I tried to use CGImageSourceCreateWithURL method like below, but it seems both height and width are equal 0. Is there any other way to get webp image from url?
CGImageSourceRef source = CGImageSourceCreateWithURL((CFURLRef)imageUrl, NULL);
NSDictionary* imageHeader = (__bridge NSDictionary*) CGImageSourceCopyPropertiesAtIndex(source, 0, NULL);
NSLog(#"Image header %#",imageHeader);
NSLog(#"PixelHeight %#",[imageHeader objectForKey:#"PixelHeight"]);
NSNumber* height = [imageHeader objectForKey:#"PixelHeight"];
NSNumber* width = [imageHeader objectForKey:#"PixelWidth"];
The webp format image is not supported in iOS. You can use URLSession to fetch image data, then use it to create NSImage with SDWebImage.
Related
I need to read the properties of an image without load or download it. In fact i have implemented a simple method that use the CGImageSourceCreateWithUrl for accomplish this.
My problem is that it is returning always error because seems that the imageSource is null. So what can i do for fix it?
In the NSURL object i pass urls like:
"http://www.example.com/wp-content/uploads/image.jpg" but also ALAssets library Id used to retrieve images inside the phone like "assets-library://asset/asset.JPG?id=E5F41458-962D-47DD-B5EF-E606E2A8AC7A&ext=JPG".
This is my method:
-(NSString *) getPhotoInfo:(NSString *)paths{
NSString *xmlList = #“test”;
NSURL * imageFileURL = [NSURL fileURLWithPath:paths];
NSLog(#"imageFileURL %#", imageFileURL);
CGImageSourceRef imageSource = CGImageSourceCreateWithURL((__bridge CFURLRef)(imageFileURL), NULL);
if (imageSource == NULL) {
// Error loading image
NSLog(#"Error loading image");
}
CGFloat width = 0.0f, height = 0.0f;
CFDictionaryRef imageProperties = CGImageSourceCopyPropertiesAtIndex(imageSource, 0, NULL);
NSLog(#"image source %#", imageSource);
return xmlList;
}
I have saw this posts for try to fix it but nothing seems working:
CGImageSourceRef imageSource = CGImageSourceCreateWithURL returns NULL
CGImageSourceCreateWithURL with authentication
accessing UIImage properties without loading in memory the image
In my project ARC is enabled.
Thanks
If you are passing the string "http://www.example.com/wp-content/uploads/image.jpg” to -fileURLWithPath: it’s going to return nil, because that string is sure not a file path, it’s a URL string.
Think of -fileURLWithPath: as just prepending the string you pass in with “file://localhost/“...so you’d end up with a URL that looks like "file://localhost/http://www.example.com/wp-content/uploads/image.jpg”. That’s not good.
You need to call [NSURL URLWithString:paths] if you’re going to be passing in entire URL strings, not just a filesystem path strings.
Working with "assets-library://asset/asset.JPG?id.........., try this code
-(UIImage*)resizeImageToMaxSize:(CGFloat)max anImage:(UIImage*)anImage
{
NSData * imgData = UIImageJPEGRepresentation(anImage, 1);
CGImageSourceRef imageSource = CGImageSourceCreateWithData((CFDataRef)imgData, NULL);
if (!imageSource)
return nil;
CFDictionaryRef options = (CFDictionaryRef)[NSDictionary dictionaryWithObjectsAndKeys:
(id)kCFBooleanTrue, (id)kCGImageSourceCreateThumbnailWithTransform,
(id)kCFBooleanTrue, (id)kCGImageSourceCreateThumbnailFromImageIfAbsent,
(id)[NSNumber numberWithFloat:max], (id)kCGImageSourceThumbnailMaxPixelSize,
nil];
CGImageRef imgRef = CGImageSourceCreateThumbnailAtIndex(imageSource, 0, options);
UIImage* scaled = [UIImage imageWithCGImage:imgRef];
//these lines might be skipped for ARC enabled
CGImageRelease(imgRef);
CFRelease(imageSource);
return scaled; }
in my ios app i am listing out some data in scroll view. When a button is clicked the datas in the page are been generated in pdf file format. Following is the bit of code.
- (void)createPDFfromUIView:(UIView*)aView saveToDocumentsWithFileName:(NSString*)aFilename{
// Creates a mutable data object for updating with binary data, like a byte array
NSMutableData *pdfData = [NSMutableData data];
// Points the pdf converter to the mutable data object and to the UIView to be converted
UIGraphicsBeginPDFContextToData(pdfData, aView.bounds, 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);
}
From the above code, i am able to generate a pdf file, but i am facing the following issue.
If i have more than 50 data, in my app i am able to see only the first 10 data and to see the others i need to scroll them. In this case when the pdf file gets generated it is taking only the data of first 10 and not the others. How to get the other data too
renderInContext: will only render what you currently see - UIScrollView is smart and will only have the views in the hierarchy that you need right now. You need a for-loop to manually scroll and redraw. This might be tricky to get right, maybe call [aView layoutSubviews] manually after scrolling to force the scrollView to rearrange the subviews instantly.
as steipete said, you can use loop to renderIncontext
- You need to calculate num of loop
numOfLoop = webview.ScrollView.ContentSize.Height/weview.frame.size.height
use loop to renderInContext
for(int i = 0; i < numOfLopp; i ++)
1.UIGraphicsBeginPDFPage()
get current context
renderIncontext
This way run correct in my app but I am getting with BIG issue when the numOfLoop lager
- you will get slow to renderInContext
- Memory will be increase -> Close app
In this way, How can I remove/release context when I am in once loop ?
Other way, you can use https://github.com/iclems/iOS-htmltopdf/blob/master/NDHTMLtoPDF.h
to generate to PDF
#steipete, #all Hi i tried the below code it generate multipage PDF, but the visible area in view is repeated for all the pages. please add any further ideas to improve the result.
-(void)createPDFfromUIView:(UIWebView*)aView saveToDocumentsWithFileName:(NSString*)aFilename
{
NSString *oldFilePath= [[NSBundle mainBundle] pathForResource:#"ABC" ofType:#"pdf"];
NSMutableData *pdfData = [NSMutableData data];
UIGraphicsBeginPDFContextToData(pdfData, aView.bounds, nil);
CFURLRef url = CFURLCreateWithFileSystemPath (NULL, (CFStringRef)oldFilePath, kCFURLPOSIXPathStyle, 0);
CGPDFDocumentRef templateDocument = CGPDFDocumentCreateWithURL(url);
CFRelease(url); size_t count = CGPDFDocumentGetNumberOfPages(templateDocument);
for (size_t pageNumber = 1; pageNumber <= count; pageNumber++)
{
UIGraphicsBeginPDFPage();
CGContextRef pdfContext = UIGraphicsGetCurrentContext();
[aView.layer renderInContext:pdfContext];
}
CGPDFDocumentRelease(templateDocument);
// 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];
[pdfData writeToFile:documentDirectoryFilename atomically:YES];
NSLog(#"documentDirectoryFileName: %#",documentDirectoryFilename);
}
Check ScrollViewToPDF example
It uses same scrollview's layer renderInContext but here PDF is created according to your requirement such as one page PDF or multiple page PDF
Note : It captures all visible as well as invisible part of scrollView
On CGImageDestinationRef Apple's reference it mentions that It can contain thumbnail images as well as properties for each image. The part with the properties works nice, by setting the properties parameter when adding a image to the CGImageDestinationRef, but I can't figure out how to add the thumbnail.
I want to add a thumbnail (or pass it directly from a CGImageSourceRef) to CGImageDestinationRef, such that when the resulting image is opened with CGImageSourceRef I can use CGImageSourceCreateThumbnailAtIndex to retrieve the original thumbnail.
NSDictionary* thumbOpts = [NSDictionary dictionaryWithObjectsAndKeys:
(id)kCFBooleanTrue, (id)kCGImageSourceCreateThumbnailWithTransform,
(id)kCFBooleanFalse, (id)kCGImageSourceCreateThumbnailFromImageIfAbsent,
[NSNumber numberWithInt:128], (id)kCGImageSourceThumbnailMaxPixelSize,
nil];
CGImageRef thumb = CGImageSourceCreateThumbnailAtIndex(iSource, 0, (CFDictionaryRef)thumbOpts);
The code above returns the thumbnail of the images that have it stored, but when I pass the image through CGImageDestinationRef, the thumbnail is lost.
Is there some way to keep the original thumbnail (or create a new one)? CGImageProperties Reference doesn't seem to have any keys where to store the thumbnail.
One way I've found to get a thumbnail back is to specify kCGImageSourceCreateThumbnailFromImageIfAbsent in the settings dictionary.
Specify the dictionary as follows
NSDictionary* thumbOpts = [NSDictionary dictionaryWithObjectsAndKeys:
(id)kCFBooleanTrue, (id)kCGImageSourceCreateThumbnailFromImageIfAbsent,
(id)kCFBooleanTrue, (id)kCGImageSourceCreateThumbnailWithTransform,
[NSNumber numberWithInt:128], (id)kCGImageSourceThumbnailMaxPixelSize,
nil];
Update: In order to add a secondary (thumbnail) image to the original CGImageDestinationRef do the following after you've added the primary image
size_t thumbWidth = 640;
size_t thumbHeight = imageHeight / (imageWidth / thumbWidth);
size_t thumbBytesPerRow = thumbWidth * 4;
size_t thumbTotalBytes = thumbBytesPerRow * thumbHeight;
void *thumbData = malloc(thumbTotalBytes);
CGContextRef thumbContext = CGBitmapContextCreate(thumbData,
thumbWidth,
thumbHeight,
8,
thumbBytesPerRow,
CGColorSpaceCreateDeviceRGB(),
kCGImageAlphaNoneSkipFirst);
CGRect thumbRect = CGRectMake(0.f, 0.f, thumbWidth, thumbHeight);
CGContextDrawImage(thumbContext, thumbRect, fullImage);
CGImageRef thumbImage = CGBitmapContextCreateImage(thumbContext);
CGContextRelease(thumbContext);
CGImageDestinationAddImage(destination, thumbImage, nil);
CGImageRelease(thumbImage);
Then in order to get the thumbnail back out, do the following
CFURLRef imageFileURLRef = (__bridge CFURLRef)url;
NSDictionary* sourceOptions = #{(id)kCGImageSourceShouldCache: (id)kCFBooleanFalse,
(id)kCGImageSourceTypeIdentifierHint: (id)kUTTypeTIFF};
CFDictionaryRef sourceOptionsRef = (__bridge CFDictionaryRef)sourceOptions;
CGImageSourceRef imageSource = CGImageSourceCreateWithURL(imageFileURLRef, sourceOptionsRef);
CGImageRef thumb = CGImageSourceCreateImageAtIndex(imageSource, 1, sourceOptionsRef);
UIImage *thumbImage = [[UIImage alloc] initWithCGImage:thumb];
CFRelease(imageSource);
CGImageRelease(thumb);
Ok, so since no one responded (even during bounty), plus after the hours I spent trying to pass the thumbnail, my guess is that the documentation for CGImageDestination is misleading. There doesn't seem to be any (documented) way to pass the image thumbnail to a CGImageDestinationRef (atleast not up to, and including, OSX 10.7.0 and iOS 5.0).
If anyone thinks otherwise, post an answer and I'll accept it (if it's correct).
There is a half-documented property for embedding EXIF thumbnails on iOS 8.0+: kCGImageDestinationEmbedThumbnail.
Apple's developer doc is empty, but the header file (CGImageDestination.h) contains the following comment:
/* Enable or disable thumbnail embedding for JPEG and HEIF.
* The value should be kCFBooleanTrue or kCFBooleanFalse. Defaults to kCFBooleanFalse */
IMAGEIO_EXTERN const CFStringRef kCGImageDestinationEmbedThumbnail IMAGEIO_AVAILABLE_STARTING(__MAC_10_10, __IPHONE_8_0);
However you can't specify arbitrary thumbail data, it will get automatically created for you.
I'm trying to get a PNG representation of the currently playing iPod artwork at a size of 250x250. However I keep getting a 640x640 image instead. Code is below. Can anybody point out the doubtless bone-headed mistake I'm making?
- (NSData *) getNowPlayingPng
{
// Assume that there is no artwork for the media item.
UIImage *artworkImage = [[UIImage alloc]init];
// Get the artwork from the current media item, if it has artwork.
MPMediaItemArtwork *artwork = [iPodController.nowPlayingItem valueForProperty: MPMediaItemPropertyArtwork];
// Obtain a UIImage object from the MPMediaItemArtwork object
if (artwork) {
artworkImage = [artwork imageWithSize:CGSizeMake(250.00, 250.00)];
}
NSData *pngimage = UIImagePNGRepresentation(artworkImage);
return pngimage;
}
i'm doing something similar and using the same code for the artworkImage. Is there a specific reason you are needing to convert to PNG? I'm just using an UIImageView component to display the artwork.
MPMediaItemArtwork *artwork = [self.nowPlaying valueForProperty: MPMediaItemPropertyArtwork];
self.audioImageView.image = [artwork imageWithSize:(CGSizeMake(320, 320))];
Why is this code setting artistImage to an image with 0 width and 0 height?
NSURL *artistImageURL = [NSURL URLWithString:#"http://userserve-ak.last.fm/serve/252/8581581.jpg"];
NSImage *artistImage = [[NSImage alloc] initWithContentsOfURL:artistImageURL];
As Ken wrote, the DPI is messed up in this image. If you want to force NSImage to set the real image size (ignoring the DPI), use the method described at http://borkware.com/quickies/one?topic=NSImage:
NSBitmapImageRep *rep = [[image representations] objectAtIndex: 0];
NSSize size = NSMakeSize([rep pixelsWide], [rep pixelsHigh]);
[image setSize: size];
NSImage does load this fine for me, but that particular image has corrupt metadata. Its resolution according to the exif data is 7.1999997999228071e-06 dpi.
NSImage respects the DPI info in the file, so if you try to draw the image at its natural size, you'll get something 2520000070 pixels across.
Last I checked, NSImage's -initWithContentsOfURL: only works with file URLs. You'll need to retrieve the URL first, and then use -initWithData:
It is more or less guaranteed that .representations contains NSImageRep* (of course not always NSBitmapImageRep). To be on a safe side for future extensions one can write something like code below. And it also takes into account multiple representation (like in some .icns and .tiff files).
#implementation NSImage (Extension)
- (void) makePixelSized {
NSSize max = NSZeroSize;
for (NSObject* o in self.representations) {
if ([o isKindOfClass: NSImageRep.class]) {
NSImageRep* r = (NSImageRep*)o;
if (r.pixelsWide != NSImageRepMatchesDevice && r.pixelsHigh != NSImageRepMatchesDevice) {
max.width = MAX(max.width, r.pixelsWide);
max.height = MAX(max.height, r.pixelsHigh);
}
}
}
if (max.width > 0 && max.height > 0) {
self.size = max;
}
}
#end