I have a little flow problem with my UICollectionView. I want to display PDF's thumbnails just like in Apple's iBook app, when I scroll my collection view I can see it's not really smooth. Here is the way I use to load my pictures :
- (UICollectionViewCell *)collectionView:(UICollectionView *)cv cellForItemAtIndexPath: (NSIndexPath *)indexPath
{
GridCell *cell = [cv dequeueReusableCellWithReuseIdentifier:#"gridCell" forIndexPath:indexPath];
...
// Set Thumbnail
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
if ([Tools checkIfLocalFileExist:cell.pdfDoc])
{
UIImage *thumbnail = [Tools generateThumbnailForFile:((PDFDocument *)[self.pdfList objectAtIndex:indexPath.row]).title];
dispatch_async( dispatch_get_main_queue(), ^{
[cell.imageView setImage:thumbnail];
});
}
});
...
return cell;
}
Method to get thumbnail :
+ (UIImage *)generateThumbnailForFile:(NSString *) fileName
{
// ----- Check if thumbnail already exist
NSString* documentsPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
NSString* thumbnailAddress = [documentsPath stringByAppendingPathComponent:[[fileName stringByDeletingPathExtension] stringByAppendingString:#".png"]];
BOOL fileExists = [[NSFileManager defaultManager] fileExistsAtPath:thumbnailAddress];
if (fileExists)
return [UIImage imageWithContentsOfFile:thumbnailAddress];
// ----- Generate Thumbnail
NSString* filePath = [documentsPath stringByAppendingPathComponent:fileName];
CFURLRef url = (__bridge CFURLRef)[NSURL fileURLWithPath:filePath];
CGPDFDocumentRef documentRef = CGPDFDocumentCreateWithURL(url);
CGPDFPageRef pageRef = CGPDFDocumentGetPage(documentRef, 1);
CGRect pageRect = CGPDFPageGetBoxRect(pageRef, kCGPDFCropBox);
UIGraphicsBeginImageContext(pageRect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextTranslateCTM(context, CGRectGetMinX(pageRect),CGRectGetMaxY(pageRect));
CGContextScaleCTM(context, 1, -1);
CGContextTranslateCTM(context, -(pageRect.origin.x), -(pageRect.origin.y));
CGContextDrawPDFPage(context, pageRef);
// ----- Save Image
UIImage *finalImage = UIGraphicsGetImageFromCurrentImageContext();
NSData *imageData = [NSData dataWithData:UIImagePNGRepresentation(finalImage)];
[imageData writeToFile:thumbnailAddress atomically:YES];
UIGraphicsEndImageContext();
return finalImage;
}
Do you have any suggestion ?
Take a look at https://github.com/rs/SDWebImage. The library works great for async image loading particularly the method setImageWithURL:placeholderImage:
You can call that method and set a place holder with a loading image or blank png and once the image you are trying to retrieve is loaded it will fill in the place holder. This should speed up your app quite a bit.
Related
I'm creating images array for UIImageView so I can use [_myImageView startAnimating]; method. I figuree out that if I cache(preload) it like this way the animation is fluent.
But in Instruments I see, that game is deallocated but there is still too much memory allocated - I think there are some fragments of this UIGraphicsBeginContext stuff.
Am I using it right, is there some other way how to dealloc it?
Thanks in advance!
- (NSMutableArray *)generateCachedImageArrayWithFilename:(NSString *)filename extension:(NSString *)extension andImageCount:(int)count
{
_imagesArray = [[NSMutableArray alloc] init];
_fileExtension = extension;
_animationImageName = filename;
_imageCount = count;
for (int i = 0; i < count; i++)
{
NSString *tempImageNames = [NSString stringWithFormat:#"%#%i", filename, i];
NSString *imagePath = [[NSBundle mainBundle] pathForResource:tempImageNames ofType:extension];
UIImage *frameImage = [self loadRetinaImageIfAvailable:imagePath];
UIGraphicsBeginImageContext(frameImage.size);
CGRect rect = CGRectMake(0, 0, frameImage.size.width, frameImage.size.height);
[frameImage drawInRect:rect];
UIImage *renderedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
[_imagesArray addObject:renderedImage];
if (_isDoublingFrames)
{
[_imagesArray addObject:renderedImage];
}
else if (_isTriplingFrames)
{
[_imagesArray addObject:renderedImage];
[_imagesArray addObject:renderedImage];
}
NSLog(#"filename = %#", filename);
}
return _imagesArray;
}
- (UIImage *)loadRetinaImageIfAvailable:(NSString *)path
{
NSString *retinaPath = [[path stringByDeletingLastPathComponent] stringByAppendingPathComponent:[NSString stringWithFormat:#"%##2x.%#", [[path lastPathComponent] stringByDeletingPathExtension], [path pathExtension]]];
if ([UIScreen mainScreen].scale == 2.0 && [[NSFileManager defaultManager] fileExistsAtPath:retinaPath] == YES)
return [[UIImage alloc] initWithCGImage:[[UIImage imageWithData:[NSData dataWithContentsOfFile:retinaPath]] CGImage] scale:2.0 orientation:UIImageOrientationUp];
else
return [UIImage imageWithContentsOfFile:path];
}
-(void) dealloc
{
[_imagesArray removeAllObjects];
_imagesArray = nil;
}
I had memory issues similar you wrote and what I would try out in your code
1) use #autoreleasepool
to wrap either the method or the content of the loop in #autoreleasepool { } to create a local pool which will be released after method is done. In your situation it seems to me wrapping the loop is better:
for (int i = 0; i < count; i++)
{
#autoreleasepool {
// the loop code
...
}}
2) kill [UIImage imageNamed]
Using imageNamed will prepare a cache (depending on the size of image) which will never be flushed out of the memory unless you reach a memory warning. Even if you set myImage.image = nil, the image is still in memory. XCode's Intruments tool Allocations view will show it nicely. What you can do is initialize UIImage like this, and iOS won't cache the image:
image = [UIImage imageWithContentsOfFile:fullpath];
You might use imageNamed in your code under loadRetinaImageIfAvailable.
Keep both two approach and let's check this out again!
I am creating pdf from UIView to pdf it works fine but i have scrollView with content which i want to convert to pdf but it only show visible part in pdf not the whole scrollView content. here is my code
-(void)createPDFfromUIView:(UIView*)aView saveToDocumentsWithFileName:(NSString*)aFilename
{
NSMutableData *pdfData = [NSMutableData data];
// Get Scrollview size
CGRect scrollSize = CGRectMake(1018,76,scrollView.contentSize.width,scrollView.contentSize.height);
// Points the pdf converter to the mutable data object and to the UIView to be converted
UIGraphicsBeginPDFContextToData(pdfData, scrollSize, nil);
UIGraphicsBeginPDFPage();
CGContextRef pdfContext = UIGraphicsGetCurrentContext();
// draws rect to the view and thus this is captured by UIGraphicsBeginPDFContextToData
[aView.layer renderInContext:pdfContext];
// remove PDF rendering context
UIGraphicsEndPDFContext();
// Retrieves the document directories from the iOS device
NSArray* documentDirectories = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask,YES);
NSString* documentDirectory = [documentDirectories objectAtIndex:0];
NSString* documentDirectoryFilename = [documentDirectory stringByAppendingPathComponent:aFilename];
// instructs the mutable data object to write its context to a file on disk
[pdfData writeToFile:documentDirectoryFilename atomically:YES];
NSLog(#"documentDirectoryFileName: %#",documentDirectoryFilename);
}
THis gives you the visible portion of the UIScrollView
CGRect visibleRect;
visibleRect.origin = scrollView.contentOffset;
visibleRect.size = scrollView.bounds.size;
float theScale = 1.0 / scale;
visibleRect.origin.x *= theScale;
visibleRect.origin.y *= theScale;
visibleRect.size.width *= theScale;
visibleRect.size.height *= theScale;
so you can use this in UIGraphicsBeginPDFContextToData(pdfData, aView.bounds, nil);
by some minor changes in the parameters.
(void)createPDFfromUIView:(UIScrollView*)aView saveToDocumentsWithFileName:(NSString*)aFilename
{
// Creates a mutable data object for updating with binary data, like a byte array
NSMutableData *pdfData = [NSMutableData data];
// Get Scrollview size
CGRect scrollSize = CGRectMake(aView.origin.x,aView.origin.y,aView.contentSize.width,aView.contentSize.height);
// Points the pdf converter to the mutable data object and to the UIView to be converted
UIGraphicsBeginPDFContextToData(pdfData, scrollSize, nil);
UIGraphicsBeginPDFPage();
CGContextRef pdfContext = UIGraphicsGetCurrentContext();
// draws rect to the view and thus this is captured by UIGraphicsBeginPDFContextToData
[aView.layer renderInContext:pdfContext];
// remove PDF rendering context
UIGraphicsEndPDFContext();
// Retrieves the document directories from the iOS device
NSArray* documentDirectories = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask,YES);
NSString* documentDirectory = [documentDirectories objectAtIndex:0];
NSString* documentDirectoryFilename = [documentDirectory stringByAppendingPathComponent:aFilename];
// instructs the mutable data object to write its context to a file on disk
[pdfData writeToFile:documentDirectoryFilename atomically:YES];
NSLog(#"documentDirectoryFileName: %#",documentDirectoryFilename);
}
This code i used to make pdf from uiscrollview and it does help but it will not be as good as if we draw on pdf -- please have look -- Pdf from UIScrollView
- (void) createPDF
{
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *directroyPath = nil;
directroyPath = [documentsDirectory stringByAppendingPathComponent:#"temp"];
NSString *filePath = [directroyPath stringByAppendingPathComponent:#"test.pdf"];
// check for the "PDF" directory
NSError *error;
if ([[NSFileManager defaultManager] fileExistsAtPath:filePath]) {
} else {
[[NSFileManager defaultManager] createDirectoryAtPath:directroyPath
withIntermediateDirectories:NO
attributes:nil
error:&error];
}
CGContextRef pdfContext = [self createPDFContext:_scrollView2.bounds path:(CFStringRef)filePath];
NSLog(#"PDF Context created");
/*
Here limit of i is no of pages in your uiscrollview or
you can use hit and trial here because there is a
length of page is going to be equal to
the visible size of uiscrollView in your application
*/
for (int i = 0 ; i< 2 ; i++)
{
// page 1
CGContextBeginPage (pdfContext,nil);
//turn PDF upsidedown
CGAffineTransform transform = CGAffineTransformIdentity;
//here 365 is equal to the height of myScrollView.frame.size.height
transform = CGAffineTransformMakeTranslation(0, (i+1) * 365);
transform = CGAffineTransformScale(transform, 1.0, -1.0);
CGContextConcatCTM(pdfContext, transform);
//Draw view into PDF
[_scrollView2.layer renderInContext:pdfContext];
CGContextEndPage (pdfContext);
[_scrollView2 setContentOffset:CGPointMake(0, (i+1) * 365) animated:NO];
}
CGContextRelease (pdfContext);
}
- (CGContextRef) createPDFContext:(CGRect)inMediaBox path:(CFStringRef) path
{
CGContextRef myOutContext = NULL;
CFURLRef url;
url = CFURLCreateWithFileSystemPath (NULL, path,
kCFURLPOSIXPathStyle,
false);
if (url != NULL) {
myOutContext = CGPDFContextCreateWithURL (url,
&inMediaBox,
NULL);
CFRelease(url);
}
return myOutContext;
}
The easiest way to convert the scrollview content into a PDF file is to have a content view as the first subview of the scrollview and using that view to take a snapshot of the scrollview. The code in Swift would look like this:
func generatePDFdata(withView view: UIView) -> NSData {
let pageDimensions = view.bounds
let outputData = NSMutableData()
UIGraphicsBeginPDFContextToData(outputData, pageDimensions, nil)
if let context = UIGraphicsGetCurrentContext() {
UIGraphicsBeginPDFPage()
view.layer.render(in: context)
}
UIGraphicsEndPDFContext()
return outputData
}
You can then use the outputData to write into a PDF file:
outputData.write(to: pdfFileUrl, atomically: true)
My client wants to share an image on Instagram. I have implemeted sharing image on instagram.But i could not share it with a special hashtag. Here is my code so far.
- (IBAction)sharePhotoOnInstagram:(id)sender {
UIImagePickerController *imgpicker=[[UIImagePickerController alloc] init];
imgpicker.delegate=self;
[self storeimage];
NSURL *instagramURL = [NSURL URLWithString:#"instagram://app"];
if ([[UIApplication sharedApplication] canOpenURL:instagramURL])
{
CGRect rect = CGRectMake(0 ,0 , 612, 612);
NSString *jpgPath = [NSHomeDirectory() stringByAppendingPathComponent:#"Documents/15717.ig"];
NSURL *igImageHookFile = [[NSURL alloc] initWithString:[[NSString alloc] initWithFormat:#"file://%#", jpgPath]];
dic.UTI = #"com.instagram.photo";
dic.delegate = self;
dic = [self setupControllerWithURL:igImageHookFile usingDelegate:self];
dic = [UIDocumentInteractionController interactionControllerWithURL:igImageHookFile];
dic.delegate = self;
[dic presentOpenInMenuFromRect: rect inView: self.view animated: YES ];
// [[UIApplication sharedApplication] openURL:instagramURL];
}
else
{
// NSLog(#"instagramImageShare");
UIAlertView *errorToShare = [[UIAlertView alloc] initWithTitle:#"Instagram unavailable " message:#"You need to install Instagram in your device in order to share this image" delegate:nil cancelButtonTitle:#"OK" otherButtonTitles:nil];
errorToShare.tag=3010;
[errorToShare show];
}
}
- (void) storeimage
{
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *savedImagePath = [documentsDirectory stringByAppendingPathComponent:#"15717.ig"];
UIImage *NewImg = [self resizedImage:picTaken :CGRectMake(0, 0, 612, 612) ];
NSData *imageData = UIImagePNGRepresentation(NewImg);
[imageData writeToFile:savedImagePath atomically:NO];
}
-(UIImage*) resizedImage:(UIImage *)inImage: (CGRect) thumbRect
{
CGImageRef imageRef = [inImage CGImage];
CGImageAlphaInfo alphaInfo = CGImageGetAlphaInfo(imageRef);
// There's a wierdness with kCGImageAlphaNone and CGBitmapContextCreate
// see Supported Pixel Formats in the Quartz 2D Programming Guide
// Creating a Bitmap Graphics Context section
// only RGB 8 bit images with alpha of kCGImageAlphaNoneSkipFirst, kCGImageAlphaNoneSkipLast, kCGImageAlphaPremultipliedFirst,
// and kCGImageAlphaPremultipliedLast, with a few other oddball image kinds are supported
// The images on input here are likely to be png or jpeg files
if (alphaInfo == kCGImageAlphaNone)
alphaInfo = kCGImageAlphaNoneSkipLast;
// Build a bitmap context that's the size of the thumbRect
CGContextRef bitmap = CGBitmapContextCreate(
NULL,
thumbRect.size.width, // width
thumbRect.size.height, // height
CGImageGetBitsPerComponent(imageRef), // really needs to always be 8
4 * thumbRect.size.width, // rowbytes
CGImageGetColorSpace(imageRef),
alphaInfo
);
// Draw into the context, this scales the image
CGContextDrawImage(bitmap, thumbRect, imageRef);
// Get an image from the context and a UIImage
CGImageRef ref = CGBitmapContextCreateImage(bitmap);
UIImage* result = [UIImage imageWithCGImage:ref];
CGContextRelease(bitmap); // ok if NULL
CGImageRelease(ref);
return result;
}
- (UIDocumentInteractionController *) setupControllerWithURL: (NSURL*) fileURL usingDelegate: (id <UIDocumentInteractionControllerDelegate>) interactionDelegate
{
UIDocumentInteractionController *interactionController = [UIDocumentInteractionController interactionControllerWithURL:fileURL];
interactionController.delegate = self;
return interactionController;
}
- (void)documentInteractionControllerWillPresentOpenInMenu:(UIDocumentInteractionController *)controller
{
}
- (BOOL)documentInteractionController:(UIDocumentInteractionController *)controller canPerformAction:(SEL)action
{
// NSLog(#"5dsklfjkljas");
return YES;
}
- (BOOL)documentInteractionController:(UIDocumentInteractionController *)controller performAction:(SEL)action
{
// NSLog(#"dsfa");
return YES;
}
- (void)documentInteractionController:(UIDocumentInteractionController *)controller didEndSendingToApplication:(NSString *)application
{
// NSLog(#"fsafasd;");
}
Note : This is working fine.
I have followed their documentation on http://instagram.com/developer/iphone-hooks/ but couldn't get better idea from it!. Now don't know what to do next step for sharing an image with hashtag and other information.
Secondly I want to retrieve all the images shared with a particular hashtag into the application.
Please guide me! Thanks in advance!
First, from iPhone Hooks, under 'Document Interaction':
To include a pre-filled caption with your photo, you can set the annotation property on the document interaction request to an NSDictionary containing an NSString under the key "InstagramCaption". Note: this feature will be available on Instagram 2.1 and later.
You'll need to add something like:
dic.annotation = [NSDictionary dictionaryWithObject:#"#yourTagHere" forKey:#"InstagramCaption"];
Second, you'll need to take a look at Tag Endpoints if you want to pull down images with a specific tag.
+(UIImage*) createCGImageFromFile:(NSString*)inName
{
if(!inName || [inName length]==0)
return NULL;
// use the data provider to get a CGImage; release the data provider
CGImageRef image= NULL;
CGFloat scale = 1.0f;
CGDataProviderRef dataProvider = NULL;
NSString *fileName = nil;
NSString *path = nil;
if([Utilities isRetinaDevice])
{
NSString *extenstion = [inName pathExtension];
NSString *stringWithoutPath = [inName stringByDeletingPathExtension];
fileName = [NSString stringWithFormat:#"/Images/%##2x.%#",stringWithoutPath,extenstion];
path = [[[NSBundle mainBundle] resourcePath] stringByAppendingString:fileName];
dataProvider = CGDataProviderCreateWithFilename([path UTF8String]);
if(dataProvider)
{
image = CGImageCreateWithPNGDataProvider(dataProvider, NULL, NO,kCGRenderingIntentDefault);
CGDataProviderRelease(dataProvider);
if(image)
{
scale = 2.0f;
}
}
}
if(image == NULL) //Try normal image
{
fileName = [NSString stringWithFormat:#"/Images/%#",inName];
path = [[[NSBundle mainBundle] resourcePath] stringByAppendingString:fileName];
dataProvider = CGDataProviderCreateWithFilename([path UTF8String]);
if(dataProvider)
{
image = CGImageCreateWithPNGDataProvider(dataProvider, NULL, NO,kCGRenderingIntentDefault);
CGDataProviderRelease(dataProvider);
}
}
// make a bitmap context of a suitable size to draw to, forcing decode
size_t width = CGImageGetWidth(image);
size_t height = CGImageGetHeight(image);
unsigned char *imageBuffer = (unsigned char *)malloc(width*height*4);
CGColorSpaceRef colourSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef imageContext =
CGBitmapContextCreate(imageBuffer, width, height, 8, width*4, colourSpace,
kCGImageAlphaPremultipliedFirst | kCGBitmapByteOrder32Little);
CGColorSpaceRelease(colourSpace);
// draw the image to the context, release it
CGContextDrawImage(imageContext, CGRectMake(0, 0, width, height), image);
CGImageRelease(image);
// now get an image ref from the context
CGImageRef cgImageRef = CGBitmapContextCreateImage(imageContext);
CGContextRelease(imageContext);
free(imageBuffer);
UIImage *outImage = nil;
if(cgImageRef)
{
outImage = [[UIImage alloc] initWithCGImage:cgImageRef scale:scale orientation:UIImageOrientationUp];
CGImageRelease(cgImageRef);
}
return outImage;//Need to release by the receiver
}
Earlier the function was not loading retina images since i was not appending #2x to the image path, i thought that apple itself will take care.
Now I modified the code to load #2x images and created UIImage using scale factor, am I missing something in above code? Is it fine?
P.S. Currently I am not facing any problem using this code but I am not 100% sure
I would use UIImage to load it (it will correct the path)
That will greatly simply your code
THEN get a CGImage from it (UIImage is basically just a thin wrapper around CG so thats no real overhead)
then proceed with your code - it looks ok to me
I am using the ImageDemo template and it works great if I code in an image from the bundle but when I try and load them from directories I have created in my app I have no luck.
Code:
- (AQGridViewCell *) gridView: (AQGridView *) aGridView cellForItemAtIndex: (NSUInteger) index
{
static NSString * PlainCellIdentifier = #"PlainCellIdentifier";
AQGridViewCell * cell = nil;
ImageDemoGridViewCell * plainCell = (ImageDemoGridViewCell *)[aGridView dequeueReusableCellWithIdentifier: PlainCellIdentifier];
if ( plainCell == nil )
{
plainCell = [[[ImageDemoGridViewCell alloc] initWithFrame: CGRectMake(0.0, 0.0, 200.0, 150.0)
reuseIdentifier: PlainCellIdentifier] autorelease];
plainCell.selectionGlowColor = [UIColor lightGrayColor];
}
NSString *fileName = [NSString stringWithFormat:#"%#/%#_tn.jpg",[manufacturerID stringValue], [[[self.collectionItems objectAtIndex:index] valueForKey:#"PhotoName"] stringByReplacingOccurrencesOfString:#" " withString:#"%20"]];
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsPath = [paths objectAtIndex:0];
NSString *savePath =[documentsPath stringByAppendingPathComponent:fileName] ;
NSData *imageData = nil;
BOOL fileExists = [[NSFileManager defaultManager] fileExistsAtPath:savePath];
if (fileExists) {
imageData = [NSData dataWithContentsOfFile:savePath];
} else {
NSString *filePath = [[NSBundle mainBundle] pathForResource:#"NoImageAvailableThumbNail" ofType:#"png"];
imageData = [NSData dataWithContentsOfFile:filePath];
}
UIImage *myImage = [UIImage imageWithData:imageData];
NSLog(#"%#", myImage);
if (myImage==nil) {
NSLog(#"NO IMAGE");
}
plainCell.image = myImage;
cell = plainCell;
return ( cell );
}
I code I am using to pull the image data I know works because I use it all over in other places in my app and I am checking for nil when I set the property on the AQGridViewCell:
- (void) setImage: (UIImage *) anImage
{
_imageView.image = anImage;
[self setNeedsLayout];
}
I don't see the check for a nil UIImage in your example there. Are you certain it's being loaded correctly? Try creating the image on one line and setting it on another so you can see it being created in the debugger. For reference, I do something similar with cached book cover images in the Kobo app, and that works. One difference though is that I use the C methods to load a UIImage from a PNG file. Something like UIImageFromPNGData(), off the top of my head (sorry replying by iPhone right now).
The only other thing I can think to check is whether the image view is hidden for some reason. Printing it in the debugger should tell you that, along with it's size, layout, etc.