSAttributedString *)attributedPlaceholder
{
    [super setAttributedPlaceholder:attributedPlaceholder];
    realAttributedPlaceholder_ = attributedPlaceholder;
}

- (void)drawPlaceholderInRect:(CGRect)rect
{
    if (realAttributedPlaceholder_ != nil)
    {
        __block NSAttributedString *placeholder = realAttributedPlaceholder_;
        __block CGFloat lastX = 0.0;

        [placeholder enumerateAttributesInRange:NSMakeRange(0, placeholder.length)
                                        options:0
                                        usingBlock:[^(NSDictionary *attrs, NSRange range, BOOL *stop) {

            CGFloat baseline = [attrs[PLACEHOLDER_BASELINE_ATTRIBUTE] floatValue];
            CGFloat leftOffset = [attrs[PLACEHOLDER_LEFT_ATTRIBUTE] floatValue];

            NSMutableAttributedString *subString = [[NSMutableAttributedString alloc]
                                                    initWithAttributedString:[placeholder
                                                    attributedSubstringFromRange:range]];

            if (placeholderTextColor_ != nil && [attrs objectForKey:NSForegroundColorAttributeName] == nil)
            {
                [subString addAttribute:NSForegroundColorAttributeName value:placeholderTextColor_ range:NSMakeRange(0, subString.length)];
            }

            CGSize stringSize = subString.size;

            [subString drawAtPoint:CGPointMake(lastX + leftOffset, (rect.origin.y + rect.size.height) - (stringSize.height + baseline))];
            lastX += stringSize.width;

        } copy]];
    }
    else
    {
        [super drawPlaceholderInRect:rect];
    }
}

@end