My target is to display an image in a view.
Considering I've an:
IBOutlet NSImageView *image for display my image
NSData *imageData for readig the image file
NSImage *imageView
In imageData is stored the image (I've used initWithContentsOfFile method).
Now, if I initialize imageView with:
NSImage *imageView = [[NSImage alloc] initWithContentsOfFile:path];
I can see the rendering of the image correctly, but in this way I'm reading twice from the file system.
If I try to:
NSImage *imageView = [[NSImage alloc] initWithData:imageData];
The displayed image is very small..like thumb
Whit CGImageRef:
CGImageSourceRef imageSource = CGImageSourceCreateWithData((CFDataRef)imageData, NULL);
CGImageRef imageRef= CGImageSourceCreateImageAtIndex(imageSource, 0, nil);
NSImage *imageView = [[NSImage alloc] initWithCGImage:imageRef size:NSZeroSize];
The image is still rendering too small.
How can I display the image in original resolution?
NSImage *imageView = [[NSImage alloc] initWithData:(NSData *)imageData];
Related
I wrote the following and no image comes up. I displayed the pointer and it comes out as "0".
In the next code block I checked the path and made shore the image was present there. Still nothing loads.
NSImageView *vi = [[NSImageView alloc] initWithFrame:CGRectMake(10, 10, 220, 220)];
[self.view addSubview:vi];
NSImage *dog = [NSImage imageNamed:#"airnow3.jpg"];
NSLog(#"pointer %d", dog);
[vi setImage:dog];
NSFileManager *filemgr;
NSString *currentpath;
filemgr = [[NSFileManager alloc] init];
currentpath = [filemgr currentDirectoryPath];
NSLog(#"%#", currentpath);
Why don't you use InitWithImage:(NSImage) instead of InitWithFrame
Maybe you should use UIImageView.
UIImageView *imageView = [[UIImageView alloc] initWithFrame: CGRectMake(10,10,220,220)];
UIImage *image = [UIImage imageNamed:#"airnow3.jpg"];
[imageView setImage: image];
[self.view addSubview: imageView];
I have an app which loads an image from the local disk and then displays it on a UIImageView. I want to set the image to aspect scale to fit.
The problem I'm having is that the imageOrientation is coming back as UIImageOrientationRight even though it's a portrait image and that's messing with how the aspect calculations are done.
I've tried a few methods of changing the meta data but both rotate the image when it gets displayed.
UIImageView *iv = [[UIImageView alloc] initWithFrame:self.frame.frame];
NSMutableString *path =[[NSMutableString alloc] initWithString: [[NSBundle mainBundle] resourcePath]];
[path appendString:#"/pic2.jpg"];
NSData *data = [NSData dataWithContentsOfFile:path];
UIImage *img = [UIImage imageWithData:data];
UIImage *fixed1 = [UIImage imageWithCGImage:[img CGImage]
scale:1.0
orientation: UIImageOrientationUp];
UIImage *sourceImage = img;
UIImage *fixed2 = [UIImage
imageWithCGImage:[img imageRotatedByDegrees:90].CGImage
scale:sourceImage.scale
orientation:UIImageOrientationUp];
iv.image = fixed1; // fixed2;
[iv setContentMode:UIViewContentModeScaleAspectFill];
[self.view addSubview:iv];
In the end I took a different approach and made the UIImageView 360 wide and placed it in the centre and this achieved the desired effect.
How can i show only a portion of the original image in a UIImageView
This question may be very familiar and old, But the reason for asking again is,i could not find a workable idea with the help of those answers
Many said set image.contentMode = UIViewContentModeCenter; (but not working)
I need almost a rectangle containing the center of the original image,How do I get this ?
I do make this working,when i am displaying a static image to my app and setting Content mode of UIImageVie as Aspect Fill.
But this is not workable in the case when i am displaying an image from url and using NSData
Adding my code and the images
NSString *weburl = #"http://topnews.in/files/Sachin-Tendulkar_15.jpg";
UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(10, 50, 108, 86)];
NSURL *url = [NSURL URLWithString:weburl];
NSData *data = [NSData dataWithContentsOfURL:url];
imageView.image = [UIImage imageWithData:data];
[self.view addSubview:imageView];
If you added the UIImageView form XIB, you can find a "mode" property there and then you can see and set different modes from there (from Interface builder). Or by programatically, you can set different modes by
imageView.contentMode = UIViewContentModeCenter;
imageView.clipsToBounds = YES;
Try this:
self.imageView.layer.contentsRect = CGRectMake(0.25, 0.25, 0.5, 0.5);
self.imageView will display middle part of image. You can calculate itself the required values of CGRect
For this kind of output, you need to crop the image according to your requirement.
Cropping code as below which can be used.
-(UIImage *) CropImageFromTop:(UIImage *)image
{
CGImageRef imageRef = CGImageCreateWithImageInRect([image CGImage], CGRectMake(0, 12, image.size.width, image.size.height - 12));
UIImage *cropimage = [[[UIImage alloc] initWithCGImage:imageRef] autorelease];
CGImageRelease(imageRef);
return cropimage;
}
you try to scale image and then add image in UiImageView and set center that image then it is in center. code of scale image is
-(UIImage *)imageWithImage:(UIImage *)image scaledToSize:(CGSize)newSize{
UIGraphicsBeginImageContext(newSize);
[image drawInRect:CGRectMake(0, 0, newSize.width, newSize.height)];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
then you set the center of that image and add in the image view i hope this is work
I'm trying to create a custom MKAnnotationView with image from a url.
What happens is that when the device has retina display, the image of the MKAnnotationView is blurred, as it double its resolution.
If the image is from the app, it will load the #2x image (if one exists), but if you set an image from a url like this for example:
- (MKAnnotationView *) mapView:(MKMapView *) mapView viewForAnnotation:(id ) annotation
{
MKAnnotationView *customAnnotationView=[[MKAnnotationView alloc]
initWithAnnotation:annotation reuseIdentifier:nil];
NSData * imageData = [[NSData alloc] initWithContentsOfURL: [NSURL URLWithString:#"http://www.interaction-design.org/images/icons/play-button-red-300x300.png"]];
UIImage *img = [UIImage imageWithData:imageData];
[customAnnotationView setImage:img ];
return customAnnotationView;
}
you will see the image on an retina display very pixelated.
Any advice what to do?
Thanks
The gist is this...
Use [[UIScreen mainScreen] scale] to ask your server for a standard or #2x image.
Create a CGImageRef from the NSData
Use the CGImageRef and [[UIScreen mainScreen] scale] to create a UIImage
The code to do that looks like this:
NSString *imagePath = #"http://www.interaction-design.org/images/icons/play-button-red-300x300";
imagePath = [imagePath stringByAppendingString:[[UIScreen mainScreen] scale] > 1 ? #"#2x.png": #".png"];
NSData *imageData = [[NSData alloc] initWithContentsOfURL: [NSURL URLWithString:imagePath]];
CGDataProviderRef dataProvider = CGDataProviderCreateWithCFData((__bridge CFDataRef)imageData);
CGImageRef imageRef = CGImageCreateWithPNGDataProvider(dataProvider, NULL, NO, kCGRenderingIntentDefault);
UIImage *image = [UIImage imageWithCGImage:imageRef scale:[[UIScreen mainScreen] scale] orientation:UIImageOrientationUp];
CGDataProviderRelease(dataProvider);
CGImageRelease(imageRef);
Just note that you will need to have two resolutions of the image on the server given the first two lines of my code. Currently the image will appear smaller on retina, larger on non retina screens.
I am trying to convert an NSImage to a CIImage. When I do this, there seems to be a huge loss in image quality. I think it is because of the "TIFFRepresentation". Does anyone have a better method? Thanks a lot.
NSImage *image = [[NSImage alloc] initWithData:[someSource dataRepresentation]];
NSData * tiffData = [image TIFFRepresentation];
CIImage *backgroundCIImage = [[CIImage alloc] initWithData:tiffData];
CIContext *ciContext = [[NSGraphicsContext currentContext] CIContext];
[ciContext drawImage:backgroundCIImage atPoint:CGPointZero fromRect:someRect];
Your problem is indeed converting to TIFF. PDF is a vector format, while TIFF is bitmap, so a TIFF will look blurry at larger sizes.
Your best bet is probably to get a CGImage from the NSImage and create the CIImage from that. Either that or just create the CIImage from the original data.
Try replacing the line
NSData * tiffData = [image TIFFRepresentation];
with
NSData * tiffData = [image TIFFRepresentationUsingCompression: NSTIFFCompressionNone factor: 0.0f];
because the documentation states that TIFFRepresentation uses the TIFF compression option associated with each image representation, which might not be NSTIFFCompressionNone. Thus, you should be explicit about wanting the tiffData uncompressed.
I finally solved the problem. Basically, I render the pdf document two times its normal resolution offscreen and then capture the image displayed by the view. For a more detailed image, just increase the scaling factor. Please see the code below for the proof of concept. I didn't show the CIImage but once you get the bitmap, just use the CIImage method to create the CIImage from the bitmap.
NSImage *pdfImage = [[NSImage alloc] initWithData:[[aPDFView activePage] dataRepresentation]];
NSSize size = [pdfImage size];
NSRect imageRect = NSMakeRect(0, 0, size.width, size.height);
imageRect.size.width *= 2; //Twice the scale factor
imageRect.size.height *= 2; //Twice the scale factor
PDFDocument *pageDocument = [[[PDFDocument alloc] init] autorelease];
[pageDocument insertPage:[aPDFView activePage] atIndex:0];
PDFView *pageView = [[[PDFView alloc] init] autorelease];
[pageView setDocument:pageDocument];
[pageView setAutoScales:YES];
NSWindow *offscreenWindow = [[NSWindow alloc] initWithContentRect:imageRect
styleMask:NSBorderlessWindowMask
backing:NSBackingStoreRetained
defer:NO];
[offscreenWindow setContentView:pageView];
[offscreenWindow display];
[[offscreenWindow contentView] display]; // Draw to the backing buffer
// Create the NSBitmapImageRep
[[offscreenWindow contentView] lockFocus];
NSBitmapImageRep* rep = [[NSBitmapImageRep alloc] initWithFocusedViewRect:imageRect];
// Clean up and delete the window, which is no longer needed.
[[offscreenWindow contentView] unlockFocus];
[compositeImage TIFFRepresentation]];
NSData *imageData = [rep representationUsingType: NSJPEGFileType properties: nil];
[imageData writeToFile:#"/Users/David/Desktop/out.jpg" atomically: YES];
[offscreenWindow release];