A SPTexture category for Sparrow that will replace or remove colors.

SPTexture+Additions.h

//
//  SPTexture+Additions.h
//  Sparrow
//
//  Created by Shilo White on 10/15/11.
//  Copyright 2011 Shilocity Productions. All rights reserved.
//

#import <Foundation/Foundation.h>
#import "SPTexture.h"
#import "SPStage.h"
#import "SPUtils.h"
#import "SPMacros.h"

@interface SPTexture (Additions)
- (id)initWithContentsOfFile:(NSString *)path removeColor:(uint)color;
- (id)initWithContentsOfFile:(NSString *)path removeColorsWithMinColor:(uint)minColor maxColor:(uint)maxColor;
- (id)initWithContentsOfFile:(NSString *)path replaceColor:(uint)color withColor:(uint)newColor;
- (id)initWithContentsOfFile:(NSString *)path replaceColorsWithMinColor:(uint)minColor maxColor:(uint)maxColor withColor:(uint)newColor;
- (id)initWithContentsOfFile:(NSString *)path replaceColorsWithMinColor:(uint)minColor maxColor:(uint)maxColor withColor:(uint)newColor andAlpha:(float)alpha;
+ (SPTexture *)textureWithContentsOfFile:(NSString *)path removeColor:(uint)color;
+ (SPTexture *)textureWithContentsOfFile:(NSString *)path removeColorsWithMinColor:(uint)minColor maxColor:(uint)maxColor;
+ (SPTexture *)textureWithContentsOfFile:(NSString *)path replaceColor:(uint)color withColor:(uint)newColor;
+ (SPTexture *)textureWithContentsOfFile:(NSString *)path replaceColorsWithMinColor:(uint)minColor maxColor:(uint)maxColor withColor:(uint)newColor;
+ (SPTexture *)textureWithContentsOfFile:(NSString *)path replaceColorsWithMinColor:(uint)minColor maxColor:(uint)maxColor withColor:(uint)newColor andAlpha:(float)alpha;
@end

@implementation SPTexture (Additions)
- (id)initWithContentsOfFile:(NSString *)path removeColor:(uint)color {
    return [self initWithContentsOfFile:path removeColorsWithMinColor:color maxColor:color];
}

- (id)initWithContentsOfFile:(NSString *)path removeColorsWithMinColor:(uint)minColor maxColor:(uint)maxColor {
    return [self initWithContentsOfFile:path replaceColorsWithMinColor:minColor maxColor:maxColor withColor:0 andAlpha:0];
}

- (id)initWithContentsOfFile:(NSString *)path replaceColor:(uint)color withColor:(uint)newColor {
    return [self initWithContentsOfFile:path replaceColorsWithMinColor:color maxColor:color withColor:newColor];
}

- (id)initWithContentsOfFile:(NSString *)path replaceColorsWithMinColor:(uint)minColor maxColor:(uint)maxColor withColor:(uint)newColor {
    return [self initWithContentsOfFile:path replaceColorsWithMinColor:minColor maxColor:maxColor withColor:newColor andAlpha:1.0f];
}

- (id)initWithContentsOfFile:(NSString *)path replaceColorsWithMinColor:(uint)minColor maxColor:(uint)maxColor withColor:(uint)newColor andAlpha:(float)alpha {
    float contentScaleFactor = [SPStage contentScaleFactor];
    NSString *fullPath = [SPUtils absolutePathToFile:path withScaleFactor:contentScaleFactor];
    if (!fullPath) [NSException raise:SP_EXC_FILE_NOT_FOUND format:@"file '%@' not found", path];
    
    UIImage *image = [UIImage imageWithContentsOfFile:fullPath];
    float width = image.size.width;
    float height = image.size.height;
    uint minRed = SP_COLOR_PART_RED(minColor);
    uint minGreen = SP_COLOR_PART_GREEN(minColor);
    uint minBlue = SP_COLOR_PART_BLUE(minColor);
    uint maxRed = SP_COLOR_PART_RED(maxColor);
    uint maxGreen = SP_COLOR_PART_GREEN(maxColor);
    uint maxBlue = SP_COLOR_PART_BLUE(maxColor);
    float newRed = SP_COLOR_PART_RED(newColor)/255.0f;
    float newGreen = SP_COLOR_PART_GREEN(newColor)/255.0f;
    float newBlue = SP_COLOR_PART_BLUE(newColor)/255.0f;
    
    return [[SPTexture alloc] initWithWidth:width height:height draw:^(CGContextRef context) {
        CGRect bounds = CGRectMake(0, 0, width, height);
        if (alpha) {
            CGContextSetRGBFillColor(context, newRed, newGreen, newBlue, alpha);
            CGContextFillRect(context, bounds);
        }
        float maskingColors[6] = {minRed, maxRed, minGreen, maxGreen, minBlue, maxBlue};
        CGImageRef maskedImage = CGImageCreateWithMaskingColors(image.CGImage, maskingColors);
        CGContextTranslateCTM(context, 0, height);
        CGContextScaleCTM(context, 1.0, -1.0);
        CGContextDrawImage(context, bounds, maskedImage);
        CGImageRelease(maskedImage);
    }];
}

+ (SPTexture *)textureWithContentsOfFile:(NSString *)path removeColor:(uint)color {
    return [[[self alloc] initWithContentsOfFile:path removeColor:color] autorelease];
}

+ (SPTexture *)textureWithContentsOfFile:(NSString *)path removeColorsWithMinColor:(uint)minColor maxColor:(uint)maxColor {
    return [[[self alloc] initWithContentsOfFile:path removeColorsWithMinColor:minColor maxColor:maxColor] autorelease];
}

+ (SPTexture *)textureWithContentsOfFile:(NSString *)path replaceColor:(uint)color withColor:(uint)newColor {
    return [[[self alloc] initWithContentsOfFile:path replaceColor:color withColor:newColor] autorelease];
}

+ (SPTexture *)textureWithContentsOfFile:(NSString *)path replaceColorsWithMinColor:(uint)minColor maxColor:(uint)maxColor withColor:(uint)newColor {
    return [[[self alloc] initWithContentsOfFile:path replaceColorsWithMinColor:minColor maxColor:maxColor withColor:newColor] autorelease];
}

+ (SPTexture *)textureWithContentsOfFile:(NSString *)path replaceColorsWithMinColor:(uint)minColor maxColor:(uint)maxColor withColor:(uint)newColor andAlpha:(float)alpha {
    return [[[self alloc] initWithContentsOfFile:path replaceColorsWithMinColor:minColor maxColor:maxColor withColor:newColor andAlpha:alpha] autorelease];
}
@end