IOS makes images blurry

#import <Accelerate/Accelerate.h>

1. Initializing a picture

Uiimageview *iv = [[Uiimageview alloc]initwithframe:[uiscreen mainscreen].bounds];

[IV setimage:[self blurryimage:[uiimage imagenamed:@ "welcome_2.jpg"] [withblurlevel:0.6]];

[Self.view Addsubview:iv];

2. How to blur a picture

-(UIImage *) Blurryimage: (UIImage *) image withblurlevel: (CGFloat) Blur

{

if (Blur <0.f | | blur > 1.F)

{

Blur = 0.5f;

}

Judging exposure level

int boxsize = (int) (blur * 100);//magnification 100 after the decimal point 2 bits are valid

Boxsize = boxsize-(boxsize% 2) + 1;//If it is even odd

Cgimageref img = image. cgimage;//Get the picture pointer

Vimage_buffer inbuffer,outbuffer;//Get Buffer

Vimage_error error;//An error class, called when the paint function is called

void *pixelbuffer;

Cgdataproviderref inprovider = Cgimagegetdataprovider (IMG);//put back an array picture

Cfdataref inbitmapdata = Cgdataprovidercopydata (Inprovider);//Copy data

Inbuffer.width = Cgimagegetwidth (IMG);//Put back the width of the bitmap

Inbuffer.height = Cgimagegetheight (IMG);//Put back the height of the bitmap

inbuffer.rowbytes = Cgimagegetbytesperrow (IMG);//Calculate the byte of the bitmap

Inbuffer.data = (void*) cfdatagetbyteptr (inbitmapdata);//fill in the picture information

Pixelbuffer = malloc (Cgimagegetbytesperrow (IMG) * Cgimagegetheight (IMG));//Create a space

if (Pixelbuffer = = NULL)

{

NSLog (@ "NO pixelbuffer");

}

Outbuffer.data = Pixelbuffer;

Outbuffer.width = Cgimagegetwidth (IMG);

Outbuffer.height = Cgimagegetheight (IMG);

outbuffer.rowbytes = Cgimagegetbytesperrow (IMG);

Error = vimageboxconvolve_argb8888 (&inbuffer, &outbuffer, NULL, 0, 0, boxsize, boxsize, NULL, Kvimageedgeextend) ;

if (Error)

{

NSLog (@ "%zd", error);

}

Cgcolorspaceref colorspace = Cgcolorspacecreatedevicergb ();

Cgcontextref CTX = cgbitmapcontextcreate (Outbuffer.data, Outbuffer.width, Outbuffer.height, 8, OutBuffer.rowBytes, ColorSpace, Kcgimagealphanoneskiplast);

Cgimageref imageref = Cgbitmapcontextcreateimage (CTX);

UIImage *returnimage = [UIImage imagewithcgimage:imageref];

Cgcontextrelease (CTX);

Cgcolorspacerelease (ColorSpace);

Free (pixelbuffer);

Cfrelease (Inbitmapdata);

Cgcolorspacerelease (ColorSpace);

Cgimagerelease (IMAGEREF);

return returnimage;

}

IOS makes images blurry