how to convert byte array to image in ios

问题

today my task is convert byte array to image

First I try to convert image to byte array :-

For converting Image to Byte array first we have to do is to convert that particular image [UIImage] to NSData.Then we will convert that NSData to Byte array. Here I will give the sample code, just go through...

//Converting UIImage to NSData
    UIImage *image = [UIImage imageNamed: @"photo-04.jpg"];

    NSData *imageData = UIImagePNGRepresentation(image);

    //Converting NSData to Byte array
    NSUInteger len = [imageData length];
    NSLog(@"Byte Lendata1  %lu",(unsigned long)len);

    Byte *byteData = (Byte*)malloc(len);
    memcpy(byteData, [imageData bytes], len);

i am try like this Convert byte to imageView

 const unsigned char *bytes = [imageData bytes];

    NSUInteger length = [imageData length];

    NSMutableArray *byteArray = [NSMutableArray array];

    for (NSUInteger i = 0; i < length; i++) {
        [byteArray addObject:[NSNumber numberWithUnsignedChar:bytes[i]]];
    }
    NSDictionary *dictJson = [NSDictionary dictionaryWithObjectsAndKeys:
                              byteArray, @"photo",
                              nil];
    NSData *jsonData = [NSJSONSerialization dataWithJSONObject:dictJson options:0 error:NULL];
    NSLog(@"");
    UIImage *image1 = [UIImage imageWithData:jsonData];

    UIImageView *imgView = [[UIImageView alloc] initWithFrame:CGRectMake(10, 10, 100, 50)];


    imgView.image=image1;

I got output convert image to byte array but i want convert byte array to image so please help me thanks in advanced.

回答1:

First, you need to convert bytes to NSData

NSData *imageData = [NSData dataWithBytes:bytesData length:length];

Then, convert the data back to image.

UIImage *image = [UIImage imageWithData:imageData];

And I suggest you should first searching about the documentations when problems occur.

Here is all:

UIImage *image = [UIImage imageNamed:@"RAC.png"];

NSData *imageData = UIImagePNGRepresentation(image);
// UIImageJPGRepresentation also work

NSInteger length = [imageData length];

Byte *byteData = (Byte*)malloc(length);
memcpy(byteData, [imageData bytes], length);

NSData *newData = [NSData dataWithBytes:byteData length:length];

UIImage *newImage = [UIImage imageWithData:newData];

UIImageView *imageView = [[UIImageView alloc] initWithImage:newImage];
imageView.frame = CGRectMake(50, 50, 100, 100);
[self.view addSubview:imageView];

回答2:

You are representing the data with wrong format

Your image is of format jpg and you are representing with PNG data.

For jpg or jpeg format you should use UIImageJPEGRepresentation

NSData * UIImageJPEGRepresentation (
   UIImage *image,
   CGFloat compressionQuality
);

The required statement will be

NSData *imageData = UIImageJPEGRepresentation(image, 0.0f);// Set Compression quality to 0.0. You can change it.

For png format you should use UIImagePNGRepresentation

NSData * UIImagePNGRepresentation (
   UIImage *image
);

The required statement will be

NSData *imageData = UIImagePNGRepresentation(image);

To convert the NSData back to UIImage, use

UIImage *image = [UIImage imageWithData:imageData];

READ THE APPLE DOCS. SEE UNDER IMAGE MANIPULATION

来源：https://stackoverflow.com/questions/22316608/how-to-convert-byte-array-to-image-in-ios

标签

ios

uiimage

bytearray

nsdata