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我有一個應用程序可以對圖像的像素進行計數，以獲取圖像中五種顏色的相對區域。 Swift 3的更新版本與聲明的圖像一起使用，該圖像位於應用程序的支持文件中，但沒有來自文檔目錄的可變圖像。我錯過了什麼？在Swift中進行像素計數3
這個版本的作品：
import UIKit
import CoreGraphics
class ComputeAreaViewController: UIViewController {
var redValue: String!
var blueValue: String!
var greenValue: String!
var whiteValue: String!
var yellowValue: String!
var totalValue: String!
//var image: UIImage!
let image = UIImage(named: "test_image.png")!
override func viewDidLoad() {
super.viewDidLoad()
/*
let fm = FileManager.default
let docsurl = try! fm.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: false)
let myurl = docsurl.appendingPathComponent("tmp.png")
image = UIImage(contentsOfFile: myurl.path)!
*/
view.layer.contents = image.cgImage!
computeArea()
}
func classifyPixel(_ r: UInt8, _ g: UInt8, _ b: UInt8, _ coverRed: inout UInt, _ coverGreen: inout UInt, _ coverYellow: inout UInt, _ coverBlue: inout UInt, _ coverWhite: inout UInt) {
if r == 255 && g == 0 && b == 0 { coverRed += 1 }
if r == 0 && g == 255 && b == 0 { coverGreen += 1 }
if r == 255 && g == 255 && b == 0 { coverYellow += 1 }
if r == 0 && g == 0 && b == 255 { coverBlue += 1 }
if r == 255 && g == 255 && b == 255 { coverWhite += 1 }
}
func computeArea() {
var coverRed: UInt = 0
var coverGreen: UInt = 0
var coverYellow: UInt = 0
var coverBlue: UInt = 0
var coverWhite: UInt = 0
var coverTotal = 0
let imageWidth = Int(image.size.width)
let imageHeight = Int(image.size.height)
let bitsPerComponent = 8
let bytesPerPixel = 4
let bytesPerRow = bytesPerPixel * imageWidth
let bufferSize = bytesPerRow * imageHeight
var bytesPointer = UnsafeMutableRawPointer.allocate(bytes: bufferSize, alignedTo: 1)
let bytesPointerSaved = bytesPointer
if let bitmapContext = CGContext(data: bytesPointer, width: imageWidth, height: imageHeight, bitsPerComponent: bitsPerComponent, bytesPerRow: bytesPerRow, space: CGColorSpaceCreateDeviceRGB(), bitmapInfo: CGImageAlphaInfo.premultipliedLast.rawValue) {
bitmapContext.draw((image.cgImage!), in: CGRect(x: 0, y: 0, width: imageWidth, height: imageHeight), byTiling: false)
for _ in 0..<imageHeight {
for _ in 0..<imageWidth {
var r: UInt8 = 0, g: UInt8 = 0, b: UInt8 = 0
r = bytesPointer.load(as: UInt8.self)
bytesPointer += 1
g = bytesPointer.load(as: UInt8.self)
bytesPointer += 1
b = bytesPointer.load(as: UInt8.self)
bytesPointer += 2
classifyPixel(r, g, b, &coverRed, &coverGreen, &coverYellow, &coverBlue, &coverWhite)
coverTotal += 1
}
}
} else {
print(#file + " " + #function + " failed to create bitmap context ")
}
bytesPointerSaved.deallocate(bytes: bufferSize, alignedTo: 1)
let fTotal = Float(coverTotal)
print("coverRed: \(100.0*Float(coverRed)/fTotal), coverGreen: \ (100.0*Float(coverGreen)/fTotal), coverYellow: \(100.0*Float(coverYellow)/fTotal), coverBlue: \(100.0*Float(coverBlue)/fTotal), coverWhite: \(100.0*Float(coverWhite)/fTotal), coverTotal: \(coverTotal), #ofPixels: \(bufferSize/bytesPerPixel)")
greenValue = String(describing: (100.0*Float(coverGreen)/fTotal))
yellowValue = String(describing: (100.0*Float(coverYellow)/fTotal))
redValue = String(describing: (100.0*Float(coverRed)/fTotal))
blueValue = String(describing: (100.0*Float(coverBlue)/fTotal))
whiteValue = String(describing: (100.0*Float(coverWhite)/fTotal))
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "computeResult" {
let areaController = segue.destination as! AreaPercentViewController
areaController.redValue = redValue
areaController.blueValue = blueValue
areaController.greenValue = greenValue
areaController.whiteValue = whiteValue
areaController.yellowValue = yellowValue
areaController.totalValue = totalValue
}
}
}
此版本不工作：
import UIKit
import CoreGraphics
class ComputeAreaViewController: UIViewController {
var redValue: String!
var blueValue: String!
var greenValue: String!
var whiteValue: String!
var yellowValue: String!
var totalValue: String!
var image: UIImage!
//let image = UIImage(named: "test_image.png")!
override func viewDidLoad() {
super.viewDidLoad()
let fm = FileManager.default
let docsurl = try! fm.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: false)
let myurl = docsurl.appendingPathComponent("tmp.png")
image = UIImage(contentsOfFile: myurl.path)!
view.layer.contents = image.cgImage!
computeArea()
}
func classifyPixel(_ r: UInt8, _ g: UInt8, _ b: UInt8, _ coverRed: inout UInt, _ coverGreen: inout UInt, _ coverYellow: inout UInt, _ coverBlue: inout UInt, _ coverWhite: inout UInt) {
if r == 255 && g == 0 && b == 0 { coverRed += 1 }
if r == 0 && g == 255 && b == 0 { coverGreen += 1 }
if r == 255 && g == 255 && b == 0 { coverYellow += 1 }
if r == 0 && g == 0 && b == 255 { coverBlue += 1 }
if r == 255 && g == 255 && b == 255 { coverWhite += 1 }
}
func computeArea() {
var coverRed: UInt = 0
var coverGreen: UInt = 0
var coverYellow: UInt = 0
var coverBlue: UInt = 0
var coverWhite: UInt = 0
var coverTotal = 0
let imageWidth = Int(image.size.width)
let imageHeight = Int(image.size.height)
let bitsPerComponent = 8
let bytesPerPixel = 4
let bytesPerRow = bytesPerPixel * imageWidth
let bufferSize = bytesPerRow * imageHeight
var bytesPointer = UnsafeMutableRawPointer.allocate(bytes: bufferSize, alignedTo: 1)
let bytesPointerSaved = bytesPointer
if let bitmapContext = CGContext(data: bytesPointer, width: imageWidth, height: imageHeight, bitsPerComponent: bitsPerComponent, bytesPerRow: bytesPerRow, space: CGColorSpaceCreateDeviceRGB(), bitmapInfo: CGImageAlphaInfo.premultipliedLast.rawValue) {
bitmapContext.draw((image.cgImage!), in: CGRect(x: 0, y: 0, width: imageWidth, height: imageHeight), byTiling: false)
for _ in 0..<imageHeight {
for _ in 0..<imageWidth {
var r: UInt8 = 0, g: UInt8 = 0, b: UInt8 = 0
r = bytesPointer.load(as: UInt8.self)
bytesPointer += 1
g = bytesPointer.load(as: UInt8.self)
bytesPointer += 1
b = bytesPointer.load(as: UInt8.self)
bytesPointer += 2
classifyPixel(r, g, b, &coverRed, &coverGreen, &coverYellow, &coverBlue, &coverWhite)
coverTotal += 1
}
}
} else {
print(#file + " " + #function + " failed to create bitmap context ")
}
bytesPointerSaved.deallocate(bytes: bufferSize, alignedTo: 1)
let fTotal = Float(coverTotal)
print("coverRed: \(100.0*Float(coverRed)/fTotal), coverGreen: \(100.0*Float(coverGreen)/fTotal), coverYellow: \(100.0*Float(coverYellow)/fTotal), coverBlue: \(100.0*Float(coverBlue)/fTotal), coverWhite: \(100.0*Float(coverWhite)/fTotal), coverTotal: \(coverTotal), #ofPixels: \(bufferSize/bytesPerPixel)")
greenValue = String(describing: (100.0*Float(coverGreen)/fTotal))
yellowValue = String(describing: (100.0*Float(coverYellow)/fTotal))
redValue = String(describing: (100.0*Float(coverRed)/fTotal))
blueValue = String(describing: (100.0*Float(coverBlue)/fTotal))
whiteValue = String(describing: (100.0*Float(coverWhite)/fTotal))
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "computeResult" {
let areaController = segue.destination as! AreaPercentViewController
areaController.redValue = redValue
areaController.blueValue = blueValue
areaController.greenValue = greenValue
areaController.whiteValue = whiteValue
areaController.yellowValue = yellowValue
areaController.totalValue = totalValue
}
}
}
「ComputeAreaViewController」類中究竟發生了什麼不起作用？如果我們確切地知道這是什麼不起作用會很有幫助 – KSigWyatt
真誠的問題 - 您是否嘗試過使用HD圖像？一個大的圖像？任何性能問題？有關使用CIAreaHistogram的想法嗎？ – dfd
使用包含「let image = UIImage（named：」test-image.png「）的版本，computeArea函數可以很好地工作，並且像素被計數爲給出結果。使用」var image：UIImage！「版本獲取圖像從文件目錄和顯示，但computeArea函數不起作用，我得到的全部是零。我懷疑它與「view.layer.contents = image：cgImage！」有關「 – user1698875