我有一个应用程序可以计算图像的像素，以获得图像中五种颜色的相对区域。 Swift 3的更新版本适用于应用程序支持文件中的声明图像，但不包含来自文档目录的可变图像。我错过了什么？
此版本有效：
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
}
}
}
此版本不起作用：
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
}
}
}
答案 0 :(得分：0)
答案是传递图像的Alpha通道。它小于1.0，将其重置为1.0修复了计数问题。