ios 将彩色照片转化成黑白等几种类型

-(UIImage *)changeColoursImageTograyScaleImage:(UIImage *)anImage type:(int)type

{

CGImageRef imageRef = anImage.CGImage;

size_t width                   = CGImageGetWidth(imageRef);

size_t height                  = CGImageGetHeight(imageRef);

size_t bitsPerComponent = CGImageGetBitsPerComponent(imageRef);

size_t bitsPerPixel           = CGImageGetBitsPerPixel(imageRef);

size_t bytesPerRow         = CGImageGetBytesPerRow(imageRef);

CGColorSpaceRef colorSpace = CGImageGetColorSpace(imageRef);

CGBitmapInfo bitMapInfo      = CGImageGetBitmapInfo(imageRef);

bool shouldInterPolate               = CGImageGetShouldInterpolate(imageRef);

CGColorRenderingIntent intent   = CGImageGetRenderingIntent(imageRef);

CGDataProviderRef dataProvider = CGImageGetDataProvider(imageRef);

CFDataRef data                         = CGDataProviderCopyData(dataProvider);

UInt8 *buffer                            = (UInt8  *)CFDataGetBytePtr(data);

NSInteger x,y;

for (y = 0; y < height; y++) {

for (x = 0; x < width; x++) {

UInt8 *tmp;

tmp = buffer + y * bytesPerRow + x * 4;

UInt8 red,green,blue;

red     = *(tmp + 0);

green = *(tmp + 1);

blue   = *(tmp + 2);

UInt8 brightness;

switch (type) {

case 0:

brightness = (77 * red + 28 * green + 151 * blue) / 256;

*(tmp + 0) = brightness;

*(tmp + 1) = brightness;

*(tmp + 1) = brightness;

break;

case 1:

brightness = (77 * red + 28 * green + 151 * blue) / 256;

*(tmp + 0) = red;

*(tmp + 1) = green * 0.7;

*(tmp + 1) = blue *0.4;

break;

case 2:

brightness = (77 * red + 28 * green + 151 * blue) / 256;

*(tmp + 0) = 255 - red;

*(tmp + 1) = 255 - green;

*(tmp + 1) = 255 - blue;

break;

default:

*(tmp + 0) = red;

*(tmp + 1) = green;

*(tmp + 2) = blue;

break;

}

}

}

CFDataRef effectedData = CFDataCreate(NULL, buffer, CFDataGetLength(data));

CGDataProviderRef effectedDataProvider = CGDataProviderCreateWithCFData(effectedData);

CGImageRef effectedCGImage = CGImageCreate(width, height, bitsPerComponent, bitsPerPixel, bytesPerRow, colorSpace, bitMapInfo, effectedDataProvider, NULL, shouldInterPolate, intent);

UIImage *effectedImage = [[UIImage alloc]initWithCGImage:effectedCGImage];

CGImageRelease(effectedCGImage);

CFRelease(effectedDataProvider);

CFRelease(effectedData);

CFRelease(data);

return effectedImage;

}

效果图：