This project contains swift playgrounds that demonstrate how to do pixel operations in swift.
- Swift4 : checkout master branch
- Swift3.x : checkout syntax/swift3.x branch
- Swift2.x : checkout syntax/swift2.x branch
- http://mhorga.org/2015/10/19/image-processing-in-ios-part-3.html
- This articles help me a lot!
RGBAImage has pixels flat memory. You can access pixels with index directly.
This is example for pixel operation
let rgba = RGBAImage(image: UIImage(named: "monet")!)!
var totalR = 0
var totalG = 0
var totalB = 0
rgba.process { (pixel) -> Pixel in
totalR += Int(pixel.R)
totalG += Int(pixel.G)
totalB += Int(pixel.B)
return pixel
}
let pixelCount = rgba.width * rgba.height
let avgR = totalR / pixelCount
let avgG = totalG / pixelCount
let avgB = totalB / pixelCount
func contrast(_ image: RGBAImage) -> RGBAImage {
image.process { (pixel) -> Pixel in
var pixel = pixel
let deltaR = Int(pixel.R) - avgR
let deltaG = Int(pixel.G) - avgG
let deltaB = Int(pixel.B) - avgB
pixel.R = UInt8(max(min(255, avgR + 3 * deltaR), 0)) //clamp
pixel.G = UInt8(max(min(255, avgG + 3 * deltaG), 0))
pixel.B = UInt8(max(min(255, avgB + 3 * deltaB), 0))
return pixel
}
return image
}
let newImage = contrast(rgba).toUIImage()
func grabR(_ image: RGBAImage) -> RGBAImage {
var outImage = image
outImage.process { (pixel) -> Pixel in
var pixel = pixel
pixel.R = pixel.R
pixel.G = 0
pixel.B = 0
return pixel
}
return outImage
}
func grabG(_ image: RGBAImage) -> RGBAImage {
var outImage = image
outImage.process { (pixel) -> Pixel in
var pixel = pixel
pixel.R = 0
pixel.G = pixel.G
pixel.B = 0
return pixel
}
return outImage
}
func grabB(_ image: RGBAImage) -> RGBAImage {
var outImage = image
outImage.process { (pixel) -> Pixel in
var pixel = pixel
pixel.R = 0
pixel.G = 0
pixel.B = pixel.B
return pixel
}
return outImage
}
public static func composite(_ rgbaImageList: RGBAImage...) -> RGBAImage {
let result : RGBAImage = RGBAImage(width:rgbaImageList[0].width, height: rgbaImageList[0].height)
for y in 0..<result.height {
for x in 0..<result.width {
let index = y * result.width + x
var pixel = result.pixels[index]
for rgba in rgbaImageList {
let rgbaPixel = rgba.pixels[index]
pixel.Rf = pixel.Rf + rgbaPixel.Rf
pixel.Gf = pixel.Gf + rgbaPixel.Gf
pixel.Bf = pixel.Bf + rgbaPixel.Bf
}
result.pixels[index] = pixel
}
}
return result
}
public static func gray5(_ image: RGBAImage) -> RGBAImage {
var outImage = image
outImage.process { (pixel) -> Pixel in
var pixel = pixel
let result = sqrt(pow(pixel.Rf, 2) + pow(pixel.Rf, 2) + pow(pixel.Rf, 2))/sqrt(3.0)
pixel.Rf = result
pixel.Gf = result
pixel.Bf = result
return pixel
}
return outImage
}
let rgba5 = RGBAImage(image: UIImage(named: "monet")!)!
gray5(rgba5).toUIImage()
public static func splitRGB(_ rgba: RGBAImage) -> (ByteImage, ByteImage, ByteImage) {
let R = ByteImage(width: rgba.width, height: rgba.height)
let G = ByteImage(width: rgba.width, height: rgba.height)
let B = ByteImage(width: rgba.width, height: rgba.height)
rgba.enumerate { (index, pixel) -> Void in
R.pixels[index] = pixel.R.toBytePixel()
G.pixels[index] = pixel.G.toBytePixel()
B.pixels[index] = pixel.B.toBytePixel()
}
return (R, G, B)
}ByteImage has only one color component.
public static func op(_ functor : (Double, Double) -> Double, rgbaImage1: RGBAImage, rgbaImage2: RGBAImage) -> RGBAImage {
let result : RGBAImage = RGBAImage(width:rgbaImage1.width, height: rgbaImage1.height)
for y in 0..<result.height {
for x in 0..<result.width {
let index = y * result.width + x
var pixel = result.pixels[index]
let rgba1Pixel = rgbaImage1.pixels[index]
let rgba2Pixel = rgbaImage2.pixels[index]
pixel.Rf = functor(rgba1Pixel.Rf, rgba2Pixel.Rf)
pixel.Gf = functor(rgba1Pixel.Gf, rgba2Pixel.Gf)
pixel.Bf = functor(rgba1Pixel.Bf, rgba2Pixel.Bf)
result.pixels[index] = pixel
}
}
return result
}
public static func add(rgba1: RGBAImage, _ rgba2: RGBAImage) -> RGBAImage {
return op((+), rgbaImage1: rgba1, rgbaImage2: rgba2)
}
public static func blending(_ img1: RGBAImage, _ img2: RGBAImage, alpha: Double) -> RGBAImage {
let result : RGBAImage = RGBAImage(width:img1.width, height: img1.height)
for y in 0..<result.height {
for x in 0..<result.width {
let index = y * result.width + x
var pixel = result.pixels[index]
let pixel1 = img1.pixels[index]
let pixel2 = img2.pixels[index]
pixel.Rf = alpha * pixel1.Rf + (1.0 - alpha) * pixel2.Rf
pixel.Gf = alpha * pixel1.Gf + (1.0 - alpha) * pixel2.Gf
pixel.Bf = alpha * pixel1.Bf + (1.0 - alpha) * pixel2.Bf
result.pixels[index] = pixel
}
}
return result
}
public static func brightness(_ img1: RGBAImage, contrast: Double, brightness: Double) -> RGBAImage {
let result : RGBAImage = RGBAImage(width:img1.width, height: img1.height)
for y in 0..<result.height {
for x in 0..<result.width {
let index = y * result.width + x
var pixel = result.pixels[index]
let pixel1 = img1.pixels[index]
pixel.Rf = pixel1.Rf * contrast + brightness
pixel.Gf = pixel1.Gf * contrast + brightness
pixel.Bf = pixel1.Bf * contrast + brightness
result.pixels[index] = pixel
}
}
return result
}public static func convolution(_ image: ByteImage, mask: Array2D<Double>) -> ByteImage {
var image = image
let height = image.height
let width = image.width
let maskHeight = mask.rowCount()
let maskWidth = mask.colCount()
for y in 0..<height - maskHeight + (maskHeight-1)/2 {
for x in 0..<width - maskWidth + (maskWidth-1)/2 {
var v = 0.0
if (y+maskHeight > height) || (x+maskWidth) > width {
continue
}
for my in 0..<maskHeight {
for mx in 0..<maskWidth {
let tmp = mask[my, mx]
v = v + (image.pixel(x+mx, y+my)!.Cf * tmp)
}
}
v = clamp(v, lower: 0.0, upper: 1.0)
print(v)
let pixel = BytePixel(value: v)
let xx = x+(maskWidth-1)/2
let yy = y+(maskHeight-1)/2
image.setPixel(xx, yy, pixel)
}
}
return image
}
let m1 = Array2D(cols:3, rows:3,
[ 0.0/5.0, -1.0/5.0, 0.0/5.0,
-1.0/5.0, 9.0/5.0,-1.0/5.0,
0.0/5.0, -1.0/5.0, 0.0/5.0])
ImageProcess.convolution(R.clone(), mask: m1).toUIImage()
let m2 = Array2D(cols: 3, rows: 3,
[
1.0/9.0, 1.0/9.0, 1.0/9.0,
1.0/9.0, 1.0/9.0, 1.0/9.0,
1.0/9.0, 1.0/9.0, 1.0/9.0,
]
)
ImageProcess.convolution(R.clone(), mask: m2).toUIImage()The MIT License
Copyright © 2015 Sungcheol Kim, https://github.com/skyfe79/SwiftImageProcessing
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.