EasyImagy
EasyImagy makes it easy to handle images in Swift.
var image = Image<RGBA>(named: "ImageName")!
print(image[x, y])
image[x, y] = RGBA(red: 255, green: 0, blue: 0, alpha: 127)
image[x, y] = RGBA(0xFF00007F) // red: 255, green: 0, blue: 0, alpha: 127
// Iterates over all pixels
for pixel in image {
// ...
}
// Converts the image (e.g. binarizations)
let binarized: Image<RGBA> = image.map { $0.gray < 128 ? .black : .white }
// From/to `UIImage`
image = Image<RGBA>(uiImage: imageView.image!)!
imageView.image = image.uiImageIntroduction
Handling images by CoreGraphics is too complicated: various formats, old C APIs and painful memory management. EasyImagy provides the easier way to handle images in exchange for some performance.
Typically Images in EasyImagy are used with RGBA. RGBA is a simple structure declared as follows.
struct RGBA {
var red: UInt8
var green: UInt8
var blue: UInt8
var alpha: UInt8
}You can access to a pixel easily using subscripts like image[x, y] and its channels by properties red, green, blue and alpha.
Image and RGBA also provide some convenient methods and properties to make it easy to process images. For example, it is possible to convert an image to grayscale combining Image#map with RGBA#gray in one line as shown below.
let result = image.map { $0.gray }Usage
Import
import EasyImagyInitialization
let image = Image<RGBA>(named: "ImageName")!let image = Image<RGBA>(contentsOfFile: "path/to/file")!let image = Image<RGBA>(data: NSData(/* ... */))!let image = Image<RGBA>(uiImage: imageView.image!)!let image = Image<RGBA>(width: 640, height: 480, pixel: .black) // a black imagelet image = Image<RGBA>(width: 640, height: 480, pixels: pixels)Access to a pixel
// Gets a pixel by subscripts
let pixel = image[x, y]// Sets a pixel by subscripts
image[x, y] = RGBA(0xFF0000FF)
image[x, y].alpha = 127// Safe get for a pixel
if let pixel = image.pixel(x, y) {
print(pixel.red)
print(pixel.green)
print(pixel.blue)
print(pixel.alpha)
print(pixel.gray) // (red + green + blue) / 3
print(pixel) // formatted like "#FF0000FF"
} else {
// `pixel` is safe: `nil` is returned when out of bounds
print("Out of bounds")
}Iteration
for pixel in image {
...
}Rotation
let result = image.rotate() // Rotate clockwiselet result = image.rotate(-1) // Rotate counterclockwiselet result = image.rotate(2) // Rotate by 180 degreesFlip
let result = image.flipX() // Flip Horizontallylet result = image.flipY() // Flip VerticallyResizing
let result = image.resize(width: 100, height: 100)let result = image.resize(width: 100, height: 100,
interpolationQuality: kCGInterpolationNone) // Nearest neighborCrop
Slicing is done with no copy cost.
let slice: ImageSlice<RGBA> = image[32..<64, 32..<64] // no copy cost
let cropped = Image<RGBA>(slice) // copy is done hereConversion
Image can be converted by map as well as Array. Followings are the examples.
Grayscale
let result: Image<UInt8> = image.map { (pixel: Pixel) -> Pixel in
pixel.gray
}// Shortened form
let result = image.map { $0.gray }Binarization
let result = image.map { (pixel: Pixel) -> Pixel in
pixel.gray < 128 ? Pixel.black : Pixel.white
}// Shortened form
let result = image.map { $0.gray < 128 ? .black : .white }Binarization (auto threshold)
let threshold = UInt8(image.reduce(0) { $0 + $1.grayInt } / image.count)
let result = image.map { $0.gray < threshold ? .black : .white }Mean filter
let kernel = Image<Float>(width: 3, height: 3, pixel: 1.0 / 9.0)
let result = image.convoluted(kernel)Gaussian filter
let kernel = Image<Int>(width: 5, height: 5, pixels: [
1, 4, 6, 4, 1,
4, 16, 24, 16, 4,
6, 24, 36, 24, 6,
4, 16, 24, 16, 4,
1, 4, 6, 4, 1,
]).map { Float($0) / 256.0 }
let result = image.convoluted(kernel)With UIImage
From UIImage
let image = Image<RGBA>(uiImage: imageView.image!)!To UIImage
imageView.image = image.uiImageInstallation
Carthage
Carthage is available to install EasyImagy. Add it to your Cartfile:
github "koher/EasyImagy" "master"
Manually
For iOS 8 or later,
- Put EasyImagy.xcodeproj into your project/workspace in Xcode.
- Click your project icon and select the application target and the "General" tab.
- Add
EasyImagy.frameworkto "Embedded Binaries". -
import EasyImagyin your swift files.
