I'm working on an OSX application where I need to store 446 CGLayers that get placed in a PDF context and am wondering if there's a way to write and read them from a file, rather than generating them when the application loads
I've read that CGLayer is no longer recommended, but I feel they really fit what I need. Also, if I use bitmapGraphicsContexts, they can pixelate when zooming in.
I am able to store them in NSArrays, both by storing them in NSValue and puting them into the array by bridging. I've also tried storing them in C arrays, but that didn't work out.
My problem comes when trying to store these arrays in a file. writeToFile: doesn't work with CGLayers, but NSKeyedArchiver/NSKeyedUnarchiver hasn't worked either, both when the layers are in NSValues or bridged.
Here's my method that attempts to write and read an array containing a single layer from a file.
+(CGLayerRef) colorAnnotations:(CGContextRef)context{
float symbolSize = 8;
CGRect glyphBox = CGRectMake(0,0, 8, 8);
CGLayerRef annotationLayer = CGLayerCreateWithContext (context,glyphBox.size, NULL);
CGContextRef annotaionLayerContext = CGLayerGetContext(annotationLayer);
CGMutablePathRef annot = CGPathCreateMutable();
//Drawing annotation
/*...*/
NSMutableArray *test = [[NSMutableArray alloc]init];
[test addObject:[[NSValue alloc] initWithBytes:&annotationLayer objCType:#encode(CGLayerRef)]];
//Getting file path in Documents directory
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *dataPath = [documentsDirectory stringByAppendingPathComponent:#"/annots.data"];
[NSKeyedArchiver archiveRootObject:test toFile:dataPath];
NSMutableArray *testLoads = [NSKeyedUnarchiver unarchiveObjectWithFile:dataPath];
CGLayerRef layerToReturn;
[[testLoads objectAtIndex:0]getValue:&layerToReturn];
return layerToReturn;
}
I get [NSKeyedArchiver encodeValueOfObjCType:at:]: unknown type encoding ('^')') was raisedfrom this, pretty sure because of the CGLayerRef type.
The lines needed to draw the different annotations I need are pretty long, so I've been trying to figure out a way to have them made and stored in a file without having to make them on startup each time. So far I'm not seeing a way to do this, but was hoping someone here may know of one and would appreciate any help.
Related
I need to convert a PNG file to Base64 data so that I can add it to a JSON object, using JXA (JavaScript Application Scripting).
JXA is limited compared to regular JavaScript so I can't immediately use functions from FileReader, etc.
From what I've read, there is no way that I know how to do this without using Objective-C/Cocoa (which I only started reading about today for this task).
I found the following code in another post:
NSArray *keys = [NSArray arrayWithObject:#"NSImageCompressionFactor"];
NSArray *objects = [NSArray arrayWithObject:#"1.0"];
NSDictionary *dictionary = [NSDictionary dictionaryWithObjects:objects forKeys:keys];
NSImage *image = [[NSImage alloc] initWithContentsOfFile:[imageField stringValue]];
NSBitmapImageRep *imageRep = [[NSBitmapImageRep alloc] initWithData:[image TIFFRepresentation]];
NSData *tiff_data = [imageRep representationUsingType:NSPNGFileType properties:dictionary];
NSString *base64 = [tiff_data encodeBase64WithNewlines:NO];
I believe it is pertinent to what I am trying to do- does anybody know how I can bridge this method to use it in JXA?
I have been reading over the JXA Cookbook's section on Syntax for calling ObjC functions, but I am having difficulty understanding it... this is all that I have come up with so far:
var desktopString = app.pathTo("desktop").toString()
var file = `${desktopString}/test.png`
ObjC.import("Cocoa");
var image = $.NSImage.alloc.initWithContentsOfFile(file)
var imageRep = $.NSBitmapImageRep.alloc.initWithData(image)
But I don't know how to proceed- I am thrown off by:
The whole initial NSArray/NSDictionary part
TIFFRepresentation (Do I need it? Where do I put it?)
NSData *tiff_data = [imageRep representationUsingType:NSPNGFileType
properties:dictionary]; (There's no alloc! Why is dictionary needed?)
NSString *base64 = [tiff_data encodeBase64WithNewlines:NO]; (Again,
no alloc.)
I would be very appreciative if somebody could point me in the right direction / give me a few pointers on how I can accomplish what I am trying to do.
Thank you in advance!
Converting an image file into an NSImage representation and then onto a base-64 string is a lot of work, and was only applicable to the answer you sourced because the OP there was coming from a starting point of having NSImage class data. As you stated that you have a .png file, the route is much simpler:
ObjC.import('Foundation');
function fileToBase64(filepath) {
const standardizedPath = $.NSString.stringWithString(filepath)
.stringByStandardizingPath;
const base64String = $.NSData.dataWithContentsOfFile(standardizedPath)
.base64EncodedStringWithOptions(0);
return ObjC.unwrap(base64String);
}
(() => {
return fileToBase64('~/Desktop/test.png');
})();
For reference, this returns identical output to the following bash shell command:
base64 --input ~/Desktop/test.png
PS. For the benefit of learning, despite what the JXA Cookbook teaches, try not to import the entire Cocoa framework into your scripts, and just import the ones specific to the objective-c classes you're using.
My program loads some data from a file and then draws them.
The file-reading part is like this:
- (void)load_file
{
NSFileHandle *inFile = [NSFileHandle fileHandleForReadingAtPath:#"map_data"];
NSData *myData=[inFile readDataToEndOfFile];
NSString *myText=[[NSString alloc]initWithData:myData encoding:NSASCIIStringEncoding];
NSArray *values = [myText componentsSeparatedByString:#"\n"];
for (NSString *string in values) {
NSArray *lines=[string componentsSeparatedByString:#" "];
if ([lines count] != 2) break;
NSPoint point= NSMakePoint([lines[0] floatValue], [lines[1] floatValue]);
[points addObject:[NSValue valueWithPoint:point]];
}
[self setNeedsDisplay:YES];
}
When debugging, I put the data file in the directory of [NSBundle mainBundle], and the program works fine.
However, when I use achieve to take the app out, it never runs. I put the data file in the same path with the app, but it seems fail to load it.
Update
I tried to use c++, but still fails.
- (void)load_file
{
ifstream inf("map_data");
double x, y;
while (inf >> x >> y) [points addObject:[NSValue valueWithPoint:NSMakePoint(x, y)]];
inf.close();
}
I tried to change the build scheme to release and run, which is fine. But whenever I go directly into the finder of app and double click it, it does not work and seems nothing is loaded.
add the file to the project as a Resource (this will cause it to be copied into the app wrapper in the right spot)
use `[[NSBundle mainBundle] pathForResource:#"map_data" ofType:nil];
That should give you the path to the file. The file should not be manually copied, it should not be next to the app wrapper, nor should you [conjecture] ever try changing or replacing the file once it is in your app wrapper.
The reason why it seems to work sometimes is mere coincidence. You are passing a partial path to NSFileHandle and it happens that the current working directory of your app sometimes points to the right spot such that the data file is available.
I'm not sure how relative paths are handled by NSFileHandle, but usually you set up paths using the NSBundle class.
NSString *path = [[NSBundle mainBundle] pathForResource:#"myfile" ofType:#"ext"];
You can also simply initialize an NSString from the contents of a file, you don't need to first read it into an NSData using NSFileHandle.
NSString *text = [[NSString alloc] initWithContentsOfFile:path
encoding:NSASCIIStringEncoding error:nil];
(Use the error parameter, if you want proper error handling)
I am able to generate a PDF with the following code. Can someone please help me with how I would add text to this? Thanks in advance.
-(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();
// draws rect to the view and thus this is captured by UIGraphicsBeginPDFContextToData
[aView drawRect:aView.bounds];
// 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);
}
I've never done this (yet, I plan getting on it tomorrow). But I think the right place to go is the Quartz 2D programming guide. It's also available from your developer documentation if you need it offline.
Basically you the same as you posted but appart from calling drawRect: you perform all the text drawing you want on that context.
There's useful information on writing simple strings on this guide
I hope it helps. It sure helped me!
I'm trying to save an NSMutableArray called queueArray so it can be loaded again after the app has been quit. I used a few tutorials to get me going and this is the code I have come up with. The problem seems to be that "initWithCoder" and "encodeWithCoder" are not being called, shown by no NSLog calls and no stopping at breakpoints. I have added the NSCoding protocol to the .h file and I know that queueArray is not nil and it contains MPMediaItems. Here is some of the code I use to try to save and load the array:
-(IBAction)saveQueuePressed {
NSString *rootPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
NSString *filePath = [rootPath stringByAppendingPathComponent:#"queueArray.archive"];
//should cause encodeWithCoder to be called
[NSKeyedArchiver archiveRootObject:queueArray toFile:filePath];
}
-(IBAction)loadQueuePressed {
NSString *rootPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
NSString *filePath = [rootPath stringByAppendingPathComponent:#"queueArray.archive"];
//should cause initWithCoder to be called
queueArray = [NSKeyedUnarchiver unarchiveObjectWithFile:filePath];
}
-(void)encodeWithCoder:(NSCoder *)coder {
NSLog(#"encodeWithCoder");
[coder encodeObject:queueArray forKey:#"savedQueueArray"];
}
-(id)initWithCoder:(NSCoder *)decoder {
NSLog(#"initWithCoder");
queueArray = [decoder decodeObjectForKey:#"savedQueueArray"];
return self;
}
Any help will be greatly appreciated!
The encodeWithCoder: and initWithCoder methods are called when you archive/unarchive an object that responds to them. From what I understand, you have those methods in your class, but the object you are actually archiving (queueArray) is not an instance of that class, it's an NSMutableArray.
If you do want to save your entire object, you can change your saveQueue method to this
-(IBAction)saveQueuePressed {
NSString *rootPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
NSString *filePath = [rootPath stringByAppendingPathComponent:#"queueArray.archive"];
// saving the array shouldn't, but saving the self object
//should cause encodeWithCoder to be called:
[NSKeyedArchiver archiveRootObject:self toFile:filePath];
}
But if you just want to save the array, I guess you can just use saveQueuePressed and loadQueuePressed, I don't think you need the encode/init WithCoder: methods
Update:
Maybe your path is not right.
Try
NSString *rootPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
NSString *filePath = [[rootPath stringByAppendingPathComponent:#"queueArray.archive"] stringByExpandingTildeInPath]];
Filipe is right! Your comment said you still didn't use his method.
I had this issue too. Switching from the dictionary's atomic write method to the keyedArchiver fixed it, luckily I only had to change one thing, the line that said writeToFile: is now the archive function.
Now my program's working. For some reason, even when responding to NSCoding, the custom object is not being encoded and breaks my dictionary. Is this a bug with iOS? I've read a fair number of Apple Manuals, but I've also seen a fair number of typos and missing info (For example, try MKMapRect functions without the videos to explain them), or Core Animations referencing the Run Loop before you learn threading, I could go on, half finished sentences in Quartz... so yeah, I've read the manuals and this perplexes me, we have to get a more open iOS SDK at some point, hopefully
I'm using a text file to save the changes made by a user on a list (the reason that I'm doing this is so that I can upload the text file to a PC later on, and from there insert it into an Excel spreadsheet). I have 3 data structures: A NSMutableArray of keys, and a NSMutableDictionary who's key values are MSMutableArrays of NSStrings.
I iterate through these data structures and compile a file string that looks much like this:
(Key);(value)\t(value)\t(value):\n(Key);(value).. .so on.
SO, onto the actual question: When I attempt to save it, it fails. I'm 99% sure this is because of the file path that I'm using, but I wanted backup to check this out. Code follows:
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES);
NSString *filePath = [paths objectAtIndex:0];
NSString *fileString = [NSString stringWithString:[self toFileString]];
if(![fileString writeToFile:filePath atomically:YES encoding:NSUTF8StringEncoding error:NULL]){
NSLog(#"File save failed");
} else {
// do stuff
}
(Code above is re-copied, since the actual code is on a different computer. It compiles, so ignore spelling errors?)
I tried using NSError, but I got bogged down in documentation and figured I might as well ask SO while trying to figure out how to properly use NSError (might be a little bit of an idiot, sorry).
99% sure it's the NSArray *paths line that's tripping it up, but I don't know how else to get the documents directory.
Edit: Problem solved, and one final question: If I save it to the App's document directory, where can I go after I close the app to see if it saved properly? If it works like I think it does, isn't it sandboxed in with the app's installation on the simulator? (i.e. no way of checking it)
NSLog() that filePath string. I think you're trying to write to the directory itself, not to a file.
Try this instead:
filePath = [[paths objectAtIndex:0]stringByAppendingPathComponent:#"myfile.txt"];
What is the file name you want to save? The method
NSArray *paths = NSSearchPathForDirectoriesInDomains(...);
NSString *filePath = [paths objectAtIndex:0];
...
if(![fileString writeToFile:filePath ...
means you are saving the string into a file path which has the same name as a folder. This will of course fail. Please give it a name, e.g.
NSString* fileName = [filePath stringByAppendingPathComponent:#"file.txt"];
if(![fileString writeToFile:fileName ...
and try again.
BTW, to use NSError:
NSError* theError = nil;
if(![fileString writeToFile:fileName ... error:&theError]) {
// ^^^^^^^^^
NSLog(#"Failed with reason %#", theError);
// theError is autoreleased.
}