iOS/Objective C: Converting RGB Data to UIImage - ios

Question

i need help converting an 24/32 bit RGB raw image to uiimage.
I've tried the examples here from Paul Solt and others, but nothing work. Anybody could please show an example or tutorial?
The image data is hold in nsdata and i would like to have a jpg or png image.
Thx
Thorsten
I'm using the code by Paul Solt, it does something, but the image looks like it have four times the image information in one image. i cant post an image here:
EDIT: i added the lines at the beginning of the method between the comments, now it works :-)
+ (UIImage *) convertBitmapRGBA8ToUIImage:(unsigned char *) buffer
withWidth:(int) width
withHeight:(int) height {
// added code
char* rgba = (char*)malloc(width*height*4);
for(int i=0; i < width*height; ++i) {
rgba[4*i] = buffer[3*i];
rgba[4*i+1] = buffer[3*i+1];
rgba[4*i+2] = buffer[3*i+2];
rgba[4*i+3] = 255;
}
//
size_t bufferLength = width * height * 4;
CGDataProviderRef provider = CGDataProviderCreateWithData(NULL, rgba, bufferLength, NULL);
size_t bitsPerComponent = 8;
size_t bitsPerPixel = 32;
size_t bytesPerRow = 4 * width;
CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB();
if(colorSpaceRef == NULL) {
NSLog(#"Error allocating color space");
CGDataProviderRelease(provider);
return nil;
}
CGBitmapInfo bitmapInfo = kCGBitmapByteOrderDefault | kCGImageAlphaPremultipliedLast;
CGColorRenderingIntent renderingIntent = kCGRenderingIntentDefault;
CGImageRef iref = CGImageCreate(width,
height,
bitsPerComponent,
bitsPerPixel,
bytesPerRow,
colorSpaceRef,
bitmapInfo,
provider, // data provider
NULL, // decode
YES, // should interpolate
renderingIntent);
uint32_t* pixels = (uint32_t*)malloc(bufferLength);
if(pixels == NULL) {
NSLog(#"Error: Memory not allocated for bitmap");
CGDataProviderRelease(provider);
CGColorSpaceRelease(colorSpaceRef);
CGImageRelease(iref);
return nil;
}
CGContextRef context = CGBitmapContextCreate(pixels,
width,
height,
bitsPerComponent,
bytesPerRow,
colorSpaceRef,
bitmapInfo);
if(context == NULL) {
NSLog(#"Error context not created");
free(pixels);
}
UIImage *image = nil;
if(context) {
CGContextDrawImage(context, CGRectMake(0.0f, 0.0f, width, height), iref);
CGImageRef imageRef = CGBitmapContextCreateImage(context);
// Support both iPad 3.2 and iPhone 4 Retina displays with the correct scale
if([UIImage respondsToSelector:#selector(imageWithCGImage:scale:orientation:)]) {
float scale = [[UIScreen mainScreen] scale];
image = [UIImage imageWithCGImage:imageRef scale:scale orientation:UIImageOrientationUp];
} else {
image = [UIImage imageWithCGImage:imageRef];
}
CGImageRelease(imageRef);
CGContextRelease(context);
}
CGColorSpaceRelease(colorSpaceRef);
CGImageRelease(iref);
CGDataProviderRelease(provider);
if(pixels) {
free(pixels);
}
return image;
}

Answer 1

solution:
my bitmap image data has only 3 bytes, but ios wants 4 bytes, the fourth is for alpha. so inserting the following code which added a 4th byte fixed the problem.
char* rgba = (char*)malloc(width*height*4);
for(int i=0; i < width*height; ++i) {
rgba[4*i] = buffer[3*i];
rgba[4*i+1] = buffer[3*i+1];
rgba[4*i+2] = buffer[3*i+2];
rgba[4*i+3] = 255;
}

Answer 2

Here is Conversion of NSData to UIImage :
NSData *imageData = UIImagePNGRepresentation(image);
UIImage *image=[UIImage imageWithData:data];
I have created PNG image using this code, hope it will works for you also.