I want to get the compressed data from a CGImageRef to send it over a network connection. To do so, i use a CGImageDestinationRef (CGImageDestinationCreateWithData).
After pulling the Data out of the CFDataRef Object the image misses a couple of rows at the bottom.
Here is what i do (cleaned for reading purpose...):
CFImageRef image = getTheImageRefIWant();
CFMutableDataRef pngData = CFDataCreateMutable (kCFAllocatorDefault, 0);
CGImageDestinationRef dataDest = CGImageDestinationCreateWithData (pngData, kUTTypePNG, 1, NULL);
CGImageDestinationAddImage (dataDest, image, NULL); //also tried this with options...
CGImageDestinationFinalize (dataDest);
CFIndex len = CFDataGetLength(pngData);
//copy data
unsigned char* m_image = malloc(len);
CFDataGetBytes (pngData, CFRangeMake(0,len), m_image);
//save data - for testing purpose
FILE *file = fopen("/path/test.png", "wb");
fwrite(m_image, 1, len, file);
//adding header and stuff - skipped here...
//send data
send(sockfd, m_image, len, 0);
If i use the CFData Object as NSData Object and save it to disk it does work:
NSData *data = [(NSData *)pngData autorelease];
[data writeToFile:@"/path/test.png" atomically:YES];
but if is use NSDatas byte method, it is the same (truncated image):
NSUInteger len = [data length];
m_image = malloc(len);
memcpy(m_image, (unsigned char*)[data bytes], len);
seems the data in CFData Object seems to be ok. But how to get the bytes properly?
Thanks for any advice.
