Generating gray (black and white) images in IOS

CodeThe purpose is to generate a gray (black and white) uiimage based on a uiimage.

The following code is from a reply in stackoverflow. Unfortunately, the original link cannot be found.

-(Uiimage *) convertimagetogreyscale :( uiimage * ) Image {  //  Create Image rectangle with current image width/height Cgrect imagerect = cgrectmake ( 0 , 0  , Image. Size. Width, image. Size. Height );  //  Grayscale Color Space Cgcolorspaceref colorspace = Cgcolorspacecreatedevicegray (); //  Create bitmap content with current image size and grayscale colorspace Cgcontextref context = cgbitmapcontextcreate (nil, image. Size. Width, image. Size. height, 8 , 0  , Colorspace, kcgimagealphanone );  //  Draw image into current context, with specified rectangle  //  Using previusly defined context (with grayscale colorspace)  Cgcontextdrawimage (context, imagerect, [Image cgimage]);  // Create bitmap image info from pixel data in current context Cgimageref imageref = Cgbitmapcontextcreateimage (context );  //  Create a new uiimage object Uiimage * newimage = [Uiimage imagewithcgimage: imageref];  //  Release colorspace, context and bitmap Information  Cgcolorspacerelease (colorspace); cgcontextrelease (context); cfrelease (imageref );  //  Return the new grayscale image     Return  Newimage ;}