Working on a pdf photo report app, and struggling with the low image quality in the pdfs that are generated.
func drawImage(index: Int, rectPos: Int) {
let image = getImage(index)
let xPosition = CGFloat(rectArray[rectPos][0])
let yPosition = CGFloat(rectArray[rectPos][1])
image.drawInRectAspectFill(CGRectMake(xPosition, yPosition, 325, 244))
}
func getImage(index: Int) -> UIImage {
var thumbnail = UIImage()
if self.photoAsset.count != 0 {
let initialRequestOptions = PHImageRequestOptions()
initialRequestOptions.resizeMode = .Exact
initialRequestOptions.deliveryMode = .HighQualityFormat
initialRequestOptions.synchronous = true
PHImageManager.defaultManager().requestImageForAsset(self.photoAsset[index], targetSize: CGSizeMake(325, 244), contentMode: PHImageContentMode.Default, options: initialRequestOptions, resultHandler: { (result, info) -> Void in
thumbnail = result!
})
}
return thumbnail
}
I then use these functions to grab the image and place it into a position on a page after UIGraphicsBeginPDFPageWithInfo(page, nil)...
I'm using BSImagePicker pod to get the images.
And finally my photoAsset is just an array of PHAsset photos that is generated after the user selects the images from the pod's CollectionView...
So far I tried all the settings for the initialRequestOptions.deliveryMode... highquality doesn't seem to make images any better.
What am I doing wrong here? Thanks!
Changing the target resolution when requesting image sets the minimum resolution of the image you are going to use.
instead of:
PHImageManager.defaultManager().requestImageForAsset(self.photoAsset[index], targetSize: CGSizeMake(325, 244)...
I simply doubled the size of the image and the image that is drawn to the pdf is better quality.
PHImageManager.defaultManager().requestImageForAsset(self.photoAsset[index], targetSize: CGSizeMake(650, 488)...
Related
When I use PHImageManager() to retrieve an image from the photo library, the image is converted from a jpeg image to a png image, and the image is degraded.
How can I retrieve the image without image degradation?
Is it a standard specification that the extension is changed from jpeg to png?
If anyone knows, please respond.
Here is a sample code I made.
img is returned as png.
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let assets: PHFetchResult = PHAsset.fetchAssets(with: .image, options: nil)
let mg: PHImageManager = PHImageManager()
guard let asset = assets.lastObject else {
return
}
let options = PHImageRequestOptions()
options.isNetworkAccessAllowed = true
options.deliveryMode = .highQualityFormat
mg.requestImage(for: asset, targetSize: PHImageManagerMaximumSize, contentMode: .aspectFit, options: options, resultHandler: { image, info in
let img = image
})
}
}
When requesting a high quality image, the result handler of requestImage may be called initially with a low quality version of the image, then later called again with the high quality version.
You can check this by inspecting the PHImageResultIsDegradedKey of the info dictionary parameter of the result handler, for example:
mg.requestImage(for: asset, targetSize: PHImageManagerMaximumSize, contentMode: .aspectFit, options: options, resultHandler: { image, info in
if info?[PHImageResultIsDegradedKey] as? Bool == true {
print("Degraded image returned, will wait for high quality image")
return
}
let img = image
})
From the documentation for PHImageManager.requestImage:
[...] Photos may call your result handler block more than once. Photos first calls the block to provide a low-quality image suitable for displaying temporarily while it prepares a high-quality image. (If low-quality image data is immediately available, the first call may occur before the method returns.) When the high-quality image is ready, Photos calls your result handler again to provide it. If the image manager has already cached the requested image at full quality, Photos calls your result handler only once. The PHImageResultIsDegradedKey key in the result handler’s info parameter indicates when Photos is providing a temporary low-quality image.
I'm using a framework called OpalImagePicker, it allows me to pick several images instead of one. It returns an array of PHAssets.
I want to get these PHAssets, turn them into image, then convert them to base64 string so that i can send them to my data base.
But there's a problem: the images have really low quality when I try to get them from the PHAsset array.
Here's my code:
let requestOptions = PHImageRequestOptions()
requestOptions.version = .current
requestOptions.deliveryMode = .opportunistic
requestOptions.resizeMode = .exact
requestOptions.isNetworkAccessAllowed = true
let imagePicker = OpalImagePickerController()
imagePicker.maximumSelectionsAllowed = 4
imagePicker.allowedMediaTypes = Set([PHAssetMediaType.image])
self.presentOpalImagePickerController(imagePicker, animated: true,
select: { (assets) in
for a in assets{
// print(a)
// self.img.append(a.image)
self.img.append(a.imagehd(targetSize: CGSize(width: a.pixelWidth, height: a.pixelHeight), contentMode: PHImageContentMode.aspectFill, options: requestOptions))
and the function:
func imagehd(targetSize: CGSize, contentMode: PHImageContentMode, options: PHImageRequestOptions?) -> UIImage {
var thumbnail = UIImage()
let imageManager = PHCachingImageManager()
imageManager.requestImage(for: self, targetSize: targetSize, contentMode: contentMode, options: options, resultHandler: { image, _ in
thumbnail = image!
})
return thumbnail
}
I tried to give "request options.version" the ".original" value, or even high quality to delivery Mode, but then it just gives me nothing (image is nil)
I'm really lost. Can someone help?
Thanks a lot.
How do we name an image programmatically. For example, assign a name to the image generated below. A name that we can use to distinguish the image from other images drawn programmatically.
func drawOval (width: CGFloat, height: CGFloat, name: String) -> UIImage {
let renderer = UIGraphicsImageRenderer(size: CGSize(width: width, height: height))
let image = renderer.image { ctx in
let path = UIBezierPath(ovalIn: CGRect(x: 0, y: 0, width: width, height: height))
path.stroke()
}
// TO DO: Assign this image a name, for example "image01"
return image
}
You can use tags on each UIImageView. I’m not aware of a way to add an identifier to a UIImage directly since it is a subclass of NSObject and not UIView. In order to add a tag to an object in Swift, the object must be a view of some kind.
To implement this, you would keep a variable outside of that function that keeps track of the current tag, then increment it in your function. For example:
var currentTag = 0
//Function now returns a UIImageView
func drawOval (width: CGFloat, height: CGFloat, name: String) -> UIImageView {
let renderer = UIGraphicsImageRenderer(size: CGSize(width: width, height: height))
let image = renderer.image { ctx in
let path = UIBezierPath(ovalIn: CGRect(x: 0, y: 0, width: width, height: height))
path.stroke()
}
let imageView = UIImageView(image: image)
imageView.tag = currentTag
currentTag += 1
return imageView
}
Then later in your code:
if (imageView.tag == 0) {
//Do something
}
//You can also use
let taggedImageView = viewWithTag(0)
EDIT: If you want to save the images and load them via one of the available UIImage initializers, you can write them to a cache folder on disk, then retrieve them using UIImage(pathToFile:):
//This will store the images in the caches directory for your app, which
//the system can clear when the device is low on storage. It will not be
//cleared while your app is open, though.
func saveImageToCacheDynamically(image: UIImage, name: String) {
let paths = FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask)
let localPath = paths[0].appendingPathComponent(“ImageCache”, isDirectory: true)
do {
if FileManager.default.fileExists(atPath: localPath.absoluteString) {
//Write the png data representation of the image to disk in plaintext format
try image.pngData().write(to: localPath.appendingPathComponent("\(name).txt"))
} else {
try FileManager.default.createDirectory(at: localPath, withIntermediateDirectories: true, attributes: nil)
//Write the png data representation of the image to disk in plaintext format
try image.pngData().write(to: localPath.appendingPathComponent("\(name).txt"))
}
} catch {
print("Error locally saving image: \(error.localizedDescription)")
}
//Later in your code...
let paths = FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask)
let localPath = paths[0].appendingPathComponent("ImageCache/\(imageIdentifier).txt")
if FileManager.default.fileExists(atPath: localPath.absoluteString) {
var fileData: Data!
do {
try fileData = Data(contentsOf: localPath)
} catch {
print("Error reading image file: \(error.localizedDescription)")
}
let image = UIImage(data: fileData)
//Do something with image
} else {
print("Error: image does not exist")
}
I believe what you are looking for is something like NSCache...
You can define a cache by something similar to this:
let imageCache = NSCache<String, UIImage>()
Then you can add objects to the cache like this, where someKeyString is the 'name' you are referring to:
imageCache.setObject(someImage, forKey: someKeyString)
And then finally you can retrieve images from the cache like
imageCache.object(forKey: someKeyString)
I would recommend using extensions or something similar to maintain a reference to your cache everywhere in your app.
** NOTE:
NSCaches are cleared when memory space is short, your app closes, etc. See here
For more permanent storage, I would recommend using UserDefaults, which Apple describes as "An interface to the user’s defaults database, where you store key-value pairs persistently across launches of your app." Use this for things like profile images or things that won't change very often. I would also recommend looking into Core Data
Hey I have been struggling with this for a couple of days now and can't seem to find any documentation out side of the standard grid views for MSStickerView sizes
I am working on an app that creates MSStickerViews dynamically - it does this via converting a UIView into an UIImage saving this to disk then passing the URL to MSSticker before creating the MSStickerView the frame of this is then set to the size of the original view.
The problem I have is that when I drag the MSStickerView into the messages window, the MSStickerView shrinks while being dragged - then when dropped in the messages window, changes to a larger size. I have no idea how to control the size when dragged or the final image size
Heres my code to create an image from a view
extension UIView {
func imageFromView() -> UIImage? {
UIGraphicsBeginImageContextWithOptions(self.bounds.size, self.isOpaque, 0.0)
defer { UIGraphicsEndImageContext() }
if let context = UIGraphicsGetCurrentContext() {
self.layer.render(in: context)
let image = UIGraphicsGetImageFromCurrentImageContext()
return image
}
return nil
}
}
And here's the code to save this to disk
extension UIImage {
func savedPath(name: String) -> URL{
let paths = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)
let filePath = "\(paths[0])/name.png"
let url = URL(fileURLWithPath: filePath)
// Save image.
if let data = self.pngData() {
do {
try data.write(to: url)
} catch let error as NSError {
}
}
return url
}
}
finally here is the code that converts the data path to a Sticker
if let stickerImage = backgroundBox.imageFromView() {
let url = stickerImage.savedPath(name: textBox.text ?? "StickerMCSticker")
if let msSticker = try? MSSticker(contentsOfFileURL: url, localizedDescription: "") {
var newFrame = self.backgroundBox.frame
newFrame.size.width = newFrame.size.width
newFrame.size.height = newFrame.size.height
let stickerView = MSStickerView(frame: newFrame, sticker: msSticker)
self.view.addSubview(stickerView)
print("** sticker frame \(stickerView.frame)")
self.sticker = stickerView
}
}
I wondered first off if there was something I need to do regarding retina sizes, but adding #2x in the file just breaks the image - so am stuck on this - the WWDC sessions seem to show stickers being created from file paths and not altering in size in the transition between drag and drop - any help would be appreciated!
I fixed this issue eventually by getting the frame from the view I was copying's frame then calling sizeToFit()-
init(sticker: MSSticker, size: CGSize) {
let stickerFrame = CGRect(x: 0, y: 0, width: size.width, height: size.height)
self.sticker = MSStickerView(frame: stickerFrame, sticker: sticker)
self.sticker.sizeToFit()
super.init(nibName: nil, bund
as the StickerView was not setting the correct size. Essentially the experience I was seeing was that the sticker size on my view was not accurate with the size of the MSSticker - so the moment the drag was initialized, the real sticker size was implemented (which was different to the frame size / autoLayout I was applying in my view)
I have a program that used sktilemap and noise map to generate maps. At the end i have a code to export the scene as an image, but the image is cropped and i see less content in the saved image than at screen (see screen capture 1 and image 2)
The code :
let w = nCol*16
let h = nLig*16
let texture = self.view?.texture(from: scene!, crop: CGRect(origin: CGPoint(x: 0, y: 0), size: CGSize(width: w, height: h)))
let image = texture?.cgImage()
let path = URL(fileURLWithPath: "/Users/MyName/testExport.png")
writeCGImage(image!, to: path)
#discardableResult func writeCGImage(_ image: CGImage, to destinationURL: URL) -> Bool {
guard let destination = CGImageDestinationCreateWithURL(destinationURL as CFURL, kUTTypePNG, 1, nil) else { return false }
CGImageDestinationAddImage(destination, image, nil)
return CGImageDestinationFinalize(destination)
}
edit : If i use self.view?.texture(from: scene!) i have the same result
If i increase the size of the crop, i have a pic 3 in high resolution (10240 × 5760 during my test) but i don't see more things, i see a background
edit2 : with your answers i was able to find the solution : for export i had to change the scene size like that :
scene?.size.height = CGFloat(nLig*tileSize)
scene?.size.width = CGFloat(nCol*tileSize)
The result is an image too heavy for imgur : you can see it https://twitter.com/GenetixVideos/status/1233686731200909312/photo/2