iphone - NSData -> UIImage -> NSData

Question

我有一个NSData对象，其中包含图像的 RGB 值。我想把它变成 UIImage (给定宽度和高度)。然后我想转换 UIImage回到NSData对象与我开始时的对象相同。

请帮助我，我已经尝试了几个小时了。

以下是我看过/尝试过的一些事情，尽管可能不太正确，因为它不起作用:

CGImageCreate
CGBitmapContextCreateWithData
CGBitmapContextGetData
CGDataProviderCopyData(CGImageGetDataProvider(imageRef))

谢谢!

这是我当前的代码:

NSMutableData *rgb; //made earlier
double len = (double)[rgb length];
len /= 3;
len += 0.5;
len = (int)len;
int diff = len*3-[rgb length];
NSString *str = @"a";
NSData *a = [str dataUsingEncoding:NSUTF8StringEncoding];
for(int i =0; i < diff; i++) {
    [toEncode appendData:a]; //so if my data is RGBRGBR it will turn into RGBRGBR(97)(97)
}
size_t width = (size_t)len;
size_t height = 1;
CGContextRef ctx; 
CFDataRef m_DataRef;
m_DataRef = (__bridge CFDataRef)toEncode;
UInt8 * m_PixelBuf = (UInt8 *) CFDataGetBytePtr(m_DataRef); 
vImage_Buffer src;
src.data = m_PixelBuf;
src.width = width;
src.height = height;
src.rowBytes = 3 * width;
vImage_Buffer dst;
dst.width = width;
dst.height = height;
dst.rowBytes = 4 * width;
vImageConvert_RGB888toARGB8888(&src, NULL, 0, &dst, NO, kvImageNoFlags);
//    free(m_PixelBuf);
//    m_PixelBuf = dst.data;
//    NSUInteger lenB = len * (4/3);
/*
 UInt8 * m_Pixel = malloc(sizeof(UInt8) * lenB);
 int z = 0;
 for(int i = 0; i < lenB; i++) {
 if(i % 4==0) {
 m_Pixel[i] = 0;
 } else {
 m_Pixel[i] = m_PixelBuf[z];
 z++;            
 }
 }*/
//    Byte tmpByte; 

CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
/*
 ctx = CGBitmapContextCreate(m_PixelBuf, 
 width, 
 height, 
 8, 
 4*width, 
 colorSpace, 
 kCGImageAlphaPremultipliedFirst ); 
 */
size_t w = (size_t)len;
ctx = CGBitmapContextCreate(dst.data, 
                            w, 
                            height, 
                            8, 
                            4*width, 
                            colorSpace, 
                            kCGImageAlphaNoneSkipFirst );     
CGImageRef imageRef = CGBitmapContextCreateImage (ctx); 
UIImage* rawImage = [UIImage imageWithCGImage:imageRef]; 

CGContextRelease(ctx); 

我收到此错误:<Error>: CGBitmapContextCreate: invalid data bytes/row: should be at least 324 for 8 integer bits/component, 3 components, kCGImageAlphaNoneSkipFirst.

Answer 1

从 NSData 到 UIImage:

[UIImage imageWithData:]

更多关于UIImage

从 UIImage 到 NSData:

UIImage *img = [UIImage imageNamed:@"some.png"];
NSData *dataObj = UIImageJPEGRepresentation(img, 1.0);

更多关于UIImageJPEGRepresentation()