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Shilo/UIImage+Additions.h

Created October 17, 2011 07:43
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  1. Shilo created this gist Oct 17, 2011.
    74 changes: 74 additions & 0 deletions UIImage+Additions.h
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    //
    // UIImage+Additions.h
    // Sparrow
    //
    // Created by Shilo White on 10/16/11.
    // Copyright 2011 Shilocity Productions. All rights reserved.
    //

    #define COLOR_PART_RED(color) (((color) >> 16) & 0xff)
    #define COLOR_PART_GREEN(color) (((color) >> 8) & 0xff)
    #define COLOR_PART_BLUE(color) ( (color) & 0xff)

    #import <Foundation/Foundation.h>

    @interface UIImage (Additions)
    - (UIImage *)imageByRemovingColor:(uint)color;
    - (UIImage *)imageByRemovingColorsWithMinColor:(uint)minColor maxColor:(uint)maxColor;
    - (UIImage *)imageByReplacingColor:(uint)color withColor:(uint)newColor;
    - (UIImage *)imageByReplacingColorsWithMinColor:(uint)minColor maxColor:(uint)maxColor withColor:(uint)newColor;
    - (UIImage *)imageByReplacingColorsWithMinColor:(uint)minColor maxColor:(uint)maxColor withColor:(uint)newColor andAlpha:(float)alpha;
    @end

    @implementation UIImage (Additions)
    - (UIImage *)imageByRemovingColor:(uint)color {
    return [self imageByRemovingColorsWithMinColor:color maxColor:color];
    }

    - (UIImage *)imageByRemovingColorsWithMinColor:(uint)minColor maxColor:(uint)maxColor {
    return [self imageByReplacingColorsWithMinColor:minColor maxColor:maxColor withColor:0 andAlpha:0];
    }

    - (UIImage *)imageByReplacingColor:(uint)color withColor:(uint)newColor {
    return [self imageByReplacingColorsWithMinColor:color maxColor:color withColor:newColor];
    }

    - (UIImage *)imageByReplacingColorsWithMinColor:(uint)minColor maxColor:(uint)maxColor withColor:(uint)newColor {
    return [self imageByReplacingColorsWithMinColor:minColor maxColor:maxColor withColor:newColor andAlpha:1.0f];
    }

    - (UIImage *)imageByReplacingColorsWithMinColor:(uint)minColor maxColor:(uint)maxColor withColor:(uint)newColor andAlpha:(float)alpha {
    CGImageRef imageRef = self.CGImage;
    float width = CGImageGetWidth(imageRef);
    float height = CGImageGetHeight(imageRef);
    CGRect bounds = CGRectMake(0, 0, width, height);
    uint minRed = COLOR_PART_RED(minColor);
    uint minGreen = COLOR_PART_GREEN(minColor);
    uint minBlue = COLOR_PART_BLUE(minColor);
    uint maxRed = COLOR_PART_RED(maxColor);
    uint maxGreen = COLOR_PART_GREEN(maxColor);
    uint maxBlue = COLOR_PART_BLUE(maxColor);
    float newRed = COLOR_PART_RED(newColor)/255.0f;
    float newGreen = COLOR_PART_GREEN(newColor)/255.0f;
    float newBlue = COLOR_PART_BLUE(newColor)/255.0f;

    CGContextRef context = nil;

    if (alpha) {
    context = CGBitmapContextCreate(NULL, width, height, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), CGImageGetColorSpace(imageRef), CGImageGetBitmapInfo(imageRef));
    CGContextSetRGBFillColor(context, newRed, newGreen, newBlue, alpha);
    CGContextFillRect(context, bounds);
    }
    float maskingColors[6] = {minRed, maxRed, minGreen, maxGreen, minBlue, maxBlue};
    CGImageRef maskedImageRef = CGImageCreateWithMaskingColors(imageRef, maskingColors);
    if (!maskedImageRef) return nil;
    if (alpha) CGContextDrawImage(context, bounds, maskedImageRef);
    CGImageRef newImageRef = (alpha)?CGBitmapContextCreateImage(context):maskedImageRef;
    if (context) CGContextRelease(context);
    if (newImageRef != maskedImageRef) CGImageRelease(maskedImageRef);

    UIImage *newImage = [UIImage imageWithCGImage:newImageRef];
    CGImageRelease(newImageRef);
    return newImage;
    }
    @end