A category for Sparrow that allows shadows on a SPTextField.

SPTextField+Shadow.h

//
//  SPTextField+Shadow.h
//  Sparrow
//
//  Created by Shilo White on 11/9/11.
//  Copyright (c) 2011 Shilocity Productions. All rights reserved.
//

#import "SPTextField.h"

@interface SPTextField (Shadow)
@property (nonatomic, assign, readwrite) BOOL shadow;
@property (nonatomic, assign, readwrite) uint shadowColor;
@property (nonatomic, assign, readwrite) float shadowX;
@property (nonatomic, assign, readwrite) float shadowY;
@property (nonatomic, assign, readwrite) float shadowBlur;
@end

SPTextField+Shadow.m

//
//  SPTextField+Shadow.m
//  Sparrow
//
//  Created by Shilo White on 11/9/11.
//  Copyright (c) 2011 Shilocity Productions. All rights reserved.
//

#import "SPTextField+Shadow.h"
#import "SPMacros.h"
#import <objc/runtime.h>

static char sShadow;
static char sShadowColor;
static char sShadowX;
static char sShadowY;
static char sShadowBlur;

@implementation SPTextField (Shadow)

@dynamic shadow;
@dynamic shadowColor;
@dynamic shadowX;
@dynamic shadowY;
@dynamic shadowBlur;

- (void)setShadow:(BOOL)shadow {
    if ([self shadow] != shadow) {
        objc_setAssociatedObject(self, &sShadow, [NSNumber numberWithBool:shadow], OBJC_ASSOCIATION_RETAIN_NONATOMIC);
    }
}

- (BOOL)shadow {
    NSNumber *shadow = objc_getAssociatedObject(self, &sShadow);
    return [shadow boolValue];
}

- (void)setShadowColor:(uint)shadowColor {
    if ([self shadowColor] != shadowColor) {
        objc_setAssociatedObject(self, &sShadowColor, [NSNumber numberWithUnsignedInt:shadowColor], OBJC_ASSOCIATION_RETAIN_NONATOMIC);
    }
}

- (uint)shadowColor {
    NSNumber *shadowColor = objc_getAssociatedObject(self, &sShadowColor);
    return (uint)[shadowColor unsignedIntValue];
}

- (void)setShadowX:(float)shadowX {
    if ([self shadowX] != shadowX) {
        objc_setAssociatedObject(self, &sShadowX, [NSNumber numberWithFloat:shadowX], OBJC_ASSOCIATION_RETAIN_NONATOMIC);
    }
}

- (float)shadowX {
    NSNumber *shadowX = objc_getAssociatedObject(self, &sShadowX);
    return [shadowX floatValue];
}

- (void)setShadowY:(float)shadowY {
    if ([self shadowY] != shadowY) {
        objc_setAssociatedObject(self, &sShadowY, [NSNumber numberWithFloat:shadowY], OBJC_ASSOCIATION_RETAIN_NONATOMIC);
    }
}

- (float)shadowY {
    NSNumber *shadowY = objc_getAssociatedObject(self, &sShadowY);
    return [shadowY floatValue];
}

- (void)setShadowBlur:(float)shadowBlur {
    if ([self shadowBlur] != shadowBlur) {
        objc_setAssociatedObject(self, &sShadowBlur, [NSNumber numberWithFloat:shadowBlur], OBJC_ASSOCIATION_RETAIN_NONATOMIC);
    }
}

- (float)shadowBlur {
    NSNumber *shadowBlur = objc_getAssociatedObject(self, &sShadowBlur);
    return [shadowBlur floatValue];
}

- (SPDisplayObject *)createRenderedContents {
    float width = mHitArea.width;
    float height = mHitArea.height;    
    float fontSize = mFontSize == SP_NATIVE_FONT_SIZE ? SP_DEFAULT_FONT_SIZE : mFontSize;
    
    UILineBreakMode lbm = UILineBreakModeTailTruncation;
    CGSize textSize = [mText sizeWithFont:[UIFont fontWithName:mFontName size:fontSize] 
                        constrainedToSize:CGSizeMake(width, height) lineBreakMode:lbm];
    
    float xOffset = 0;
    if (mHAlign == SPHAlignCenter)      xOffset = (width - textSize.width) / 2.0f;
    else if (mHAlign == SPHAlignRight)  xOffset =  width - textSize.width;
    
    float yOffset = 0;
    if (mVAlign == SPVAlignCenter)      yOffset = (height - textSize.height) / 2.0f;
    else if (mVAlign == SPVAlignBottom) yOffset =  height - textSize.height;
    
    mTextArea.x = xOffset; 
    mTextArea.y = yOffset;
    mTextArea.width = textSize.width; 
    mTextArea.height = textSize.height;
    
    BOOL shadow = self.shadow;
    CGColorRef baseColorRef = [UIColor colorWithRed:SP_COLOR_PART_RED(mColor)/255.0f green:SP_COLOR_PART_GREEN(mColor)/255.0f blue:SP_COLOR_PART_BLUE(mColor)/255.0f alpha:1.0f].CGColor;
    CGColorRef shadowColorRef = NULL;
    if (shadow) {
        uint shadowColor = [self shadowColor];
        shadowColorRef = [UIColor colorWithRed:SP_COLOR_PART_RED(shadowColor)/255.0f green:SP_COLOR_PART_GREEN(shadowColor)/255.0f blue:SP_COLOR_PART_BLUE(shadowColor)/255.0f alpha:1.0f].CGColor;
    }
    
    SPTexture *texture = [[SPTexture alloc] initWithWidth:width height:height
                                                    scale:[SPStage contentScaleFactor]
                                               colorSpace:SPColorSpaceRGBA
                                                     draw:^(CGContextRef context)
                          {
                              if (shadow) CGContextSetShadowWithColor(context, CGSizeMake([self shadowX], -[self shadowY]), [self shadowBlur], shadowColorRef);
                              
                              if (!mBorder)
                              {
                                  CGContextSetStrokeColorWithColor(context, baseColorRef);
                                  CGContextSetLineWidth(context, 1.0f);
                                  CGContextStrokeRect(context, CGRectMake(0.5f, 0.5f, width-1, height-1));
                              }
                              
                              CGContextSetFillColorWithColor(context, baseColorRef);     
                              
                              [mText drawInRect:CGRectMake(0, yOffset, width, height)
                                       withFont:[UIFont fontWithName:mFontName size:fontSize] 
                                  lineBreakMode:lbm alignment:(UITextAlignment)mHAlign];
                          }];
    
    SPImage *image = [SPImage imageWithTexture:texture];
    [texture release];
    
    return image;
}
@end

Hello Shilo!

Thanks for this great category :DDD
I added the category to one project, and I realized that if we don't specify the property border, all the SPTextField assume border=YES as default, then I changed the line 119 to: if (mBorder) [removing the "!"] and it seems the problem is gone.

Regards.