why some UIimages don't show up in iphone - iphone

Question

hi I am currently developing a small app on ios 4.3 , using objective c
as part of the app I need to manipulate an Image that I have downloaded from the web.
the following code shows up a missing image:
(the original is in a class but I just put this together as a test scenario so that it could be easily copy pasted)
- (void)viewDidLoad
{
[super viewDidLoad];
[self loadImage:#"http://www.night-net.net/images/ms/microsoft_vista_home_basic.jpg"];
[self getCroped:CGRectMake(10, 50, 80, 160)];
[self getCroped:CGRectMake(90, 50, 80, 80)];
[self getCroped:CGRectMake(90, 130, 40, 80)];
[self getCroped:CGRectMake(130, 130, 40, 40)];
[self getCroped:CGRectMake(130, 170, 40, 40)];
}
-(void) loadImage : (NSString*) url
{
_data = [NSData dataWithContentsOfURL:
[NSURL URLWithString: url]];
}
-(UIImageView*) getCroped:(CGRect) imageSize{
UIImage *temp = [[UIImage alloc] initWithData:_data];
UIImage *myImage = [self resizedImage:temp and:CGSizeMake(160,160) interpolationQuality:kCGInterpolationHigh];
UIImage *image = [self croppedImage:myImage and:imageSize];
UIImageView *imageView = [[UIImageView alloc] init];
imageView.image = image;
imageView.frame = imageSize;
[[self view] addSubview:imageView];
return imageView;
}
- (UIImage *)croppedImage:(UIImage*) image and: (CGRect)bounds {
CGImageRef imageRef = CGImageCreateWithImageInRect([image CGImage], bounds);
UIImage *croppedImage = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
return croppedImage;
}
- (UIImage *)resizedImage:(UIImage*) image and:(CGSize)newSize interpolationQuality:(CGInterpolationQuality)quality {
BOOL drawTransposed = NO;
return [self resizedImage:image
and:newSize
transform:[self transformForOrientation:newSize]
drawTransposed:drawTransposed
interpolationQuality:quality];
}
// Returns a copy of the image that has been transformed using the given affine transform and scaled to the new size
// The new image's orientation will be UIImageOrientationUp, regardless of the current image's orientation
// If the new size is not integral, it will be rounded up
- (UIImage *)resizedImage:(UIImage*) image and:(CGSize)newSize
transform:(CGAffineTransform)transform
drawTransposed:(BOOL)transpose
interpolationQuality:(CGInterpolationQuality)quality {
CGRect newRect = CGRectIntegral(CGRectMake(0, 0, newSize.width, newSize.height));
CGRect transposedRect = CGRectMake(0, 0, newRect.size.height, newRect.size.width);
CGImageRef imageRef = image.CGImage;
// Build a context that's the same dimensions as the new size
CGContextRef bitmap = CGBitmapContextCreate(NULL,
newRect.size.width,
newRect.size.height,
CGImageGetBitsPerComponent(imageRef),
0,
CGImageGetColorSpace(imageRef),
CGImageGetBitmapInfo(imageRef));
// Rotate and/or flip the image if required by its orientation
CGContextConcatCTM(bitmap, transform);
// Set the quality level to use when rescaling
CGContextSetInterpolationQuality(bitmap, quality);
// Draw into the context; this scales the image
CGContextDrawImage(bitmap, transpose ? transposedRect : newRect, imageRef);
// Get the resized image from the context and a UIImage
CGImageRef newImageRef = CGBitmapContextCreateImage(bitmap);
UIImage *newImage = [UIImage imageWithCGImage:newImageRef];
// Clean up
CGContextRelease(bitmap);
CGImageRelease(newImageRef);
return newImage;
}
// Returns an affine transform that takes into account the image orientation when drawing a scaled image
- (CGAffineTransform)transformForOrientation:(CGSize)newSize {
CGAffineTransform transform = CGAffineTransformIdentity;
transform = CGAffineTransformTranslate(transform, newSize.width, 0);
transform = CGAffineTransformScale(transform, -1, 1);
return transform;
}
at first I thought this is caused by a lack of memory, but I have tested for that and that doesnt seem to be the problem,thanks in advance ofir

Answer 1

I've had issues in the past with images not appearing within UIWebViews if they contain unicode characters in the filename. I wonder if this might be the same thing. Try renaming your image?

Answer 2

doing this should be possible and low on memory cost as I did the same test,using flash to create an iphone app that does the same thing, and it works.
but I would much prefer using objective c so the question still stands