I would like to append pdf files, i ll be getting NSData from server which i am saving as PDF, i want to add more data to existing PDF, i tried appending NSData which is appending the no.of bytes but if i save it as PDF then it only saves the appended part not the main part.
Example:
NSMutableData of existing PDF is firstdata
NSData of second PDF that i got from server is seconddata
now i have appended firstdata with seconddata and save it in a file this will only save the PDF part that is there in seconddata.
can anyone help me in solving this.
Related
In my swift App, I need to convert Image as String, then I need to send to Server , i.e POST. Then, if I need to GET, I dont want to decode that. Response having Image file name and path.
ONline Converter:
If I convert the sample image through online converter, HERE. I am getting following string. If I pass this string to API, I can get image successfully.
Output:
iVBORw0KGgoAAAANSUhEUgAAAJAAAACQCAYAAADnRuK4AAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR.... .....CIBhIIgQRCIIEQSCAQAgmEQAIhkEAIJBAIgQRCIIEQSCAEEgiEQAIhkEAIJCgN/F+AAQAXoGXl+IGgwwAAAABJRU5ErkJggg==
Through My Coding
If I convert the sample image through Coding, I am getting following string. If I pass this string to API, Successfully adding. But, I unable to view that image manually in browser too.
More Over,, Two Output Strings are not same. I dont know why? Kindly guide me, how to solve this?
Code:
var image : UIImage = UIImage(named: "home_recharge.png")!
var imageData = UIImagePNGRepresentation(image)
let base64String = imageData.base64EncodedStringWithOptions(NSDataBase64EncodingOptions.allZeros)
println("base64String \(base64String)")
Output:
iVBORw0KGgoAAAANSUhEUgAAAJAAAACQCAYAAADnRuK4AAAAAXNSR0IArs4c6QAAABxpRE9UAAAAAgAAAAAAAABIAAAAKAAAAEgAAABIAAAKygzM7MwAAAqWSURBVHgB7FwJ0JZDHC9yhJTkLuRMjuQ+opAr5zjGqAwZx...... .......FlIs5ASSDNQLA7EMtYMpBlICaQZKBYHYhlrBtIMpATSDBSLA7GMNQNpBlICaQaKxYFYxpqBNAMpgTQDxeJALGPNQJqBlECagWJxIJaxZiDNQP8B+6MkTad9NtcAAAAASUVORK5CYII=
You use png image representation but server saves the image with .jpg extension so browser tries to read image as JPEG file and fails.
You should replace UIImagePNGRepresentation with UIImageJPEGRepresentation or save image with .png extension.
The reason why browser can open online converter result image despite it has wrong extension is possibly that UIImagePNGRepresentation strips the image of its meta data and online converter not so browser can not figure the real type of image with wrong extension without meta data.
I'm currently use binary data saved in Core Data object to generate UIImage as code below.
UIImage * postImage = [UIImage imageWithData:image];
double imageRatio = postImage.size.height / postImage.size.width;
[imageContent setFrame:CGRectMake(imageContent.frame.origin.x, imageContent.frame.origin.y, imageContent.frame.size.width, imageContent.frame.size.height * imageRatio)];
[imageContent setImage:postImage];
However, I found there's a little bit slow when generate image.
Should I save image locally when retrieve data from server instead?
Which way is faster?
Thanks,
Save the image locally (e.g. in the Documents or Caches directory) instead of in the Core Data database. You get no benefit from storing binary data in the database as you will never search or index by this data, and it will just bloat your database. Just store an NSString reference to the filename/path you save the image to.
I imagine the UIImage:imageWithData method is slower when compared with reading an image from file that is already in a suitable image format.
save image locally and in your coreData save the location and name "URL" for that image
save your image locally such as PNG or JPEG instead of NSData.
I'm trying to create a way to save the interface of my app in a JSON file. While static elements I can define by their frames and/or center points, the interface does include a single image selected from the photo library. Because some iPhones have 8MP cameras, I can anticipate that some images would be very large.
I would like to be able to save this interface and send it over by email, so another app user can re-open the file and see the same interface with the image included.
Currently I'm using JSONKit to save my data into a JSON object. This means that the email will contain a single JSON file containing both the layout parameters and the image. I've never worked with such large JSON files, so the question is - will having several megs of image data within JSON present parsing issues? Or should I select some other file container that would have : first part JSON file, second part raw image data and then separate that file into a JSON string and a raw data string?
This is what I'm using currently to get a JSON file. After adding NSData to JSON, the convert to json method returns nil
NSString* currentURL = webView.request.mainDocumentURL.absoluteString;
[dictionary setValue:currentURL forKey:#"webViewAddress"];
//this call correctly returns the json string
NSLog(#"%#", [dictionary JSONString]);
NSLog(#"+++++++++++++++++++++++++++++++++++++");
NSData* imageData = UIImagePNGRepresentation(arOverlayView.image);
//after this call, the json returns nil
[dictionary setValue:imageData forKey:kimageData];
NSLog(#"%#", [dictionary JSONString]);
If you are using email as a transport mechanism, your binary data will have to end up as something like Base64 encoded at some point in its life. There is no "raw" format for email, there is only text.
At best you could implement Base85 encoding which is more efficient than Base64
So you are going to have to suck up the large file sizes unless you invent your own transport mechanism - such as a point to point TCP/IP based link.
Is it possible to add custom dictionary fields to an images metadata?
The following statement
writeImageDataToSavedPhotosAlbum:metadata:completionBlock:
Allows images to be added with metadata.
Is this dictionary (the metadata dictionary) treated as a normal dictionary?
I mean, Is it possible to add custom fields to it.
Of course the original metadata dictionary needs to be copied, but once this is done can it be edited and used.
Also when would this be done? If an image is captured with the iphone and I want to add stuff to the metadata, will this be writing an image twice, or is the first captured images metadata available, modified and then the image is saved with the metadata?
Yes it is possible to add custom distionary fields to image metadata. You can use unused dictionary keys to write your data within the image metadata. Just u have to do is when u capture the image and get it through image picker, just save it at a location and obtain it's metadata by using :
NSData *imgData = UIImageJPEGRepresentation(imageView.image, 1);
CGImageSourceRef source = CGImageSourceCreateWithData((CFMutableDataRef)imgData, NULL);
NSDictionary *metadata = [(NSDictionary *) CGImageSourceCopyPropertiesAtIndex(source,0,NULL)autorelease];
Then edit image metadata and save image by using :
writeImageDataToSavedPhotosAlbum:metadata:completionBlock:
It will save the new image with metadata inside the iPhone photo library then u can delete the old image if u want.
Hope it might help!!!
Obj-C or Monotouch.Net C# answers are fine.
I have a Base64 string that is a PDF document received over a web service. I can get the NSData.
How do I take the NSData and save it as a PDF?
-- I get the NSData this way --
byte[] encodedDataAsBytes = System.Convert.FromBase64String (myBase64String);
string decoded = System.Text.Encoding.Unicode.GetString (encodedDataAsBytes);
NSData data = NSData.FromString (decoded, NSStringEncoding.ASCIIStringEncoding);
The simplest way to save it is probably to use NSData's writeToFile:options:error: method.
I found that using the .NET framework works better than trying to use the iOS framework for this problem. This will take any file and convert it to it's original then save it to the iPhone/iPad device. "path" is just a folder on the dev ice.
using (var f = System.IO.File.Create (path))
{
byte[] encodedDataAsBytes = System.Convert.FromBase64String (Base64PDFString);
f.Write (encodedDataAsBytes, 0, encodedDataAsBytes.Length);
}
I'm working on a project where I recently had to accomplish the same thing you are describing. I get base64 encoded PDF files as strings from a .NET web service which need to be decoded to their original and saved as PDF files in the applications documents directory.
My solution was:
Use ASIHTTPRequest to communicate with the web service.
I then use TBXML to parse incoming xml and get the base64 as an NSString.
To decode the string I use a method from QSUtilities library called decodeBase64WithString.
Finally I save the result with NSData's writeToFile.
I have tested and successfully used this method with PDF files that are up to 25mb. I also had a couple of test runs with a 48mb file but that file made the decodeBase64WithString method take up too much memory and my app crashed. Haven't found a solution to this yet..
If you are working with multiple large files be sure to free up your memory once in a while. I got all my files in one loop in which I had to use my own nsautorelease pool and drain it at the end of the loop to free up any autoreleased objects.