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.
Related
Detail
We can export the raw texture data including other layers or slices in KTX format after we capture the frame by the frame capture.
After that, we can import by using MTKTextureLoader.
let texture = try! await loader.newTexture(URL: Bundle.main.url(forResource: "texture", withExtension: "ktx")!)
Goal
But how to programmatically export the MTLTexture to KTX format in Swift?
You can check ImageIO whether ImageIO supports the format you want to export to:
Call CGImageDestinationCopyTypeIdentifiers() from ImageIO module to get a list of all the UTI that the CGImageDestination supports.
For example, these are the types ImageIO supports on my machine:
(
"public.jpeg",
"public.png",
"com.compuserve.gif",
"public.tiff",
"public.jpeg-2000",
"com.apple.atx",
"org.khronos.ktx",
"org.khronos.ktx2",
"org.khronos.astc",
"com.microsoft.dds",
"public.heic",
"public.heics",
"com.microsoft.ico",
"com.microsoft.bmp",
"com.apple.icns",
"com.adobe.photoshop-image",
"com.adobe.pdf",
"com.truevision.tga-image",
"com.ilm.openexr-image",
"public.pbm",
"public.pvr"
)
Then, use CGImage to output it:
let texture: MTLTexture = ... // input texture
let ciContext = CIContext(mtlDevice: texture.device)
let ciImage = CIImage(mtlTexture: texture, options: nil) // you might need to add `.oriented(.downMirrored)` here
let colorspace = CGColorSpace(name: CGColorSpace.sRGB)
let cgImage = ciContext.createCGImage(ciImage, from: .init(origin: .zero, size: .init(width: texture.width, height: texture.height)), format: .RGBA8, colorSpace: colorspace)!
let uniformType: UTType = ... // uniform type from CGImageDestinationCopyTypeIdentifiers
let outputURL: URL = ... // the url
try FileManager.default.createDirectory(at: outputURL.deletingLastPathComponent(), withIntermediateDirectories: true) // you might needs this to create intermediate directories
let destination = CGImageDestinationCreateWithURL(outputURL as CFURL, uniformType.identifier as CFString, 1, nil)!
CGImageDestinationAddImage(destination, cgImage, nil)
let imageOutputSuccessfully = CGImageDestinationFinalize(destination)
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
I m using CGImageSourceCreateThumbnailAtIndex to convert the Data into UIImage , but if I convert around 7-8 image using this method application gets slow, instead of this If I use UIImage(data:imageData) everything works fine. How to fix this issue , I need to use CGImageSourceCreateThumbnailAtIndex to resize the image.
Below is the code I m using.
convenience init?(data: Data, maxSize: CGSize) {
let imageSourceOptions = [kCGImageSourceShouldCache: false] as CFDictionary
guard let imageSource = CGImageSourceCreateWithData(data as CFData, imageSourceOptions) else {
return nil
}
let options = [
// The size of the longest edge of the thumbnail
kCGImageSourceThumbnailMaxPixelSize: max(maxSize.width, maxSize.width),
kCGImageSourceCreateThumbnailFromImageAlways: true,
kCGImageSourceShouldCacheImmediately: true,
kCGImageSourceCreateThumbnailWithTransform: true,
] as CFDictionary
// Generage the thumbnail
guard let cgImage = CGImageSourceCreateThumbnailAtIndex(imageSource, 0, options) else {
return nil
}
print("Generating Image....")
self.init(cgImage: cgImage)
}
I had the same problem when batch processing images. Take a look at your RAM usage, it's off the charts. According to Apple, with CGImageSourceCreateWithData and CGImageSourceCreateWithURL, "You’re responsible for releasing this type using CFRelease."
Apple Docs
With Swift, you can do it using:
autoreleasepool {
let img = CGImageSourceCreateWithURL ...
}
I've been trying to wrap my head around this problem with no luck. I have a very simple Swift command-line application which takes one argument - image path to load. It crops the image and filters that image fragment with SepiaTone filter.
It works just fine. It crops the image to 200x200 and filters it with SepiaTone. Now here's the problem that I'm facing - the whole process takes 600ms on my MacBook Air. Now when I RESIZE (instead of cropping) input image to the same dimensions (200x200) it takes 150ms.
Why is that? In both cases I'm filtering an image which is 200x200 in size. I'm using this particular image for testing (5966x3978).
UPDATE:
It's this particular line of code that takes 4x longer when dealing with cropped image:
var ciImage:CIImage = CIImage(cgImage: cgImage)
END OF UPDATE
Code for cropping (200x200):
// parse args and get image path
let args:Array = CommandLine.arguments
let inputFile:String = args[CommandLine.argc - 1]
let inputURL:URL = URL(fileURLWithPath: inputFile)
// load the image from path into NSImage
// and convert NSImage into CGImage
guard
let nsImage = NSImage(contentsOf: inputURL),
var cgImage = nsImage.cgImage(forProposedRect: nil, context: nil, hints: nil)
else {
exit(EXIT_FAILURE)
}
// CROP THE IMAGE TO 200x200
// THIS IS THE ONLY BLOCK OF CODE THAT IS DIFFERENT
// IN THOSE TWO EXAMPLES
let rect = CGRect(x: 0, y: 0, width: 200, height: 200)
if let croppedImage = cgImage.cropping(to: rect) {
cgImage = croppedImage
} else {
exit(EXIT_FAILURE)
}
// END CROPPING
// convert CGImage to CIImage
var ciImage:CIImage = CIImage(cgImage: cgImage)
// initiate SepiaTone
guard
let sepiaFilter = CIFilter(name: "CISepiaTone")
else {
exit(EXIT_FAILURE)
}
sepiaFilter.setValue(ciImage, forKey: kCIInputImageKey)
sepiaFilter.setValue(0.5, forKey: kCIInputIntensityKey)
guard
let result = sepiaFilter.outputImage
else {
exit(EXIT_FAILURE)
}
let context:CIContext = CIContext()
// perform filtering in a GPU context
guard
let output = context.createCGImage(sepiaFilter.outputImage!, from: ciImage.extent)
else {
exit(EXIT_FAILURE)
}
Code for resizing (200x200):
// parse args and get image path
let args:Array = CommandLine.arguments
let inputFile:String = args[CommandLine.argc - 1]
let inputURL:URL = URL(fileURLWithPath: inputFile)
// load the image from path into NSImage
// and convert NSImage into CGImage
guard
let nsImage = NSImage(contentsOf: inputURL),
var cgImage = nsImage.cgImage(forProposedRect: nil, context: nil, hints: nil)
else {
exit(EXIT_FAILURE)
}
// RESIZE THE IMAGE TO 200x200
// THIS IS THE ONLY BLOCK OF CODE THAT IS DIFFERENT
// IN THOSE TWO EXAMPLES
guard let CGcontext = CGContext(data: nil,
width: 200,
height: 200,
bitsPerComponent: cgImage.bitsPerComponent,
bytesPerRow: cgImage.bytesPerRow,
space: cgImage.colorSpace ?? CGColorSpaceCreateDeviceRGB(),
bitmapInfo: cgImage.bitmapInfo.rawValue)
else {
exit(EXIT_FAILURE)
}
CGcontext.draw(cgImage, in: CGRect(x: 0, y: 0, width: 200, height: 200))
if let resizeOutput = CGcontext.makeImage() {
cgImage = resizeOutput
}
// END RESIZING
// convert CGImage to CIImage
var ciImage:CIImage = CIImage(cgImage: cgImage)
// initiate SepiaTone
guard
let sepiaFilter = CIFilter(name: "CISepiaTone")
else {
exit(EXIT_FAILURE)
}
sepiaFilter.setValue(ciImage, forKey: kCIInputImageKey)
sepiaFilter.setValue(0.5, forKey: kCIInputIntensityKey)
guard
let result = sepiaFilter.outputImage
else {
exit(EXIT_FAILURE)
}
let context:CIContext = CIContext()
// perform filtering in a GPU context
guard
let output = context.createCGImage(sepiaFilter.outputImage!, from: ciImage.extent)
else {
exit(EXIT_FAILURE)
}
Its very likely that the cgImage lives in video memory and when you scale the image it actually uses the hardware to write the image to a new area of memory. When you crop the cgImage the documentation implies that it is just referencing the original image. The line
var ciImage:CIImage = CIImage(cgImage: cgImage)
must be triggering a read (maybe to main memory?), and in the case of your scaled image it can probably just read the whole buffer continuously. In the case of the cropped image it may be reading it line by line and this could account for the difference, but thats just me guessing.
It looks like you are doing two very different things. In the "slow" version you are cropping (as in taking a small CGRect of the original image) and in the "fast" version you are resizing (as in reducing the original down to a CGRect).
You can prove this by adding two UIImageViews and adding these lines after each declaration of ciImage:
slowImage.image = UIImage(ciImage: ciImage)
fastImage.image = UIImage(ciImage: ciImage)
Here are two simulator screenshots, with the "slow" image above the "fast" image. The first is with your code where the "slow" CGRect origin is (0,0) and the second is with it adjusted to (2000,2000):
Origin is (0,0)
Origin is (2000,2000)
Knowing this, I can come up with a few things happening on the timing.
I'm including a link to Apple's documentation on the cropping function. It explains that it is doing some CGRect calculations behind the scenes but it doesn't explain how it pulls the pixel bits out of the full-sized CG image - I think that's where the real slow down is.
In the end though, it looks like the timing is due to doing two entirely different things.
CGRect.cropping(to:)
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)...