iOS turns color photos into black and white

-(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 = (*red + + * Green + 151 * blue)/ ;

* (tmp + 0) = brightness;

* (tmp + 1) = brightness;

* (tmp + 1) = brightness;

Break ;

case 1:

Brightness = (*red + + * Green + 151 * blue)/ ;

* (tmp + 0) = red;

* (tmp + 1) = green * 0.7;

* (tmp + 1) = blue *0.4;

Break ;

Case 2:

Brightness = (*red + + * Green + 151 * blue)/ ;

* (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;

}

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iOS turns color photos into black and white