IOS picture file format judgment, fillet picture

1. Fillet picture

//set up a circular picture (for use in a category)-(UIImage *) cutcircleimage {uigraphicsbeginimagecontextwithoptions (self.size, NO,0.0); //Get ContextCgcontextref CTR =Uigraphicsgetcurrentcontext (); //Set the CircleCGRect rect = CGRectMake (0,0, Self.size.width, self.size.height);    Cgcontextaddellipseinrect (CTR, rect); //croppingCgcontextclip (CTR); //draw the picture up[self drawinrect:rect]; UIImage*image =Uigraphicsgetimagefromcurrentimagecontext ();    Uigraphicsendimagecontext (); returnimage;}

2. image File Format judgment

//get the picture extension by the first byte of the image data-(NSString *) Contenttypeforimagedata: (NSData *) data {uint8_t C; [Data getBytes:&c Length:1]; Switch(c) { Case 0xFF:            return @"JPEG";  Case 0x89:            return @"PNG";  Case 0x47:            return @"gif";  Case 0x49:            Case 0x4d:            return @"TIFF";  Case 0x52:              if([Data length] < A) {                returnNil; } nsstring*teststring = [[NSString alloc] Initwithdata:[data subdatawithrange:nsmakerange (0, A)] [encoding:nsasciistringencoding]; if([TestString Hasprefix:@"RIFF"] && [teststring hassuffix:@"WEBP"]) {                return @"WEBP"; }            returnNil; }    returnNil;} NSString*path =@"Http://xxx.xxx.xxx/xxx.png"; NSData*data =[NSData Datawithcontentsofurl:[nsurl Urlwithstring:path];//calledNSString *string=[self contenttypeforimagedata:data];//the output is PNGNSLog (@"%@",string);

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IOS picture file format judgment, fillet picture